Food Chemistry
Zeinab Nooshi Manjili; Alireza Sadeghi Mahoonak; Vahid Erfani Moghadam; Mohammad Ghorbani; Hoda Shahiri Tabarestani
Abstract
Introduction
Seeds and nuts have received increasing attention due to their nutritional value and the high therapeutic properties of their bioactive compounds. Most of the seeds are used as nuts, and some of them are considered agricultural waste. Pumpkin seeds have a high content of protein (30–40% ...
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Introduction
Seeds and nuts have received increasing attention due to their nutritional value and the high therapeutic properties of their bioactive compounds. Most of the seeds are used as nuts, and some of them are considered agricultural waste. Pumpkin seeds have a high content of protein (30–40% in terms of dry matter). Proteins are among the vital health-giving components that provide nitrogen, essential amino acids and energy necessary for normal cells. Pumpkin seeds are a good source of amino acids such as valine, histidine, isoleucine, leucine, threonine and methionine. Protein hydrolysate is a mixture of peptides and amino acids that can show antioxidant, antimicrobial, anticancer, antidiabetic and antihypertensive properties. During hydrolysis, proteins are broken into small peptides and amino acids. Since enzymatic hydrolysis is performed in relatively mild conditions and no amino acid damage occurs, this type of hydrolysis is preferred over acid and alkaline hydrolysis. Hydrolysates obtained from pumpkin seed protein have bioactive properties, especially antioxidant activity. Pretreatment of proteins before enzymatic hydrolysis acts to improve the release of bioactive peptides from different proteins. Pretreatment can facilitate the unfolding the structure of proteins and thus increase the access of enzymes to peptide bonds. The main properties of microwaves usually show three characteristics: penetration, reflection and absorption. Microwave assisted enzymatic hydrolysis can shorten the time and improve the speed of the reaction. The purpose of this research was to investigate the antioxidant activity of pumpkin seed protein hydrolysates (Cucurbita maxima L.) by alcalase enzyme in two conditions: without pretreatment and using microwave pretreatment.
Material and Methods
In this study, Pumpkin (Cucurbita maxima L.) was purchased from the local market of Astane Ashrafieh in Gilan province. The seeds were scooped manuallyand then dried in an oven at 50°C for 72 hours. After the production of protein concentrate from pumpkin seeds, the chemical properties of the concentrate, such as the amount of fat, protein, ash and moisture, were measured. The isolated pumpkin seed solution was exposed to microwave energy with a power of 450-900 watts for 30–90 seconds and was used as a substrate solution in enzymatic hydrolysis experiments. It should be noted that after measuring the total antioxidantactivityr for different powers and times of microwave pretreatment, the power of 600 watts for 60 seconds was selected and applied before enzymatic hydrolysis. Enzymatic hydrolysis was done by alcalase enzyme with a concentration of 0.5 to 2.5% compared to the protein substrate during 20 to 190 minutes, and the optimum temperature and pH of alcalase were determined in order to produce hydrolysates with antioxidant activity. Antioxidant activity was measured by using DPPH free radical inhibition, total antioxidant activity and iron chelation activity methods.
Result and Discussion
Bioactive peptides produced by the enzymatic hydrolysis of proteins have significant antioxidant properties. Pumpkin seeds can be used as a rich source of nutrients and bioactive compounds in various food industries. The results showed that the maximum amount of antioxidant activity without pre-treatment was achieved in 165 minutes with a 2.2% ratio of E/S by using DPPH free radical scavenging activity (40.5%), total antioxidant power (0.79), and iron chelation activity (96.2%) methods. By using microwave pre-treatment, the maximum amount of antioxidant activity was achieved in a shorter time and with less enzyme (105 minutes and E/S ratio 1.5%) using DPPH free radical scavenging (52%), total antioxidant power (0.711), and iron chelation activity (93%). Therefore, it can be concluded that using microwave assisted enzymatic hydrolysis , in addition to achieving hydrolysates with proper antioxidant activity, is a suitable method to save time and reduce enzyme concentrations used in enzymatic hydrolysis.
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 Chemistry
Fatemeh Ghannadiasl; Zahra Jahdoust
Abstract
In recent years, the use of propolis in food products has received attention owing to its functional role. This study was conducted to investigate the effect of different concentrations of propolis extract on the total polyphenol content and antioxidant activity of raw milk. For this purpose, an aqueous ...
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In recent years, the use of propolis in food products has received attention owing to its functional role. This study was conducted to investigate the effect of different concentrations of propolis extract on the total polyphenol content and antioxidant activity of raw milk. For this purpose, an aqueous extract of dry propolis was prepared and stored in dark-colored bottles at 4 °C until the day of experiments. The propolis extract was added to raw milk in concentrations of 0, 4.7, 9.1, 16.6, and 28.5%. Total phenolic content and antioxidant activity were measured using the colorimetric Folin-Ciocalteu method and DPPH assay, respectively. Measurements were performed on the first day at zero hour and after 6 and 24 h of treatment, and the storage temperature was maintained at 5°C until analyzed. The amount of total polyphenol increased with the increase in the concentration of propolis extract in the treated milk in 0 hour; accordingly, the lowest and the highest amounts of total polyphenol were related to control milk and milk containing 28.5% propolis extract, respectively. A decreasing trend was observed in total polyphenol in the control sample and raw milk containing 4.7% propolis extract during 24 hours. There was an increase in total polyphenol content in raw milk containing 9.1% and 16.6% propolis extracts, the trend of changes in raw milk containing 28.5% extract was insignificant. The addition of propolis extract caused an increase in the antioxidant activity and total phenolic content in raw milk. According to the results, it is recommended to carry out more studies to clarify the functions of propolis's total polyphenol content and its interaction with milk proteins.
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
Shabnam Parichehreh; Gholamhossein Tahmasbi; Mohammad Eslampanah; Pejvak Khaki
Abstract
Iranian men are at risk of developing gastrointestinal cancer caused by H. pylori. It is very imperative to find effective methods to control this bacterium as there are currently no very effective treatments for it. Honey has been shown to have antimicrobial properties against various pathogens. ...
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Iranian men are at risk of developing gastrointestinal cancer caused by H. pylori. It is very imperative to find effective methods to control this bacterium as there are currently no very effective treatments for it. Honey has been shown to have antimicrobial properties against various pathogens. This study analyzed 15 honey samples from A. florea bees, collected from different floral and geographical origins, for their antimicrobial efficacy against H. pylori. Using atomic absorption measurements, the honey samples were also tested for their phenolic and flavonoid content, protein concentration, and mineral content. Antioxidant activity was determined using the FRAP, DPPH, and ABTS methods. The antibacterial activity of honey samples was investigated both in-vitro and in-vivo in the gastrointestinal tract of mice. Statistical analysis revealed a significant positive correlation between antioxidant activity and antibacterial activity. All honey samples showed antimicrobial activity in-vitro, among which jujube honey from Bushehr exhibiting the highest activity. Differences in antioxidant and antimicrobial activities were likely due to the flora of the plants and the geographic region from which the honey was harvested. Based on these results, A. florea honey may be used in the prevention and treatment of H. pylori-associated infections and inflammation of the gastrointestinal tract. This feature can be applied to the control of Helicobacter pylori along with other available measures.
Food Biotechnology
Ehsan Safari; Hassan Barzegar; Hossein Jooyandeh; Behrooz Alizadeh Behbahani; Mohammad Noshad
Abstract
Introduction
The addition of chemical preservatives increases the shelf life of food products, but prolonged and indiscriminate use of chemical preservatives increases the resistance of microorganisms and the health risks associated with theiruptake. Medicinal plants have a wide variety in the ...
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Introduction
The addition of chemical preservatives increases the shelf life of food products, but prolonged and indiscriminate use of chemical preservatives increases the resistance of microorganisms and the health risks associated with theiruptake. Medicinal plants have a wide variety in the world as well as in Iran. In recent years, the use of natural preservatives such as plant extracts and essential oils, due to their importance and role in controlling the growth of pathogenic microorganisms, has been proposed as an alternative to chemical preservatives. Black pepper is an aromatic medicinal plant. The specific properties of black pepper essential oil, such as its antimicrobial and antioxidant activity, have also been confirmed. Amphotericin B is one of the effective antibiotics for treating infections caused by pathogenic fungi. The mechanism of action of amphotericin B is to destroy fungal cells in such a way that by binding to ergosterol in the cell membrane of fungi, it creates pores and eventually destroys them. One of the most important and common antibiotics used in the treatment of infections caused by pathogenic bacteria is chloramphenicol. This antibiotic is effective against gram-positive and gram-negative bacteria due to its broad spectrum. The aim of this study was to identify bioactive functional groups, antioxidant potential, phenol and total flavonoid compounds and to evaluate the antimicrobial activity of black pepper extract against Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, Bacillus coagulans and Aspergillus niger.
