Food Biotechnology
Zahra Ziaei Ghahnavieh; Mohammad Reza Raji; Abdollah Ehteshamnia; Seyed Sajad Sohrabi
Abstract
IntroductionExcessive human exposure to chemicals in agricultural practices contribute to the production of unhealthy and environmentally destructive products. For this reason, natural coatings are used to prevent adverse changes in the quality of various products. Natural coatings can be ...
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IntroductionExcessive human exposure to chemicals in agricultural practices contribute to the production of unhealthy and environmentally destructive products. For this reason, natural coatings are used to prevent adverse changes in the quality of various products. Natural coatings can be a barrier on the outer surface of food to prevent the loss of aromatic compounds, and moisture content and provide the possibility of selective natural exchange of some gases and increase shelf life post harvest. Considering the economic importance of button mushrooms and the need to provide optimal solutions to increase shelf life post harvest, the present study was conducted to investigate the effect of natural coatings based on chitosan nanoparticles and nanohydroxyapatite on increasing the shelf life of button mushrooms.Materials and MethodsFor this purpose, the effect of these coatings was evaluated in a factorial experiment in the form of a completely randomized design with three repetitions to prevent adverse changes in button mushroom quality. Button mushrooms were covered with different concentrations of chitosan nanoparticles (zero, 1% and 2%) and nanohydroxyapatite (0, 40, 80 mg) for 28 days. The mushrooms that were prepared for coating were divided into 9 groups. One sample without coating and 8 samples were coated with different percentages of chitosan nanoparticles and nanohydroxyapatite and coded. All mushroom sampless were immersed in each of the coating solutions for five minutes. The mushrooms were then taken out of the solutions and placed on the mesh basket (at room temperature) for 15 to 30 minutes so that the additional amount of coating material drips. Then the mushrooms were weighed individually and six numbers were transferred in three replicates in single-use plastic containers with perforated lids. Then they were transferred to the refrigerator. The control sample was immersed in distilled water for 5 minutes instead. The data was measured on days 0, 7, 14, 21 and 28. After coating, the characteristics of total phenol, flavonoid, antioxidant capacity, total protein, ascorbic acid content, and electrolyte leakage of mushrooms were recorded and analyzed during 28 days of storage.Results and DiscussionBased on the results, the highest amount of total phenol, flavonoid, antioxidant capacity, ascorbic acid content, total protein, and the lowest amount of electrolyte leakage were obtained in 1% nano chitosan coating containing 40 mg of nanohydroxyapatite during 28 days of storage. In the control treatment (without coating), the lowest amount of total phenol, flavonoid, antioxidant capacity, ascorbic acid content, total protein, and the highest amount of electrolyte leakage were obtained during 28 days of storage.ConclusionDue to the high perishability of button mushroom, its maintenance is very important. Coating is considered as one of the methods of keeping quality of button mushrooms. The purpose of this study was to evaluate the effect of natural coating based on chitosan nanoparticles and nanohydroxyapatite on the total phenolic, flavonoid, antioxidant capacity, ascorbic acid content, electrolyte leakage, and total protein of mushrooms on zero, 7, 14, 21, and 28 day, in order to maintain quality and increase the shelf life of button mushroom. For this purpose, the coating of chitosan nanoparticles (zero, 1%, 2%), nanohydroxyapatite (zero, 40, 80 mg), and the combination of chitosan nanoparticles with nanohydroxyapatite in the mentioned concentrations were used. Finally, according to the findings of this study, it can be stated that coating with 1% nano chitosan containing 40 mg of nanohydroxyapatite can increase the shelf life of button mushroom up to 14 days post harvest, with increased marketability.
Food Biotechnology
Marjan Nouri
Abstract
IntroductionFish supplies a type of nutrients containing protein and long-chain omega-3 polyunsaturated fatty acids (n-3 PUFAs) and micronutrients such as selenium, iodine, potassium, D and B-vitamins. Groupers are one of the best fishes in the south of Iran that are extensively distributed in tropical ...
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IntroductionFish supplies a type of nutrients containing protein and long-chain omega-3 polyunsaturated fatty acids (n-3 PUFAs) and micronutrients such as selenium, iodine, potassium, D and B-vitamins. Groupers are one of the best fishes in the south of Iran that are extensively distributed in tropical and warm waters all over the world. The perishability is considered as one of the main problems for fish with high nutritional value in food supply chains during the shelf life. The use of edible coatings indicates a novel method to extend the shelf life. The aim of present research was to apply biodegradable chitosan/ chia mucilage coating containing Rubia tinctorum L. plant extract (0, 0.5, 1 and 2 % as T1, T2, T3 and also T4) on the surface of grouper fillet fish to maintain qualitative and microbial attributes during the shelf life (1, 15, 30 and 45 days).Materials and MethodsThe qualitative and qualitative assays (peroxide index (meq O2/kg sample), thiobarbituric acid (mg MA/kg), total volatile nitrogen (mg /100 g) and trimethylamine (mg /100 g)), microbial counts (aerobic mesophilic and lactic acid bacteria, total coliforms, mold and also yeast), texture (hardness, adhesion, flexibility, cohesiveness and gumminess), sensory attributes (taste, smell, color, texture and overall evaluation) and measurement of identified biogenic amines were carried out during the shelf life.Results and DiscussionThe results illustrated that oxidation parameters of treatments such as peroxide index, trimethylamine, total volatile nitrogen components and thiobarbituric acid were declined by increasing the extract concentration in a fixed time period (p ≥ 0.05). The highest and lowest microbial loads were obtained in T1 and T4 during the storage, respectively. The microbial counts increased significantly (p < 0.05) by extending the storage time of treatments and on the other hand, this decreased significantly (p < 0.05) by increasing the concentration of Rubia tinctorum L. extract in a fixed period of time. The utilization of Rubia tinctorum L. extract and chia mucilage in a coating of chitosan created a synergistic effect and led to a lower microbial load in treatments. On the other hand, a reduction was occurred in textural attributes particularly cohesiveness and hardness through moisture loss and drying of coating surface in fillets during storage (p < 0.05). The softening tissue could be related to the higher microbial activities during storage, although intensity of these changes was lower in T3 and T4 treatments due to the lower microbial load, which indicated the positive effect of Rubia tinctorum L. extract on maintaining tissue quality. All examined factors changed and most of the mentioned parameters in T1 and T2 exceeded the permissible limit during storage, but T3 and T4 had better conditions during storage. Finally, fish fillet coated with 1 % Rubia tinctorum L. extract (T3) compared to others demonstrated better sensory evaluation at the end of shelf life, which was selected as the superior treatment. The type and amount of biogenic amines in control and T3 (superior sample) illustrated that the highest amine compound was recorded for histamine at 79.87 (mg/kg) on the 15th day and the lowest level in tyramine at 0.79 (mg/kg) on the 1st day of storage. The concentration of amines increased significantly during storage time (p < 0.05).ConclusionThe results shown that applying chitosan/ chia mucilage coating including Rubia tinctorum L. extract has significant effect on extending the shelf life of fish fillets.
Food Biotechnology
Fatemeh Rahmani; Ali Moayedi; Marteza Khomeiri; Mahboobeh Kashiri
Abstract
Nowadays, plant-based dairy alternatives have gained considerable attention. However, the textural and sensorial characteristics of plant-based products limit their acceptance. The exploitation of lactic acid bacteria has been proposed as a promising approach to developing plant-based dairy analogs. ...
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Nowadays, plant-based dairy alternatives have gained considerable attention. However, the textural and sensorial characteristics of plant-based products limit their acceptance. The exploitation of lactic acid bacteria has been proposed as a promising approach to developing plant-based dairy analogs. In this study, the performance of three proteolytic lactic acid bacteria in the induction of soymilk gelation was compared and their effects on the physicochemical properties of resulting gels were investigated. Lactiplantibacillus plantarum MCM4, Streptococcus thermophilus, and Weissella confusa MDM8) were inoculated to the soy milk matrix, and incubated at 37 °C until reaching pH 4.7. To understand the effects of acidifying and proteolytic activity of starter culture, syneresis, cell counts, free amino acid content (O-phthalaldehyde method), evaluation of proteolysis using sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and textural parameters of soymilk gels during fermentation were investigated. There was a significant difference among the strains in terms of viable cell counts and proteolytic activity during fermentation (p < 0.05). The amount of syneresis was also different among the resulted gels as it was in the range from 61% (sample fermented with S. thermophilus) to 69.5% (fermented with L. plantarum MCM4). The main soy proteins were degraded to different extents as a function of fermentation time. Texture analysis showed that fermentation of soymilk with W. confusa MDM8 resulted in soy gel with higher firmness and consistency, while the sample fermented with L. plantarum MCM4 had higher adhesiveness and viscosity index. Overall, it can be concluded that L. plantarum MCM4, W. confusa MDM8, and S. thermophilus can be introduced as starter cultures for the production of novel soymilk gels with reasonable properties.
Food Biotechnology
Parisa Raei; Morteza Khomeiri; Alireza Sadeghi Mahoonak; Ali Moayedi; Mahboobeh Kashiri
Abstract
IntroductionNowadays, antibiotic resistance is increasing in all parts of the world and is emerging and expanding globally. Due to their natural antimicrobial properties and low tendency to develop bacterial resistance, antimicrobial peptides can be a good candidate as an alternative to synthetic antibiotics. ...
