Food Technology
Aliehsadat Rafaathaghighi; Leila Jafari; abdolmajid Mirzaalian Dastjerdi; Farzin Abdollahi
Abstract
Indian jujube fruit (Ziziphus mauritiana Lam.) is a perishable tropical fruit with high nutritional value. In the present study, in order to increase their storage life, Indian jujube fruits were treated separately with alginate (Al) and Zataria multiflora essential oil (ZEO) (0.5 and 1.0%), or in combination ...
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Indian jujube fruit (Ziziphus mauritiana Lam.) is a perishable tropical fruit with high nutritional value. In the present study, in order to increase their storage life, Indian jujube fruits were treated separately with alginate (Al) and Zataria multiflora essential oil (ZEO) (0.5 and 1.0%), or in combination with Al and ZEO, and then were stored at 6±1 °C and 90-95% RH for up to 28 days. The results showed that all the postharvest treatments maintained the fruit quality as compared to the untreated control. The Al + ZEO treatment was effective in reducing the rate of respiration. This combined treatment resulted in lower levels of percent weight loss, decay, and firmness of fruit tissue during storage. Moreover, coated fruits contained higher levels of ascorbic acid compared to untreated fruits. These results showed that applying a combination of Al and ZEO can assist in delaying Indian jujube fruits' senescence process, and can increase their storage life.
Food Biotechnology
Nasim Najafi; Hajar Abbasi
Abstract
Due to its health benefits, fresh sprouted cereals are considered popular food source. They are very sensitive and highly susceptible to microbial spoilage during transportation, processing, and storage. This phenomenon makes them potentially high-risk fresh products. This study aimed to assess the effect ...
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Due to its health benefits, fresh sprouted cereals are considered popular food source. They are very sensitive and highly susceptible to microbial spoilage during transportation, processing, and storage. This phenomenon makes them potentially high-risk fresh products. This study aimed to assess the effect of emulsion coating consisting of Dracocephalum kotschyi essential oil (0, 50, 150, 250, 300 ppm)-chitosan solution (0, 0.3, 0.38, 0.63, 0.75%) during the immersion time (10, 25, 55, 85, 100 s) on the microbial properties of fresh sprouted wheat stored at 4°C. The Response Surface Methodology (RSM) was adopted in modeling the independent variables’ effects. The results shown that increase in the essential oil and chitosan solution concentration reduced the microbial spoilage. High concentration of Dracocephalum kotschyi oil decreased the fungus population after 12 days. Coating of sprouted wheat at optimized level of independent variables (0.62% chitosan, 57 ppm Dracocephalum kotschyi oil and 29.49 s immersion time) reduced the microbial and fungal populations. This treatment can reduce weight loss, and maintain tissue firmness, total phenolic, and ascorbic acid content of the sprouted wheat during cold storage, with no effect on its sensory properties. Our findings indicate that nanoemulsion coating based on chitosan and Dracocephalum kotschyi oil at appropriate levels could be beneficial in maintaining sprouted wheat quality and increasing its shelf-life.
Food Chemistry
Zeinab Ghasemi Arshad; Abdollah Ehtesham Nia; Eisa Hazbavi; Hassan Mumivand; Morteza Soleimani Aghdam
Abstract
IntroductionThe increase in people's awareness of the negative effects of chemical preservatives has led to more research on the antimicrobial effect of plant essential oils and their potential to be used as preservative compounds. Strawberry (Fragaria ananassa cv. qingxiang) is one of the ...
