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, ...
Read More
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
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 ...
Read More
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 Technology
Masoumeh Shokri; Mostafa Rahmati-Joneidabad; Mokhtar Heidari; Mousa Rasouli; Ahmad Zareh
Abstract
Introduction
Chitosan, as a bio-polymer, has many applications in agriculture. Coating fruits and vegetables with chitosan plays a positive role in increasing their shelf-life, since the chitosan coating reduce growth of fungi and preserves the quality of the fruits longer.
Materials and Methods
This ...
Read More
Introduction
Chitosan, as a bio-polymer, has many applications in agriculture. Coating fruits and vegetables with chitosan plays a positive role in increasing their shelf-life, since the chitosan coating reduce growth of fungi and preserves the quality of the fruits longer.
Materials and Methods
This study was conducted to evaluate the effect of chitosan treatments (0, 0.25, 0.5 and 1%) and storage time (0, 20, 40 and 60 days) on maintaining quantitative and qualitative parameters and shelf life of grape fruit of Fakhri cultivar. The experiments were factorial based on a completely randomized design with three replications. The fruits were stored for 2 months. Some characteristics of fruits including percentage of weight loss, percentage of berries abscission, percentage of decay of berries, browning of berries and biochemical characteristics including titratable acidity, ascorbic acid content, total phenol, enzymes activity including peroxidase (POD), phenylalanine ammonia-lyase (PAL) and polyphenol oxidase (PPO) were measured in order to investigate the best treatment.
Results and Discussion
The results showed that the traits under study were affected by different concentrations of chitosan, with the lowest percentage of weight loss associated with the concentration of 0.5% chitosan. Chitosan, by forming a semi-permeable membrane, regulates gases,and reduces the transfer of water from fruit tissues. The lowest amount of browning of berries was observed in the concentration of 0.5% chitosan. Chitosan is partly prevented from increasing the activity of brown-peroxidase in chitosan-treated fruits. There was no significant difference in concentration of 0.5% chitosan with 1% concentration. The lowest percentage of contamination and percentage of berries abscission was observed in 1% chitosan concentration. It seems that these treatments prevent the effects of ethylene levels and the formation of a swab layer at the site of fruit attachment to the cluster. The slightest increase in the titratable acidity and the lowest decrease of ascorbic acid was observed in the concentration of 1% chitosan. Higher levels of ascorbic acid in fruits that are coated with chitosan may be due to decreased oxygen levels and respiration inhibition. The highest total phenol was related to the control treatment, which may be due to the loss of chlorophyll and the onset of synthesis of phenolic compounds. The highest level of activity of PAL enzyme was observed in the concentration of 0.5% chitosan and the control. This enzyme is stimulated by various live and non-living stresses. In general, the highest activity of peroxidase enzyme was observed in the concentration of 0.5% chitosan and the highest activity of polyphenol oxidase in 1% concentration of chitosan.
Conclusion
It seems that the concentration of 1% chitosan can improve the quality of fruits for a longer time while increasing the shelf life of fruit.
Food Biotechnology
Behrooz Alizadeh Behbahani; Mohammad Noshad; Mostafa Rahmati-Joneidabad
Abstract
[1]Introduction: Oxidation and food pathogens are considered two important and influential factors affecting food quality and health. Recently, due to the increasing demand for natural products, the application of synthetic preservatives to control microbial growth and lipid oxidation have been decreased ...