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IntroductionNowadays, antibiotic resistance is increasing in all parts of the world and is emerging and expanding globally. Due to their natural antimicrobial properties and low tendency to develop bacterial resistance, antimicrobial peptides can be a good candidate as an alternative to synthetic antibiotics. Bioactive peptides are produced using enzymatic hydrolysis by enzymes extracted from microorganisms and plants, digestive enzymes, and fermentation by proteolytic starter cultures. Enzymatic hydrolysis of proteins is performed by commercial proteases or a combination of several proteolytic enzymes. Commercial proteases are expensive due to their specificity. Among the strategies for protein hydrolysis with the aim of obtaining bioactive peptides is microbial fermentation, which is more environmentally friendly and has a high potential for use in industry due to its relatively low cost compared to commercial enzymes. It is a suitable method for the hydrolysis of sesame meal protein. Bacillus species are bacteria that have high proteolytic activity and are able to produce different endopeptidases in the fermentation medium. The activity of endopeptidases in the environment containing proteins causes the production of peptides with small sizes and free amino acids in higher amounts compared to enzymatic hydrolysis, which is one of the advantages of using Bacillus species with high proteolytic activity compared to pure enzymes. In general, the purpose of this research was to produce sesame meal protein hydrolysate by fermentation with Bacillus subtilis and to investigate its antimicrobial and antioxidant activity. Materials and MethodsIn this study, at the first step, sesame meal was defatted with hexane at a ratio of 1:5, then it was dried and sesame meal protein isolate was extracted, and the optimization of fermentation conditions was determined by the response surface methodology (RSM). Independent variables, including temperature (30 to 45 ˚C), time (12 to 36 h), and substrate concentration (2 to 6%), were considered. The antioxidant properties of the treatments, including DPPH radical scavenging activity, ferric ion reducing power, and antimicrobial activity, were investigated, and the optimum treatment was selected. Then the protein hydrolysate was freez-dried and stored at -20 °C. Results and DiscussionAccording to the results, temperature (39.68 °C), time (30.07 h), and substrate concentration (4.85%) were selected as optimum conditions. Under these conditions, DPPH radical scavenging activity and ferric ion reducing power of hydrolysate were 63.57% and 0.9951 (absorbance at 700 nm), respectively. The inhibition percentages of Staphylococcus aureus (59.58%), Escherichia coli (6.55%), Listeria monocytogenes (62.43%), and Clostridium perfringens (50.97%) were obtained in the optimized condition. Bacillus subtilis, in the presence of sesame meal protein, showed significant (p<0.05) protease activity over time. After 48 hours, the clear zone diameter was determined to be 22 mm. The clear zone created by this strain showed that Bacillus subtilis has high proteolytic activity and can be a suitable bacterium for hydrolyzing sesame meal protein with the aim of obtaining hydrolysates with the highest antimicrobial and antioxidant activities. The antimicrobial activity of the protein hydrolysate can be due to the higher degree of hydrolysis. By increasing the hydrolysis time, peptides with low molecular weight are produced, which cause better interaction with the microbial cell membrane, disrupt the membrane, and lead to the inhibition of the microorganism. According to the results, the sesame meal protein hydrolysate showed more inhibitory effect against gram-positive bacteria than gram-negative bacteria (Escherichia coli). Researchers reported that the difference in sensitivity to antimicrobial compounds between gram-positive and gram-negative bacteria can be attributed to the structure and composition of the cell envelope (cytoplasmic membrane or outer membrane, and cell wall). In general, the bioactivity properties of protein hydrolysate depend on the amino acid composition, sequence, and molecular weight of the amino acids. The antioxidant activity can be due to the high content of polar and aromatic amino acids. By further hydrolysis of proteins, peptides and polar free amino acids are produced that interact with free radicals and converted into safe and stable intermediate products. ConclusionIn this study, Bacillus subtilis strain was used to ferment sesame meal protein, which is a rich source of protein, to produce protein hydrolysate with maximum antimicrobial and antioxidant activities. Results showed that the protein hydrolysate obtained from sesame meal protein isolate had antimicrobial and antioxidant activities. It can be used as a natural antimicrobial or antioxidant agent in the formulation of food or pharmaceutical industry to improve the health of society.
Food Biotechnology
Hadis Taghvatalab; Dornoush Jafarpour
Abstract
Introduction Scientific evidence is mounting that synthetic chemicals used as food additives may have harmful impacts on health and the biological system and cause many diseases and damages to the human body. Also, many consumers are concerned about the use of artificial ingredients to maintain ...
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Introduction Scientific evidence is mounting that synthetic chemicals used as food additives may have harmful impacts on health and the biological system and cause many diseases and damages to the human body. Also, many consumers are concerned about the use of artificial ingredients to maintain the quality and safety of foods. Therefore, the use of natural preservatives and food preservation methods based on natural compounds have attracted the attention of researchers. Edible films and coatings are useful materials, mainly produced from biodegradable polymers including polysaccharides (gums), proteins, and lipids, and are commonly used for the shelf life extension of foods. The primary edible films /coatings are promising alternative methods to preserve, and retard the adverse chemical reactions and microbial growth. They also can act as a carrier of antimicrobials, antioxidant substances, and other additives. Sage seed gum (SSG) is a water-soluble polysaccharide obtained from Sage (Salvia macrosiphon). It is an environmentally-friendly biodegradable material that can form high-viscosity aqueous solution and exhibit pseudoplastic behavior. Essential oils (EOs) are volatile and aromatic oily liquids extracted from various plants. Most of the EOs have antimicrobial and antioxidant activities due to their phenolic compounds, terpenes and terpenoids. A promising technique is incorporating EOs into coating solutions as active film/coating to extend the shelf life of food products. Bay leaf (Laurus nobilis) is an aromatic evergreen tree or large shrub with green, glabrous leaves. It is used as a flavoring agent and an essential ingredient in food preparation. Bay leaf has received much attention due to its antimicrobial, antioxidant, anti-inflammatory and immune system stimulating properties. Hence, the aim of the present study was to evaluate the antimicrobial and antioxidant properties of SSG coating incorporated with different concentrations of bay leaf EO (BLEO) and its nanoemulsion (BLNEO). Materials and Methods The active packaging was produced based on the gum of sage seed containing BLEO and BLNEO. After preparing the EO from bay leaves, their corresponding NEO was produced and the characterization of nanoparticles was evaluated in terms of droplet size, polydispersity index (PDI) and zeta potentials. Then, the antimicrobial and antioxidant properties of BLEO and BLNEO were compared. After that, SSG coatings were prepared with 1.5% and 3% BLEO and their corresponding NEO forms. Subsequently, the antioxidant (DPPH and ABTS) and antimicrobial (against Bacillus cereus, and Staphylococcus aureus, Pseudomonas aeruginosa, and Escherichia coli) properties of the produced films were investigated. Results and DiscussionGas chromatography-mass spectrometry (GC-MS) identified 1,8-Cineole and α- Terpinyl acetate as the major components of BLEO. The BLNEO exhibited a droplet size of approximately 92.4 nm and a zeta potential of -45.1 mV. In comparison to the control and SSG, it was found that the group comprising EO and NEO significantly (p<0.05) showed superior free radical scavenging capacity. SSG-3% BLNEO had the highest DPPH inhibition percentage (69.54%). According to the results, EO at the nanoscale can scavenge more free radicals than EO (p<0.05). Antimicrobial inhibition zone of different treatments against selected gram positive and gram negative bacteria showed that all bacteria were strongly inhibited after the addition of BLEO into the SSG. Moreover, data revealed that the growth of the studied pathogens was completely inhibited in a dose-dependent manner (p<0.05). SSG-BLNEO exhibited better antimicrobial activity than SSG-BLEO coating and its antimicrobial activity was significantly enhanced by increasing BLNEO concentration (p<0.05). This phenomenon is attributed to the protective role of encapsulation and the slow release of EO from the coating matrix, resulting in enhanced antimicrobial activity. Nanoemulsions, owing to their small droplet size and high surface area, offer superior efficacy compared to conventional emulsions. Consequently, the gradual release of essential oils from nanoemulsion-based edible coatings contributes to their enhanced antimicrobial performance. ConclusionThese findings suggest that the SSG-BLNEO edible active coating possesses promising applications as an antimicrobial and antioxidant agent for food packaging applications.
Food Biotechnology
Soheyl Reyhani Poul; Sakineh Yeganeh; Reza Safari
Abstract
IntroductionOne of the synthetic and harmful preservatives used in sausage formulation is sodium nitrite. This compound helps to increase the shelf life and marketability of meat products by preventing the growth of anaerobic bacteria, especially clostridium, exerting an antioxidant effect, stabilizing ...
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IntroductionOne of the synthetic and harmful preservatives used in sausage formulation is sodium nitrite. This compound helps to increase the shelf life and marketability of meat products by preventing the growth of anaerobic bacteria, especially clostridium, exerting an antioxidant effect, stabilizing the red color of meat and improving the taste. Despite these benefits, sodium nitrite is very dangerous for health and it can cause malignant diseases. For this reason, it is necessary to replace this substance using a natural preservative. Pigments extracted from aquatics such as astaxanthin due to having antioxidant activity, antimicrobial properties and pink color may be a good substitute for sodium nitrite. However, these pigments must be nanoencapsulated at first due to their sensitivity to food processing conditions, including high temperatures. The aim of the current research at the first was to extract astaxanthin from Haematococcus pluvialis microalgae using the acid-acetone method and pigment nanoencapsulation using maltodextrin-sodium caseinate combined coating. Then, sodium nitrite in the sausage formulation was replaced by the carrier nanocapsules with different proportions and oxidative and microbial spoilage tests, color and sensory evaluations were performed for different treatments. Materials and MethodsAt first, astaxanthin pigment was extracted from Haematococcus pluvialis using the acid-acetone technique. Then, the extracted pigment was nanoencapsulated using maltodextrin-sodium caseinate combined coating and the resulting (carrier) nanocapsules in the form of treatments A (120 mg/kg sodium nitrite), B (120 mg/kg nanocapsules carrying astaxanthin), C (90 mg/kg sodium nitrite+30 mg/kg nanocapsules carrying astaxanthin), D (60 mg/kg sodium nitrite+60 mg/kg nanocapsules carrying astaxanthin) and E (30 mg/kg sodium nitrite+90 mg/kg nanocapsules carrying astaxanthin) were replaced sodium nitrite in the sausage formulation. These treatments were evaluated in terms of oxidative and microbial spoilage, color indices and sensory properties during 28 days of storage at refrigerator along with the control (without sodium nitrite and carrier nanocapsules). This research was conducted in a completely randomized design. Data were analyzed by one-way analysis of variance and the difference between the means was evaluated by Duncan's test at 95% confidence level. Results and DiscussionAccording to the results, the lowest levels of thiobarbituric acid and peroxide value during the storage period were related to treatments B, E and D (p>0.05). Treatments A and C had no significant difference in terms of thiobarbituric acid and peroxide value until day 14 (p>0.05), but with increasing storage time, this difference became significant and treatment A showed higher values (p<0.05). The results of this section showed that the power of astaxanthin in controlling oxidative spoilage is significantly greater than sodium nitrite, and if the purpose is only to control this type of spoilage, there is no need to replace or use sodium nitrite. The results also showed that in terms of controlling microbial spoilage, sodium nitrite has more power than nanocapsules carrying astaxanthin. So that, the lowest amount of total volatile basic nitrogen (TVB-N) and the most standardized pH were related to treatments A, C and D (p>0.05) during the storage period (p<0.05). Treatments B and E (p>0.05) were ranked next (p<0.05) in terms of the two mentioned indicators. The results of this section showed that if sodium nitrite reduced from 120 mg/kg to 60 mg/kg and replaced by nanocapsules carrying astaxanthin in the sausage formulation, the resulting product has the same antimicrobial power as the product containing 120 mg/kg sodium nitrite. Evaluation of the color and sensory properties of treatments showed that A, C and D treatments are at a higher level than B, E (treatments) and control in terms of color indices and general acceptance (p<0.05). The comparison of the color indices and sensory properties of the treatments on days 0 and 28 of storage at refrigerator showed that the color and sensory indices remained constant in the formulated treatments, unlike the control. Conclusion Nanocapsules carrying astaxanthin with maltodextrin-sodium caseinate combined coating as a natural product with many properties in health, control and prevention of various diseases, have a high efficiency to replace the sodium nitrite in sausage formulation. So that, if 30 to 60 mg/kg of the permissible limit of 120 mg/kg of sodium nitrite in the sausage formulation is replaced by nanocapsules carrying astaxanthin, the resulting product will be similar to the product containing 120 mg/kg of sodium nitrite in terms of shelf life, resistance to oxidative and microbial spoilage, color indices and sensory properties.
Food Biotechnology
Mina Rasoulifar; Alireza Sadeghi; Fahimeh Hajinia; Maryam Ebrahimi; Mohammad Ghorbani
Abstract
IntroductionWheat bread is a staple food worldwide, and bread making using sourdough is one of the oldest technologies. In this regard, the use of legume sourdough is important in improving the quality of wheat bread. Sprouted legumes are also proper substrates rich in bioactive compounds for sourdough ...
