Full Research Paper
Food Engineering
Mohammad Reza Salahi; Seyed Mohammad Ali Razavi; Mohebbat Mohebbi
Abstract
Introduction
Emulsion-filled gel is a sort of gel system that traps oil droplets as a filler and contains a wide range of semi-solid to solid food products. It can also be utilized as a dual system to distribute and control the release of both lipophilic and hydrophilic bioactive and micronutrient ...
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Introduction
Emulsion-filled gel is a sort of gel system that traps oil droplets as a filler and contains a wide range of semi-solid to solid food products. It can also be utilized as a dual system to distribute and control the release of both lipophilic and hydrophilic bioactive and micronutrient substances. The main polymers involved in gel formation in food products are proteins and polysaccharides. Using molecular interactions between biopolymers, a wide range of rheological and physicochemical properties of gels can be methodically created. As a result, the interaction between proteins and polysaccharides has received a lot of attention in order to generate novel products. Because of their functional qualities and high nutritional value, whey proteins are frequently used in the food industry. As a result, mixed gels based on whey protein have gained a lot of attention. k-Carrageenan is commonly utilized in the food industry as a gelling and firming agent. Because k-Carrageenan, like whey protein isolate, can form a gel independently, its interaction with whey protein isolate in emulsion gel systems appears appealing. Therefore, in this study, the effect of k-Carrageenan gum (0.0, 0.1, 0.3, 0.5, and 0.7%) on the textural (uniaxial compression test), rheological (steady shear, strain sweep, and frequency sweep tests), and water holding capacity of cold-set emulsion-filled gel based on whey protein isolate was investigated.
Materials and Methods
Whey protein isolate (WPI) (98.9% protein, dry basis) was given as a gift by Agropur Ingredients Co. (Le Sueur, Minnesota, USA). -Carrageenan and CaCl2 ( : 147.01 gr/mol) were purchased from Sigma Aldrich Co. (USA) and Merck Co. (Darmstadt, Germany), respectively. Sunflower oil was supplied from local supermarket. Stock dispersions of WPI and -Carrageenan were prepared by dissolving sufficient amounts of their powders in deionized water. To prepare uniform oil in water emulsion, sunflower oil was added to the WPI dispersion and the obtained mixture homogenized first using a laboratory rotor-stator homogenizer (15000 rpm, 3 min), then by an ultrasonic homogenizer (20 kHz, 5 min). The prepared emulsion and -Carrageenan dispersions were poured into Schott bottles and heated in a water bath (90 °C, 40 min). WPI emulsion and AG dispersion were mixed in a cylindrical container on a stirring plate at a speed of 600 rpm for 6-8 min to obtain a homogeneous mixture. After decreasing the temperature to 60 °C for the ion-induced gelation, the mixtures were charged with CaCl2 (10 mM). The prepared samples were incubated in a refrigerator overnight to stabilize the 3D network. The final mixed EFG samples contained 5.5% WPI, 20% oil, and 0, 0.1, 0.3, 0.5, and 0.7% (w/w) of k-carrageenan. The tests performed on emulsion-filled gel samples were: 1) steady shear (0.01-10 s-1), 2) strain sweep (strain: 0.1-1000%, frequency: 1 Hz), 3) frequency sweep (frequency: 0.1-100 Hz, strain: 0.5%), 4) uniaxial compression (target strain: 80%, deformation speed:1 mm/s), and 5) water holding capacity (by utilizing a microcentrifuge, 600×g for 10 min).