Materials and Methods
In this study, the antimicrobial effect of black pepper aqueous extract was investigated against Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, Bacillus coagulans and Aspergillus niger by disc diffusion agar, well diffusion agar, minimum inhibitory concentration, and minimum bactericidal concentration methods. Total phenol and flavonoid contents of the species were determined by Folin-Ciocalteu and AlCl3 assays, respectively. Three biochemical assays, namely 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2-azinobis 3-ethyl-benzothiazoline-6-sulfonic acid (ABTS) free radical scavenging and β- caroten/linoleic acid activity systems, were used to evaluate antioxidant activity. Identification of functional groups as well as the structure of organic compounds in black pepper extract was also performed by Fourier transform infrared spectroscopy (FTIR). To evaluate the synergistic effect of black pepper extract in combination with amphotericin B and chloramphenicol antibiotics, Sub-MIC was used.
Results and Discussion
The peaks observed in aqueous black pepper extract confirmed the presence of O-H (3000-3500 cm-1), C-H (2800-3000 cm-1), C=O (1613.62-1633.52 cm-1) and C-O (100.57-1038.82 cm-1) functional groups of bioactive compounds. The total phenol and flavonoids content of the extract were 45.12 mg GAE/g extract and its flavonoid content was 29.66 mg QUE/g extract which had an important role in its antioxidant activity. The aqueous black pepper extract had remarkable DPPH free radical scavenging activity (IC50=32.37 μg/ml), ABTS free radical scavenging activity (IC50=28.45 μg/ml) and beta-carotene bleaching inhibitory effect (46.45%), revealing the electron/hydrogen donating ability of the essential oil. The results of measuring the antimicrobial activity of extract by disk diffusion and agar well showed that black pepper extract showed more antimicrobial effect on gram-positive bacteria Staphylococcus aureus and Bacillus coagulans than gram-negative bacteria Escherichia coli and Pseudomonas aeruginosa. This could be due to the difference in their cell wall structure. Aspergillus niger is the most sensitive species to aqueous black pepper extract. The minimum inhibitory concentrations of extract for Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, Bacillus coagulans and Aspergillus niger were equal to 32, 16, 4, 8 and 4 mg/ml, respectively. The minimum bactericidal concentration of black pepper extract for two bacterial species, Escherichia coli and Pseudomonas aeruginosa was more than 512 mg/ml. Also, the minimum bactericidal concentration for Staphylococcus aureus and Bacillus coagulans was 128 and 256 mg/ml, respectively, and 128 mg/ml for Aspergillus niger. The results of interaction of black pepper extract with chloramphenicol antibiotic showed that the Escherichia coli, Pseudomonas aeruginosa and Staphylococcus aureus were synergistic, but antagonism was observed for the gram-positive Bacillus coagulans.
Food Engineering
Behnaz Vafania; Milad Fathi; Sabiheh Soleimanian Zad
Abstract
The aim of this research was to investigate the efficiency of nozzle-less electrospinning for encapsulation of ajwain essential oil (as a hydrophobic bioactive) using two hydrocolloids (chitosan/gelatin) in order to enhance its antioxidant properties and stability for food applications. Nanofibers were ...
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The aim of this research was to investigate the efficiency of nozzle-less electrospinning for encapsulation of ajwain essential oil (as a hydrophobic bioactive) using two hydrocolloids (chitosan/gelatin) in order to enhance its antioxidant properties and stability for food applications. Nanofibers were spun using chitosan/gelatin in ratios of 1:6, 1:8 and 1:10 and ajwain concentrations of 20 and 40%. Solution properties (i.e. viscosity and electrical conductivity) were measured. Encapsulation efficiency and loading capacity data illustrated an enhancement with increasing of essential oil concentration. Fibers diameter and morphology were studied by scanning electron microscopy (SEM). The chitosan/gelatin nanofibers with ratio of 1:6 containing 40% essential oil had the highest encapsulation efficiency (99.9%), loading capacity (39.9%) and the smallest diameter (146 nm). Attenuated total reflection Fourier-transform infrared spectroscopy (ATR-FTIR) proved that during electrospinning, no any chemical interaction was occurred between ingredients and differential scanning calorimetry (DSC) data showed that essential oil was well encapsulated in nanofibers. Antioxidant properties were analyzed by 2,2-diphenyl-1-picrylhydrazylradical and approved the efficiency of encapsulation for protection of antioxidants.
Food Technology
Zahra Sadri Saeen; Mohammadreza Khani; Vajiheh Fadaei Noghani
Abstract
[1]Introduction: Butter is a type of dairy product made of sweet cream or sour cream. It is a perishable food that can be spoiled due to chemical changes during storage. Rancidity is one of the main problems caused by lipolysis and oxidation of fatty acids, which cause off-flavor and reduce the nutritional ...
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[1]Introduction: Butter is a type of dairy product made of sweet cream or sour cream. It is a perishable food that can be spoiled due to chemical changes during storage. Rancidity is one of the main problems caused by lipolysis and oxidation of fatty acids, which cause off-flavor and reduce the nutritional quality of butter. By adding low concentrations of antioxidant compounds, autooxidation can be prevented or delayed. It is also possible to increase the shelf life of butter by adding antioxidants. However, the carcinogenic effect of some synthetic antioxidants and consumer preference has led manufacturers to use more natural antioxidants. Chia seeds contain significant amounts of protein, fat, carbohydrates, minerals, and vitamins. Moreover, many bioactive compounds with high antioxidant potential are found in chia seeds such as phenolic acids, flavonoids, tocopherols, and sterols. Therefore, the present study was conducted to investigate the effects of chia seed extract in sweet cream butter to improve its chemical and sensory properties during refrigeration storage. Materials and Methods: For this purpose, the alcoholic extract of chia seed was prepared by adding chia seed powder to 70% ethanol (5% w/v) with stirring for 24 h, at room temperature. The filtered extracts were concentrated with a rotary evaporator. The concentrated mixture was dried in an oven at 40 °C and kept in an amber glass container in the refrigerator at 4 °C until the experiment was performed. Total phenolics content and antioxidant activity of chia seed extract were evaluated by the Folin–Ciocalteu colorimetric method using gallic acid as standard and for free radical scavenging ability by DPPH (2,2-diphenyl-1-picryl-hydrazyl) method, respectively. Then, chia seed extract was added to butter with different percentages (0.05, 0.1, 0.25, and 0.5%) and its effects on chemical properties including acidity, acid value, peroxide value, and thiobarbituric acid were evaluated for two months at 15-day intervals in refrigerated storage. Also, sensory properties including color, odor, taste, texture, and overall acceptance of butter samples were assessed using 15 untrained evaluators based on a 5-point hedonic test as above conditions. The results were reported as means± standard deviation and they were analyzed with analysis of variance using the software SPSS version 14. Statistical differences were analyzed by Duncan’s multiple range test (p<0.05). Results and Discussion: The results of total polyphenols content were 1108.78 ± 111.79 mg gallic acid per 100 g of extract and radical scavenging activity of chia seed extract in the concentration range of 4 to 20% was 35.17 ± 0.47 to 64.92 ± 2.95%. Also, the efficient concentration (EC50) of chia seed extract was 12.13 ± 0.59 mg/L in this study. It is known that the smaller the EC50, it will be the greater the antioxidant or free radical scavenging activity. According to the results, it was found that the concentration of chia extract has a significant effect on free radical scavenging (p<0.05) so that with increasing the concentration of the extract, its inhibitory properties increased. The results showed that the addition of different concentrations of chia seed extract and storage time were significant on the acidity and acid value of butter samples so that with increasing the amount of chia seed extract in treatments, the amounts of acidity and acid value increased significantly (p<0.05). Also, the acidity and acid value in all samples of butter increased significantly with increasing storage time during refrigeration (p<0.05). However, the amount of these two indices in treatments containing chia extract increased at a slower rate than the control sample during storage time, which could be due to the effect of phenolic compounds in chia seed extract in controlling the activity of lipolytic enzymes. Moreover, the results revealed that with increasing the concentration of the chia seed extract from the 15th day to the end of the storage period, the amounts of peroxide value and thiobarbituric acid of butter treatments significantly decreased compared to the control sample (p<0.05). This is due to the antioxidant effects of phenolic compounds in chia seed extract that delay the oxidation process. In this study, all chemical indices increased significantly during the storage time (p<0.05). All the samples in evaluated sensory properties were significantly different from the control sample (except odor) during 60 days of storage (p<0.05), in this way treatments had better sensory scores in color and taste properties compared to the control. In general, a concentration of 0.5% chia extract delayed oxidative damage, but in terms of sensory evaluation, a treatment containing 0.25% chia extract is selected and introduced as the most desirable treatment.
Food Chemistry
Seyed Hamidreza Ziaolhagh; Sima Zare
Abstract
Walnuts have a high nutritional value because of their high levels of essential compounds for human health. Phenolic compounds have beneficial properties, including anti-cancer and antimicrobial properties. In this study, the amount of the extracted antioxidants from different parts of walnut, ...
