اثر پوشش‌دهی با کیتوزان و عصاره برگ گردو در ماندگاری پسته

پسته، یکی از محصولات صادراتی ایران، در شرایط نامساعد در طول دوره انبارمانی، کپک زدگی، آفت زدگی و تولید سموم بویژه آفلاتوکسین توسط آسپرژیلوس پاراسیتیکوس و آسپرژیلوس فلاووس و جذب رطوبت باعث افت شدید کیفیت محصول می‌شود. هدف از این مطالعه تعیین اثر پوشش‌دهی پسته با محلول کیتوزان و عصاره برگ گردو در ماندگاری محصول می باشد. برای این منظور پسته‌ها با استفاده از محلول‌های 1.5 و 3 % (وزنی/ حجمی) کیتوزان و عصاره برگ گردو تهیه شده به صورت تکی و ترکیبی پوشش‌دهی شدند و تاثیر آن بر ویژگی‌های آفات زنده، حسی، عدد پراکسید، شمارش کپک ومخمر و رطوبت طبق استاندارد ملی ایران در طی مدت نگهداری مورد بررسی قرار گرفت و نتایج با آزمون آنالیز واریانس در سطح احتمال 5% تجزیه و تحلیل شدند.پسته‌های پوشش داده شده به صورت معنی‌داری از نظر میزان آفات زنده با نوع شاهد متفاوت بود (p<0.05). نتایج نشان داد که در طی مدت نگهداری سه ماهه، پوشش کیتوزان با عصاره گردو، تاثیر معنی‌داری روی ویژگی‌های حسی پسته پوشش داده شده نداشت. در هر یک از زمان‌ها، رطوبت نمونه شاهد (3.12%) نسبت به پسته‌های پوشش‌دهی شده (4.99% برای نمونه حاوی 3% کیتوزان و 3% عصاره گردو) به طور معنی‌داری کمتر بود (p<0.05). با افزایش غلظت کیتوزان، اثر آنتی‌اکسیدانی و ضد‌میکروبی و ضد آفاتی آن افزایش یافته و ضمن حفظ ویژگی‌های حسی به طور موثری در جلوگیری از اکسایش و فعالیت قارچی در پسته موثر بود. کمترین میزان پراکسید برای نمونه حاوی 3% کیتوزان و 1.5% عصاره گردو مشاهده شد. با توجه به نتایج به دست آمده، بهترین غلضت محلول 1.5% کیتوزان و 1.5% عصاره برگ گردو به صورت ترکیبی برای افزایش ماندگاری پسته پیشنهاد شد.

The Effect of Chitosan Coating Incorporated with Walnut Leaf Extract on Shelf Life of Pistachio

