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.
Seyed Hamidreza Ziaolhagh
Abstract
In this study, some preservative solutions were used as an alternative to sulphur fumigation. For this purpose, sodium metabisulfite, calcium chloride, sodium acetate, and sodium carbonate solutions at concentrations of 0.5, 1 and 2 percent were applied. Grapes (Sorkh-e-Fakhri var.) were dipped in different ...
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In this study, some preservative solutions were used as an alternative to sulphur fumigation. For this purpose, sodium metabisulfite, calcium chloride, sodium acetate, and sodium carbonate solutions at concentrations of 0.5, 1 and 2 percent were applied. Grapes (Sorkh-e-Fakhri var.) were dipped in different concentrations of each solution for 2 minutes. After dipping, the surface water of grapes was dried by natural air blowing and then, put in conventional baskets and stored at 0.5-1°C at 85-95% RH for 6 months. The percentage of moldiness, soluble solids, reducing sugar, acidity, and pH of the samples were determined after 2, 4, and 6 months of storage. The results of this study showed that the effect of type of preservative used and the storage time, on the percentage of moldiness and pH and acidity of all samples were significant at 1% level. Sodium metabisulfite had the highest inhibitory effect on mold growth. Calcium chloride had the greatest effect on moisture retention. In addition, the highest pH was observed in samples immersed in sodium carbonate solution. In the case of interactions, the effect of type of preservative and storage time on moldiness, moisture content, brix, sugar content, and acidity, and also the type of preservative and its concentration on moldiness and acidity of samples were significant. According to the obtained results, it was shown that the grapes could be stored for 6 months by dipping them in 0.5% sodium metabisulfite for 2 minutes before cold storage.
Seyed Mohsen Mortazavi; Hossein Jalali; Seyed Hamidreza Ziaolhagh
Abstract
In this study, the probiotic bacterium Lactobacillus acidophilus with different percentages of pomegranate peel powder (0, 0.5, 1, 1.5, and 2%) were used to produce a functional camel milk-based beverage. The physicochemical, antioxidant and sensory properties of the resulting drinks were evaluated. ...
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In this study, the probiotic bacterium Lactobacillus acidophilus with different percentages of pomegranate peel powder (0, 0.5, 1, 1.5, and 2%) were used to produce a functional camel milk-based beverage. The physicochemical, antioxidant and sensory properties of the resulting drinks were evaluated. The results showed that enrichment of milk with pomegranate peel powder improved the survival of probiotic bacteria from 6.95 to 7.35 Log CFU/ml. Addition of pomegranate peel to beverages increased their antioxidant activity from 7 to 85.33, 9.13 to 93.66 and 0.126 to 0.435 as measured by DPPH free radical scavenging, ABTS+ free radical scavenging and reduction potency tests, respectively. Rheological studies also showed that the addition of pomegranate peel powder to beverages increased their viscosity from 5.65 to 21.5 mPa. Adding pomegranate peel powder to beverages also changed the color factors (L*, a* and b*) so that increasing the level of pomegranate peel powder increased the red and yellow color in the samples. Also, the results of the sensory evaluation, including taste, appearance, smell and general acceptance indicated that the produced beverages were well-liked by consumers. However, the results of sensory evaluation showed that adding high percentages of pomegranate peel powder to beverages could reduce the sensory acceptance of the final product.
Nahid Jafari; Seyed Hamidreza Ziaolhagh; Abdorreza Mohammadi Nafchi
Abstract
Introduction: Potato is the fourth most important agricultural product after rice, wheat, and corn. Potato produces more dry matter, protein, and minerals per unit area in comparison with other crops. Many of the ingredients in potato are important, due to their beneficial effects on health. Hence, this ...