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IntroductionThe increase in people's awareness of the negative effects of chemical preservatives has led to more research on the antimicrobial effect of plant essential oils and their potential to be used as preservative compounds. Strawberry (Fragaria ananassa cv. qingxiang) is one of the most popular and widely consumed berries due to its taste, sweetness and healthy function. The taste of strawberry is related to its hardness, viscosity, sugars, protein, total soluble solid, titratable acidity content and minerals like P, K, Ca and Fe. It is a good source of polyphenolic compounds such as flavanols and has antioxidant activity. This, together with higher vitamin C content in strawberries, contributes beneficial effects on the maintenance of consumer health. Strawberry has higher antioxidant activities than orange, grape, banana, apple, etc. Strawberries are among the fruits sensitive to mechanical and physiological damage and have a fast metabolism and deterioration during the storage period. For this reason, it is necessary to use safe methods to control spoilage and maintain the quality of strawberry fruit during storage. Materials and Methods The experiment was conducted in a completely randomized design, in a 5 x 4 factorial scheme (5 treatments x 4 periods evaluated), with four replications The first variable was the type of material with different concentrations in five levels including 0, 0.3%, 0.6% carvacrol, the combination of chitosan with 0.3% and 0.6% carvacrol, and the second variable was storage time in four periods including 0, 10, 20, 30 days of storage. The harvested fruits were kept at 4°C and with a relative humidity of 90±5% and parameters such as weight loss, pH, firmness of the fruit tissue, acidity (TA), soluble solids (TSS) and taste index, vitamin C, phenol and flavonoid, fruit shelf life (number of days) during the storage period were investigated and studied. Results and Discussion The ANOVA results showed that the effect of the type of treatment and storage time on all investigated traits except for the firmness of the fruit texture was significant at the probability level of 1%. The fruits treated with the combination of chitosan and carvacrol 0.6% had more texture firmness, vitamin C, total phenol content and the amount of soluble solids and better shelf life than the control. In all four storage times, the highest content of total phenol (2.49 mg of gallic acid per 100 gr FW), total flavonoid (0.435 mg of Quercetin per 100 gr FW) and firmness (3.80 N) was related to the combined treatment of chitosan with carvacrol 0.6% and the lowest amount was related to the control. The firmness of the fruit tissue gradually decreased during storage, but this process was observed at a significantly slower rate in the treated fruits. ConclusionConsidering the increase of 10 and 12 days of shelf life post- harvest of the combined treatment of chitosan + 0.6% carvacrol compared to other treatments and the control, hence the application of chitosan pre harvest and the use of 0.6% carvacrol edible coatings can be recommended as a safe and low-cost strategy to increase the shelf life post harvesting of 'Parus ' strawberry cultivar.
Food Technology
Azade Farazmand; Hossein Jalali; Ali Najafi
Abstract
Introduction Potato strips are one of the most widely consumed products, and due to their high oil content, they have caused public health concerns. Therefore, efforts to reduce oil absorption can alleviate these concerns to some extent. Edible coating is an effective way to reduce oil uptake, because ...
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Introduction Potato strips are one of the most widely consumed products, and due to their high oil content, they have caused public health concerns. Therefore, efforts to reduce oil absorption can alleviate these concerns to some extent. Edible coating is an effective way to reduce oil uptake, because the oil absorption is a surface phenomenon. Edible coatings should adhere well to the surface of the product and provide a uniform and complete coverage for the product. Preventing the migration of oxygen, carbon dioxide, aromas, oils, moisture, improving the appearance of food and mechanical properties. In this study, the possibility of reducing oil absorption in French fries was investigated using okra mucilage and chitosan as edible coatings. Material and Methods The okra was washed and then cut into about 1 cm pieces and poured into containers with lids. Then water in a ratio of 2:1 weight of okra was added to the container and completely covered its surface. The okra were refrigerated for 72 hours until the mucilage was completely extracted. Then the mucilage was smoothed. This solution was considered as 100% mucilage solution. To prepare a 50% solution of okra mucilage, 100% solution was mixed with an