The present study was performed to investigate the effect of nettle hydroalcoholic extract (NE) with edible sodium alginate (SA) coating on the quality of rainbow trout fillet (Oncorhynchus mykiss) during a 12-day refrigeration period (4±1˚C). NE was extracted by ethanol solvent and the chemical compounds of NE were determined. Experiments were performed on 4 treatments (T1: control treatment, T2: SA 2%, T3: SA+NE 0.5% and T4: SA+NE 1%) in three replications. The results of chemical tests performed in comparison with the control sample showed that the samples containing the SA and NE were able to control the increase of chemical and microbial parameters (p<0.05). At the end of the storage period, the lowest amount of peroxide value, thiobarbituric acid and total volatile basic nitrogen, and the lowest amounts of lactic acid-producing bacteria, total bacterial count, psychrotrophic values were observed in SA+NE 1% (p<0.05). The results of the sensory evaluation showed that the mentioned treatment maintained the quality of the fillet until the end of the storage period. In general, edible coating of SA with NE can delay the process of lipid oxidation and microbial spoilage and maintain or improve the sensory properties of refrigerated fish fillets. پرونده مقاله

The aim of this study was to investigate the impacts of NaCl, bile salts, and their combinations on the viability of Lactobacillus casei in probiotic yogurt. For this purpose, the antibacterial activity of NaCl and bile salts was investigated via the microdilution technique by determining the minimum inhibitory concentration (MIC) against L. casei. Further, the stress effects of 50% MIC on NaCl and bile salts on the L. casei were examined by comparing the stress treatments with the control in terms of the L. casei population, pH, acidity, and syneresis percentage in probiotic yogurt during storage in the refrigerator for 28 days. According to the results, the L. casei population and pH decreased in all the treatments during the storage time, such that the intensity of the decrease in the control treatment was lesser than in other stress treatments (p<0.05). The acidity and percentage of syneresis during the storage time increased for all the treatments, with the increase being less in control than in the other stress treatments (p<0.05). The control scored the highest in the sensory evaluation (p<0.05). In conclusion, applying stresses below the MIC had a negative effect on the survival of L. casei in the probiotic yogurt until the end of 28 days and the outcome was not as expected. پرونده مقاله

An edible coating of chitosan (CH) containing cumin essential oil (CEO) was used in this study to increase the shelf life of chicken fillets during refrigerated storage (4±1 ˚C). CEO was extracted by Clevenger apparatus, and the chemical compounds of CEO were determined. Four treatments were produced to investigate the shelf life of chicken fillets: T1: Control (C), T2: CH, T3: CH-CEO (0.75%), and T4: CH-CEO (1.5%). The chemical parameters (peroxide value, thiobarbituric acid, and total volatile basic nitrogen), microbial parameters (total bacterial counts, psychrotrophic bacteria, lactic acid bacteria), and sensory attributes (taste, odor, color, texture, and general acceptance) of the chicken fillets were periodically evaluated. Cumin aldehyde (25.79%), gamma-terpinene (21.95%), propanol (18.17%), p-menta-1,4-dien 7-al (11.73%), and beta-pinene (9.27%) were the chemical compounds of CEO. It was shown by the results that the microbial load and chemical oxidation of chicken fillets were inhibited by the active edible coating (p<0.05) and that better preservation effects have resulted from higher essential oil concentration (p<0.05). T4 achieved the best chemical, microbial and sensory results in most tests at the end of the storage period. The shelf life of chicken fillets during storage in the refrigerator was increased by the CH edible coating containing CEO, as demonstrated by this study. پرونده مقاله

In this study nine new varieties of sunflower seeds were obtained and subjected to oil extraction using soxhlet apparatus. The extracted oil was analyzed for fatty acid composition and phosphorus content to measure the phospholipid concentration. The results indicated that Armavirski variety had the highest oil content. The fatty acid composition of the extracted oils indicated that Armavirski followed by Alstar varieties had the highest concentrations of oleic acid and lower concentrations of linoleic acid as compared to other varieties. Therefore the two varieties mentioned earlier might be considered as suitable substrates for frying and cooking practices. پرونده مقاله

In this project, different nettle plants from north regions of Iran including Tonekabon, Amol and Gorgan were collected. The oil was extracted using soxhlet extraction apparatus and was subjected to series of physical and chemical tests and determinations consisting of refractive index, melting point, smoke point, nonsaponifiable matter, Iodine value, saponification value, peroxide value, totox value, acid values, kreis test and fatty acids composition. Among the samples collected the one obtained from Gorgan had the highest oil content. Fatty acid analysis of the extracted oils indicated a high degree of unsaturation where linolenic acid accounted for 28.7 % of the total fatty acids with an unusual concentration of C17:0. The oil also showed a high concentration of nonsaponifiable matter where the sterol constituted the major part of this fraction. پرونده مقاله

یکی از چالش‌های اصلی در استفاده از پروبیوتیک‌ها زنده و فعال نگه‌داشتن آن‌ها در حین فرآیند تولید و نگهداری مواد غذایی است. از این رو مطالعه حاضر با هدف بررسی اثر استرس‌ کمتر از حداقل غلظت بازدارندگی بر زنده‌مانی لاکتوباسیلوس کازئی و برخی از خصوصیات فیزیکوشیمیایی ماست پروبیوتیک در طی دوره نگهداری در یخچال انجام شد. اسانس گیاه زیره سبز به روش تقطیر با بخار آب استخراج و ترکیب آن با دستگاه گاز کروماتوگرافی طیف سنج جرمی GC/MS تعیین شد. سپس اثر استرس اسانس زیره سبز به میزان 50 درصد MIC، به‌عنوان تیمار استرس در مقایسه با شاهد روی جمعیت باکتری‌های لاکتوباسیلوس کازئی، pH، اسیدیته و درصد آب‌اندازی در ماست‌های پروبیوتیک طی 28 روز نگهداری در یخچال مورد ارزیابی قرار گرفت. تجزیه و تحلیل داده‌ها به روش آنالیز واریانس Tukey در نر‌م‌افزار SPSS نسخه 18 صورت گرفت. مطابق نتایج مربوط به ترکیبات تشکیل دهنده اسانس، بیشترین ترکیب را پروپانال- 2متیل-3- فنیل با 2/24 درصد تشکیل داده بود. همچنین نتایج مربوط به ماست نشان داد، تعداد باکتری لاکتوباسیلوس کازئی و pH در هر دو تیمار طی دوره نگهداری کاهش یافته بود به‌طوری که شدت کاهش pH در تیمار تحت استرس در مقایسه با تیمار شاهد بیشتر بود (05/0P <). اما تغییرات باکتری لاکتوباسیلوس کازئی در دو تیمار اختلاف معنی داری باهم نداشتند (05/0P >). مقدار اسیدیته و درصد آب‌اندازی طی دوره نگهداری برای هر دو تیمار افزایش یافته بود و شدت افزایش در تیمار تحت استرس بیشتر از شاهد بود (05/0> .(P در مجموع نتایج مطالعه حاضر نشان داد اعمال استرس‌های کمتر از حداقل غلظت بازدارندگی باعث زنده‌مانی باکتری لاکتوباسیلوس کازئی به مقدار توصیه شده ( CFU/ ml107 -106) در ماست پروبیوتیک تا پایان دوره نگهداری شده بود. پرونده مقاله