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IntroductionWheat bread is a staple food worldwide, and bread making using sourdough is one of the oldest technologies. In this regard, the use of legume sourdough is important in improving the quality of wheat bread. Sprouted legumes are also proper substrates rich in bioactive compounds for sourdough fermentation to produce enriched products. Furthermore, application of herbal extracts in sourdough formulation is a simple way to enhance organoleptic properties and mold-free shelf-life of the produced sourdough bread. Considering positive effects of sourdough on techno-functional properties of the produced bread, the aim of the present study was to enhance quality parameters of wheat bread using controlled fermented sprouted lentil containing fennel extract. Materials and MethodsIn the present study, predominant lactic acid bacteria (LAB) were isolated using the sequential back-slopping process from fermented sprouted lentil containing fennel extract. The isolates were screened based on their antifungal activities against Aspergillus niger. The selected isolates were identified through amplification of the target sequence with 1500 bp from its 16S rDNA gene and sequencing of the PCR products. After that, controlled fermentation containing selected LAB isolates (as a starter culture) was performed in processing of wheat bread. Crumb hardness, specific volume, water activity, overall acceptability and surface growth rate of the target fungus were compared in the produced breads. In order to determine the effects of the substrate, fermentation and germination, suitable samples were produced. The results of the present study were also analyzed in a completely randomized design with three replications, and Duncan test at P<0.05 significant difference was used to compare the mean. Results and DiscussionSequencing results of the PCR products (amplicons) led to the identification of Pediococcus acidilactici as the selected LAB isolate. Addition of lentil sourdough to wheat bread significantly (P<0.05) reduced the weight loss and crumb hardness of wheat bread and also increased its specific volume without significant effect. Among the produced breads, the lowest specific volume was belonged to the sample containing lentil and the highest specific volume was observed in the control sample. Moreover, fermentation and sprouting reduced the surface growth of A. niger in the produced breads. The surface growth rate of the fungus in the bread containing fermented sprouted lentil was also significantly lower than those of the control sample. In addition, wheat bread containing fermented sprouted lentil received the highest overall acceptability score among the produced enriched breads. It is reported that the positive effects of controlled sourdough on textural features of the produced bread are mainly associated with the acidification activity of the starter culture used. Production of organic acids and other inhibitory metabolites by the sourdough starter culture is also involved in its antifungal activity in the product. Moreover, production of volatile and non-volatile aroma precursors during sourdough fermentation affect sensory attributes of the sourdough bread. ConclusionNowadays, consumer demand for healthy products with minimal processing and with no synthetic additives such as clean-label foods, and the use of bio-preservatives (application of microorganisms and their metabolites to prevent spoilage and increase the shelf-life of the product) has become a growing trend. Application of legumes as a good source of protein, other nutrients and essential components in bread formulation is important for their use in the daily diet. According to the results of the present study, controlled fermented sprouted lentil containing fennel extract can be used as an antifungal compound and texture improver in bakery industries. Overall, the use of plant extracts with antifungal effects as well as controlled fermentation of sourdough with selected LAB as protective/starter culture can reduce the use of chemical preservatives in bread.
Food Biotechnology
Elnaz Mehrabi; Mojtaba Bonyadian; Aziz A. Fallah
Abstract
IntroductionRecently, the use of new packaging materials and natural additives for improving the durability and preservation of foods has been increasingly considered. Edible coatings containing plant extracts lead to increase the shelf life of food, do not cause environmental contamination, and do not ...
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IntroductionRecently, the use of new packaging materials and natural additives for improving the durability and preservation of foods has been increasingly considered. Edible coatings containing plant extracts lead to increase the shelf life of food, do not cause environmental contamination, and do not endanger the health of the consumer. Fish is a food rich in amino acids, vitamins and minerals, and polyunsaturated fatty acids, especially omega-3, which has made it more and more popular in the human diet. However, the presence of a significant amount of polyunsaturated fatty acids as well as easily digestible proteins has turned fish into a highly perishable commodity. Fresh seafood spoils rapidly due to the enzymatic and bacterial activities that occur after death, as well as the spoilage caused by the oxidation of polyunsaturated fatty acids and the high concentration of hematin compounds and metal ions of fish muscle, such as iron, and their pH which is close to neutral. Therefore, the use of natural coatings that can increase the shelf life of food and attract the consumers should be given more attention. Iran is the largest fishery producer in the region, thus, providing new methods to increase the shelf life of these products until the time of consumption can guarantee the safety and be effective in the economic prosperity of this industry. Therefore, the present study was designed to investigate the effect of chitosan coating along with the volatile oil of ginger plant on the shelf life of salmon fillets stored in refrigerator to reduce microbial growth, reduce chemical reactions, and increase the storage life of salmon fillets in refrigerator. Material and MethodsRainbow trout fish with an approximate weight of 600 grams were purchased from the market. Fish were washed with sterile distilled water, and cut into 60-gram pieces after separating the head and tail and eviscerating. The prepated fish were randomly divided into 4 groups. The control group was without any treatment but the treatment groups were immersed in chitosan containing different concentrations of Ginger essential oils. All the samples were kept in zipped bags at refrigerator (4°C) for 15 days. Microbial tests (Mesophilic, Psychrophilic, Coliform, and Lactic acid bacteria count), chemical tests (pH, TVN, TBARS), and sensory tests (color, smell, taste, texture, and overall acceptance) were performed on days 1, 4, 7, 12 and 15. The data obtained from the microbial and chemical tests were analyzed by one-way analysis of variance and the data obtained from the sensory tests were analyzed by the Kruskal-Wallis test in Sigma Stat 4 statistical software, considering P<0.05. Results and Discussion The results of bacterial tests showed that chitosan coating with ginger essential oil had a significant effect on reducing the growth of mesophilic, coliform, lactic acid bacteria and psychrophilic bacteria compared to the control and chitosangroups during 15 days of storage in the refrigerator (P<0.05). During the storage period, chitosan-treated groups containing 1.5% and 0.75% of ginger volatile oil had the best microbial quality in terms of mesophilic bacteria, Psychrophilic bacteria, lactic acid- bacteria, and coliforms. Also, in samples immersed in chitosan coating with ginger essential oil, the pH, TVN and TBARS values at the end of the storage period were significantly lower than the control and chitosan group (P<0.05). The results showed that pH, TVN, and TBARS did not exceed the defined standard for fish meat at the end of the storage period in the groups treated with ginger volatile oil. Sensory characteristicsindicated that the groups treated with chitosan coating containing ginger essential oils showed better sensory characteristics in terms of color, taste, smell, texture, and overall acceptance than the control and chitosan groups during the storage period (P<0.05). ConclusionBased on the results of the present study using the chitosan coating combined with ginger volatile oils has antimicrobial and antioxidant properties, which can reduce the oxidation of fats and microbial loads, while maintaining the organoleptic quality and increasing the shelf life of fish meat at refrigerator temperature. In comparison between treated groups, the use of chitosan along with 0.75% volatile oil of ginger is recommended, because by using a smaller amount of volatile oil, the microbial, chemical, and organoleptic properties can be kept at the standard level until the 15th day. Acknowledgments The authors are grateful to Shahrekord University's Research Vice-Chancellor for supporting this project.
Food Biotechnology
Shadi Atashgahi; Ali Moayedi; Alireza Sadeghi Mahoonak; Hoda Shahiri Tabarestani; Alireza Sadeghi
Abstract
Soy whey (SW) is a byproduct from tofu and soy protein isolate (SPI) production that contains various nutrients such as protein, amino acids, minerals, carbohydrates, isoflavones. In this study, SW was fermented with lactic acid bacteria (LAB) with the aim to enhance total phenolic contents (TPC), Gamma ...
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Soy whey (SW) is a byproduct from tofu and soy protein isolate (SPI) production that contains various nutrients such as protein, amino acids, minerals, carbohydrates, isoflavones. In this study, SW was fermented with lactic acid bacteria (LAB) with the aim to enhance total phenolic contents (TPC), Gamma amino butyric acid (GABA) and antioxidant activity. Eight different LAB strains were selected and the activity and cell counts of the most potent strains were investigated during fermentation. The results showed that all the isolates were able to grow in SW and the increase in incubation time led to significantly (p<0.05) decrease the pH of all samples from 5.75 to 4.5. Among eight LAB isolates, Lactiplantibacillus plantarum MCM4 and Weissella confusa MDM8 showed higher activity in terms of acid production, increase in TPC content and proteolytic activity. The sample fermented by L. plantarum MCM4 had the highest content of free amino acids (1.73 mg/ml) and the unfermented sample with 0.9 mg/ml had the lowest content. GABA concentration varied from 6.15 mg/mL (unfermented) to 24.175 mg/100 mL (SW fermented with L. plantarum MCM4). In this research, it was found that fermentation increased the antioxidant capacity of SW in such a way that the highest amount was observed in sample fermented with Lactiplantibacillus plantarum MCM4. A positive correlation (R2= +0.72) was found between viable cell counts and proteolysis. It can be concluded that, fermentation with L. plantarum MCM4 and W. confusa MDM8 can be applied as an approach to valorize SW.
Food Biotechnology
Pouya Ramezani; Ali Motamedzadegan
Abstract
The effects of traditional livestock farming on the environment and its limited scalability contribute to the persistent worldwide dilemma of food insecurity. Growing animal cells under regulated conditions has given rise to cultured meat, which might be a more ethical and ecological option. The potential ...
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The effects of traditional livestock farming on the environment and its limited scalability contribute to the persistent worldwide dilemma of food insecurity. Growing animal cells under regulated conditions has given rise to cultured meat, which might be a more ethical and ecological option. The potential of cultured meat to solve issues with food security is critically examined in this review article, which does so by thoroughly analyzing its effects on global food systems, sustainability prospects, technical breakthroughs, and related obstacles. Life cycle analyses show that the environmental impact of producing cultured meat is much lower than that of producing traditional meat. Significant scientific advancements have moved the production of cultured meat closer to commercial viability, including scaffold advances, tissue engineering, bioreactor design, and cell line optimization. There are still a number of formidable obstacles to overcome, including establishing large-scale manufacturing at a reasonable cost, negotiating intricate regulatory environments, guaranteeing product safety, and cultivating customer acceptability. To overcome these challenges and realize the promise of cultured meat to improve food and nutrition security while promoting environmental sustainability and animal welfare, an interdisciplinary strategy incorporating scientific, technical, regulatory, and social views is essential.
Food Biotechnology
Dina Shahrampour; Morteza Khomeiri; Seyed Mohammad Ali Razavi; Mahboobeh Kashiri
Abstract
IntroductionIncreasing public awareness of the impact of diet on health has increased the demand for healthy food products, especially probiotics. Probiotics are living and non-pathogenic microorganisms with beneficial effects on the host when consumed on a regular basis and sufficient amounts ...