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Introduction: Potato is the fourth most important agricultural product after rice, wheat, and corn. Potato produces more dry matter, protein, and minerals per unit area in comparison with other crops. Many of the ingredients in potato are important, due to their beneficial effects on health. Hence, this product is very suitable for human consumption. Osmotic dehydration is used to remove a portion of water from foods such as fruits and vegetables, by immersion in high osmotic solutions such as sugars and salts. Osmotic dehydration is a relatively simple and economical process that improves the texture and rehydration properties of the products and prevents enzymatic browning by preventing the activity of polyphenol oxidases. In this process, the acid is removed and the sugar is absorbed, thus the composition of the fruits is changed and the taste and total acceptance of the product are improved. Osmotic dehydrating method has been used for drying various products such as carrots, mangoes, pineapples, strawberries, bananas, apples, apricots, and many other fruits. In this research, the effects of osmotic pre-treatment on qualitative and sensory properties of dried potatoes were investigated.
Materials and methods: In this study, Agria cv. potato samples were used and after washing, were completely peeled and cut into pieces of 3.5 × 0.5 × 0.5 cm. The treatments used in this study included osmotic solution concentration (at 0, 10 and 20% sodium chloride levels), osmotic solution temperature (30, 45 and 60°C), and immersion time in osmotic solution (at three levels 60, 240 and 720 minutes). The proportion of potato sticks to osmotic solution in all experiments was 1:6. After applying osmotic pre-treatment, samples were dried in an oven with a temperature of 60°C and a flow rate of 1.5 m/s to reach a moisture content of 8-10%. The moisture content, rehydration capacity, shrinkage, browning, color indices, and sensory properties (taste, color, shape, strength, and total acceptance) of potato samples were evaluated after the drying process and the response surface methodology (RSM) based on central composite design (CCD) were used to determine the optimal conditions for osmotic pre-treatment.
Results and discussion: The results of statistical analysis of the data showed that osmotic time and osmotic solution concentration had a significant effect on moisture content of potato slices. By increasing the time and decreasing the concentration of osmotic solution, moisture content of dried potato samples increased. The immersion time and osmotic solution temperature did not have any significant effect on the rehydration of potato slices, but the effect of osmotic solution’s concentration was statistically significant. By increasing the concentration of osmotic solution, the rehydration rate of potato samples decreased. The results showed that the interaction of temperature and concentration of osmotic solution had a significant effect on the degree of shrinkage of potato slices. Osmotic time and osmotic solution concentration had statistically significant effects on the browning index of potato slices, in a way that by increasing the concentration of osmotic solution, the browning index of potato samples decreased initially and then increased. The results of statistical analysis of the color indices showed that the osmotic solution temperature had a significant effect on the brightness (L*) of the potato slices, while the concentration of osmotic solution significantly affected their yellowness (b*) and the temperature and concentration of osmotic solution had a significant effect on the redness (a*) of the potato slices. By increasing the concentration of osmotic solution, the overall change in the color (E) of potato samples at high temperatures of osmotic solution first increased and then decreased. Sensory evaluation results showed that concentration, time, and temperature of osmotic solution had no significant effect on the sensory properties of potato sticks, except for taste. By increasing the temperature and time of immersion in osmotic solution, the taste scores of the samples increased. According to the results of optimization by the surface response method, the concentration of 2%, temperature of 46° C and dipping time of 173 min was introduced as favorable conditions.
Meysam Abediyan; Seyed Hamidreza Ziaolhagh; Ali Najafi
Abstract
Introduction. Apricot is a soft fruit that normally does not have any resistance to transportation and storage conditions. In addition, apricots are climacteric fruits, produces high levels of ethylene during ripening process and have a high respiration rate. For this reason, they are very susceptible ...