equal amount of distilled water and filtered. To produce a solution of 0.75 and 1.5% of chitosan, 7.5 and 15 g of chitosan powder was dissolved in 1000 ml of 1% acetic acid and then adjusted to pH 5. Then 5 g of glycerol was added as a plasticizer. The potato slices were first blanched in 0.5% calcium chloride solution at 90°C for 5 minutes. Then, they were immersed in coating solutions at 60°C for 5 minutes. After coating, the potato strips were fried at 180°C using a fryer and then various characteristics including coating percentage, oil absorption, and moisture content, texture firmness, peroxide value, acid number, color indices and sensory properties were examined. Design Expert 8.0.7.1 software was used to analyze the results and to draw the curves. Results and Discission The results showed that the increasing the amount of chitosan led to better coating formation in comparison with okra. The highest coverage was observed in the concentration of 1.2% chitosan and 0% okra mucilage (2.38%) and the lowest was observed in the control sample (0.11%). It was also observed that with increasing the concentration of chitosan and okra mucilage, the amount of oil absorption decreases. However, the amount of oil absorption in high concentrations of okra mucilage increased slightly. The highest oil uptake in the control sample was 20% and the lowest was observed in the sample of fried strips covered with 41% okra mucilage and 1.5% chitosan at 15.44%. The obtained model of oxidation index was not significant. The effect of okra mucilage and chitosan concentration on the texture of the samples (p <0.05) and the color indices of a* (p<0.01) and L* (p <0.05) were significant. For sensory attributes, the highest and the lowest taste score was observed for samples coated with 100% okra mucilage and 0.75% chitosan and samples coated with 18% okra mucilage and 0% chitosan respectively. Conclusion The aim of this project was to reduce the oil absorption of fried potato strips by coating them with chitosan and okra mucilage. Optimization to minimize the consumption of okra and chitosan mucilage showed that coating with 74% okra and 0.89% chitosan is suitable for coating potato slices. The desirability of this optimization was 71%, which is a reasonable percentage.
Food Chemistry
Mahbobe Mohammadi; Soheila Aghaei Dargiri; Somayeh Rastegar
Abstract
The use of edible coatings has been considered as an effective solution to improve the shelf life and quality of fruits. In this research, increase in the shelf life of citrus fruits (Citrus aurantifolia cv. Mexican lime) coated with Persian gum and pomegranate seed oil was investigated. Different treatments ...
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The use of edible coatings has been considered as an effective solution to improve the shelf life and quality of fruits. In this research, increase in the shelf life of citrus fruits (Citrus aurantifolia cv. Mexican lime) coated with Persian gum and pomegranate seed oil was investigated. Different treatments of lemon fruit coated with Persian gum and pomegranate seed oil with concentrations (zero (control), 0.5% and 1% gum, combination of 0.5% and 1% gum and pomegranate seed oil, 0.05% and pomegranate seed oil 0.05 percent) were prepared and after 24 days of storage at ambient temperature (20 ± 2 °C and relative humidity of 50-60 percent) were statistically evaluated in the form of a completely random design with three replications. The results of this research showed that the treatments used had an effective role in controlling the weight loss of fruit during storage. Thus, the lowest percentage of weight loss was observed in the pomegranate seed oil treatment. Except pomegranate seed oil treatment, other treatments showed less TSS than the control. In most of the treatments, the content of phenol, flavonoid and antioxidant was at a higher level than the control. The average comparison results showed that the fruits coated with 1% gum (85.36 units/ml) showed significantly more peroxidase activity than the control (60.35 U/ml). Persian gum edible coating 1% and 0.5% as well as Persian gum 1% in combination with pomegranate seed oil significantly controlled the activity of polyphenol oxidase enzyme. The treated samples showed less yellowness (b*) than the control. In general, the best marketability was observed in fruits coated with 1% gum. Therefore, it is recommended to use this coating to preserve the freshness and quality of the Mexican lime fruit during storage in the environment.
Mahyar Rad; Hamed Ghafori; Zohreh Gholami
Abstract
Introduction: Edible mushrooms are among the most perishable products that begin to lose quality immediately after harvest, and the short shelf-life of these products will cause problems when it comes to the marketing and distribution of these products in a fresh form. Edible coatings are a good tool ...