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IntroductionIncreasing public awareness of the impact of diet on health has increased the demand for healthy food products, especially probiotics. Probiotics are living and non-pathogenic microorganisms with beneficial effects on the host when consumed on a regular basis and sufficient amounts (106 cfu/gr or ml). A significant number of probiotics become inactive during various food processes (thermal, mechanical and osmotic stress), storage condition (exposure to oxygen, UV light and low or high temperature) or during interaction with food ingredients. In addition, the breakdown and passage of food through the digestive system can also affect the survival and ability of probiotics to form colony in the intestine. Therefore, it is a challenge for food manufacturers to maintain and deliver live probiotic cells in sufficient quantities via food product. On the other hand, the variety of probiotic food products in the market, especially in Iran, is low and is mainly limited to dairy products, fermented drinks and pickles. Bioactive edible films and coatings are defined as biopolymer-based structures that carry bioactive components such as vitamins, enzymes, peptides, etc, and slowly release them on the food surface during storage. Biopolymers such as polysaccharides, proteins, and lipids are used in the preparation of edible films and coatings. Trapping probiotic bacteria in the structure of edible films and coatings is a new approach that has been proposed to increase the survival of these microorganisms and to develop new probiotic products in the food industry. Materials and MethodsIn this study, an alginate-based probiotic bioactive film containing L. plantarum was fabricated after centrifuging of overnight culture of probiotic bacterium from MRS medium and adding the bacterial cells into film forming solution. The effect of bacterial addition on physical, mechanical and prevention properties of alginate film was evaluated. In addition, the effect of two temperatures 4 °C and 25 °C on the survival of embedded probiotic bacterium in the film structure during one month of storage was also investigated by microbial count assay on MRS agar medium. Then, the model food was covered with probiotic film and the survival of probiotic bacterium during storage at 4 °C was determined. Results and DiscussionThe results showed that the population of probiotic bacterium declined about 4.61% after drying of alginate film solution. Addition of probiotic bacterium to the alginate film increased the thickness, turbidity, and tensile strength of the film, while had no significant effect on solubility, water activity, Elongation (%) and microstructure of alginate film. In addition, the probiotic film containing bacteria had less Lightness (L*), and moisture content than the control film. Also, the incorporation of L. plantarum in alginate film could decrease the water vapor permeability (WVP) from 0.755 to 4.51 (×10-10 g m-1s-1pa-1). The total color difference (ΔE) of alginate film containing probiotic bacteria compared to control film without probiotic bacteria was 1.1. The SEM images were confirmed the proper and uniform distribution of probiotic L. plantarum cells on the surface of alginate film. The survival percentage of L. plantarum in alginate film after one month of storage at 4 °C and 25 °C was 96.84 and 47.29%, respectively. Also, the population of embedded bacteria in the film structure on the food model (sausage) surface after three weeks storage in refrigerator was in desired level of probiotic products (> 106 cfu / gr). Conclusion The viability of probiotic bacteria after the application of alginate film containing L. plantarum on the surface of food model (sausage) during cold storage remained at the optimal recommended level for three weeks. Therefore, alginate film is recommended as a suitable carrier for probiotic microorganisms to produce new functional products.
Food Biotechnology
Asma Entezari; Nasser Sedaghat; Golshan Shakeri
Abstract
Introduction The main sources of Salmonella for humans are pork, beef, chicken, eggs, fruits, vegetables, and their derivatives such as mayonnaise, and peanut butter. Different species of Salmonella can adapt, grow or survive at different environmental conditions. Salmonella enterica is a majorcause ...
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Introduction The main sources of Salmonella for humans are pork, beef, chicken, eggs, fruits, vegetables, and their derivatives such as mayonnaise, and peanut butter. Different species of Salmonella can adapt, grow or survive at different environmental conditions. Salmonella enterica is a majorcause of food borne illness in humans, and Salmonella typhimurium and Salmonella enteritidis serovars are the most prevalent. One strategy is to use active packaging to reduce the microbial load or prevent the growth of microorganisms on food. Recently, antimicrobial active packaging has received much attention due to maintaining food quality, safety, and increasing shelf life. Among the antimicrobials used in the food industry, bacteriophages have a very good efficiency to control pathogenic bacteria. Pullulan has a good ability to form a film, its film has good characteristics such as transparency, odorlessness, tastelessness, solubility in water, and low permeability to oxygen and fat, However, the major obstacle is related to its price. The combination of polysaccharides with proteins has been done in order to improve the performance and reduce the costs of films. Gelatin is a suitable option to combine with pullulan in terms of good mechanical properties, reduced permeability, and its good price. Different ratios of gelatin and pullulan were studied and suitable film selected, but it needed to modify, so nanofibers cellulose was added in order to improve the mechanical properties and water resistance. Adding cellulose nano fiber can be a good and appropriate option. The aim of this research was to evaluate theantibacterial effectiveness of gelatin-pullulan- nanofibers cellulose composite film containing bacteriophage against Salmonella typhimurium at two different temperatures. Materials and MethodsGelatin and pullulan powders were weighted separately and mixed together (20gelatin-80pullulan). Nanofiber cellulose was extracted from rice bran and was used at three different levels (1%, 3%, and 5%). Commercial bacteriophage solution was added to each of the films separately and the films were prepared by molding method. Thickness, moisture content, solubility, swelling, tensile strength, and elongation of gelatin-pullulan film containing nanofibers were studied. Zone inhibitory of films containing different percentage of cellulose nanofibers on the agar media against Salmonella typhimurium (104 CFU.ml-1) was evaluated. The, antibacterial effect of selected film on the poultry meat inoculated with S. typhimurium (104 CFU.g-1) and several phages on the surface meat at 4 and 12 was also investigated. Results and Discussion The results indicated that gelatin-pullulan films containing different percentages of cellulose were showed approximately 2 mm of zone inhibitory compare to films free of phages. Also, inhibitory among films at different percentage of nanofiber cellulose did not show significant change. Antibacterial effect on poultry meat was dependent on temperature, films loaded with bacteriophages at higher temperature (12 ) was more effective compare to lower temperature (4 ). The populations of S. typhimurium were decreased 1 log and 0.7 log than control samples at 4 after 7 and 9 days respectively, while at 12 , 1 log and around 2.55 log decrease was found after 1 and 9 days, respectively. In a study, beef inoculated with salmonella was treated by SALMONELEXTM bacteriophage and resulted in 1.29 log reduction of pathogenic bacteria compared to the control sample (Yeh et al., 2017). In another study, the antibacterial effect of double-layer poly lactic acid/xanthan film at 10 °C compared to 4 °C against pathogenic bacteria of Salmonella and Listeria was determined and found that at10 °C, the number of pathogenic bacteria was decreased more than at 4 °C (Radford et al., 2017).. Kamali et al. (2022b) reported that the release of phages from the film of 30 poly lactic acid/70 whey protein to the meat surface after one hour was 63.22 % and 63.18 % at 4 °C and 10 °C, respectively, which means no significant difference, after one day at both temperatures.
Food Biotechnology
Shohreh Nikkhah; Fakhri Shahidi; Mohebbat Mohebbi; Farideh Tabatabaei Yazdi
Abstract
IntroductionCucumber is an economically important crop, containing vitamins, minerals, antioxidants, and flavonoids. However, due to loss of weight and firmness, microbial contamination, mechanical damage, and yellowing, the storage duration of cucumber is limited to 3–5 days at room temperature. ...
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IntroductionCucumber is an economically important crop, containing vitamins, minerals, antioxidants, and flavonoids. However, due to loss of weight and firmness, microbial contamination, mechanical damage, and yellowing, the storage duration of cucumber is limited to 3–5 days at room temperature. Therefore, pretreatments are crucial for prolonging its shelf life. Chitosan is a cationic polysaccharide and can interact electrostatically with anionic, partially demethylated pectin. Besides, chitosan has inhibitory effects on fungal rot and prevents weight loss in fruits. Pectin can form excellent films. Because of increasing demand to reduce synthetic chemicals as antimicrobial agents, substances derived from plants, such as essential oils, can play a significant role in the future. Several essential oils and essential oil components have shown antimicrobial activity against spoilage and pathogenic microorganisms during fruit and vegetable storage. Essential oils of thyme and cinnamon contained phenolic groups have been found to be most consistently effective against microorganisms, however, essential oils are volatile and irritant. Therefore, forming an inclusion complex using b-cyclodextrin can improve solubility, control volatile, and induce off-flavors and unpleasant odor of the essential oils. The objectives of this study were to develop the microencapsulated thymol (thyme) and trans-cinnamaldehyde (cinnamon) essential oils to produce antimicrobial agents and subsequently evaluate the effectiveness of edible coating made of chitosan and pectin containing microencapsulated trans-cinnamaldehyde or thymol essential oils to improve qualitative and quantitative characteristics and shelf life of cucumber.Materials and MethodsThe inclusion complexes of trans-cinnamaldehyde and thymol in beta-cyclodextrin (CD) were prepared separately by freeze-drying. Each essential oil was dispersed in 1000 ml of beta-cyclodextrin aqueous solution (16 mmol/L, 18.15 g) in molecular ratio 1:1 (2.4 gr thymol, 2.11 gr trans-cinnamaldehyde) and mixed in a laboratory stirrer for 24 hour at room temperature , then frozen (-70 ºc) and freeze-dried (<20Pa, 48 h). Lyophilized samples were stored inside a freezer (-20 ºc) until further use. Cucumbers cv. Nagene with uniform size, appearance, ripeness and without mechanical damage or fungal contamination were selected. Then They were then sanitized by immersion in chlorine solution (150 mg/kg) for 1 min and air dried. Edible coatings were prepared as three immersion solutions of chitosan, pectin, and calcium chloride (CaCl2). The fruits were coated with pectin (1%) and chitosan (0-0.5%-1%) containing beta-cyclodextrin microencapsulated trans-Cinnamaldehyde or thymol each (0-0.25%-0.5%). After coating by chitosan, the fruits were immersed in 1% Calcium chloride solution to induce crosslinking reaction. After dipping step, fruits dried for 8 minutes at room temperature to remove the excess solution attached to the surface .Uncoated fruits served as control. Then fruits were preserved in cold storage (temperature: 10ºc; relative humidity: 90-95%) for 15 days. chemical (total soluble solids, titratable acidity) and physical (total color difference, Hardness, and weight loss) Characterization of fruits were measured immediately after harvest and after 5, 10 and15 days. Microbial tests (total count, mold, and yeast) were done at the end of preservation time. Analytical data were subjected to analysis of variance and factorial adopted completely randomized design and a Duncan comparison test was used. Results and DiscussionThe results showed that weight loss, total soluble solids, and the total color difference increased and hardness and titratable acidity decreased gradually in all samples during cold storage (<0.05). Chitosan and essential oils slowed down this rising or decreasing trends. Interactive effects of chitosan, essential oil type, essential oil concentration, and storage time had positive effects on these quality attributes. The fruits coated with the highest concentration of chitosan (1%) and thymol (0.5%) essential oils showed the least weight loss, loss of hardness, and color change throughout 15 days of storage. Besides thymol in comparison with trans-Cinnamaldehyde was more efficient to prevent yeasts and molds on the surface of cucumber. By increasing chitosan and essential oil amounts, the ability of inhibiting microbial growth by coating is enhanced. ConclusionThe results of chemical, physical and microbial tests, showed that multi-layer coating solution containing chitosan 1% with thymol 0.5% was effective in extending the shelf life of cucumber. The combined usage of microencapsulated thymol essential oil and chitosan-based coating on cucumber could be considered a healthy and effective treatment that reduces microbial spoilage and preserves quality and color characteristics in cucumber and represents an innovative method for commercial application. Therefore, this coating can be used as an alternative to chemical fungicides to prevent fungal rot of cucumber and other fruits, however, it is suggested that more studies should be done in this field.