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Walnuts have a high nutritional value because of their high levels of essential compounds for human health. Phenolic compounds have beneficial properties, including anti-cancer and antimicrobial properties. In this study, the amount of the extracted antioxidants from different parts of walnut, including the walnut kernel, hard shell and green husk by ethanol and water was compared with those of the ultrasound-assisted extraction. This study was performed by determining the amount of polyphenols present and the free radical scavenging power of DPPH. The results showed that the effect of all factors was statistically significant at 99% statistical level. The highest rate of extraction of phenolic compounds (1.09 mg Gallic acid/g) and the highest rate of free radical scavenging of DPPH (6.86%) was related to the use of ethanol solvent for extraction. It was also shown that the hard walnut shell has the highest amount of phenolic compounds (1.1 mg Gallic acid per gram of extract) and the walnut kernel has the highest antioxidant properties (7.99%). Ultrasonic pretreatment increased the extraction efficiency of phenolic compounds and antioxidant properties so that this process increased the extraction of phenolic compounds from the green husk of walnut by 1.22 mg Gallic acid/g and increased the antioxidant properties of the kernel walnut by 13.51% compared to other parts.
Elnaz Saffari Samani; Hossein Jooyandeh; Behrooz Alizadeh Behbahani
Abstract
Introduction: Shirazi thyme is a perennial herbaceous plant related to Lamiaceae family growing in central and southern regions of Iran. This study aimed to assess chemical composition, bioactive functional groups, antioxidant potential, total phenol, and total flavonoids of Shirazi thyme essential ...
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Introduction: Shirazi thyme is a perennial herbaceous plant related to Lamiaceae family growing in central and southern regions of Iran. This study aimed to assess chemical composition, bioactive functional groups, antioxidant potential, total phenol, and total flavonoids of Shirazi thyme essential oil (STEO) and also to evaluate its cell toxicity effect against the colorectal cancer cell line (HT29). Materials and Methods: The chemical composition of STEO was identified by gas chromatography-mass spectrometry. The bioactive functional groups of STEO were measured by Fourier transform infrared at spectra range of 500- 4000 cm-1. The total phenol and total flavonoids of STEO were determined by folin- ciocalteu and aluminum chloride colorimetric method, respectively. MMT method was performed to measure the cell toxicity of STEO against the colorectal cancer cell line (HT29). The cells were cultured on DMEM high glucose medium supplemented with 10% fetal bovine serum and penicillin/streptomycin and incubated at 37°C with 95% relative humidity and 5% CO2 concentration. The antioxidant activity of STEO was evaluated by DPPH and ABTS free radicals scavenging assays. Duncan test at 5% probability and SPSS software (version 18) was performed to compare the means of obtained results. Results and Discussion: Based on GC/MS spectrometry, a total of 29 constituents were identified and quantified in the STEO representing more than 99% of total constituents. Thymol with 39.3% and Carvacrol with 30% were the most constituents of STEO. The other major compound of STEO were Benzene (8.52%), γ-Terpinene (5.27%), and Caryophyllene (2.97%). The presence of peak at a wavelength of 320- 1000 cm-1 demonstrates O-C bound that could be related to organic compounds such as alcohols, carboxylic acids, esters, and ethers. The peaks occurred at spectral range between 2800- 3000 cm-1 (particularly at 2869.6 up to 2960.8 cm-1) are related to the stretching mode of C-H bounds and are mostly associated with alcoholic compounds in the essence. The amount of total phenol and flavonoids of STEO were 64.05 mg gallic acid equivalent/g and 11.68 mg quercetin equivalent/g, respectively. Results obtained from antioxidant activity of STEO with DPPH and ABTS free radicals scavenging showed that by increasing of STEO, the inhibition level of free radicals was enhanced. The inhibition percent of free radicals by using DPPH and ABTS at 1000 ppm concentration were 63.69% and 64.33%, respectively. The cell toxicity results of different STEO concentrations against the cell line HT29 revealed that survival of HT29 cells at 1, 3.125, 6.25, 12.5, 25, 50, 100 and 200 ppm of STEO were 100, 70.15, 61.19, 59.33, 38.83, 25.68, 20.65 and 12.2%. According to the results of this study, as the concentration of STEO increased, its effect on the cell line HT29 enhanced and the cell percentage viability decreased. Some antioxidant activity of STEO could be interrelated to its phenolic compounds. Based on the results of antioxidant activity, the amount of total phenol and flavonoids and the effect of STEO on cell toxicity against the cell line HT29, it seems that the use of STEO is applicable in the pharmaceutical and food industries
Nafiseh Karimi; Rezvan Pourahmad; Salman Taheri; Orang Eyvazzadeh
Abstract
Introduction: Yogurt contains valuable compounds, some of which enter yogurt whey and if discarded, remains unused. Yogurt whey has a high nutritional value due to its high quality biological proteins which can be a good source of bioactive peptides. Bioactive peptides are food-derived peptides that ...
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Introduction: Yogurt contains valuable compounds, some of which enter yogurt whey and if discarded, remains unused. Yogurt whey has a high nutritional value due to its high quality biological proteins which can be a good source of bioactive peptides. Bioactive peptides are food-derived peptides that are small in size and usually consist of 3- 20 amino acids. These peptides are considered as functional ingredients. Bioactive
peptides have antioxidants and antimicrobial properties. The aim of this study was to investigate the effect of adding bioactive peptide derived from enzymatic hydrolysis of yogurt whey on physicochemical, sensory and microbial properties of doogh during storage.
Materials and Methods: In this study, peptide derived from tryptic hydrolysis of yogurt whey protein fractionated by RP- HPLC was used. Minimum inhibitory concentration (MIC) and Minimum bactericidal concentration (MBC) of this peptide were determined against Staphylococcus aureus and Escherichia coli. This peptide was incorporated to heated doogh at concentrations of 12, 20, 24, 40, 48, and 80 mg/mL. Moreover, doogh samples were inoculated with 106 CFU/mL Staphylococcus aureus and Escherichia coli. Doogh samples were stored for two months. During 60 days storage, bacterial count, pH, acidity, ABTS radical cation inhibitory activity and sensory properties (taste, odor, texture, color and overall acceptance) of doogh samples were studied.
Results and Discussion: The MIC of yogurt whey peptide against Staphylococcus aureus and Escherichia coli was 12.2 and 24.4 mg/mL, respectively. Moreover, the MBC of yogurt whey peptide against Staphylococcus aureus and Escherichia coli was 12.2 and 48.8 mg/mL, respectively. Addition of this peptide to doogh showed that during storage period, the Staphylococcus aureus and Escherichia coli counts, pH and ABTS cation radical inhibitory activity of the samples were significantly decreased, but acidity was increased (p<0.05). The peptide of yogurt whey showed good antioxidant and antibacterial activities in doogh samples. By increasing the level of peptide in samples, the ABTS cation radical inhibitory activity was significantly increased (p<0.05). During storage, the control sample (without bioactive peptide) showed the highest reduction in antioxidant activity and the lowest reduction was related to the sample containing 48.8 mg/mL bioactive peptide. The ABTS cation radical inhibitory activity of the control sample and sample containing 48.8 mg/mL bioactive peptide was 9.72 and 3.66 Unit/mL, respectively on the 60th day. By increasing the levels of bioactive peptide, pathogenic bacteria counts were decreased (p<0.05). The sample containing the highest level of peptide (48.8 mg/mL) was free of Staphylococcus aureus and E. coli on the 20th day of storage. The control sample and samples containing 12.2 and 24.4 mg/mL bioactive peptide were free of these pathogenic bacteria on the 60th and 40th days, respectively. The highest rate of acidity and pH changes was related to the control sample and sample containing 48.8 mg/mL bioactive peptide had the lowest changes during storage. The acidity of control sample and sample containing 48.8 mg/mL bioactive peptide was 0.68 and 0.56% lactic acid, respectively on the 60th day.The results of sensory evaluation showed that in the control sample and sample containing the lowest level of peptide (12.2 mg/mL), the score of sensory characteristics decreased during the storage period, however, the use of the highest level of yogurt whey peptide (48.8 mg/mL) in the doogh formulation was able to reduce the rate of loss of sensory properties and maintain product quality over time. The sample containing 48.8 mg/mL bioactive peptide had the highest score of overall acceptability. Finally, the concentration of 48.8 ppm peptide can be considered as the best level to enrich the doogh in terms of physicochemical, microbial and sensory properties. Therefore, it is concluded that bioactive peptide derived from yogurt whey can be used as a natural antioxidant and antimicrobial agent in fermented dairy products like doogh.