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Introduction. Apricot is a soft fruit that normally does not have any resistance to transportation and storage conditions. In addition, apricots are climacteric fruits, produces high levels of ethylene during ripening process and have a high respiration rate. For this reason, they are very susceptible to physiological and microbial spoilage and have a very short shelf life. Thus, it is difficult to export this product with good quality and low waste or it is very limited. Application of edible coatings could increase the storability of apricots and delay their spoilage. Edible coatings cover the surface of the fruit and function as a barrier against water vapor, respiration gasses, and microorganisms. The effect of different natural polymers as edible coatings on the quality and shelf life of different fruits has been investigated by many researchers. Chitosan has been used in the formulation of edible coatings to extend the shelf life of citrus, papaya, strawberries and grapes (Arnon et al. 2014; Ali et al. 2011; mehrzad et al. 2011; Mostofi et al. 2011). Apples coated with whey protein concentrate showed more lightness compared with non-coated ones (Perez-Gago et al. 2006). In most studies, the effects of single edible coatings on the quality of fruits have been studied. In this research the quantitative and qualitative changes during ripening and cold storage of apricots coated with different formulations of whey protein concentrate, sodium alginate and chitosan were studied.
Materials and methods "Rajabali" variety apricots were picked up at optimum maturity and damaged ones were separated. Edible coating solutions were prepared by dissolving different amounts of whey protein concentrate, sodium alginate and chitosan in to distilled water. Glycerol was used as plasticizer. The apricots were dipped in the prepared solutions with different concentrations for at least five minutes. Then they were stored for 35 days at 2°C. Some quantitative and qualitative characteristics of coated apricots, such as weight loss, acidity, color, texture, shrinkage, browning reactions, vitamin C, and microbial load were determined after 0 and 35 days of storage. The results were analyzed by response surface methodology based on central composite design with five replications at the central point.
Results & discussion. The statistical analysis of the results by central composite design (CCD) indicated that the different concentrations of whey protein did not have any significant effect on weight loss during storage. The weight loss decreased as the concentration of sodium alginate and chitosan increased. Chitosan and sodium alginate had an important role in maintaining firmness. The firmness of apricots were highest at the upper limit of sodium alginate (1%) and chitosan concentrations (2%). The b* (yellowness) and L* (lightness) values of the apricots were increased as the concentration of chitosan was increased and the concentration of sodium alginate decreased. No significant difference was observed between the a* values (redness) of apricots treated with different coatings. In addition, the acidity of the apricots was increased by increasing the concentration of chitosan and decreased by increasing the concentration of sodium alginate. Browning of the coated fruits was also increased as the concentration of chitosan was increased to 1%. Increasing the concentration of sodium alginate increased the shrinkage of the apricots at low concentrations of whey protein concentrate and decreased it at high concentrations of whey protein concentrate. It was also shown that increasing concentrations of chitosan would reduce microbial load. The optimization of the formulations with Design Expert software showed that the best formulation of edible coating for preserving apricots was 1.45% of chitosan, 1.25% of alginate, and 0 percent for Whey protein concentrate.
Mohammad Sani Shariatpanahi; Seyed Hamidreza Ziaolhagh
Abstract
Since the waste of agricultural and horticultural products is high, appropriate methods should be used to produce products with high quality and shelf life for export. In Iran a great part of fruits and vegetables are dried conventionally and farmer use So2 gas for preservation and color stability of ...
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Since the waste of agricultural and horticultural products is high, appropriate methods should be used to produce products with high quality and shelf life for export. In Iran a great part of fruits and vegetables are dried conventionally and farmer use So2 gas for preservation and color stability of dried apricots ,but this gas is allergic and carcinogenic and effort to find suitable substitutes for this substance would be an efficient method to the health of the society. So, in this study 3 apricot varieties were selected to evaluate the drying quality and to determine the so2 replacement methods. The selected varieties (Noori, Khaybei 2 and Nasiri) were treated with citric acid, (0.3%), ascorbic acid (0.3%), sodium meta bisulfate (0.4%) and a 50% mixture of ascorbic and citric before drying and then were compared with control samples(without any treatment). After drying, the characteristics such as Brix, pH, moisture contents, browning index, acidity and organoleptic properties were evaluated. Results showing that the effect of variety on moisture, browning, pH, acidity and organoleptic properties were significant (P