Results and Discussion
According to the results of steady shear test, all samples had a shear thinning behavior, and based on the power-law model, this behavior was intensified in the presence of k-Carrageenan; and with increasing the gum concentration from 0 to 0.7%, the consistency coefficient increased from 339.9 to 545.7 Pa.s. In the strain sweep test, with the increase in the gum concentration, the values of the elastic and viscous modulus in the linear region and the modulus at the crossover point increased, and tan dLVE decreased from 0.17 to 0.13, which indicated an increase in the strength of the emulsion gel network structure. Based on the frequency sweep test, with the increase in k-Carrageenan concentration, the parameters and , network strength and network expansion increased from 5311.8 Pa, 939.9 Pa, 1.5380 Pa.s1/z and 10.05 in the control sample to 25080 Pa, 3574.9 Pa, 16097.7 Pa.s1/z and 16.41 in the sample containing 0.7% k-Carrageenan, respectively. Moreover, the frequency dependency of elastic modulus decreased from 0.095 in the control sample to 0.050 in the 0.7% k-Carrageenan contained sample. According to the large deformation test, in general, in the composite emulsion-filled gels, the values of apparent modulus of elasticity and fracture stress were higher and fracture strain and fracture energy were lower than in the control sample. Also, the results showed that different k-Carrageenan concentrations had no significant effect on the water holding capacity.
Conclusion
The obtained results showed that k-Carrageenan had considerable influence on the rheo-mechanical features of cold-set emulsion-filled gels based on whey protein which can add to the knowledge base for the production of new functional foods.
Full Research Paper
Food Technology
Fatemeh Ghorbanpour; Vahid Hakimzadeh; Hassan Rashidi
Abstract
Introduction
One of the relatively new dairy products is cheese sauce, which can increase the consumption of cheese per capita and replace unhealthy sauces. Process functionality achieved by adding useful compounds to food in order to improve properties of foods while maintaining its appearance. ...
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Introduction
One of the relatively new dairy products is cheese sauce, which can increase the consumption of cheese per capita and replace unhealthy sauces. Process functionality achieved by adding useful compounds to food in order to improve properties of foods while maintaining its appearance. Nowadays, due to the importance of some compounds such as essential fatty acids, antioxidants and fiber, the demand for consuming products containing these compounds in the diet is increasing. Date kernel extract contains fiber, antioxidants, lignans and essential fatty acids. Also, date kernels contain micronutrient such as selenium, iron, calcium, phenolic compounds, sterols, tocopherols, metal ions and essential amino acids. The functional properties of phenolic compounds and flavonoids in date kernels have also been proven. On the other hand, whey as a by-product in dairy plants has many nutritional properties and contains many essential and functional amino acids. In addition to the nutritional properties of whey powder, its technological properties such as creating viscosity are considered important in sauces formulation. The purpose of this research was to prepare cheese sauce using such compounds so that while preparing a useful product, it is possible to prevent the wastage of valuable by-products.
Materials and Methods
In this research, in order to prepare cheese sauce powder, the homogenized mixture was turned into powder by a spray dryer at 180°C. During the treatment of samples, date kernel extract was formulated at three levels of zero (control), 5 and 15%. In the treatments, one sample without whey and another sample with 15% of the final formula was considered. The effect of Date kernel extract and whey on the physicochemical properties of cheese sauce powder samples were investigated by determining solubility, dry matter, protein, total phenol, pH, viscosity and antioxidant activity. The organoleptic properties of samples, were also studied in 5-hedonic points. The results were analyzed in the form of a completely randomized design with 6 treatments and 3 replications. The software used was SPSS and the comparison of mean was done by Duncan's method at the 5% level. Graphs were plotted using Excel software.
Results and Discussion
The results showed that increasing the level of date kernel extract in the formulation of cheese sauce powder containing whey led to the improvement of the antioxidant power of cheese sauce and its phenolic compounds due to the presence of compounds such as gallic acid and cysteine amino acids in whey. High levels of date kernel extract in the presence of whey improved its solubility due to the increase in the amount of protein and dry matter of the sauce powder. It was also observed in the results obtained from the viscosity measurement that the presence of whey along with the date kernel extract reduced the viscosity by adjusting the percentage of carbohydrates. The result obtained in relation to the reduction of protein percentage in the conditions of simultaneous use of whey and date kernel extract was probably due to the precipitation of whey proteins based on the interaction with the carbohydrate components of date kernel extract leading to formation of unsolved products during the drying process. The presence of protein and essential amino acids, carbohydrates and fiber, mineral salts, vitamins and antioxidants in the final product increased the percentage of dry matter in samples containing high percentage of extract along with whey. Changes in pH were also not significant in different treatments. Overall, the results showed that the use of seemingly useless compounds can be significantly effective on the properties of cheese sauce and improve the properties of cheese sauce and finally produce a functional product.