Pistachio, one of the export products of Iran, under unfavorable conditions during storage mold spoilage and toxins production, especially aflatoxins by Aspergillus parasiticus and Aspergillus flavuse, and moisture absorption decrease the quality of the product. The main objective of this study was evaluating the effect of pistachio coating with chitosan and walnut leaf extract solution in its shelf life. Pistachios were coated by prepared 1.5 and 3% (w/v) chitosan and walnut leaves extract solutions individually and binary and its impact on the moisture content, peroxide value, pests, fungal count and sensory properties of the pistachios were assessed base on national standards of Iran. Data were analyzed by ANOVA test and mean comparisons at a confidence level of 5%. The pests in coated pistachios were significantly different from control ones (p < 0.05). The effect of chitosan edible coating with walnut leaves extract during storage time on the sensory properties was not significant. In each time, moisture content of control sample (3.12%) was significantly lower than coated ones (4.99% for the sample containing 3% chitosan and 3% walnut extract)(p < 0.05). Besides, increasing concentrations of chitosan were increased antioxidant and antimicrobial effects, maintained the sensory properties and were effective in preventing oxidation and fungal activity in pistachios. The lowest peroxide content was observed for samples containing 3% chitosan and 1.5% walnut extract. According to the results, the best solution containing a composition of 1.5% chitosan and 1.5% walnut leaf extract was suggested to increase the shelf life of pistachio. Pistachio, one of the export products of Iran, under unfavorable conditions during storage mold spoilage and toxins production, especially aflatoxins by Aspergillus parasiticus and Aspergillus flavuse, and moisture absorption decrease the quality of the product. The main objective of this study was evaluating the effect of pistachio coating with chitosan and walnut leaf extract solution in its shelf life. Pistachios were coated by prepared 1.5 and 3% (w/v) chitosan and walnut leaves extract solutions individually and binary and its impact on the moisture content, peroxide value, pests, fungal count and sensory properties of the pistachios were assessed base on national standards of Iran. Data were analyzed by ANOVA test and mean comparisons at a confidence level of 5%. The pests in coated pistachios were significantly different from control ones (p < 0.05). The effect of chitosan edible coating with walnut leaves extract during storage time on the sensory properties was not significant. In each time, moisture content of control sample (3.12%) was significantly lower than coated ones (4.99% for the sample containing 3% chitosan and 3% walnut extract)(p < 0.05). Besides, increasing concentrations of chitosan were increased antioxidant and antimicrobial effects, maintained the sensory properties and were effective in preventing oxidation and fungal activity in pistachios. The lowest peroxide content was observed for samples containing 3% chitosan and 1.5% walnut extract. According to the results, the best solution containing a composition of 1.5% chitosan and 1.5% walnut leaf extract was suggested to increase the shelf life of pistachio. Pistachio, one of the export products of Iran, under unfavorable conditions during storage mold spoilage and toxins production, especially aflatoxins by Aspergillus parasiticus and Aspergillus flavuse, and moisture absorption decrease the quality of the product. The main objective of this study was evaluating the effect of pistachio coating with chitosan and walnut leaf extract solution in its shelf life. Pistachios were coated by prepared 1.5 and 3% (w/v) chitosan and walnut leaves extract solutions individually and binary and its impact on the moisture content, peroxide value, pests, fungal count and sensory properties of the pistachios were assessed base on national standards of Iran. Data were analyzed by ANOVA test and mean comparisons at a confidence level of 5%. The pests in coated pistachios were significantly different from control ones (p < 0.05). The effect of chitosan edible coating with walnut leaves extract during storage time on the sensory properties was not significant. In each time, moisture content of control sample (3.12%) was significantly lower than coated ones (4.99% for the sample containing 3% chitosan and 3% walnut extract)(p < 0.05). Besides, increasing concentrations of chitosan were increased antioxidant and antimicrobial effects, maintained the sensory properties and were effective in preventing oxidation and fungal activity in pistachios. The lowest peroxide content was observed for samples containing 3% chitosan and 1.5% walnut extract. According to the results, the best solution containing a composition of 1.5% chitosan and 1.5% walnut leaf extract was suggested to increase the shelf life of pistachio. Pistachio, one of the export products of Iran, under unfavorable conditions during storage mold spoilage and toxins production, especially aflatoxins by Aspergillus parasiticus and Aspergillus flavuse, and moisture absorption decrease the quality of the product. The main objective of this study was evaluating the effect of pistachio coating with chitosan and walnut leaf extract solution in its shelf life. Pistachios were coated by prepared 1.5 and 3% (w/v) chitosan and walnut leaves extract solutions individually and binary and its impact on the moisture content, peroxide value, pests, fungal count and sensory properties of the pistachios were assessed base on national standards of Iran. Data were analyzed by ANOVA test and mean comparisons at a confidence level of 5%. The pests in coated pistachios were significantly different from control ones (p < 0.05). The effect of chitosan edible coating with walnut leaves extract during storage time on the sensory properties was not significant. In each time, moisture content of control sample (3.12%) was significantly lower than coated ones (4.99% for the sample containing 3% chitosan and 3% walnut extract)(p < 0.05). Besides, increasing concentrations of chitosan were increased antioxidant and antimicrobial effects, maintained the sensory properties and were effective in preventing oxidation and fungal activity in pistachios. The lowest peroxide content was observed for samples containing 3% chitosan and 1.5% walnut extract. According to the results, the best solution containing a composition of 1.5% chitosan and 1.5% walnut leaf extract was suggested to increase the shelf life of pistachio.