Sara Forouzandeh; Mohammad Fazel
Abstract
[1]Introduction: Nowadays, various methods have been developed to transfer and improve the absorption of lipophilic compounds in food in the form of coating. Colloidal emulsion-based systems are widely used in commercial systems. Chia seed oil is an oil rich in unsaturated fatty acids, especially omega ...
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[1]Introduction: Nowadays, various methods have been developed to transfer and improve the absorption of lipophilic compounds in food in the form of coating. Colloidal emulsion-based systems are widely used in commercial systems. Chia seed oil is an oil rich in unsaturated fatty acids, especially omega 3 and omega 6, which can be used as the oily phase of nanoemulsions. The aim of this study was to investigate the fatty acid composition of chia seed oil and the effect of oil to water ratio and emulsifier on the properties of nanoemulsions of this oil. Materials and Methods: Clean chia seeds were purchased as a pack from Zistfa Company and all other chemicals were purchased from Marack, Pars Shimi and Dr. Majelli companies. By using the oil set machine, the seeds were treated by cold pressing method and oil extraction efficiency was calculated .Gas chromatography (GC) was used to identify and measure the fatty acid composition of chia seed oil. In this study, nanoemulsions were produced in three levels of oil to water (20%, 35% and 50%) and in three levels of oil emulsifier (5%, 10% and 15%).To produce nanoemulsions, the aforementioned ratios were first calculated and determined .Then, Weigh the tweens 20 and 80 with chia seed oil and water and mix the emulsifiers with the chia seed oil on the stirrer. Then a mixture of 20 and 80 tweens and oil was added dropwise to the weighed distilled water. The mixture was stirred gently by a magnet. After this step, the mixture is placed in the refrigerator to reduce its temperature. After this time, it was placed in an ice bucket and placed in an ultrasonic homogenizer for 9 minutes at a power of 300 watts to form nanoemulsions. Then, the properties of nanoemulsions including particle size and distribution, coating efficiency and antioxidant properties were evaluated. Vasco model DLS (Dynamic light scattering) was used for the particle size. The particle size of nanoemulsions was determined by this device using dynamic light diffraction method. DPPH method was used to measure the antioxidant activity of oils and nanoemulsions and the antioxidant activity was calculated by using the formula. To evaluate the efficiency of coating of nanoemulsions, the amount of surface oil and total oil was measured and the efficiency was calculated by using the formula. The release rate of nanoemulsions was evaluated for 7 weeks. The tests were performed in three replications. Experimental data were analyzed in a completely randomized design with factorial test and Duncan test was used to compare the mean data. Software (Excel, 2010) was used to draw the graphs Results and Discussion: According to the results obtained in this study, it can be said that chia seed oil contains a high percentage of unsaturated fatty acids and has a very high level of antioxidant properties (88.43%), which has antioxidant properties in the structure of nanoemulsions. Oil is better preserved in water. Other results showed that with increasing oil content of nanoemulsions, particle size, antioxidant properties and release increased and the coating efficiency decreased. Also, by increasing the ratio of emulsifier to oil in nanoemulsions, the coating efficiency and antioxidant properties increase and the particle size and release decreases. In the results obtained from these tests, the minimum particle size was 14.08 nm and the highest coating efficiency was 96.40%. The antioxidant activity of the samples was evaluated in the range of 5.61% to 21.43%. Also, the average release of samples at the end of 7 weeks of the study reached nearly 18%. During storage, the treatments were quite stable for five months, which could be due to the low particle size and low release of samples. Considering the mentioned advantages, using nanoemulsions of this oil is a suitable option for enriching beverages.
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. ...
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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.
Food Biotechnology
Rana Tahmasbi; Mahta Mirzaei; Mohammadreza Khani
Abstract
Introduction: Fermented foods, probiotic, prebiotics, and symbiotic, are among the most important groups of functional food that have attracted the attention of researchers during the last years. Proteolytic activity of lactic acid bacteria can lead to the production of peptides in the fermented product. ...
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Introduction: Fermented foods, probiotic, prebiotics, and symbiotic, are among the most important groups of functional food that have attracted the attention of researchers during the last years. Proteolytic activity of lactic acid bacteria can lead to the production of peptides in the fermented product. The produced peptides can exhibit different biological activities such as antioxidant, antihypertensive, etc. that are influenced by the type of protein source, type of bacteria, time and conditions of fermentation process. Fermentation of various cereals such as quinoa seeds with high sugar and protein content by lactic acid bacteria can lead to the production of antioxidant peptides and improving their nutritional properties. Materials and Methods: In this study, the role of Lactobacillus reuteri and Lactobacillus acidophilus and the combination of two bacteria on the progress of fermentation and antioxidant activity of quinoa extract was investigated. The fermentation process was started by separate and simultaneous inoculating of Lactobacillus reuteri and Lactobacillus acidophilus and continued for 72 hours at 37° C. Sampling was performed every 24 hours of fermentation and samples were kept at -20° C for further analysis. The parameters such as pH, acidity, amount of soluble protein, degree of hydrolysis, amount of phenolic compounds and DPPH and ABTS radical scavenging activity were determined. Results and Discussion: Lactobacillus acidophilus showed higher acidification capacity than Lactobacillus reuteri. The amount of acidity in the sample fermented by Lactobacillus acidophilus increased from 0.27 to 1.13 % after 72 hours, while this amount was measured as 0.80 % for sample fermented by Lactobacillus reuteri. The amount of soluble protein and the degree of hydrolysis increased in samples fermented by both species. However, the largest increase was related to the sample fermented by Lactobacillus reuteri, so that the amount of soluble protein increased from 0.72 to 0.88 mg / ml and the value of free amino groups increased from 20.28 to 58.14 µM leucin/ mg protein during 72 hours of fermentation. The DPPH and ABTS radical scavenging activity increased in all fermented samples. The highest antioxidant activity was observed in samples fermented by Lactobacillus reuteri, followed by a combination of two bacteria (50:50) and Lactobacillus acidophilus. The amounts of phenolic compounds increased in all fermented samples. However, the highest increase was related to the sample fermented by Lactobacillus reuteri, so that it increased from 0/73 to 16.21 mg Gallic acid / ml after 72 hours of fermentation. Therefore, the results showed that despite the higher acidifying power of Lactobacillus acidophilus in quinoa extract, but Lactobacillus reuteri exhibited higher proteolytic activity, more ability to produce antioxidant peptides and also release phenolic compounds during the fermentation process.Simultaneous use of the two bacteria did not intensify the proteolytic activity and antioxidant activity of peptides, and the greatest increase in acidity, proteolysis, and antioxidant activity occurred in the first 24 hours of fermentation. Fermented extracts showed higher ABTS radical inhibitory activity than DPPH radical inhibition, indicating the hydrophilic nature of most produced antioxidant compounds. The highest levels of antioxidant activity were observed in samples fermented by Lactobacillus reuteri, a combination of Lactobacillus reuteri and Lactobacillus acidophilus (50:50) and Lactobacillus acidophilus, respectively. The results showed that fermentation by Lactobacillus reutri has the greatest effect on the production of antioxidant peptides and the release of phenolic compounds. The results of this study confirm the effectiveness of fermentation methods on improving the healing properties of quinoa extract and Lactobacillus reuteri was a more effective bacterium in fermentation and production of antioxidant peptides compared to Lactobacillus acidophilus. Simultaneous use of two bacteria did not increase the intensity of fermentation and did not improve the antioxidant activity compared to single use of each bacteria. Finally, the results of this study showed that fermentation of quinoa extract improves its antioxidant properties and has the potential to be used as a fermented beverage.
Food Chemistry
Roxana Alizadeh Firozeh; Mahta Mirzaei; Vajiheh Fadaei Noghani
Abstract
Introduction: Bioactive peptides are protein fragments with 2 to 20 amino acids that have different biological properties depending on the type of amino acids and peptide sequences, including antioxidant, antihypertensive, and antidiabetic. These peptides are inactive in their parent protein sequences ...