Full Research Paper
Food Chemistry
Fatemeh Sadat Khanagaei; Fateme Akrami Mohajeri; Elaheh Askari; Hossein Fallahzadeh; Elham Khalili Sadrabad
Abstract
Introduction
Canola oil with high unsaturated fatty acids and nutritional value is susceptible to oxidation due to lipid oxidation. Lipid oxidation leads to a reduction of nutritional quality, sensory and safety characteristics of the vegetable oils. To retard lipid oxidation, the synthetic antioxidants ...
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Introduction
Canola oil with high unsaturated fatty acids and nutritional value is susceptible to oxidation due to lipid oxidation. Lipid oxidation leads to a reduction of nutritional quality, sensory and safety characteristics of the vegetable oils. To retard lipid oxidation, the synthetic antioxidants are usually used in the vegetable oils. By increasing the public concern about health problems of synthetic antioxidants, the use of natural antioxidants is increasing. Lavender (Lavandula officinalis) is an evergreen plant native to the Mediterranean. The presence of linalool, linalyl acetate, 1,8-cineole B-ocimene, terpinen-4-ol, and camphor in lavender essential oil, make it a good natural antioxidant which could use in food industry. Therefore, in the current research, it was aimed to investigate the antioxidant effect of lavender essential oil on the stability of canola oil.
Material and Method
The lavender was bought from Golestan province and dried in room temperature. The lavender essential oil was prepared by hydro distillation of flower heads. Then, the phenolic compounds were determined using GC-MASS. The Total phenolic content (TPC), flavonoid content (TFC), and antioxidant activity (FRAP and DPPH) of lavender essential oil were evaluated. Then, lavender essential oil in concentrations of 200, 400, 600, 800, and 1000 mg/kg was added to the crude canola oil compared to canola oils without antioxidants and synthetic antioxidant TBHQ (100 and 200 mg/kg). Then, the samples were kept at 60 to 70 oC for 12 days. The analysis was done in an interval of 24 h for 12 days. Lipid oxidation of samples was determined by peroxide value, p-anisidine value, TOTOX value, and thiobarbituric acid each 24 h. analyses of Data were done by one-way analysis of variance (ANOVA) using SPSS software and the means were compared by the Tukey multiple range test.
Result and Discussion
According to the GC-MS analysis, 1, 8-cineole (59.45 %), linalool acetate (32.48 %), linalool (6.31 %), and limonene (1.06 %) were identified as the major constituent of lavender essential oil. Also, Total phenol, flavonoid, FRAP and DPPH (IC50) contents of lavender essential oil were 71.55 mg GAE/g, 82.66 mg of rutin/100 g, 12.63 mmol H2SO4, and 55.88 mg/ml, respectively. According to the results, all lipid oxidation indexes were increased after twelve days of storage. In general, lavender essential oil was effective in retarding the oxidation of canola oil at a temperature of 70 oC. Also, the concentration of 1000 mg/kg of the essential oil had antioxidant activities similar to the TBHQ in 100 mg/kg concentration.
Conclusion
It was showed that lavender essential oil, as a natural antioxidant, has the ability to react with the radicals resulting from the oxidation of lipids and causes the interruption of oxidation chain reactions and increases the time and decreases the rate of oxidation. As observed, the oxidation of canola oil in all samples, especially the samples without antioxidants or antioxidants to a lesser extent, increased significantly with increasing storage time. In general, lavender essential oil at L1000 concentration and also in some oxidation indices of lavender essential oil at L800 concentration has an effective role in preventing the oxidation of canola oils like synthetic antioxidant TBHQ.
Full Research Paper
Food Biotechnology
Parisa Raei; Morteza Khomeiri; Alireza Sadeghi Mahoonak; Ali Moayedi; Mahboobeh Kashiri
Abstract
Introduction
Nowadays, 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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Introduction
Nowadays, 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 Methods
In 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 Discussion
According 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.
Conclusion
In 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.