Read More
[1]Introduction: Oxidation and food pathogens are considered two important and influential factors affecting food quality and health. Recently, due to the increasing demand for natural products, the application of synthetic preservatives to control microbial growth and lipid oxidation have been decreased significantly. Therefore, natural antioxidant and antimicrobial compounds are receiving more 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. Furthermore, secondary metabolites in plant extracts and essential oils are able to control and inhibit free radical-mediated reactions. The olive tree (Olea europaea) is an evergreen plant that grows in tropical and subtropical regions. Iran is one of the most important olive growers in the world due to its suitable conditions for olive cultivation. The leaves of the olive plant have a high potential for the production of various products such as tea and extracts. Olive leaf extract can be used as a raw material in the production of various products, due to exhibiting various biological activities such as antimicrobial and antiviral activity, lipid stabilizer, blood pressure regulator, antioxidant activity, and free radical scavenger. The leaves of the olive tree also contain various phenolic compounds, mainly Oleuropein and hydroxytyrosol, with antioxidant and antimicrobial activities. Therefore, in this study, the amount of phenolic and flavonoid compounds of olive leaf ethanolic extract and its antioxidant effect and antimicrobial properties on Escherichia coli, Enterobacter aerogenesis, Bacillus cereus and Listeria innocua were investigated. Materials and Methods: The olive leaf ethanolic extract was prepared through maceration method and its total phenolic content (Folin-Ciocalteu method), total flavonoids content (aluminum chloride colorimetric assay), antioxidant activity (ABTS and DPPH free radical scavenging methods), and antimicrobial effect on E. coli, E. aerogenesis, B. cereus and L. innocua (based on disk diffusion agar, well diffusion agar, minimum inhibitory concentration, and minimum bactericidal concentration) were determined according to standard methods. Data were analyzed by SPSS software through one-way ANOVA and Duncan test at p<0.05. Results and Discussion: The ethanolic extract of olive leaves contained 176.58 ± 0.72 mg GAE/g total phenol and 69.85 ± 0.26 mg QE/g total flavonoids. In addition, ethanolic extract of olive leaf was able to inhibit free radicals DPPH (70.62 ± 0.59%) and ABTS (76.15 ± 0.43%). The antimicrobial results showed that the antimicrobial effect of the extract depended on its concentration and type of bacteria. Antimicrobial effect was increased as a function of ethanolic extract, and Gram-positive bacteria (B. cereus and L. innocua) were more sensitive to ethanolic extract of olive leaf than Gram-negative bacteria (E. aerogenesis and E. coli). Generally, B. cereus and E. aerogenesis were the most sensitive and resistant microbial strains to ethanolic extract of olive leaf, respectively.The results of this study showed that the high antioxidant and antimicrobial activity of olive leaf ethanolic extract is mainly due to its phenolic and flavonoid compounds. Olive leaf ethanolic extract was able to neutralize DPPH and ABTS free radicals. Also, Gram-positive bacteria were more sensitive to ethanolic extract of olive leaf than Gram-negative bacteria. In general, the ethanolic extract of olive leaf can be used as a nutraceutical to control or prevent the growth of spoilage/infection-causing microorganisms and free radical reactions in food and the human body. However, more in-depth studies are needed to determine the mechanism of antimicrobial and antioxidant effects of olive ethanolic extract in vitro and in vivo.
Food Biotechnology
Mostafa Rahmati-Joneidabad; Behrooz Alizadeh Behbahani; Mohammad Noshad
Abstract
[1]Introduction: Economic losses can occur due to the growth of fungi on foods that lead to food spoilage and plant diseases. Fruits and vegetables are often exposed to microbial activity, caused by pathogenic fungi, during post-harvest storage. Diseases of food origin are a growing public health problem. ...
Read More
[1]Introduction: Economic losses can occur due to the growth of fungi on foods that lead to food spoilage and plant diseases. Fruits and vegetables are often exposed to microbial activity, caused by pathogenic fungi, during post-harvest storage. Diseases of food origin are a growing public health problem. Thus, food safety has become a major public concern as microbial contamination increases the risk of foodborne illnesses and shortens the shelf life of foods. Infection with fungi such as Aspergillus, Rhizopus, and Penicillium species is considered as the primary cause of rapid spoilage of fresh produce, which reduces their quality and shelf life. Synthetic fungicides have been applied to solve this problem for many years. Nonetheless, the adverse effects of synthetic chemicals on human health and the emergence of fungicide-resistant strains have motivated the scientists and food industries to find out safe preservatives to control postharvest rot/diseases. On this point, natural antimicrobial agents such as plant extracts and essential oils are gaining more and more interest. In this study, we used Levisticum officinale Koch essential oil, which its antimicrobial and antioxidant activity has been reported in literatures. Materials and Methods: L. officinale Koch essential oil was obtained by hydrodistillation method and its total phenol content, total flavonoids, antioxidant activity (based on DPPH and ABTS free radical scavenging and β-carotene bleaching tests) and its antifungal effect against fungi causing apple and orange rotting (Alternaria alternata, Penicillium expansum, Penicillium digitatum, Penicillium italicum, and Botrytis cinerea) were examined according to antimicrobial tests of disk diffusion agar, well diffusion agar, minimum inhibitory concentration, and minimum fungicidal concentration. Results and Discussion:L. officinale Koch essential oil contained 61.27 ± 0.34 mg GAE/g and 20.14 ± 0.21 mg QE/g total phenol and flavonoids, respectively. Its antioxidant activity, based on DPPH free radical scavenging, ABTS free radical scavenging, and β-carotene bleaching inhibition were 69.72 ± 0.65%, 78.54 ± 0.3% and 57.50 ± 0.41%, respectively. L. officinale Koch essential oil was effective against all fungal species and the highest susceptibility was observed for Penicillium expansum. According to the results, L. officinale Koch essential oil can be used as a natural antifungal agent to prevent post-harvest diseases of fruits and vegetables.