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Introduction: Bioactive peptides are protein fragments with 2 to 20 amino acids that have different biological properties depending on the type of amino acids and peptide sequences, including antioxidant, antihypertensive, and antidiabetic. These peptides are inactive in their parent protein sequences but are released during fermentation, enzymatic hydrolysis, or food processing, and exhibit a positive effect on body function and health being. Lentil protein hydrolysate containing antioxidant peptides can be considered as an ingredient of functional foods. One major challenge in using protein hydrolysate in the formulation of functional foods is their stability against the various processes applied to food such as heat and pH treatments. Materials and Methods: In this study, Lentil protein (Lens esculinaris) was hydrolyzed by Alcalase enzyme under controlled conditions (enzyme/substrate ratio of 90 Anson unit (AU)/ kg protein, 55°C, one hour). The intensity of enzymatic hydrolysis was monitored by the OPA method and antioxidant activity was evaluated based on DPPH and ABTS radical scavenging activity. The heat stability of lentil protein hydrolysate was evaluated by heating samples at 37, 50, 75 (for 15 -60 min), and 90°C (for 5 minutes). The pH stability was investigated by exposing the sample at a pH of 2, 5, 7, 9, And 11 for 1 hr and then adjusting on 7. OPA method was also used to evaluate the possible effect of pH and heat treatments on the content of free amino groups. Results and Discussion: The results showed that hydrolysis of Lentil protein by Alcalase under controlled conditions produced antioxidant peptides. Heating at 37, 50, and 75°C for 15 minutes reduced the DPPH radical scavenging activity by 1.25, 4.9, and 10.17% and ABTS radical scavenging activity by 3.8, 6.8, and 9%, respectively. The results of the OPA assay also showed a significant (P<0.05) decrease in the number of free amino groups in protein hydrolysate exposed to heat treatment. With increasing the time of treatment up to 60 minutes, the antioxidant activity decreased more significantly (P<0.05), simultaneously with a decrease in the content of free amino acid groups in the protein hydrolysate sample. So that, after heat treatment at 37, 50, and 75 ° C for 60 minutes, the free amino acid groups reached from 33/66 μM leucin /mg protein to 29.51, 27.59, and 25.68 μM leucin /mg protein and the most decrease in antioxidant activity was measured for samples exposed to 75°C for 60 minutes. It caused a 27.2%, and 29.2% reduction in DPPH and ABTS radical scavenging activity, respectively. Also, exposure to heat treatment at 90°C for 5 minutes caused a 15% and 13% decrease in DPPH and ABTS radical scavenging activity. The results obtained from consideration the antioxidant activity of samples exposed to pH treatment (2, 5, 7, 9, and 11 for 1 hour) showed the highest antioxidant activity of peptides at neutral pH and confirmed that acidic and alkaline conditions caused a significant decrease in antioxidant activity (P<0.05). As exposure to pHs 2 and 11 for one hour led to respectively 16.3 and a 29.2% decrease in DPPH radical scavenging activity and 16 and 18.2% decrease in ABTS radical scavenging activity. The results of the OPA assay also confirmed the role of acidic and basic pH on less exposure of free amino acid groups in protein structure.The results showed the potential of using Alcalase enzyme to hydrolyze Lentil protein and produce antioxidant peptides and the Lentil protein hydrolysate with antioxidant activity exhibited relative stability toward different heat and pH treatments. It was concluded that peptides retained 88% and 76% of antioxidant activity at maximum heat (90 ° C for 5 minutes) and pH treatment ( pH=11, for 1 hour). According to the results of the OPA assay, the observed decrease in antioxidant activity may be due to the changes that happen in protein and peptide structure when are exposed to heat and pH treatments. Altogether, our results showed that Lentil protein hydrolysate can be considered as a potential food ingredient with stable antioxidant activity.
Food Technology
Fahimeh Hajinia; Alireza Sadeghi; Alireza Sadeghi Mahoonak; Morteza Khomeiri; Yahya Maghsoudlou; Ali Moayedi
Abstract
Introduction: Bread is the main source of nutrients and it is a cheap staple food in the daily diet of people in many parts of the world. One of the most important ways to improve the quality of bread is to ferment cereals and use fruit resources. Cereal fermentation has a well-known potential to improve ...
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Introduction: Bread is the main source of nutrients and it is a cheap staple food in the daily diet of people in many parts of the world. One of the most important ways to improve the quality of bread is to ferment cereals and use fruit resources. Cereal fermentation has a well-known potential to improve the nutritional properties of the baked goods. It stabilizes the levels of various bioactive compounds, retards starch retrogradation and increases mineral bioavailability. A diet rich in cereal and fruit-based products could improve human health. Oat grain has a high functional potential due to its composition. This grain is known to be an excellent source of dietary fiber, antioxidants and a well-balanced protein fraction. Jujube fruit is also getting popularized due to the high content of vitamins, phenolic, polysaccharides and natural colorant agents. The quality of available commercially jujube depends on the contents of its bioactive compounds and micronutrients. There is no report about simultaneous application of fermented oat and jujube powder in processing of wheat bread. Accordingly, the aims of this study were to produce a supplemented wheat bread containing these ingredients, and evaluate the textural and antioxidant properties of the product. Materials and methods: In the present study, controlled fermented oat containing selected LAB isolated from oat sourdough (as starter culture) was used to produce supplemented wheat bread. Crumb hardness, porosity, specific volume, overall acceptability and antioxidant activity in wheat bread containing fermented oat, jujube powder and their mixture were investigated in comparison with the control (wheat bread). All the experiments were done in triplicates. A complete randomized design with the least significance difference (LSD) post-hock was also used to statistical analysis of the data at p < /em>< 0.05 by SPSS (version 20) software. Results and Discussion: The highest amount of crumb hardness was observed in the sample containing mixture of controlled fermented oat and jujube powder, meanwhile the lowest amount of hardness was belonged to the control sample. The results of specific volume showed an inverse relationship between the values of hardness and specific volume, and the lowest specific volume was observed in sample containing controlled fermented oat along with jujube powder. The highest amount of specific volume was also observed in the control sample. The porosity of all the produced breads was also significantly (p < /em><0.05) higher than the control sample, and the highest porosity was observed in the sample containing controlled fermented oat. The amount of produced gaseous compounds and carbon dioxide during fermentation affect the porosity of the produced bread. Furthermore, water retention capacity is also involved in increase in bread specific volume. Water reduces the stiffness of protein structures and allows better air to enter the dough texture and more specific volume of the product. Wheat breads containing controlled fermented oat + jujube powder and jujube powder (alone) had the highest antioxidant activity, and the control sample had the lowest antioxidant activity. During fermentation, the amount of phenolic compounds or flavonoids increases, and fermentation also causes the synthesis or release of various compounds that have antioxidant properties. Characterization of wheat bread containing the optimal formulation of controlled fermented oat and jujube powder didn’t show significant effect on the overall acceptability of the product. The presence of fiber in fortified breads is likely to increase water uptake, which in turn increases water retention capacity, reduces dough stability and increases overall acceptability. Fruits and whole grains are rich in phytochemicals such as phenolic compounds. Application of phenolic compounds in bread processing, in addition to improve antioxidant properties, affects the physicochemical properties of the dough and the quality characteristics of the produced bread due to various interactions with flour compounds such as gluten and starch. Accordingly, the combined use of plant-rich resources such as jujube powder and fermented oat, which are rich in minerals and micronutrients, can be used to improve the nutritional and quality characteristics of the supplemented wheat bread as a simple and efficient method. Due to the adverse effects of chemical additives and improvers, the importance of providing natural alternatives such as fermented substrates and plant resources in wheat bread processing is quite necessary. The best alternatives for this purpose include sourdough and fiber-rich plant. Wheat bread containing a mixture of controlled fermented oat and jujube powder had the highest crumb hardness and the lowest specific volume. Antioxidant activity in all samples was significantly higher than the control sample and wheat bread containing a controlled fermented oat and jujube powder with 90.52% had the highest amount of antioxidant activity. According to the results, controlled fermented oat and jujube powder, as functional ingredients, may be successfully incorporated into the wheat bread with positively effects on its quality characteristics.
Food Chemistry
Mohammad Taghi Golmakani; Gholam Reza Mesbahi; Nasireh Alavi; Azita Hosseinzade Farbudi
Abstract
Introduction: Food wastes and losses are produced during all phases of food life cycles. The highest wastes belong to the processing of fruits and vegetables. Bioactive compounds have the potential to be extracted from the by-products of fruits and vegetables which can be used in the food processing. ...