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Introduction: Edible mushrooms are among the most perishable products that begin to lose quality immediately after harvest, and the short shelf-life of these products will cause problems when it comes to the marketing and distribution of these products in a fresh form. Edible coatings are a good tool for prolonging the useful life of foods and increasing their quality without contaminating the environment. Materials and Methods: In this study, the possibility of increasing the shelf-life of a button mushroom using blanching followed by coating with carboxymethyl cellulose and sodium metabisulfite was studied. Independent variables included concentrations of carboxymethyl cellulose and sodium metabisulfite (0-2%) and storage time up to 16 days at 4 ° C. This experiment was designed on the basis of three-level factors consisting of 6 central points after 0, 4, 8 and 16 days of storage at 4°C. Factors determined on a button mushrooms included pH measurements, weight loss percentage, soluble solids, texture, color, browning level, total microorganisms count as well as mold and yeast count. Results & Discussion: The results of this study indicated that the sample coated with 2% carboxymethyl cellulose and 2% sodium metabisulfite resulted in an increase in pH level as well as soluble solids. In addition, the slightest color change, weight loss and reduction in tissue stiffness were observed in this sample. The sample coated with 2% carboxymethyl cellulose with 2% sodium metabisulfite had also the lowest total microorganisms count and the count of mold and yeast stored at 4 ° C after 16 days. Based on the results of this study, carboxymethyl cellulose and sodium metabisulfite coatings can be used as an appropriate coating agents for the preservation of organoleptic, chemical, microbial properties and shelf-life of button mushrooms.
Behrooz Alizadeh Behbahani; Fakhri Shahidi
Abstract
Introduction: Meat and meat products undergo chemical and microbial spoilage during production, transportation, storage and consumption. Antimicrobial edible coatings containing natural herbal extracts and essential oil possess various benefits and are currently used to design novel active biodegradable ...
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Introduction: Meat and meat products undergo chemical and microbial spoilage during production, transportation, storage and consumption. Antimicrobial edible coatings containing natural herbal extracts and essential oil possess various benefits and are currently used to design novel active biodegradable packaging. Natural polysaccharides are considered as potentially good candidates to fabricate edible coatings and provide a shelf life extender. There are no researches in the literature concerning the potential effect of Carum copticum essential oil (CCEO) enriched Scutellaria lateriflora seed mucilage (SLSM) based edible coatings on the quality and shelf life of lamb during refrigeration storage. The objective of this study was therefore to investigate the inhibitory effect of CCEO loaded SLSM edible coating towards lipid oxidation and microbial spoilage of lamb during cold storage conditions. Materials and methods: In this study, SLSM was extracted from whole seeds using hot-water extraction. Edible coating was prepared by dissolving 2 g of the extracted SLSM and 0.1 g of Tween 80 in 100 mL of sterilized distilled water. The mixture was stirred and heated for 2 h. Afterwards, CCEO was added to the SLSM solution at 0, 1, 1.5, and 2%, and the obtained solution was used as an antimicrobial coating for extending the shelf-life of lamb slices. The control and the coated lamb samples were analyzed periodically for microbiological (total viable count, psychrotrophic count, Escherichia coli, Staphylococcus aureus and fungi), chemical (peroxide value and pH), and sensory characteristics (color, odor and overall acceptability). Results and discussion: SLSM extended the microbial shelf life of lamb by 3 days, whereas SLSM + 1% CCEO, SLSM + 1.5% CCEO and SLSM + 2% CCEO resulted in a significant shelf life extension of the lamb by 6, 6, and 6 days, respectively as compared to the control samples. The results demonstrate that the EO-rich edible coating functions as an oxygen barrier and, in turn, limits the growth of most important and aerobic psychrotrophic bacteria, i.e. Pseudomonas species, which are mainly responsible for the fresh lamb spoilage under aerobic conditions. The results showed that the pH of lamb coated with SLSM and samples containing CCEO was lower than the control. The results showed that the peroxide value in the control sample increased from 0.4 to 9.7 meq oxygen/kg during 9 days of refrigerated storage. Based on the finding of this study, the use of CCEO-loaded coating manifestly lowered the meat lipid oxidation. The resultant edible coating manifestly improved the shelf life of lamb through suppressing microbial spoilage and inhibiting lipid oxidation. The coating containing 2% CCEO conferred good quality characteristics to the lamb and expanded its refrigeration shelf life.