Food Biotechnology
Mostafa Rahmati-Joneidabad; Behrooz Alizadeh Behbahani
Abstract
Introduction: Apple fruit is highly susceptible to fungal spoilage by Penicillium, Botrytis, and Alternaria species. Currently, the use of synthetic fungicides is considered to be the most accessible method of managing and controlling post-harvest diseases of vegetables and fruits, especially apples. ...
Read More
Introduction: Apple fruit is highly susceptible to fungal spoilage by Penicillium, Botrytis, and Alternaria species. Currently, the use of synthetic fungicides is considered to be the most accessible method of managing and controlling post-harvest diseases of vegetables and fruits, especially apples. However, increasing concern about environmental pollution, the toxicity, and the resistance of fungal pathogens to synthetic fungicides have resulted in an increased demand for less dangerous methods. In this regard, the use of compounds of natural origin that have potential antifungal activity (such as herbal essential oils), can be an effective solution to control and prevent post-harvest diseases of vegetables and fruits. In this study, the potential antifungal activity of Thymus daenensis essential oil was evaluated against fungi species causing apple rot (i.e., Penicillium expansum, Alternaria alternata, and Botrytis cinerea). The chemical compounds, total phenol and flavonoids content, and antioxidant activity of the essential oil were also determined. Materials and Methods: In this study, the essential oil of T. daenensis was extracted by the hydrodistillation method and its main chemical compounds were identified and quantified by gas chromatography coupled to mass spectrometry apparatus. Total phenols and flavonoids content of the essential oil were measured using the Folin-Ciocalteu and Aluminum chloride colorimetric methods, respectively. The in-vitro antioxidant activity of T. daenensis essential oil was evaluated based on the DPPH/ABTS free radical scavenging activity, beta-carotene bleaching, and ferric reducing antioxidant power (FRAP) assays. The antifungal effect of the essential oil against Penicillium expansum, Alternaria alternata, and Botrytis cinerea was investigated by the disk diffusion agar (DDA), well diffusion agar (WDA), minimum inhibitory concentration (MIC), and minimum fungicidal concentration (MFC). Results and Discussion: The T. daenensis essential oil was rich in thymol (69.88%), γ-terpinen (8.49%), p-cymene (8.20%), and carvacrol (3.55%). In addition, the total phenol and flavonoids content of the essential oil were 91.45 mg GAE/g and 42.28 mg QE/g, respectively, which had an important role in its antioxidant activity. The T. daenensis essential oil had remarkable DPPH free radical scavenging activity (IC50= 29.30 mg/ml), ABTS free radical scavenging activity (IC50 = 22.68 mg/ml), beta-carotene bleaching inhibitory effect (62.22%), and ferric reducing antioxidant power (30.10 μM QE/g), revealing the electron/hydrogen donating ability of the essential oil. Antifungal results showed that P. expansum was the most sensitive fungi species to the essential oil and lower concentrations of the essential oil were required to inhibit the growth of or kill the species, due to the presence of phenolic compounds (such as thymol and carvacrol) in the oil. Indeed, reactive aromatic nucleus and phenolic OH groups in the structure of phenolic compounds can form hydrogen bonds with –SH groups at the active sites of target enzymes, leading to the deactivation of the fungal enzymes. In addition, the lipophilic nature of the essential oils makes them to be highly absorbed by the lipophilic mycelia and consequently suppress the growth of fungi species. Based on the results, the T. daenensis essential oil could be used as a natural antifungal agent and synthetic fungicide substitute to prevent the growth of pathogenic fungi on apple fruit or other food products and increase their shelf-life.