Food Biotechnology
Behrooz Alizadeh Behbahani; Mostafa Rahmati-Joneidabad; Mohammad Noshad
Abstract
IntroductionThe use of safe ingredients to preserve food is steadily increasing. The high time and cost of production and approval of synthetic food additives and the reduction of public acceptance of these compounds have caused serious problems in their utilization. Excessive use of synthetic preservatives, ...
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IntroductionThe use of safe ingredients to preserve food is steadily increasing. The high time and cost of production and approval of synthetic food additives and the reduction of public acceptance of these compounds have caused serious problems in their utilization. Excessive use of synthetic preservatives, which some of them are suspected to be toxic, has completely eliminated these additives and led to the use of natural alternatives to preserve or extend the shelf life of food products. Many plant-based bioactive compounds are good alternatives to synthetic antimicrobial and antioxidant supplements. Plant extracts have significant biological activity including antioxidant, antibacterial, and antifungal properties, which has increased their use in food products. In addition, plant-derived antimicrobial compounds have been considered in the pharmaceutical industry to control microbial pathogens. Natural antioxidant and antimicrobial compounds are receiving a lot of research and industrial attention in food preservation technologies. In the last 2 decades, the use of herbal medicines rich in bioactive molecules (including polyphenols, carotenoids and flavonoids) with medicinal and health effects such as delaying the onset of some diseases such as cardiovascular disorders, diabetes, and cancer have increased.The plant Prosopis farcta grown in arid and semi-arid regions. In Iran, it is found in the southern regions of the country. In traditional medicine, this plant is used to prevent hyperlipidemia and hyperglycemia, to treat hemorrhoids, intestinal diseases and diarrhea, and leprosy, and to reduce abortion. In addition, antimicrobial and antioxidant properties of various species of Prosopis have been reported. Accordingly, in this study, after examining the of total phenols and flavonoids concentrations, the antioxidant and antimicrobial properties of ethanolic extract of Prosopis farcta were determined. Materials and MethodsThe ethanolic extract of P. farcta was obtained maceration method. Total phenol content (by Folin-Ciocalteu reagent method), total flavonoid content (by aluminum chloride method), antioxidant activity (by DPPH and ABTS free radical scavenging and beta-carotene bleaching methods), and antimicrobial effect against Escherichia coli, Shigella dysentery, Staphylococcus aureus, and Bacillus subtilis (by disk diffusion agar, well diffusion agar, minimum inhibitory concentration, and minimum fungicidal concentration) of the extract were evaluated. Results and Discussion farcta ethanolic extract showed high phenol content (145.58 ± 1.30 mg GAE/g), while its total flavonoid content was 72.37 ± 1.48 mg QE/g. Antioxidant activity of ethanolic extract of melon root using different methods of DPPH and ABTS free radical scavenging and beta-carotene bleaching inhibition were 62.60, 71.82 and 54.50%, respectively. Antibacterial activity of P. farcta ethanolic extract against Escherichia coli, Shigella dysentery, Staphylococcus aureus, and Bacillus subtilis according to disk diffusion agar and well diffusion agar methods showed that the antimicrobial activity of the extract was concentration dependent and Shigella dysentery and Staphylococcus aureus were the most resistant and sensitive bacterial strains to the extract respectively. The minimum inhibitory concentrations of ethanolic extract of P. farcta root for Escherichia coli, Shigella dysentery, Staphylococcus aureus, and Bacillus subtilis were 8, 8, 4 and 4 mg/ml, respectively; while the minimum bactericidal concentrations for these bacteria were 128, 256, 32 and 64 mg/ml, respectively. ConclusionIn the present study, ethanolic extract obtained from the roots of P. farcta was identified as a rich source of phenolic and flavonoid compounds. The ethanolic extract showed effective antimicrobial and antioxidant properties. The results greatly indicated the promising effect of P. farcta root extract against Gram-positive and Gram-negative bacterial species. As the microbial resistance is constantly increasing, ethanolic extract of P. farcta root can be considered as a suitable complementary option to tackle this problem. In addition, the identification of individual components of P. farcta ethanolic extract and their biological functions or their combination with common antioxidant and antimicrobial agents could be the subject of future research.
Food Biotechnology
Soheyl Reyhani Poul; Sakineh Yeganeh; Zeynab Raftani Amiri
Abstract
Introduction Since heat treatments and special standards are not used in the production of traditional (homemade) tomato paste, fungal and bacterial spoilage in the product occurs extensively during storage in the refrigerator (4°C). Astaxanthin extracted from aquatics has antimicrobial activity ...
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Introduction Since heat treatments and special standards are not used in the production of traditional (homemade) tomato paste, fungal and bacterial spoilage in the product occurs extensively during storage in the refrigerator (4°C). Astaxanthin extracted from aquatics has antimicrobial activity and color similar to tomato and can probably be effective in preventing spoilage of tomato paste. In addition, astaxanthin has other properties in the field of preventing and controlling diseases and maintaining human health, which justifies its use in food formulations as an enrichment. Since heat, enzyme, acid, etc. treatments are practiced during the production of tomato paste, these factors may change the structure and thus the function of astaxanthin. For this reason, astaxanthin nanoencapsulation is necessary for its use in tomato paste formulation. Materials and Methods In this research, first, astaxanthin was extracted from Haematococcus pluvialis microalgae using the acid-acetone combined method. Then, this pigment was nanoencapsulated using maltodextrin-sodium caseinate coating and the resulting nanocapsules were used together with the pure form of astaxanthin in the formulation of tomato paste. The research treatments were control, tomato pastes containing 3 and 6% astaxanthin (A and B, respectively) and also 3, 6 and 9% nanocapsules carrying the pigment (C, D and E, respectively). These treatments were kept at refrigerator for 28 days and were evaluated (on days 0, 7, 14, 21 and 28) in terms of the total number of fungi, Howard's number (HMC), pH, fungal flora, total bacteria count, amount of lactic acid bacteria and sensory properties. This research was conducted in a completely randomized design. Data were analyzed by One-way Anova and the difference between the means was evaluated by Duncan's test at 95% confidence level. Results and Discussion The results showed that the fungi proliferation, total count and lactic acid bacteria were slower than the control during the storage period in the treatments containing astaxanthin and its carrying nanocapsules, and the minimum number of the mentioned microorganisms and Howard's number were related to treatments D and E (p>0.05). Treatments C, B and A were ranked next in this respect (p<0.05). The number of fungi in two treatments D and E from day 0 to 28 varied from 128 to 332 cfu/gr. Also, the Howard number of these treatments was recorded from 18 to 34% in the mentioned time period. However, these two indices in the control ranged from 121 to 792 cfu/gr and 18 to 91%, respectively, during the storage period. The count of total bacteria and the amount of lactic acid bacteria in the control on day 28 were equal to 8.9 cfu/gr and 311 mg/kg, respectively, but these two values were recorded in the E and D treatments on the same day, about 4.8 cfu/gr and 110 mg/kg, respectively. Counting the total number of fungi, bacterias and also Howard's number in control and other treatments showed that the effect of nanocapsules carrying astaxanthin on microbial growth and proliferation is significantly greater than pure astaxanthin (p<0.05). The pH of the treatments varied from 3.9 to 5.8 during the storage period and the most standardized pH (3.9-4.4) was recorded in C, D and E (p>0.05) treatments (p<0.05). The pH of two treatments A and B (p>0.05) was higher than the three mentioned treatments and lower than the control (p<0.05). This finding showed that nanocapsules carrying astaxanthin have a greater effect on controlling the pH of tomato paste than pure astaxanthin during storage at refrigerator (p<0.05). The identification of the fungal flora of the treatments on the 28th day confirmed that two genus of Penicillium and Aspergillus form the main flora of the product. The results of the sensory evaluation of the treatments on day 0 showed that adding astaxanthin and its carrier nanocapsules does not change the color, aroma, taste and texture indicators (subsequently the general acceptance) of tomato paste (p>0.05). On the 28th day, the mentioned sensory indices only in the two treatments D and E were not significantly different from the 0 day, but they changed negatively in the other treatments (p<0.05). Conclusion According to the findings of the present research, astaxanthin extracted from Haematococcus pluvialis microalgae has the ability to inhibit fungal and bacterial spoilage and stabilize the sensory properties of tomato paste stored at refrigerator. This properties were improved by adding nanoencapsulated pigment using maltodextrin-sodium caseinate combined coating. Since there were no significant differences between the two treatments containing 6% and 9% of nanocapsules carrying astaxanthin (D and E) in terms of quality indices and microbial spoilage, therefore, the treatment containing 6% nanocapsules is introduced as the optimal treatment.
Food Biotechnology
Mahdieh Mostafidi; Mohammad Reza Sanjabi; Naheed Mojgani; Sohyel Eskandari; Sepideh Arbabi Bidgoli
Abstract
Introduction The food and water contamination with heavy metals is increasing due to the environmental pollutions. Heavy metals are the elements with the density of more than 5 g/cm3 and have become a serious problem as a result of the urbanization and industrialization. These toxic metals pollute ...
