جستجوی مقالات مرتبط با کلیدواژه « پوشش کیتوزان » در نشریات گروه « صنایع غذایی »

Recently, the use of new packaging materials and natural additives for improving the durability and preservation of foods has been increasingly considered. Edible coatings containing plant extracts lead to increase the shelf life of food, do not cause environmental contamination, and do not endanger the health of the consumer. Fish is a food rich in amino acids, vitamins and minerals, and polyunsaturated fatty acids, especially omega-3, which has made it more and more popular in the human diet. However, the presence of a significant amount of polyunsaturated fatty acids as well as easily digestible proteins has turned fish into a highly perishable commodity. Fresh seafood spoils rapidly due to the enzymatic and bacterial activities that occur after death, as well as the spoilage caused by the oxidation of polyunsaturated fatty acids and the high concentration of hematin compounds and metal ions of fish muscle, such as iron, and their pH which is close to neutral. Therefore, the use of natural coatings that can increase the shelf life of food and attract the consumers should be given more attention. Iran is the largest fishery producer in the region, thus, providing new methods to increase the shelf life of these products until the time of consumption can guarantee the safety and be effective in the economic prosperity of this industry. Therefore, the present study was designed to investigate the effect of chitosan coating along with the volatile oil of ginger plant on the shelf life of salmon fillets stored in refrigerator to reduce microbial growth, reduce chemical reactions, and increase the storage life of salmon fillets in refrigerator.

Rainbow trout fish with an approximate weight of 600 grams were purchased from the market. Fish were washed with sterile distilled water, and cut into 60-gram pieces after separating the head and tail and eviscerating. The prepated fish were randomly divided into 4 groups. The control group was without any treatment but the treatment groups were immersed in chitosan containing different concentrations of Ginger essential oils. All the samples were kept in zipped bags at refrigerator (4°C) for 15 days. Microbial tests (Mesophilic, Psychrophilic, Coliform, and Lactic acid bacteria count), chemical tests (pH, TVN, TBARS), and sensory tests (color, smell, taste, texture, and overall acceptance) were performed on days 1, 4, 7, 12 and 15. The data obtained from the microbial and chemical tests were analyzed by one-way analysis of variance and the data obtained from the sensory tests were analyzed by the Kruskal-Wallis test in Sigma Stat 4 statistical software, considering P<0.05.

 The results of bacterial tests showed that chitosan coating with ginger essential oil had a significant effect on reducing the growth of mesophilic, coliform, lactic acid bacteria and psychrophilic bacteria compared to the control and chitosangroups during 15 days of storage in the refrigerator (P<0.05). During the storage period, chitosan-treated groups containing 1.5% and 0.75% of ginger volatile oil had the best microbial quality in terms of mesophilic bacteria, Psychrophilic bacteria, lactic acid- bacteria, and coliforms. Also, in samples immersed in chitosan coating with ginger essential oil, the pH, TVN and TBARS values at the end of the storage period were significantly lower than the control and chitosan group (P<0.05). The results showed that pH, TVN, and TBARS did not exceed the defined standard for fish meat at the end of the storage period in the groups treated with ginger volatile oil. Sensory characteristicsindicated that the groups treated with chitosan coating containing ginger essential oils showed better sensory characteristics in terms of color, taste, smell, texture, and overall acceptance than the control and chitosan groups during the storage period (P<0.05).

Based on the results of the present study using the chitosan coating combined with ginger volatile oils has antimicrobial and antioxidant properties, which can reduce the oxidation of fats and microbial loads, while maintaining the organoleptic quality and increasing the shelf life of fish meat at refrigerator temperature. In comparison between treated groups, the use of chitosan along with 0.75% volatile oil of ginger is recommended, because by using a smaller amount of volatile oil, the microbial, chemical, and organoleptic properties can be kept at the standard level until the 15th day.