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Introduction: Food wastes and losses are produced during all phases of food life cycles. The highest wastes belong to the processing of fruits and vegetables. Bioactive compounds have the potential to be extracted from the by-products of fruits and vegetables which can be used in the food processing. Extraction of flavor compounds, phenolic compounds, enzymes, and organic acids from wastes of fruits – pomace, peel, and seeds of citrus fruits, pomace and leave of apple, seeds of grape, and peel of kiwifruit – and vegetables – pomace of carrot, husk of garlic, skin of onion, peel of potato, and skin of tomato – have been reported (Sagar et al., 2018).Sour orange, Citrus aurantium, is one of the species of citrus fruits. Sour orange seeds contain fats, protein, and bitter compounds which affect citrus processing (Ye et al., 2017). Naringin, neohesperidin, flavon, caffeic acid, p-coumaric acid, ferulic acid, and sinapic acid have been detected in methanolic extract of sour orange seeds (Bocco et al., 1998).Bioactive compounds are recovered from food wastes through various conventional and novel extraction techniques. Microwave-assisted extraction is one of the most used novel and environmentally friendly extraction methods. Advantages of microwave-assisted extraction over conventional extraction techniques include automated operation, more effective and selective heating, and less extraction time (Vinatoru et al., 2017).The objective of this study was optimization of microwave-assisted extraction of sour orange seed coat extract in terms of microwave power level, extraction time, sample quantity, and solvent volume on yield, bioactive compounds (total phenolic content and total flavonoid content), and antioxidant activity (free radical scavenging activity, ferric ion reducing antioxidant power, cupric ion reducing antioxidant capacity, and ferrous ion chelating). Also, optimum conditions of microwave-assisted extraction was compared to that of conventional magnetic stirrer-assisted extraction method. Materials and methods: Sour orange seeds were purchased from Limondis Company (Beyza, Fars province, Iran). Microwave-assisted extraction conditions including microwave power level (100, 200, and 300 W), extraction time (5, 10, and 15 min), sample quantity (5, 10, and 15 g), and solvent (methanolvolume 100, 150, and 200 mL) were optimized. Yield, bioactive compounds (total phenolic content (Habibi et al., 2015) and total flavonoid content (Habibi et al., 2015)), and antioxidant activity (free radical scavenging activity (Habibi et al., 2015), ferric ion reducing antioxidant power (Rekha et al., 2012), cupric ion reducing antioxidant capacity (Pascu et al., 2014), and ferrous ion chelating (Oyetayo et al., 2009)) of sour orange seed coat extract were evaluated. After determining the optimum conditions of microwave-assisted extraction, yield, bioactive compounds (total phenolic content and total flavonoid content), and antioxidant activity of sour orange seed coat extract were compared to those of conventional magnetic stirrer-assisted extraction method. Design Expert software (Version 10, Stat-Ease, Minneapolis, MN) was employed for analyzing four variables – microwave power level, extraction time, sample quantity, and solvent volume – at three levels consisting 30 experimental runs. Response surface methodology concerning central composite design (6 center points, quadratic model, and face center = 1) was applied. Results and discussion: Optimum conditions of microwave-assisted extraction were microwave power level of 200 W, extraction time of 12 min, sample quantity of 5 g, and solvent volume of 200 mL. Under optimum conditions, yiled, total phenolic content, total flavonoid content, IC50, ferric ion reducing antioxidant power, cupric ion reducing antioxidant capacity, and ferrous ion chelating were11.57%, 15550.50 µg gallic acid equivalent/g, 1476.22 µg quercetin equivalent/g, 11.33 mg/mL, 7.12 mg ascorbic/g, 6.44 mg ascorbic acid/g, and 0.43 mg EDTA/g, respectively. Intermediate microwave power level (200 W) can be more suitable from an industrial perspective and energy consumption (Jokić et al., 2012). Further increase in microwave power level, i.e. higher than 200 W, causes thermal degradation of bioactive compounds (Dahmoune et al., 2013), decreasing total phenolic content, total flavonoid content, and antioxidant activity of sour orange seed coat extract. The highest extraction time gives the bioactive compounds a chance to diffuse and release from the cell matrix to the surrounding environment (solvent). The highest solvent volume was selected as the optimum extraction condition. By increasing solvent volume up to 200 mL, meaning a greater gradient in bioactive compound concentration, mass transfer was also improved (Dahmoune et al., 2013). Also, the minimum sample quantity (5 g) was determined in optimum conditions. Increasing sample quantity (while the solvent volume remained constant) reduces the surface area available for the solvent to penetrate the sample matrix. As a result, higher sample quantity caused lower extraction of bioactive compounds (Ballard et al., 2010). There were no significant differences between yield, bioactive compounds, and antioxidant activity of extract obtained by conventional-assisted extraction method in comparison with those of microwave-assisted extraction. In conclusion, microwave-assisted extraction, as a green and fast method, can be proposed as a suitable and practical method for extraction of bioactive compounds from sour orange seed coat.
Food Biotechnology
Sahar Roshanak; Behrooz Alizadeh Behbahani; Fakhri Shahidi; Farideh Tabatabaei Yazdi; Alireza Vasiee; Neda Hashemi
Abstract
Usage of natural products like herbals, provide unlimited opportunities for novel and suitable additives. Mocheh can be used in fresh form or as an ingredient in soup and salad. This study was aimed to determine the antimicrobial and antioxidant activities of Mocheh (Lepidium draba) extract. The antimicrobial ...
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Usage of natural products like herbals, provide unlimited opportunities for novel and suitable additives. Mocheh can be used in fresh form or as an ingredient in soup and salad. This study was aimed to determine the antimicrobial and antioxidant activities of Mocheh (Lepidium draba) extract. The antimicrobial activity of Mocheh extract was tested against Bacillus subtilis, Pseudomonas aeruginosa, Staphylococcus aureus and Aspergillus niger. The extract showed a strong antimicrobial activity with a concentration dependence and a broad antimicrobial spectrum for all tested microorganism species. The results showed that MIC of leaf extract of Lepidium draba on Aspergillus niger, Pseudomonas aeruginosa, Bacillus subtilis and Staphylococcus aureus was 128, 128, 128 and 128 mg/mL respectively. The results showed that MBC/MFC of leaf extract of Mocheh on the examined microorganisms was 256, 256, 256 and 256 mg/mL respectively. The values obtained for total flavonoid content and total phenolic contents were 22.13 µg/mL and 18.88 mg/mL, respectively. Measured value in the radical scavenging activity was IC50= 168/21 µL/mL. The results showed that Mocheh leaf aqueous extract is a novel source of natural antimicrobial and antioxidant agents for the food and pharmaceutical industries.
Food Biotechnology
Sahar Roshanak; Behrooz Alizadeh Behbahani; Fakhri Shahidi; Farideh Tabatabaei Yazdi; Alireza Vasiee; Neda Norouzi
Abstract
In this research, the chlorophyll content, total flavonoid content (TFC), total phenolic content (TPC) and antioxidant activity of aqueous extract of Dandelion was determined. In addition, the effect of aqueous extract of Dandelion, obtained by maceration, was tested on various food borne and food spoilage ...
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In this research, the chlorophyll content, total flavonoid content (TFC), total phenolic content (TPC) and antioxidant activity of aqueous extract of Dandelion was determined. In addition, the effect of aqueous extract of Dandelion, obtained by maceration, was tested on various food borne and food spoilage microorganisms. Antimicrobial activity of leaf extract of Dandelion was investigated using disk agar diffusion, well agar diffusion, minimum inhibitory concentration and minimum bactericidal/fungicidal concentration methods. The values obtained for TFC, TPC, chlorophyll a and b were 22.82 (µg/mL), 116.89 (mg/mL), 0.081 (mg/l) and, 0.063 (mg/l), respectively. The result of the radical scavenging activity was IC50= 68.81µl/mL. The results showed that MIC of leaf extract of Dandelion on Aspergillus niger, Salmonella typhimurium, Bacillus subtilis and Staphylococcus epidermidis was 512, 256, 256 and 64 mg/ml respectively. MBC for Aspergillus niger was more than 512, for Salmonella typhimurium, and Bacillus subtilis was 512, and for Staphylococcus epidermidis was 128mg/ml. In addition, the diameter of inhibitory growth zone in well diffusion method was more than disk diffusion. Generally, it can be stated that the aqueous leaf extract of Dandelion on Gram-positive bacteria showed more antimicrobial activity than Gram-negative bacteria, while there is no significant inhibition on mold. Based on the results of this study, Dandelion aqueous extract might be used as a natural agent to prevent the growth of food borne microorganisms, particularly, that cause food poisoning that leading to the reduction of gastroenteritis risk.
Food Biotechnology
Bahareh Majdi; Mohammad Amin Mehrnia; Hassan Barzegar; Behrooz Alizadeh Behbahani
Abstract
Introduction: Antioxidants by Quenching free radicals and preventing lipid oxidation, retard spoilage, discoloration and rancidity of foods. Due to adverse effects of synthetic antioxidants such as carcinogenicity and liver injury, consumers’ attention toward natural antioxidants are increasing. ...