Peyvand Gholipour; Mohammad Fazel
Abstract
Introduction: Ficus carica, commonly known as fig, is among the oldest types of fruit known to mankind. Drying is defined as a thermal process under controlled conditions in order to reduce the moisture in different types of food via evaporation. Edible films and coatings are used to enhance food quality ...
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Introduction: Ficus carica, commonly known as fig, is among the oldest types of fruit known to mankind. Drying is defined as a thermal process under controlled conditions in order to reduce the moisture in different types of food via evaporation. Edible films and coatings are used to enhance food quality by precluding oxidation and color changes in inappropriate conditions. Carboxymethyl cellulose (CMC) is thus widely used to improve food shelf life.
Materials and methods: All experiments were carried out on fresh edible green variety figs planted in the county of Neyriz Estahban. The figs were then immersed in the following solutions:
Distilled water as a control variable without coating; carboxy methyl cellulose (CMC) solution 1% containing 0.25 gr/L glycerol; and CMC solution 1% containing 0.25 gr/L glycerol and 2% ascorbic acid. Preliminary tests including average diameter, pH, total flavonoids content, and antioxidant activity were performed on the figs. The fruits were dried using a device designed by the authors. At 60 ̊C, 70 ̊C, and 80 ̊C, the airflow in the device was 0.5 m/s, 1.0 m/s, and 1.5 m/s, respectively. After drying the samples, secondary experiments were performed which, in addition to the previous tests, included texture analysis, water reabsorption, volume measurement, shrinkage, and color analysis. A total of 27 treatments were applied in 3 rounds. A full factorial design was employed for statistical analyses while average values were compared via Duncan’s test at 5% significance. Calculations were performed using SPSS 16.0.
Results & Discussion: Using CMC coating, shrinkage increased compared to the control sample. As airflow accelerates from 0.5 m/s to 1.5 m/s, higher levels of shrinkage are observed. This could be attributed to the drier surface of the fruit caused by faster airflow. Shrinkage increases with the speed of airflow going from 0.5 m/s to 1.5 m/s. This is because at higher speeds, the sample is dried in a shorter period of time and sustains less damage.
Water reabsorption was found to decrease with higher temperature and airflow. Weak reabsorption results from the breakdown of the internal structure of the fruits.
CMC-ascorbic acid, CMC, and the control sample had the highest to lowest levels of firmness, respectively. The acid was found to preserve the internal cellular structure and preserve its breakdown. Moreover, firmness increases with the drying temperature.
According to the results, the samples coated with CMC and CMC-ascorbic acid had lower pH compared to the control sample. Airflow speed and temperature are inversely and directly related to pH, respectively.
In the CMC-ascorbic acid treatment, antioxidant capacity increased compared to the other two treatments. This may be associated with ascorbic acid’s higher ability to act as a carrier of anti-browning agents. Also, higher levels of antioxidant behavior were observed with higher temperature as it causes faster drying. Moreover, the coating acts to preserve the antioxidant and eliminates the impact of temperature.
The highest amount of flavonoids was observed in the CMC-ascorbic acid treatment followed by the control sample and the CMC treatment. This is because the ascorbic acid serves to maintain the flavonoids in the samples. The flavonoid content increases with the airflow speed since the sample is dried in a shorter duration and the flavonoids are preserved. However, higher temperature reduces the flavonoid content since heat damages the pigment.
The application of the CMC coating (alone or in combination with ascorbic acid) increased luminance compared to the control sample due to the preventative effect of the edible coating on the oxidation of the pigments in the fig samples. With faster airflows, surface moisture begins to vary which causes the coating to become lighter with higher L*. An increase in the temperature leads to lower L* as the heat causes the carotenoids and chlorophyll to break down and form brown pigments in the samples.