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Introduction The food and water contamination with heavy metals is increasing due to the environmental pollutions. Heavy metals are the elements with the density of more than 5 g/cm3 and have become a serious problem as a result of the urbanization and industrialization. These toxic metals pollute water, soil, plants, and eventually foodstuffs and our bodies. Several methods exist to remediate heavy metal pollution in waters such as membrane filtration, ion exchange mechanisms, or by precipitation. Yet, these techniques are not cost effective, in some cases, and do produce wastes that need to be properly disposed of. Microbial bioremediation could be an alternative. The use of microbes for remediation of heavy metals has been well studied. Some microorganisms, especially soil bacteria, have the ability to tolerate these contaminants. In addition, certain bacterial strains are capable of binding to heavy metals or transforming them into less toxic forms. Low operating costs, usable in foodstuffs, selective removal for specific toxic metals, minimal use of chemicals (resulting in low sludge production) and high efficiencies at very low levels of heavy metals are some of the advantages of biosorption methods. In this regard, the purpose of this study was to investigate the ability of active and passive absorption of heavy metals by a number of Lactic Acid Bacteria (LAB) strains in laboratory environment and food. Materials and Methods Seven LAB isolates including Lacticaseibacillus casei (RTCC 1296-3), Lacticaseibacillus rhamnosus (RTCC 1293-2), Lactiplantibacillus plantarum (RTCC 1290), Limosilactobacillus fermentum (RTCC 1303), Enterococcus faecium (RTCC 2347), Lactobacillus helveticus (RTCC 1304) and Lactobacillus acidophilus (RTCC 1299) were obtained from Razi type culture collection (RTCC), located at Razi vaccine and Serum Research Institute, Iran. All isolates were cultured in MRS (Scharlau, Spain) broth medium, at 37 °C for 24 hours, under anaerobic conditions. Pure cultures were preserved for long term by freezing at -70°C with 20% Glycerol. Heavy metals including Nitrate of Pb (II), Cd (II) and Ni (II) were purchased from Merck (Darmstadt, Germany). All standard solutions were prepared from the stock solutions containing 1000 mgl-1 in distilled water. Other chemicals used in study including Nitric acid (65%) and Hydrogen peroxide (37%), were also purchased from Merck, Germany. This study was conducted in two in- vitro and in-vivo phases; in the in- vitro phase, seven strains of bacteria with probiotic properties (L. casei, L. rhamnosus, L. plantarum, L. fermentum, Ent. facium, L. helveticus and L. acidofilous) were screened and then their ability to bind to cadmium (Cd), Lead (Pb) and nickel (Ni) in aqueous solution was investigated. Then, in the in-vivo stage, three probiotic strains that had the highest biosorption efficiency in the previously stage were selected and their effect with a ratio of 1:1:1 and contact time of 15 and 30 minutes on the removal of these toxic metals in coriander, leek and parsley fresh vegetables was evaluated. The residual concentrations of heavy metals in solution were measured by Inductively Coupled Plasma Mass Spectrometer (ICP-MS; ELAN DRC-e, PerkinElmer SCIEX, Canada) and Morphology of bacteria cell surfaces incubated with metals were monitored by scanning electron microscopy (JEOL JSM 5400 LV, Japan). Results and DiscussionThe results of the in vitro stage showed that the most ability to heavy metals adsorption was related to the Ent. Facium bacterium which were equal to 79.75±0.11, 75.28±0.05 and 83.99±0.10% for Pb, Cd and Ni, respectively. In general, the removal efficiency of heavy metals by LAB bacteria in the inactive and killed state was significantly higher than the active removal efficiency of these bacteria, so that the highest percentage of passive absorption of lead, cadmium and nickel metals by inactive strains of L. casei, L. plantarum and Ent. Facium were 90.01, 81.98 and 86.56%, respectively. Electron microscopy observations and energy dispersive X-ray (EDX) analysis confirmed that the majority of these toxic metals significantly damage the surface of living cells by accumulating and binding on the surface of bacterial cells. A combination of three bacterial strains had a synergistic effect on the binding properties of toxic metals compared to the single state of these bacteria, so that in both active and inactive states, 90-99% of heavy metals from edible leafy vegetables were removed in less than 15 minutes. The results of this research generally showed that the binding capacity of dead biomass is significantly high and it is possible to dispose and reuse biomass in case of biological absorption.
Food Biotechnology
Asad Abbaspour Anbi; Masoud Seidgar; Masoud Neyriz Nagadehi
Abstract
The present investigation was done to study the effects of Lactococcus lactis (L. lactis) subsp. lactis on the shelf life of the vacuum-packaged Oncorhynchus mykiss. Fish fillets were prepared and divided into 5 different treatment groups including control (distilled water), 2% and 4% supernatant, and ...
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The present investigation was done to study the effects of Lactococcus lactis (L. lactis) subsp. lactis on the shelf life of the vacuum-packaged Oncorhynchus mykiss. Fish fillets were prepared and divided into 5 different treatment groups including control (distilled water), 2% and 4% supernatant, and 106 CFU/g L. lactis subspecies lactis. The pH, Thiobarbituric Acid Reactive Substances (TBARS), Total volatile Nitrogen (TVN), and Peroxide Value (PV) of the fillets were determined on days 0, 5, 10, and 15 while maintained at 4˚C. Protein expression and destruction were analyzed using the SDS-PAGE. The organoleptic assessment was done using five expert sensory panelists. Contents of TBARS, TVN, pH, and PV were increased throughout the storage period (P <0.05). An increase in the concentration of supernatant caused a significant decrease in the content of TBARS, TVN, pH, and PV (P <0.05). The highest and lowest contents of TBARS, TVN, pH and PV on 15th day were belonged to the control (3.367±0.04 mg MDA/kg) and pure bacteria (0.70±0.02 mg MDA/kg), control (87.20±6.40 mg/100g) and 4% supernatant (40.79±0.61 mg/100g), pure bacteria (6.23±0.04) and 4% supernatant (5.44±0.07) and control (12.22±0.01 meq/kg) and 4% supernatant (3.08±0.06 meq/kg) groups, respectively. Protein destruction was lower in the fillet samples treated with pure bacteria and 4% supernatant. The highest scores of the odor, flavor, texture, and color were obtained for fillets treated with 4% supernatant, pure bacteria, pure bacteria, and 4% supernatant and pure bacteria, respectively. The results revealed that treating O. mykiss fillets with 4% supernatant and 106 CFU/g of pure L. lactis subsp. lactis can extend the shelf life of O. mykiss fillets.
Food Biotechnology
Nasim Najafi; Hajar Abbasi
Abstract
Due to its health benefits, fresh sprouted cereals are considered popular food source. They are very sensitive and highly susceptible to microbial spoilage during transportation, processing, and storage. This phenomenon makes them potentially high-risk fresh products. This study aimed to assess the effect ...
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Due to its health benefits, fresh sprouted cereals are considered popular food source. They are very sensitive and highly susceptible to microbial spoilage during transportation, processing, and storage. This phenomenon makes them potentially high-risk fresh products. This study aimed to assess the effect of emulsion coating consisting of Dracocephalum kotschyi essential oil (0, 50, 150, 250, 300 ppm)-chitosan solution (0, 0.3, 0.38, 0.63, 0.75%) during the immersion time (10, 25, 55, 85, 100 s) on the microbial properties of fresh sprouted wheat stored at 4°C. The Response Surface Methodology (RSM) was adopted in modeling the independent variables’ effects. The results shown that increase in the essential oil and chitosan solution concentration reduced the microbial spoilage. High concentration of Dracocephalum kotschyi oil decreased the fungus population after 12 days. Coating of sprouted wheat at optimized level of independent variables (0.62% chitosan, 57 ppm Dracocephalum kotschyi oil and 29.49 s immersion time) reduced the microbial and fungal populations. This treatment can reduce weight loss, and maintain tissue firmness, total phenolic, and ascorbic acid content of the sprouted wheat during cold storage, with no effect on its sensory properties. Our findings indicate that nanoemulsion coating based on chitosan and Dracocephalum kotschyi oil at appropriate levels could be beneficial in maintaining sprouted wheat quality and increasing its shelf-life.
Food Biotechnology
Zohre Noruzi Motlagh; Mahmoud A. Mahdavi; Reza Gheshlaghi
Abstract
Introduction Carotenoids have many effects on human health. These compounds are produced by plants and microalgae. The extraction of carotenoids from microalgae such as Chlorella has received much attention, since microalgae grow all year round (regardless of the season) and at a much faster rate ...
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Introduction Carotenoids have many effects on human health. These compounds are produced by plants and microalgae. The extraction of carotenoids from microalgae such as Chlorella has received much attention, since microalgae grow all year round (regardless of the season) and at a much faster rate than plants in non-arable lands. The aim of this research was to optimize the concentrations of nutrients (nitrogen and phosphorous) in the growth medium of microalgae with the objective of maximizing carotenoids content. At the optimized nutrient conditions, the effect of phytohormones on production of carotenoids using Chlorella sorokiniana IG-W-96 was investigated. Materials and MethodsChlorella sorokiniana IG-W-96 was cultivated in BG11 growth medium with light intensity of 25000 lux and light: dark cycle of 16: 8 supplied with compressed air flow of 0.5 vvm containing 6% vol carbon dioxide. Under three concentrations of nitrate (0.04, 0.25, 1.5 ) and three concentrations of phophate (0.01, 0.04, 0.16 ) and carotenoid concentration was measured. Full factorial experimnetal design was performed and the resuts of the experiments were analyzed using Minitab (ver. 21.01.1). Finally, the best concentrations of nitrate and phosphate were chosen for pigments production, and at that concentration, naphthalene acetic acid (0, 2.5, 5, 7.5, 10 and 12 ppm) was added to the culture medium to check its effect on pigments production. By measuring the dry weight of C. sorokiniana, its growth rate was determined. After extracting the pigments with solvent, the concentration of the pigments was determined by measuring the amount of light absorption. Results and DiscussionDry weightThe results showed that the highest amount of dry weight was related to the treatment with nitrate amount of 0.25 , and nitrate more and less than this amount caused a decrease in growth. This result was not dependent on the amount of phosphate and was true for all phosphate concentrations. Nitrate reduction from 1.5 to 0.25 increased the growth of microalgae up to 81.8%, so that the dry weight of 0.88 reached 1.6 . However, reduction of nitrate from 0.25 to 0.04 decreased the dry weight by 65.6%. In order to reach the maximum growth rate, it is necessary to determine the appropriate concentration of each nutrient. CarotenoidsUnlike the dry weight, not only the pigment production did not decrease with the excessive of nitrate concentration, but also the maximum amount of pigment production was related to the treatment with the maximum amount of nitrate concentration. Based on the results obtained, the concentration of carotenoids was higher in the concentration of 1.5 of nitrate and 0.04 of phosphate (6.7 ).When the nitrate concentration was very low (0.04 ), changing the phosphate concentration had no significant effect on the production rate of any of the pigments. Only when the nitrate concentration was high (1.5 ), change in phosphate concentration caused a change in pigments concentration. The increase of phosphate concentration from 0.01 to 0.04 increased the carotenoids concentration to 1.65-fold. Of course, increasing phosphate concentration to 0.16 did not affect the pigments concentration. Based on the statistical analysis, the P-value<0.05 indicated that the effect of the factors and the model was significant. In this situation, in order to increase the production of carotenoids, naphthalene acetic acid was added to the phytohormone culture medium. At the optimal concentration of 2.5 ppm of naphthalene acetic acid, the concentration of carotenoids increased by 26.71% and reached 8.49 . However, phytohormone had no significant effect on dry weight. ConclusionCarotenoid production using microalgae could be maximized through optimization of nutrients concentrations (nitrate and phosphate) in the growth medium. Phytohormones could further increase the prodcution of carotenoids at optimum concnetrations.
Food Biotechnology
Masume Atharinia; Nasrin Zonourian; Sare Davarzani
Abstract
IntroductionTomato paste is one of the processed tomato products that has a long shelf life and is used as an important food ingredient all over the world. According to global statistics, Iran is among the top ten producers of tomato paste in the world, Iran ranks fourth to fifth in the world in the ...