Full Research Paper
Food Engineering
Moein Inanloodoghouz; Fakhreddin Salehi; Mostafa Karami; Ashraf Gohari Ardabili
Abstract
Introduction
Fruits have a limited harvest season, and the amount of their waste is significant. Drying extends the shelf life of food, and the infrared dryer reduces the time and cost of the drying process. In this study, the effect of sonication at different powers and temperatures along with edible ...
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Introduction
Fruits have a limited harvest season, and the amount of their waste is significant. Drying extends the shelf life of food, and the infrared dryer reduces the time and cost of the drying process. In this study, the effect of sonication at different powers and temperatures along with edible coating with xanthan and wild sage seed gums on the drying process of cornelian cherry by an infrared dryer was investigated.
Material and Methods
Solutions of xanthan and wild sage seed gums were used for coating of fresh cornelian cherry. Xanthan gum powder (food grade) was purchased from FuFeng Co. (China). Wild sage seed gum was extracted and used in powder form after drying and grinding to prepare the gum solution. In this study, various concentration of gums solutions (xanthan and wild sage seed) were first prepared in a graduated glass beaker and placed in an ultrasonic bath (Backer vCLEAN1-L6, Iran). The fruits were immersed in the gum solutions (inside the beakers) and sonicated for 5 min (40 kH). Infrared dryer with an infrared radiation source (250 W, near-infrared (NIR), Noor Lamp Company, Iran) was used for drying samples. The distance of samples from the radiation lamp was 10 cm. After each pretreatment (sonication and coating), the samples were dried, until reaching a constant weight. The mass changes of samples were recorded using a Lutron GM-300p digital balance (Taiwan). The rehydration tests were conducted with a water bath (R.J42, Pars Azma Co., Iran). Dried samples were weighed and immersed for 30 minutes in distillated water in a 200 ml glass beaker at 50°C. Then, the extra moisture was drained for 30 s and the samples were re-weighed. The rehydration ratio values (%) of dried samples were determined as the ratio of the final weight of rehydrated samples over the dried samples weight × 100. The color of the cornelian cherry was calculated by determining the lightness (L*) and chromaticity (redness (a*) and yellowness (b*)), and was measured using a scanner (Hp Scanjet 300, China) and Image J software (V.1.42e, USA). The Folin-Ciocalteu (Folin-Ciocalteu's phenolics reagent, Sigma-Aldrich, USA) method was followed for measuring the total phenolics content of dried cornelian cherry. The absorbance of samples (765 nm, UV-VIS spectrophotometer, XD-7500, Lovibond, Germany) was compared with the Gallic acid standard curve. The results were expressed as mg GAE/g dry matter. Effect of applied power by the ultrasonic device at three levels of 0, 75, and 150 W and the effect of temperature at three levels of 20°C, 40°C, and 60°C on the rehydration and total color difference index of dried cornelian cherry were investigated. Also, the effect of coating with xanthan and wild sage seed gums on preserving phenolic compounds, antioxidant activity, and sensory properties of the product was evaluated.
Results and Discussion
The average drying time of uncoated cornelian cherry, coated with xanthan gum, and wild sage gum was 62 min, 48.7 min, and 48.4 min, respectively. The examined treatments in this research did not have a significant effect on rehydration change of the dried product. Ultrasonic pretreatment at both 75 and 150 W powers had a decreasing effect on the color changes, which indicates improvement of color and prevention of color change and decrease in desirability. The effect of coating on color changes was also investigated, and the amount of color changes in the uncoated, coated with xanthan gum and wild sage seed gum samples was equal to 26.71, 26.02, and 31.36, and there was no significant difference between them (p>0.05). Using wild sage seed gum preserved more of phenolic and antioxidant compounds. The total phenolics content of fresh cornelian cherry, and dried samples including market, without coating, coated with xanthan gum, and coated with wild sage seed gum was 23.0, 4.7, 0.8, 9.8, and 12.1 mg gallic acid/g, respectively. The market sample had a significant difference with other dried samples dried by infrared (p<0.05). The sample from the market had the least DPPH radical scavenging activity (p<0.05). The market sample scored as the lowest sensory evaluation and had a significant difference with all samples in all sensory attributes (p<0.05).