Using the CMC-ascorbic acid coating increases a* in figs. Furthermore, as the temperature goes up from 60 ̊C, a* also increases.
The coated samples demonstrate higher levels of b* compared to the control sample. In fact, the coating preserves the pigments and thus maintains the yellow color of the figs. The value of b* is directly related to the speed of the airflow because it decreases drying time. As a result, the product undergoes less heat. Finally, higher temperature leads to higher b* in the dried figs.
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.
Malahat Safavi; Majid Javanmard
Abstract
In this study, the effects of coating with whey protein concentrate (7.5% w/v) alone and/or in combination with rice bran oil (0.2, 0.4, 0.6 g in 100 ml coating solution) and Zataria multiflora extract (1 and 2 μL in 100 ml coating solution) on the quality attributes and egg shelf life were carefully ...
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In this study, the effects of coating with whey protein concentrate (7.5% w/v) alone and/or in combination with rice bran oil (0.2, 0.4, 0.6 g in 100 ml coating solution) and Zataria multiflora extract (1 and 2 μL in 100 ml coating solution) on the quality attributes and egg shelf life were carefully observed and analyzed. Weight loss, Haugh index, yolk index, pH, air cell depth, shell strength and the impact of this coating on the microbial load of the eggs surface were studied at the end of each week (during the 4 weeks of storage in a room environment temperature and humidity). After 4 weeks of storage, it was observed that the weight loss in all of the treated eggs with whey protein concentrate and 0.2 gr of rice bran oil (experimental group) was significantly lower than that of the control group(P<0/05). With regard to Haugh index and yolk index, egg shelf life increased about 4 weeks compared with the control samples. Haugh Index changes revealed that the coated samples remained at grade A after 3 weeks of storage, while the control samples were relegated from grade AA to B after one week. Haugh and yolk Indices in all coated eggs were more than those of the control group. In the coated groups, Haugh and yolk indices of the coated samples with whey protein concentrate and 0.2 g rice bran oil and with whey protein concentrate and 0.2g of rice bran oil and 1 micro liter of Zataria multiflora extract were more than those of the other coated eggs and the control group eggs. PH values of the control group were higher than those of the coated groups during the storage of the eggs. The shell strength of the coated group was more than that of the control group (uncoated) and in coated samples, whey protein concentrate and 0.2 gr of rice bran oil coated samples had high shell strength. In the other treatments no significant differences were observed. The depth of the air cell of the coated groups was determined to be less than that of the control group during the storage period. The minimum inhibitory concentration was 1 μL of Zataria multiflora extract. The results showed that 1 μL concentration of Zataria multiflora extract reduces the microbial load of the egg shell surface to 87% and 2 μL reduced total bacterial load to zero. In sensory evaluation, from evaluator point of view, the coated eggs had more overall acceptance than the uncoated group (control), and in the treatment group coated eggs, those containing a low percentage of rice bran oil had higher overall acceptability. In conclusion, coating as a practical and cost effective method can maintain the quality parameters of eggs and lead to durability of supply conditions in addition to the product marketability.
Azam Ayoubi; Nasser Sedaghat; Mahdi Kashani-Nejad; Mohebbat Mohebbi; Mehdi Nasiri mahalati
Abstract
Introduction: Raisin is a principal traditional export product of Iran and has a special position in the foreign trade of the country.During storage, the product turns sticky and hard due to exudates syrup and moisture loss. To solve this problem, the application of edible coating would be an appropriatesolution. ...