Meat is prone to contamination and spoilage due to its composition and production. Therefore, in order to extend its shelf life, the use of antioxidant and antimicrobial compounds has always been the focus of researchers' attention.The present study was conducted to evaluate effects of edible chitosan (2%) coating containing Cuminum cyminum essential oil (1%) on the shelf-life of meat in modified atmosphere packaging at refrigerated storage. The meat samples were separated into three groups uncoated (control), treated with chitosan coated without Cuminum cyminum essential oil and immersed in chitosan coated with Cuminum cyminum essential oil.  Then Samples were packed in MAP (80% O2 and 20% CO2) conditions and stored at 4°C up to 21 days and evaluated periodically (on days 0, 3, 6, 9, 12, 15, 18 and 21) for microbiological (Total microbial counts, lactic acid bacteria, Enterobacteriaceae and Pseudomonas spp.) and chemical (pH, TBA and TVN) characteristics. Microbial analysis indicated that coating had significant influence (p<0.001) on reduction of increasing trends of Total microbial counts, lactic acid bacteria, Enterobacteriaceae and Pseudomonas spp.bacteria. From the aspects of chemical factors, the containing chitosan coating groups showed lower pH, TBA and TVN than those without coating. According to the results, chitosan coating significantly improved (P<0.05) quality of samples. This study also indicated that the effect of chitosan containing Cuminum cyminum essential oil on samples was to retain their good quality characteristics and extend the shelf life during refrigerated storage, which was supported by the results of microbiological, chemical, and sensorial properties.

Lipid oxidation and microbial growth are the most important factors affecting the quality and Spoilage of the meat in refrigerated storage conditions. In this study, the effect of using chitosan, Medlar concentrate, ginger essential oil alone and in combination with each other on improving the quality and shelf life of chicken meat kept in the refrigerator was investigated.8 groups in this study during 12 days were stored at refrigerator and Microbial (aerobic mesophilic & Psychotrophic Plate count) and chemical (PV, TBA, TVB-N) and. sensory parameters were measured at days 0, 4, 8 and 12. Total phenol and reducing power tests were also performed to evaluate the antioxidant properties .Based on the results of GC/MS, the major compounds of ginger essential oil were α-Zingiberene (36.54%), b-Sesquiphellandrene (16.45%) and trans-γ-Cadinene (10.27%) were formed. The results of this study showed that the chitosan-coated treatment containing 2% ginger essential oil and medlar concentrate, decreased the microbial parameters significantly (P<0.05) as compared to control group during the storage period (P<0.05).the oxidation indices of chicken meat samples had significantly fewer changes (P<0.05), had the strongest antioxidant and sensory effect on other groups during storage. The results of microbiological, chemical and sensory analysis of this study showed that the effect of chitosan coating containing 2%ginger essential oil and medlar concentrate was effective in increasing the shelf life and quality of chicken meat for 12 days during storage in the refrigerated condition.

Iran is one of the largest pistachio producer and exporter in the world. Under unfavorable conditions during storage, pistachio quality will be reduced due to undesirable reactions. This study was conducted to evaluate the influence of chitosan coating with different molecular weights and concentrations on oxidation activity in the Akbary variety of pistachio nuts. Therefore, using acetic acid as 1% (v/v), chitosan with low molecular weight (LMC) and medium molecular weights (MMC) at concentrations of 0.5%, 1% and 1.5% V/W were prepared and pistachios were coated by them. In order to prepare control group, coating was performed with water and acetic acid as 1% V/V. Coated pistachios were packed in polyethylene bags and kept at room temperature and relative humidity (25-27 °C and 35-45%) for six months. Samples were examined every two weeks for peroxide and thiobarbituric acid value during storage. The results showed that during storage, chitosan coating reduced the rate of oxidation significantly (P <0.05). The LMC exhibited higher anti- oxidant activity than MMC and increased concentration correlated with higher antioxidant activity. The thiobarbituric acid value of pistachios was always zero due to non-formation of secondary compounds of oxidation reactions. In this research, LMC was found appropriate edible coating material for pistachio nuts.