Conclusion
From the panelist’s point of view, the sample coated with wild sage seed gum was the best sample, and the highest score for sensory parameters and overall acceptance was associated with this sample.
Full Research Paper
Food Technology
Reza Farahmandfar; Samaneh Forghani
Abstract
Introduction
Edible oils constitutes a chief component of human diets in our daily life to supply essential fatty acids, energy, and nutrients to human. The nutritional value of edible oils varies depending on the type of oil, processing methods, extraction techniques, and storage conditions. Generally, ...
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Introduction
Edible oils constitutes a chief component of human diets in our daily life to supply essential fatty acids, energy, and nutrients to human. The nutritional value of edible oils varies depending on the type of oil, processing methods, extraction techniques, and storage conditions. Generally, edible oils are high in triacylglycerols with minor compositions. The presence of high amount of unsaturated fatty acids in the structure of triacylglycerol leads to a reduced shelf life of oils. This is associated to the undesired lipid oxidation that occurs when unsaturated fatty acids are exposed to light, oxygen, and heat. This is a major concern in food industry as it might result in undesired food quality deterioration involving reduction of nutritional components and off-flavors. The demand for nutritious and healthy animal and vegetable oils has been increased with a growth in population and economic progress. Therefore, researches for functional and nutritious edible oils has gained world attention on the technology to process edible oils. The use of ultrasound as a new technology in food processes is increasing due to its potential for changing materials and processing speed. This technique displays several advantages over conventional techniques in terms of time, energy consumption, and higher output. Ultrasonic processing is used in the food industry for numerous processes on high lipid containing food products in cutting, cooking, homogenization/emulsification, and microbial inactivation. The aim of this study was to investigate the effect of ultrasound time (0, 20, 40 and 60 min) on physicochemical properties of corn oil, soybean oil and kilka fish oil.
Materials and Methods
Commercial kilka fish oil, corn oil and soybean oilwere purchased from local market. All of the chemicals and reagents used were analytical reagent grade. Each oil was poured at 250 ml Beaker and then treated with an ultrasonic probe at a frequency of 20 kHz for a specified period of time. Oil chemical and physical properties such as acid value (mg/g), peroxide value (meq O2/kg), oxidative stability index (h), thiobarbituric acid value (mg/kg), conjugated diene value (%), fatty acid composition, fourier transform infrared (FTIR) spectroscopy and color parameters (L*, a*, b* and ∆E) were determined. Data analysis was done using SPSS software and completely random design.
Results and Discussion
The results of this study showed that with increasing the duration of ultrasound, acid value, peroxide value, TBA value and conjugate diene value, increased and the induction period decreased. On the other hand, ultrasound treatment led to increase palmitic acid, stearic acid, oleic acid, saturated fatty acids (SFA) and monounsaturated fatty acid (MUFA), and decrease linoleic acid, linoleic acid (and palmitoleic acid, eicosapentaenoic acid and docosahexaenoic acid in kilka fish oil), polyunsaturated fatty acid (PUFA), polyunsaturated fatty acid/saturated fatty acids (PUSFA/SFA), unsaturated fatty acid/saturated fatty acids (USFA/SFA), Cox value in corn, soybean, and kilka fish oils. Ultrasound did not change the fourier transform infrared spectroscopy but did change some color parameters. Sonication caused an increase in L* (more lightness) of corn oil, a decrease in a* (more greenness) of soybean oil, an increase in b* (more yellowness) of corn and soybean oils, and a decrease in ∆E compared to control samples. Probably, ultrasound causes destruction and isomerization of the double bands of pigments and as a result changes in color indices. According to the results of this study, ultrasound treatment accelerated the oxidation and degradation of oils and as a result, changed some of the physicochemical properties of the oil, which varied according to the type of oil.
Full Research Paper
Food Technology
Aliakbar Gholamhosseinpour; Saeed Zare
Abstract
Introduction
Cheese is a term that encompasses a diverse group of fermented dairy products produced globally, available in a variety of flavors, textures, and shapes. It is rich in proteins, minerals, and vitamins, all contributing to its high nutritional value. Among these, brined ultrafiltered ...