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Introduction: Raisin is a principal traditional export product of Iran and has a special position in the foreign trade of the country.During storage, the product turns sticky and hard due to exudates syrup and moisture loss. To solve this problem, the application of edible coating would be an appropriatesolution. Edible coating may enhance the boundary layer resistance resulting to the enhanced shelf life of the product. Edible coatings are thin layers of edible materials applied to the product surface in addition to or as a replacement for natural protective waxy coatings and provide a barrier to oxygen, water and solute movement. They are also applied in foods to minimize the migration of components within the food systems or between the foods and their surrounding environment. They are used directly on the food surface by spraying, dipping or brushing to create a modified atmosphere. There are different kinds of films which are used such as polysaccharide, protein, lipid and composites. Lipid based coatings are primarily used for their hydrophobic properties which make them good barriers to water loss. In addition to preventing water loss, lipid coatings have been used to improve appearance by generating a shiny coverin fruits and vegetables, and to decrease respiration, thereby extending shelf life. The moisture barrier properties of hydrophilic coatings can sometimes be improved by addition of lipid materials The purpose of this research was to study the effect of lipid based edible coating (glycerylmonoestearate and carnauba wax) on physicochemical and microbial properties of raisin. Material and methods: Raisin samples (cvAskari)were dried usingsoda oil method and treated with coating materials based on lipid with essential oil of thyme (thymus vulgaris).Glycerylmonoestearate, carnauba wax and tween 80 were purchased from Sciencelab, Sigma-Aldrich and Merck Co. respectively. Raisinswerecoated with the following coating solutions: -Aqueous solution of tween 80 (0.5% w/w) -Aqueous solution of glycerylmonoestearate (0.5% w/w), tween 80 (0.5% w/w) -Aqueous solution of glycerylmonoestearate (0.5% w/w), tween 80 (0.5% w/w), 150 ppm essential oil of thyme -Aqueous solution of carnauba wax (0.5% w/w), tween 80 (0.5% w/w) -Aqueous solution of carnauba wax (0.5% w/w), tween 80 (0.5% w/w), 150 ppm essential oil of thyme Control sample was treated with aqueous solution of tween 80 (0.5% w/w).Distilled water was used for preparing all of coating solutions. Coating solutions were stirred and heated to 75oC (melting point of coating materials) for 30 min on a hotplate with a magnetic stirred to obtain uniform solutions. Dipping technique was used for coating of raisins. The coated raisins were placed on a basket to drip off residual coating solution and were dried in 25oC. The raisin smples were packaged in a 3 laminatedlayer bags (PE/PA/PE) with thickness of 80µ by Henkelman packaging machine and were stored at20, 35 and 50oC for 12 weeks. During the storage period, moisture content, water activity, hardness, color parameters (L*(lightness), a*(redness) and b*(yellowness)), percent of pestilence and microbial properties (total count, mold and yeast) were evaluated. Hardness of raisins was determined in apuncture test using a QTS texture analyzer (CNS Farnelll, Essex, UK) equipped with a needle probe (stainless steel cylinder of 2 mm of diameter with a conical needle bit) and a test speed of 60 mm. min−1 during the test. Hardness was defined as maximum force to puncture raisin from the top to a 2mm depth (Rolleet al. 2011).For colormeasurement, raisins were placed in to a black wooden box (interior size of 0.5 (width) × 0.5 (length) × 0.8 (height) m3 and were illuminated using 3 fluorescent tube lights (10W, 6500K; 40cm in length). A digital camera (Canoon EOS 1000D, Powershot, Taiwan) was located vertically at a distance of 20cm from the raisin surface. The images were preprocessed by Adobe Photoshop software, version 5.5. The Color properties were analyzed using ImageJ software, version 1.44o. The experiments were factorial with a completely randomized design. The coating material, temperature and storage time were the independent variables. Analysis of variance (ANOVA) was conducted for data using MSTAT-C software, version 1.42 (Michigan State University). Differences among the mean values were also determined using Duncan’s Multiple Range test. A significant level was defined as a probability of 0.05. The experiments were carried out on 4, 8 and 12 weeks after storage with three replications. Results and discussion: Results showed that coating, temperature and storage time would have considerable effect on the physicochemical and microbial properties of raisin. Coating caused decreasein moisture loss, hardness, lightness and redness. Increasing temperature and storage time increasedmoisture loss and hardness. Minimum hardness values were measured for 20 oC and 4 weeks storage and maximum hardness values were related to 50 oC and 12 weeks storage. Also it seems that increasing temperature and storage time influences thehardness by increasing moisture loss. Increasing temperature and storage time significantly decreased L* (p≤0.01). Increased enzymatic browning in raisins with increasing temperature was accompanied by an increase in a* value, and a decrease in b* value and caused to presenting dull colors. Total count, mold and yeast of coated samples decreased during storage period. Carnauba wax was more effective than glycerylmonoestearate on stability of raisin. Essential oil of thyme also caused improving color and microbial properties. Least values of redness (-2), total count (2.06 log cfu/g) and mold and yeast (1.32 log cfu/g) were related to carnauba wax coating with essential oil of thyme.