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Introduction: Antioxidants by Quenching free radicals and preventing lipid oxidation, retard spoilage, discoloration and rancidity of foods. Due to adverse effects of synthetic antioxidants such as carcinogenicity and liver injury, consumers’ attention toward natural antioxidants are increasing. Turmeric (Curcuma longa) is a medicinal plant frequently used in food industry and pharmacology. In this research, chemical composition, structure and type of bond, antioxidant capacity, total phenol, flavonoid and cytotoxic effect of Turmeric essential oil (TEO) on colorectal cancer cells (HT29) were investigated. Materials and methods: TEO was extracted using Clevenger apparatus by aqueous distillation method. To identify chemical composition, 1 µl essential oil was injected in gas chromatography-mass spectrometry and essential oil composition and quantity were determined by comparing with standards. Functional groups and qualitative identification of turmeric essential oil were done using Fourier-transform infrared spectroscopy (FTIR) in range of 500 – 4000 cm-1. Antioxidant capacity of TEO was determined suing ABTS, DPPH and β-carotene/linoleic acid bleaching assay. Total phenol and flavonoid were measured by colorimetric methods. MTT test was used to find cytotoxic concentrations of TEO on colorectal cancer cell line (HT29). Results and discussion: The 18 compounds identified in TEO accounted for 97.91% and the highest compound was turmerone by 40%. The other compounds were curlone, zingiberene and benzene with 34, 8.30 and 4.18% respectively. Infrared spectrum in range of 3600-3400 cm-1 (specially 3516 cm-1) and peaks at 2930, 1621, 1515 and 1447 cm-1 were due to stretching vibration of O-H, C-H, C=O, C=C bonds of aromatic ring and aromatic groups of curcuminoids. 1515 cm-1 peak was due to stretching vibration of C=O bond of sesquiterpenes (turmerone). Observed peaks at 1378 and 1308 cm-1 confirmed the presence of alkanes or bending vibrations of CH3 groups in curcuminoids (curcumin). Antioxidant potential of TEO according to DPPH and ABTS methods and β-carotene bleaching assay was 25.15, 93.90 and 72.76 %, respectively. Total phenol and flavonoid content of TEO were 38.91 mg GAE/g and 87.9 mg QE/g. The results showed that by increasing essential oil concentration from 3.125 to 200 mg/mL survival rate of HT29 changed from 66.76 to 9.88%.
Mohammad Hojjati; Behrooz Alizadeh Behbahani
Abstract
Introduction: There is a remarkable interest in developing natural antimicrobial compounds of essential oils and plant extracts origin, due to the increase of bacterial resistance to common antibiotics. On the other hand, lipid oxidation in raw or processed materials leads to food rancidity and deterioration. ...
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Introduction: There is a remarkable interest in developing natural antimicrobial compounds of essential oils and plant extracts origin, due to the increase of bacterial resistance to common antibiotics. On the other hand, lipid oxidation in raw or processed materials leads to food rancidity and deterioration. In this way, synthetic antioxidants such as butylated hydroxytoluene (BHT) and butylated hydroxyanisole (BHA) are used to prolong the storage stability of food products. Nevertheless, the toxicologists and nutritionists have documented the side effects and potential toxic effects of synthetic antioxidants. Herbs contain a wide variety of phenolic compounds such as phenolic acids, flavonoid, tannins and so forth. These bioactive compounds could be therefore used as natural antioxidants and antimicrobial agents to suppress lipid oxidation and food spoilage. In this context, Allium jesdianum extracts were obtained and their antioxidant and antimicrobial activities were investigated. Materials and methods: A. jesdianum was exposed to methanolic and aqueous maceration-based extraction methods to extract its bioactive compounds with positive biological activity. The extraction yield, total phenolic compounds, antioxidant activity (based on DPPH and ABTS radical scavenging activity), and antimicrobial activity (based on disc diffusion agar, minimum inhibitory concentration, and minimum bactericidal concentration methods) of the methanolic and aqueous extracts were evaluated and compared to each otherr. Results and discussion: The methanolic extract of A. jesdianum had higher extraction yield of 7.1±0.2% compared to the aqueous extract with 4.6±0.28% extraction yield, mainly due to the ability of methanol to extract both nonpolar and semi-polar compounds. The total phenolic compounds of the methanolic extract were also remarkably higher than the aqueous counterpart (88.28% vs. 68.29% mg gallic acid/g dried extract), indicating that the solvent type plays a significant role in extracting bioactive compounds. However, the aqueous extract was able to significantly scavenge DPPH and ABTS radicals compared to the methanolic extract. This means that the presence of phenolic compounds is not the only factor affecting the antioxidant activity of plant extracts. The bioactive extracts of A. jesdianum were able to suppress the growth of or kill the examined bacteria P. aeruginosa, E. coli, E. aerogenes, L. innocua, and S. pyogenes; and this effect was more pronounced in the methanolic extract. Therefore, A. jesdianum methanolic and aqueous extracts could be used as natural preservatives to improve the oxidative stability of food products rich in unsaturated fatty acids, and to inhibit the growth of spoilage and pathogenic microorganisms, treat infections, and increase the safety of food products.
Mohammad Reza Toorani; Reza Farhoosh; Mohammad Taghi Golmakani; Ali Sharif
Abstract
Introduction: Lipid oxidation is one of the most important factors affecting the loss of quality or the deterioration of edible oils. This reaction is accompanied by the production of harmful compounds that may threaten consumer’s health. Several parameters affect the severity of the oxidation ...
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Introduction: Lipid oxidation is one of the most important factors affecting the loss of quality or the deterioration of edible oils. This reaction is accompanied by the production of harmful compounds that may threaten consumer’s health. Several parameters affect the severity of the oxidation reaction, among them temperature is one of the most important parameter to consider. Lipid oxidation increase significantly with the increase of temperature, which drastically reduces the length of the shelf life of the oils. Numerous methods have been used to postpone the oxidation of oils that one of the most useful methods is the addition of antioxidants. Nowadays, natural antioxidants have been located in the hotspot of attention from safety and sensory characteristics point of view. Sesamol as a valuable natural antioxidant may help to provide healthy edible oils. The determination of thermal kinetic data and the evaluation of thermodynamic indices have long been used to the better identify the mechanisms and the events caused by temperature elevation. Examining the temperature and time variables together and merging these components could provide valuable information about the environmental effects of foodstuffs. These parameters are particularly important for edible oils. Hence, the kinetic-thermal information of the oils oxidation in the presence of sesamol may provide the valuable assistance in explaining the storage conditions of various edible oils in the presence of this antioxidant. Materials and methods: The sesamol's ability to quench free radicals was determined by DPPH test and at 517 nm. The oil purification process was performed by adsorption column chromatography in order to eliminate minor components that may be interfere with the oxidation reaction. The evaluation of the accelerated oxidation process in presence of sesamol was carried out in a dry oven and through monitoring the accumulation of hydroperoxides (peroxide value) over time at 60, 80 and 100 °C. The peroxide value was measured spectrophotometrically at 500 nm. The induction period of oils oxidation was determined through two lines fitted on initiation and propagation steps of the oxidation curve. The rate constants of the oils oxidation and sesamol consumption, the peroxide value corresponding to the length of induction period (PVIP), the minimum sesamol concentration to demonstrate the antioxidant activity and the oxidative stability time of lipid systems at ambient temperature were also determined by oxidation kinetic data. Results and discussions: The results of inhibitory test showed that the amount of sesamol required to inhibit 50 percent of the DPPH radicals is equal to 1 mM. The induction period of olive oil has reached to over 520 h in presence of 0.01% sesamol at 60 °C, whereas sesame and canola oils were placed in the subsequent positions with nearly 330 and 325 h, respectively. The average extent of PVIP (all sesamol concentrations) for two lipid systems i.e. sesame and canola oils was close to each other and drastically higher from olive oil. This delocalization of the numbers suggests that the PVIP is independent of the antioxidant concentration available and is affected by the fatty acids structure of oils. The effect of temperature elevation on the rate constant of oxidation for different oils did not follow the same pattern, so that the slope of increase of the rate constant for olive oil was very mild than to the other two oils. The results showed that the increase in temperature has markedly increased the rate of sesamol consumption, so that unsaturated lipid systems have undergone significant changes in this regard. Increasing the temperature increased the minimum concentration required for the antioxidant activity of sesamol. This pattern was linear for olive oil and hyperbolic for sesame and canola oils.
Forouzan Jalali-zand; Mohammad Goli
Abstract
Introduction: Microencapsulation is represented as a technology of packaging solids, liquids, or gaseous materials in miniature sealed capsules that can release their contents at controlled speeds under specific conditions. The packaged materials can be pure materials or a mix, which are also called ...