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Introduction
Cheese is a term that encompasses a diverse group of fermented dairy products produced globally, available in a variety of flavors, textures, and shapes. It is rich in proteins, minerals, and vitamins, all contributing to its high nutritional value. Among these, brined ultrafiltered cheeses are soft cheeses that undergo their ripening process in brine. In recent times, this type of cheese has gained popularity, securing a significant consumer market in our country. Food hydrocolloids, comprising polysaccharides and proteins, are extensively utilized in the food, and biomedical industries. They function as thickening agents, forming gels with controlled functionality and specific physical properties. Additionally, they act as stabilizers in various dispersions and serve as carriers for bioactive compounds. Many hydrocolloids, such as whey proteins or dietary fibers, also possess health-promoting properties and can provide essential nutrients necessary for maintaining human biological activity. Beyond their nutritional benefits, food hydrocolloids find applications in advanced materials like food packaging, biomedical materials, biopolymers, polymer electrolytes, mineral nanoparticle synthesis, and organic pollutant removal. Natural hydrocolloids are typically non-toxic and environmentally friendly. They are made naturally from plants, animals, algae, or microorganisms. They are employed to enhance the physicochemical, structural, rheological, and sensory properties of dairy products. Persian gum, derived from the almond tree (Amygdalus scoparia Spach), is one such natural hydrocolloid commonly used as an herbal remedy in Iran. It is commercially available in various colors, shapes, and sizes. Its low cost, availability, biodegradability, and capability to substitute stabilizers and emulsifiers have increased its utilization in the food and pharmaceutical industries.
Materials and Methods
After being received and initially cooled, raw cow milk underwent pasteurization and was stored for the ultrafiltration process. Persian gum (PG) was incrementally incorporated into a specific quantity of warm retentate and thoroughly blended. This mixture was then combined with the remaining retentate to produce retentates with PG concentrations of 0.03%, 0.05%, and 0.1%. These mixtures were then subjected to homogenization and pasteurization. Following these processes, the retentate was cooled to a temperature range of 35-40°C. It was then poured into containers for coagulation, to which microbial rennet and a starter culture comprising Lactobacillus lactis subsp. lactis, Lactococcus lactis subsp. cremoris, and Streptococcus thermophilus were added. After roughly 6 hours, once the curd pH dropped to 5.1, a 12% brine solution was introduced into the container. Finally, the containers were sealed and placed in a 4°C cold storage for microbial, physicochemical, and sensory evaluations over a 90-day storage period. Statistical analysis was conducted using the Minitab software (version 16.2.0.0 for Windows, Minitab Inc., Coventry, United Kingdom) at a 95% confidence level.
Results and Discussion
Based on the obtained results, during the storage period, no microbial spoilage (including coliforms, molds, and yeasts) was observed in the control and gum-containing samples. The ash content (%), gumminess (N), chewiness (Nmm), adhesiveness (Ns), and fracturability (N) of the samples increased initially up to day 45 and then decreased. The acidity (% lactic acid) of the samples continuously increased during the storage period, while the amount of fat (%) of samples showed a decreasing trend. An increase in gum concentration led to a significant decrease (p≤0.05) in the acidity (167.22 to 123.11 %), gumminess (8.35 to 1.30 N) and chewiness (216.19 to 38.83 Nmm) of the samples, while the ash content (3.69 to 3.92 %) and cheese adhesiveness (0.66 to 0.80 Ns) increased significantly (p≤0.05). Regarding sensory properties, color and appearance, and aroma scores of the cheeses were not significantly affected by the storage time. The interaction effect of time and gum concentration did not create a significant difference in texture and flavor scores, while their single effects were significant (p≤0.05). Overall acceptance of the samples was only significantly affected by the gum concentration (p≤0.05), and the interaction effect of time and concentration did not significantly affect the overall acceptance score. Finally, the cheese containing 0.5% gum received the highest sensory score compared to other samples, while the cheese containing 0.1% gum received the lowest sensory score. Considering the positive effect of Persian gum on various cheese properties, especially texture improvement, its utilization in industrial cheese production, as well as investigating its combined effects with other hydrocolloids, is recommended.
Full Research Paper
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.
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