Sanaz Ojnordi; Majid Javanmard; Simin Asadollahi
Abstract
Due to environmental risks generated by application of non-degradable and synthetic films, many researches have shown increasing tendency to edible coatings for storing food such as fruits and vegetables. Whey protein is considered one of the most common sources of edible coatings and its use has been ...
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Due to environmental risks generated by application of non-degradable and synthetic films, many researches have shown increasing tendency to edible coatings for storing food such as fruits and vegetables. Whey protein is considered one of the most common sources of edible coatings and its use has been studied in the current research. In this paper, the simultaneous effect of coating with whey protein and Zataria multiflora Boiss extract on the quality of peach kept in refrigerator has been studied. According to response surface methodology, were measured 20 treatments repeating 6 times in the center point and effects of the three factors including whey protein (2. 5 to 5 gr), Zataria multiflora Bioss extract (0 to 500 μL) and glycerol (0. 375 to 2. 25 gr) on the physicochemical characteristics, fungal decay and organoleptic traits of peach, were investigated in the condition 5±2 ̊C and 80% relative humidity during 21 days of storage. According to the results, by increasing Zataria multiflora Bioss extract concentration and whey protein of the coating, microbial decay and weight loss of the fruit was reduced and texture and soluble solids were conserved. Peel colour changes of the coated fruit was not significant compare to control and the coated samples had a light and bright colour. Coating peach resulted in natural ripening of the fruit and the coated fruits were softer and juicier than the fruits without any coating. The coating formulations had significant effect on TSS and TA. Optimized points of variables for achieving a coating with the maximum effect on shelf life improvement of peach (Prunus Persica cv. Anjiri) are: whey protein 4. 7475 gr, Zataria multiflora Bioss extract 498. 00 μL and glycerol 0. 6212 gr.
Azam Seraji; Babak Ghanbarzadeh; Mahood Sowti Khiabani; Sara Movahhed
Abstract
In this study, the effect of edible coating and osmotic dehydration, as pre-treatments before drying of cucurbit, were investigated. Cucurbit samples were cut spirally and coated by carboxy methyl cellulose (CMC) 1% and ascorbic acid 0.1% solutions and then processed by osmotic dehydration. Proportion ...
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In this study, the effect of edible coating and osmotic dehydration, as pre-treatments before drying of cucurbit, were investigated. Cucurbit samples were cut spirally and coated by carboxy methyl cellulose (CMC) 1% and ascorbic acid 0.1% solutions and then processed by osmotic dehydration. Proportion of sample to solution was 1:10 and the solution containing sucrose %45, salt%25 and citric acid %1 (W/W) was selected as the best osmotic solution. Finally, the cucurbit samples were dried by oven (at 80 ˚C for 3 hours). The effects of CMC based coating on water loss (WL), solid gain (SG), immersion time, amount of salt, sucrose, citric acid absorption and color and sensory acceptability of samples were evaluated. The results showed that CMC based coating decreased SG without decreasing effect on WL which in turn decreased drying time of osmotic dehydrated samples in oven. Furthermore, the coated, osmotic dehydrated samples showed higher color quality and sensory acceptability in comparison to the control samples.