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IntroductionTomato paste is one of the processed tomato products that has a long shelf life and is used as an important food ingredient all over the world. According to global statistics, Iran is among the top ten producers of tomato paste in the world, Iran ranks fourth to fifth in the world in the field of aseptic paste production. Alicyclobacillus bacteria are considered as a risk for pasteurized acidic food industries. These bacteria enter the product through soil-contaminated fruits, production equipment of the factories and finally produce metabolites such as guaiacol, causing an unpleasant taste in the product. Materials and Methods In order to investigate the microbial contamination of canned tomato paste in the country, 46 samples of canned tomato paste in the amount of 184 cans of 800 grams were purchased from the market. Regarding the purchase of samples from the market, we tried to buy a different production date and production series for each sample (approximately 4 cans for each brand from each production series). The purchased samples were sent to the Microbiology Department of the Standard Research Institute laboratory for microbiology tests. At the same time, the culture media of thermophilic bacteria (Orange Serum Agar, Thermoacidurans Agar from 4 available brands) were tested for performance control. The canned tomato paste samples were incubated at 30°C ± 1°C for 14 days and 55°C ± 1°C for 7 days. Results and Discussion The contents of both examined samples were tested separately for thermophilic bacteria, mesophilic bacteria, mold and yeast. Out of the 46 samples prepared with different production dates and production series, which were 46 cans of tomato paste, 28 samples were positive in terms of contamination with thermophilic bacteria. According to the number of contaminated samples, it was found that 60.86% of the samples were contaminated. Colonies grown on Thermoacidurans Agar medium were examined morphologically. For further investigations, gram staining was performed. All the stained colonies morphologically showed the form of gram-positive rod-shaped bacilli. Biochemical tests including catalase and oxidase were performed to identify Alicyclobacillus species. All the grown colonies were catalase positive and oxidase negative. The final identification of the species was done by performing molecular tests based on specific primers designed from Alicyclobacillus gene. These tests were performed in three stages: genomic DNA extraction, polymerase chain reaction and electrophoresis. Using the PCR method, the grown colonies were analyzed for two types of bacteria, Alicyclobacillus acidocaldarius and Bacillus coagulans. According to the results obtained from sequencing with designed primers in the NCBI database, it showed 100% similarity with the registered sequences, which are all different strains of the Alicyclobacillus acidocaldarius species. None of the colonies were detected as Bacillus coagulans species. Since Alicyclobacillus acidocaldarius was isolated from soil for the first time, the presence of these bacteria in the product indicates the contamination of raw materials with soil. ConclusionIn this research, the presence of Alicyclobacillus bacteria in canned tomato paste was confirmed. Due to the high heat resistance of this bacteria, there is a possibility of the presence of Alicyclobacillus in the all stages of tomato paste production, which have entered the product through the soil, and 95°C ± 3°C pasteurization temperature in 30 minutes is not effective in removing this bacteria completely. Most acidophilus thermophilic bacteria, such as Alicyclobacillus family, are not pathogenic bacteria. Their presence in food may make the food taste bad or smelly, but it does not pose a risk to the health of the consumer. Therefore, in order to reduce the risk of spoilage and to prevent the growth of bacterial spores in the product, it is essential not to expose the product to high temperatures for a long time. It is also necessary to perform rapid cooling after heat treatment and keep the product at a temperature below 30°C. AcknowledgementThis article is the result of a common research project of Microbiology and Biology Research Group of Standard Research Institute and Kermanshah Standard Regional Research Group. We hereby thank and appreciate the cooperation of the microbiology research group of the Standard Research Institute and the Kermanshah General Directorate of Standards. We are also very grateful to Rogin Talk Company as the employer of this project.
Food Biotechnology
َAlireza Hemmati; Ali Ganjloo; Kambiz Varmira; Mandana Bimakr
Abstract
Introduction It is believed that edible oils and fats with high levels of unsaturated fatty acids are susceptible to oxidation. Soybean oil as one of the four important edible oils has high content of polyunsaturated fatty acids and so prone to oxidation. Generally, lipid oxidation leads to deterioration ...
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Introduction It is believed that edible oils and fats with high levels of unsaturated fatty acids are susceptible to oxidation. Soybean oil as one of the four important edible oils has high content of polyunsaturated fatty acids and so prone to oxidation. Generally, lipid oxidation leads to deterioration of nutritional quality and organoleptic properties of edible oils and fats as well as accelerate the development or progression of cancer, mutagenesis, carcinogenesis, aging and cardiovascular diseases through the formation of free radicals. Therefore, edible oils and fats fortification with antioxidant compounds in order to protect them against oxidation is essential. In recent years, numerous studies were carried out on exploration of natural and safe antioxidant compounds due to the consumers concerns about potential health risk of synthetic antioxidants, such as butylatedhydroxyanisole (BHA), butylatedhydroxytolene (BHT), tert-butylhydroquinone (TBHQ) and propylgallate (PG). In this regard, TBHQ as the most powerful synthetic antioxidant is prohibited as food additive in Japan, Canada and Europe. Ferulago angulata Boiss which called chavir or chavil belongs to the family of Apiacea consisting of 35–40 species that 8 species grow in Iran. It was reported that Ferulago species are used in folk medicine for their tonic, digestive, sedative, aphrodisiac properties from ancient times. Therefore, in the current study, the oxidation development of soybean oil enriched with F. angulata essential oil (EO) during accelerated storage was investigated. Materials and Methods EO from freeze dried aerial parts of F. angulata was extracted through hydrodistillation using Clevenger type apparatus. Gas chromatography-mass spectrometry (GC-MS) was used to identify main components of the EO. Total phenolic and flavonoid content of the EO were assessed using Folin–Ciocalteu and aluminium chloride colorimetry methods, respectively. Antioxidant activity of EO was measured through 2, 2-Diphenyl-1-picrylhydrazyl (DPPH) and reducing power (RP) tests. Then, the EO of F. angulata at three concentrations, i.e. 200 ppm (SO-200), 400 ppm (SO-400), and SO-Mixture (100 ppm TBHQ + 100 ppm EO) were added to soybean oil. The synthetic antioxidant of TBHQ at the concentration of 200 ppm was added as control. The effect of EO from freeze dried aerial parts of F. angulata on oxidative stability of soybean oil stored under accelerated conditions at 65 ºC for 24 days was evaluated through acidity, peroxide (PV), p-anisidine (p-An) and TOTOX values. Results and Discussion Extraction yield, total phenolic and flavonoid contents of EO of F. angulata were 2.5% v/w, 188 mg GAE/g and 70.90 mg QE/g respectively. Furthermore, DPPH free radical scavenging activity and RP were 55.45-13.21% and 3.61-2.72 in the concentration range of 1.6-4.6 mg/ml of EO, respectively. Based on GC-MS analysis, the EO contains 41 natural compounds, representing 96.97% of the total EO. F. angulata EO could effectively reduce the acidity, PV and p-An values. For control sample, the maximum values of acidity, PV peroxide, p-An and TOTOX were 1.52 mg KOH/g, 10.60 meq O2/kg, 12.48 and 33.68 respectively after 24 days under accelerated conditions. While these values were 0.085 mg KOH/g, 4.5 meq O2/kg, 9.16 and 18.16 respectively for the soybean oil containing the lowest concentration of EO of F. angulata. Conclusion The results confirmed the instability of soybean oil during storage as well as the ability of EO from F. angulata for soybean oil protection against oxidation. As a result, EO from aerial parts of F. angulata could be suggested as a natural and effective antioxidant to be used instead of TBHQ as a synthetic antioxidant for soybean oil stabilization.
Food Biotechnology
Hossein Zanganeh; Fakhri Shahidi; Seyed Ali Mortazavi; Behrooz Alizadeh Behbahani
Abstract
IntroductionOxidation reactions and microorganisms’ activity are considered as the most important factors affecting the quality of food products. Recently, in the light of the inefficiency of some chemical preservatives against microorganisms and the presence of toxic residues in food products, ...
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IntroductionOxidation reactions and microorganisms’ activity are considered as the most important factors affecting the quality of food products. Recently, in the light of the inefficiency of some chemical preservatives against microorganisms and the presence of toxic residues in food products, the use of natural antimicrobials and antioxidants has been increased. Natural antimicrobial compounds have the potential to control microbial contamination and reduce the use of antibiotics. Plant essential oils are natural compounds with the potential to be used as active ingredients in the food, pharmaceutical, and cosmetic industries. Various studies have shown that essential oils have antifungal, antibacterial, antiviral, and antioxidant activity. The essential oils are considered as superb preservatives with various biological functions. Essential oils are generally recognized as safe product (GRAS) which can be used as an alternative to synthetic additives.Grapefruit (Citrus paradisi) peel and fruit contain active ingredients such as acids, flavonoids, vitamin C, and potassium, and its essential oil is composed of terpenic hydrocarbons, such as citral, limonene, citronelal, and geraniol. Although plant essential oils have antimicrobial and antioxidant properties, one of the main problems of these natural compounds is their high volatility and instability. In this context, nanoemulsion formulations are frequently used to increase the stability and efficiency of these biologically active compounds. This study is therefore aimed to nanoemulsifying the grapefruit essential oil and evaluate its antioxidant and antimicrobial properties. Materials and Methodsβ-carotene, linoleic acid, ABTS (2,2’-Azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt), and DPPH (2,2-diphenly-1-picrylhydrazyl) were purchased from Sigma-Aldrich Co. (USA). Mueller Hinton Broth (MHB) and Mueller Hinton Agar (MHA) were supplied from Merck Co. (Darmstadt, Germany). Grapefruit peel was dried at ambient temperature and then powdered. The obtained powder was then transferred to a Clevenger device containing 750 ml of distilled water to perform the distillation extraction (3 h). The resulting grapefruit essential oil was stored at 4 °C until use. Grapefruit essential oil was prepared using the hydrodistillation method, and then nanoemulsified. The antioxidant activity of the nanoemulsified essential oil was investigated by DPPH and ABTS radical scavenging activity and beta-carotene/linoleic bleaching test. The nanoemulsified essential oil or methanolic (control) was mixed with DPPH solution and the mixture was then stored at ambient temperature for 30 min, in a dark place. The control sample was prepared by methanol. The absorbance of the samples was measured at 517 nm. To determine the ABTS-RS activity, the nanoemulsified essential oil was briefly charged with methanolic ABTS radical cation solution and the resulting mixture was left at room temperature for 30 min. Afterward, the absorbance was read at 734 nm. A spectrophotometric method was applied to monitor β-carotene/linoleate solution bleaching in the presence of the nanoemulsified essential oil. To do this, the absorbance of the solution was recorded at 490 nm after 120 min against the control sample at time zero and after 120 min. Antibacterial effect of the grapefruit essential oil nanoemulsion was also evaluated against Escherichia coli ATCC 25922, Salmonella typhi ATCC 6539, Pseudomonas aeruginosa ATCC 27853, Listeria innocua ATCC 33090, Staphylococcus aureus ATCC 25923, Bacillus cereus ATCC 14579, Bacillus subtilis ATCC 23857, Streptococcus pyogenes ATCC 19615, and Staphylococcus epidermidis ATCC 12228, based on disk diffusion agar, well diffusion agar, minimum inhibitory concentration, and minimum bactericidal concentration. Results and DiscussionsThe results showed that the nanoemulsion of grapefruit essential oil had a remarkable antioxidant effect of 42.27 mg/ml, 33.27 mg/ml and 54.54%, respectively, based on DPPH, ABTS, and beta-carotene-linoleic acid bleaching tests. According to disk diffusion agar and well diffusion agar results, the lowest inhibition zone was related to E. coli and the highest inhibition zone was observed in L. innocua. The minimum inhibitory concentration for L. innocua and S. aureus (the most sensitive bacteria) was 25 mg/ml, and E. coli, S. typhi, and P. aeruginosa had the highest inhibitory concentration. Also, the lowest bactericidal concentration was related to L. innocua and S. aureus bacteria and the highest concentration was observed for E. coli, S. typhi and P. aeruginosa. The nanoemulsified essential oil generally exhibited greater antibacterial activity against Gram-positive species. This could be mainly due to the difference in the cell wall composition of Gram-positive bacteria in comparison to Gram-negative; Gram-positive bacteria have a thicker mucopeptide layer in their cell wall, while Gram-negative bacteria have only a thin layer of mucopeptide and the wall structure is mainly composed of lipoprotein and lipopolysaccharide, thereby leading to a higher resistant to antibacterial agents According to the results, grapefruit essential oil nanoemulsion can be used as a natural antioxidant and antimicrobial agent to control oxidation reactions and the growth of spoilage and pathogenic microorganisms.