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Introduction: Microencapsulation is represented as a technology of packaging solids, liquids, or gaseous materials in miniature sealed capsules that can release their contents at controlled speeds under specific conditions. The packaged materials can be pure materials or a mix, which are also called coated material, core material, actives, internal phase (Fang & Bhandari, 2010). Selenium is a micronutrient essential element for human health, which is toxic in high concentrations. Selenium is a component of selenoproteins that plays an enzymatic and structural roles in human biochemistry. Selenium is known as an antioxidant and catalyzer for active thyroid hormone production. The aim of this study was to optimize the microencapsulation of sodium selenite (100-900 mg per 20 mL final spray solution) using a combination of Arabic gum (25-29% per 20 mL final spray solution) and Persian gum (1-5% per 20 mL final spray solution) as capsule wall applying modified solvent evaporation method to produce microcapsules with the highest encapsulation efficiency (EE) and the smallest possible particle size using the response surface method (RSM) with central composite design (α = 2 with 6 central points and 2 repetition in axial and factorial points). Materials and Methods: In this research, production of encapsulated sodium selenite at different concentration (100, 300, 500, 700 and 900 mg/20 cc) with Arabic gum (25%, 26%, 27%, 28% and 29%) and Analogous Farsi gum (5%, 4%, 3%, 2% and 1%) as wall materials by solvent evaporation method was studied. The optimization of microcapsules based on the highest encapsulation efficiency and smallest microcapsules size was studied using RSM. Based on the mentioned parameters, 2 optimum conditions were chosen. The first one was a condition where the samples produced with 135 mg sodium selenite in 20 ml sprayed solution, 27% and 3% Arabic and Farsi gum, respectively. In this condition the encapsulation efficiency was 79.63% whereas the microcapsules size was 49.98 µm. The second condition was followed by producing samples with 109 mg sodium selenite in 20 ml sprayed solution, 28% and 2% Arabic and Farsi gum with result of 95.10% encapsulation efficiency and the size of 46.71 µm. Finally 390 ppm capsules of the first condition and 480 ppm capsules of second condition (equal to 8.6 ppm sodium selenite salt), synthesized BHA (200 ppm) and sodium selenite salt (8.6 ppm) were added to a free anti-oxidant soybean oil and were kept at 55°C at 0, 23 and 46 days which was equal with 20°C at 0, 180 and 360 days. In this condition, peroxide value, acidity, Thiobarbituric acid, Anisidine value, Totox value and anti-oxidant activity of free anti-oxidant soybean oil were evaluated using SPSS software. Results & Discussion: The results achieved by RSM showed that sodium selenite concentration had reverse relation on encapsulation efficiency whereas there was direct relation with Arabic and Farsi gum concentration. Also the size of microcapsules with had direct relation on sodium selenite concentration whereas Arabic and Farsi gum concentration had reverse relation. The result of SPSS analyses showed that with presence of the encapsulated sodium selenite anti-oxidant and synthesized BHA anti-oxidant in soybean oil, peroxide value, acidity, Thiobarbituric acid, Anisidine value, Totox value decreased whereas anti-oxidant activity of soybean oil increased. Based on anti-oxidant characteristics in soybean oil, recommended treatments in this research are: condition 2 ˃ condition 1 ≥ BHA ˃ sodium selenite salt ˃ control sample without anti-oxidant. The results of this study recommend the incorporation of encapsulated sodium selenite (condition 1 and 2) for increasing the shelf life of soybean oil as an alternative to synthesized BHA.
Maryam Mandegari; Abdol Majid Mirzaalian Dastjerdi; Laleh Mosharaf; Maryam Tatari
Abstract
Introduction: Pomegranate (Punica granatum L.) is an important horticultural fruit that is generally very well adapted to the Mediterranean climate. Arils are the edible part of this fruit, being rich in anthocyanins and bioactive compounds such as phenolic compounds and flavonoids which act as antioxidants ...
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Introduction: Pomegranate (Punica granatum L.) is an important horticultural fruit that is generally very well adapted to the Mediterranean climate. Arils are the edible part of this fruit, being rich in anthocyanins and bioactive compounds such as phenolic compounds and flavonoids which act as antioxidants and free radical scavengers. Susceptibility to chilling injury in pomegranate fruits is a major limiting factor in storing fruits at low temperatures. Below 5 °C, pomegranate fruits show symptoms such as surface pitting, browning, discoloration, and decay. The control of temperature is an effective tool for extending the shelf life of fresh horticultural products. Oxidative stress, as caused by an excess of reactive oxygen species (ROS), is usually associated with chilling injury in fruits. Nitric oxide (NO) is an important gas molecule, the involvement of which in many physiological processes can protect plant cells against oxidative stress by reducing the accumulation of ROS. Postharvest studies have shown that the application of NO gas can extend the storage life of a range of horticultural produce by delaying ripening or senescence. Due to the high number of pomegranate cultivars in Iran, limited amounts of information exist on how the qualitative characteristics of arils in the Malas pomegranate can be affected by nitric oxide and different temperatures during storage. The Malas cultivar comprises a large share of pomegranate exports from Iran. In this research, the positive effects of nitric oxide were examined on reducing the chilling injury and maintaining the fruit quality of pomegranate. The application of this treatment at different concentrations and different storage temperatures led to variable effects on the qualitative characteristics of arils in the Malas pomegranate. Materials and methods: Malas pomegranate fruits were harvested commercially from Isfahan Province and were transferred to the Food Industry Laboratory of Isfahan Natural Resources Research. The fresh arils were separated from fruit tissues and were immersed in solutions of nitric oxide (0, 5 and 10 μM/L) for 5 min. After draining, the arils were placed in packaging films of polyethylene and were immediately stored at 2, 4 and 8 °C for 21 days. Several parameters were measured every 7 days during the storage time. These were the weight loss, total soluble solids, titratable acidity, TSS/TA, acid ascorbic, total phenol, total anthocyanin content, antioxidant activity, MA, ion leakage, POD, PPO activity and sensory evaluation. The current study was carried out as a factorial assay and was based on a completely randomized design with three replications. Data were processed by ANOVA using the SAS software version 9.4. Significant differences were identified using Duncan’s test at 1% probability level. Results and discussion: Results showed that the total anthocyanin content, total phenol, antioxidant activity, and titratable acidity decreased during storage time. The control group and the treatment with low temperatures significantly reduced the qualitative characteristics of arils during storage. The water content of arils treated with 5 and 10 μM nitric oxide was maintained considerably for 21 days during storage. According to these results, unlike titratable acidity and ascorbic acid which decreased in both treated and untreated fruits, there was an increase in the total soluble solids and POD activity of arils during storage. However, nitric oxide reduced the rate of these changes, whether it be the decrease or increase in the measured parameters. During the experiment, the control samples showed lower values of quality regarding all parameters. The use of nitric oxide in fruits reduced lipid peroxidation and ion leakage significantly, whereas the antioxidant activity increased. The decrease in ion leakage was observed most notably in fruits that were treated with 10 μM nitric oxide. Furthermore, low temperatures managed to disrupt the metabolic balance of reactive oxygen species, leading to the accumulation and destruction of antioxidant enzymes. In the present study, exogenous treatments with nitric oxide at 5 and 10 μM significantly reduced the lipid peroxidation content and electrolyte leakage of arils being stored at cold temperatures, compared to untreated arils. Nitric oxide suppressed the activity of polyphenol oxidase (PPO) and preserved the physical appearance and the internal quality of pomegranate arils. The decrease in phenolic compounds (29.32%) and antioxidant activity (39.91%), besides the increase in lipid peroxidation (38.37%) and ion leakage (36.98%), caused deteriorations in the appearance and organoleptic properties of the control samples. To alleviate these problems, nitric oxide has beneficial effects on maintaining the anthocyanin content of pomegranate arils by partially inhibiting PPO enzyme activity during storage. It prolongs the postharvest life, helps to preserve the quality of pomegranate arils, suppresses the formation of ethylene, reduces the respiratory rate and controls weight loss, in addition to maintaining the firmness of fruits. Delaying the changes in peel color and TSS are also considered as useful effects of nitric oxide on pomegranate arils. Nitric oxide impeded the process of senescence by slowing down PPO-related activities, thereby maintaining the total phenolic content of pomegranate arils.In conclusion, the application of nitric oxide was observed to reduce ion leakage and PPO activity in pomegranate arils, while also maintaining the quality of arils. Ultimately, the use of 10 µM nitric oxide at 8 °C can be suggested as the most optimum treatment herein.
Maryam Azizkhani; Fatemeh Adinehpour
Abstract
In order to inhibit the oxidation of lipids, improve the oxidative stability of foods and to minimize the hazard risk to human health, antioxidants are added to food materials in industrial processing. In this work, the antioxidant potential of cinnamon (Cinnamomum zeylanicum), ajowan (Carum copticum) ...
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In order to inhibit the oxidation of lipids, improve the oxidative stability of foods and to minimize the hazard risk to human health, antioxidants are added to food materials in industrial processing. In this work, the antioxidant potential of cinnamon (Cinnamomum zeylanicum), ajowan (Carum copticum) and zataria (Zataria multiflora Boiss.) essential oils (EOs) at different concentrations (0, 1 and 1.5%) on free fatty acid content (FFA), peroxide value (PV) and thiobarbituric acid reactive substances (TBARS) of grape seed oil stored at 60ºC was evaluated. Ajowan treated samples (1.5%) showed the lowest (1.02%) and zataria treated samples (1%) expressed the highest (1.19%) FFA value among EO-treated samples. Samples treated with 1.5% cinnamon showed the lowest PV (69.5 meq O2/ kg) at the end of the storage period. Following control, the highest PV was seen in samples treated with zataria (1%). Grape seed oil samples treated with 1 and 1.5% cinnamon showed the lowest TBARS values during the whole storage period (one month). TBARS of zataria treated samples increased slightly toward the end of storage and a similar trend in TBARS was observed for samples treated with ajowan. The antioxidant activity of EOs in grape seed oil followed in descending order was cinnamon, ajowan, and zataria.