Food Biotechnology
Mostafa Rahmati-Joneidabad; Behrooz Alizadeh Behbahani; Mohammad Noshad
Abstract
IntroductionStrawberry and grapes are generally infected with pathogenic fungi (e.g., Aspergillus niger, Botrytis cinerea, Rhizopus stolonifera, etc.). Synthetic fungicides are commonly used as the first line of defense against post-harvest pathogens on packaging lines. However, disposal of toxic waste ...
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IntroductionStrawberry and grapes are generally infected with pathogenic fungi (e.g., Aspergillus niger, Botrytis cinerea, Rhizopus stolonifera, etc.). Synthetic fungicides are commonly used as the first line of defense against post-harvest pathogens on packaging lines. However, disposal of toxic waste is a costly process and the hazardous waste causes serious environmental problems. In addition, fungal pathogens have shown a worrying trend of resistance to these fungicides, thus shortening the shelf life of products. Compounds that can be equally effective in controlling pathogens, but preventing or minimizing the waste problems will be inevitable. The large volume of internationally processed agricultural products, as well as the increasing demand for organically produced fruits, emphasizes the need to replace synthetic fungicides with safer and biodegradable alternatives. Natural plant-derived products effectively meet this criterion and have great potential to influence modern agricultural research. Catechins and other polyphenols in green tea show strong antioxidant activity. Also, the antimicrobial activity of green tea extract against Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, and Candida albicans has been reported. Therefore, the present study was performed to prepare the ethanolic extract of green tea and to determine the content of total phenol, total flavonoids, antioxidant activity, and its antifungal effect against Aspergillus niger, Botrytis cinerea, and Rhizopus stolonifer (causing rot in strawberry and grapes). Materials and MethodsFresh green tea leaves were dried at room temperature and then powdered. Then, ethanol (70%) was added to the powdered leaves (solvent to powder ratio of 10:1 v/w) and the mixture was refluxed for 120 min. The resulting mixture was filtered through a filter paper and then concentrated under vacuum and finally dried in an oven.Total phenol content (by Folin-Ciocalteu reagent at 756 nm), total flavonoid content (spectrophotometrically at 510 nm), antioxidant activity (by DPPH and ABTS radical scavenging methods), and antifungal effect (by disk diffusion agar, well diffusion agar, minimum inhibitory concentration, and minimum fungicidal concentration) of the extract were evaluated. Results and DiscussionThe extract contained 175.60 mg GAE /g total phenol and 47.53 mg QE/g total flavonoids and its antioxidant activity using DPPH and ABTS free radical assays was 78.89% and 86.57%, respectively. The results of antifungal activity showed that the diameter of the growth inhibition zone increased significantly with increasing the concentration of the extract, and Botrytis cinerea and Rhizopus stolonifer were the most sensitive and resistant fungal strains to the extract, respectively. The minimum fungicidal concentrations for the strains of Botrytis cinerea and Rhizopus stolonifer were 64 and 512 mg/ml, respectively. ConclusionThe results of the present study showed that the ethanolic extract of green tea could be considered as potential source of natural antioxidant and antifungal agents. The presence of phenolic and flavonoid compounds may be responsible for the antifungal and antioxidant effects of the extract. However, due to the fact that this study was performed with the crude extract of green tea, it is difficult to identify compounds responsible for antifungal and antioxidant activity. On this point, only the separation of the components of the extract allows the detection of antifungal and antioxidant compounds. This study provides a basis for further researches, in particular the use of these antioxidants and antifungal compounds. Green tea extract is especially suitable for products with high sensitivity to lipid oxidation and infection with molds.
Food Biotechnology
Saeedeh Fatemizadeh; Mohammad Bagher Habibi Najafi; Dennis Sandris Nielsen
Abstract
IntroductionCronobacter sakazakii is an opportunistic pathogen, which has been linked to the contamination of powdered infant formula, and associated with outbreaks leading to fatalities in neonatal intensive care units. Few studies have explored the direct interaction between probiotics and C. sakazakii. ...
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IntroductionCronobacter sakazakii is an opportunistic pathogen, which has been linked to the contamination of powdered infant formula, and associated with outbreaks leading to fatalities in neonatal intensive care units. Few studies have explored the direct interaction between probiotics and C. sakazakii. In this study, the effect of a Lactiplantibacillus plantarum strain (M17) along with the standard strain Lactobacillus plantarum (ATCC 8014) and the well-characterized probiotic strain Lactobacillus rhamnosus GG on the adhesion of C. sakazakii to intestinal epithelial cells was analyzed. Materials and MethodsAcid and bile tolerance of M17 was evaluated in the presence of pepsin and pancreatin. L-arginine hydrolysis was investigated using an arginine-including medium. Auto-aggregation and co-aggregation assays were performed by absorbance measurement. Minimum inhibitory concentrations of the antimicrobials recommended by the European Food Safety Authority were established. Total lactic acid and the ratio of D/L lactate isomers were determined with a Megazyme enzymatic kit. The ability of the isolate to produce biogenic amines was tested by qualitative and quantitative monitoring. Hemolysis was assessed phenotypically on MRS agar enriched with sheep blood. The strain was tested for its capability to adhere to mucin and Caco-2 cells. The antagonistic effects of the strain against C. sakazakii were further evaluated in vitro on mucin and cultured Caco-2 cells. The LAB strain was added simultaneously with, before, and after C. sakazakii to Caco-2 cells for competition, exclusion and displacement assays, respectively. Data analysis was performed in R using one-way analysis of variance, and the experimental groups were compared with the controls using Tukey’s test. P values <0.05 were considered statistically significant. Results and DiscussionThere was no significant difference in the survival rate of M17 and L. plantarum ATCC 8014 at pH = 4. After 2 h of incubation at pH = 2.5, the survival rate of L. plantarum ATCC 8014 was estimated to be higher than strain M17, but this difference was not significant. After 4 hours of incubation at pH = 8, M17 showed a higher survival rate than L. plantarum ATCC 8014, and this difference was significant after transfer from pH = 4. These results confirm the appropriate viability of M17 in the gastrointestinal tract. Both M17 and L. plantarum ATCC 8014 developed the color yellow in the L-arginine hydrolysis assay, which confirms the safety of these strains. The percentage of auto-aggregation for M17, L. plantarum ATCC 8014, and Lactobacillus rhamnosus LGG was estimated at 24.38, 25.28, and 32 after 6 hours, respectively, and no statistically significant difference between the two isolates were noticed. Given the auto-aggregation and co-aggregation parameters of M17, this strain may constitute a defense mechanism against C. sakazakii. Strain M17 showed resistance to kanamycin and clindamycin antibiotics. With intrinsic resistance, the risk of transferring resistance genes is not only speculative, but practically impossible. Intrinsic resistance of lactic acid bacteria may be considered desirable because it ensures their survival when the host is treated with antibiotics. Both D and L isomers of lactic acid were produced by the studied strains. In humans, D(-)-lactic acidosis is a rare metabolic complication that has only been reported in individuals with short bowel syndrome). Clinical studies have shown that the consumption of probiotic bacteria producing D(-)-lactic acid is safe for children and does not cause a long-term increase in blood D(-)-lactic acid. The reference L. plantarum strain and M17 did not produce biogenic amine precursors, and had no ß-hemolytic activity. Mucin adhesion assay exhibited that M17 has less adhesion (12.10 ± 1.14 %) than L. plantarum ATCC 8014 (13.33 ± 2.30 %) and LGG (15.93 ± 2.06 %) although these differences were not statistically significant. However, the amount of adhesion for the positive control sample Escherichia coli K12 (25.19 ± 4.40 %) was significantly higher than those of the other strains. Compared to the positive control, M17 had a significantly lower adhesion rate (6.8 ± 1.41) to CaCo-2 cells. This value was estimated at 13.77 ± 3.53 % for the reference strain and 21.6 ± 7.54 % for Lactobacillus fermentum PCC (positive control). In antagonistic assays, M17 was able to reduce the adhesion of C. sakazakii to mucin and CaCo-2 cells in all three methods of exclusion/inhibition, competition and displacement. Statistical analysis of the results does not show a significant difference between M17 and LGG. Therefore, the performance of M17 is similar to that of the standard probiotic LGG. ConclusionLactic acid bacteria with acceptable ability to adhere to epithelial cells can be suitable for colonization in the intestine. They can act as a barrier to fight pathogens through various competitive mechanisms, such as co-aggregation with pathogens and adhesion. The M17 strain has an acceptable immune profile and probiotic properties because it shows an acceptable antagonistic activity against C. sakazakii invasion. AcknowledgementThis study was supported by Ferdowsi University of Mashhad (Research affairs) [project No.:46718] and the research infrastructure at the University of Copenhagen.
Food Biotechnology
Mina Seifzadeh
Abstract
Collagen has diverse general and biomedical applications and its important role in the future of society have made it a key biopolymer for human health and well-being. Therefore, the present study was conducted with the objectives of extracting collagen from the skin of farmed carp, determining the quality ...
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Collagen has diverse general and biomedical applications and its important role in the future of society have made it a key biopolymer for human health and well-being. Therefore, the present study was conducted with the objectives of extracting collagen from the skin of farmed carp, determining the quality characteristics of collagen, and comparing them. Collagen was extracted from the skin of carp fishes by acidic enzymatic method using 0.5 M acetic acid and pepsin in 48 hours. Collagen treatments (5 treatments) included collagen prepared from the skin of common species, grass carp, bighead, silver, and cow (control). Collagen treatments were not capable of hemolysis and did not show toxic effects on human fibroblast cells. Heavy metals (0.01-0.18 ppm) in collagen extracted from cultured carp species were within the standard range. The color (brightness) of experimental collagen (92.74-93.68) and control (92.38) showed no significant difference (p<0.05). Amino acids cysteine and tryptophan were not observed in collagen. Glycine and hydroxylysine amino acids (352 and 3 residues 1000g-1, respectively) had the highest and lowest amounts in collagen. Amino acids profile and collagen production efficiency (10.51-10.59%) did not show significant differences in carp fish species (p<0.05). Based on the results of the present study, production efficiency, safety and quality characteristics of collagen in cultured carp species did not show any significant difference (p<0.05), and no significant difference was observed between these characteristics and the control (p<0.05). Therefore, the skin of these species can be used to produce collagen and introduce it to the industry as a substitute for mammalian collagen.
