حفظ کیفیت میوه چیکو (manilkara zapota) در مدت انبارمانی با کاربرد آمینواسیدها (فنیل‎‌آلانین، گلوتاتیون و ال‌آرژنین) و تنظیم‌کننده رشد (ملاتونین)

فساد میوه چیکو (manikara zapota) عمدتا به‎دلیل حساسیت به شرایط دمایی و کاهش رطوبت رخ می‎دهد که تاثیر منفی بر کیفیت و ماندگاری آن دارد. این پژوهش با هدف ارزیابی تاثیر آمینواسیدها و تنظیم‌کننده رشد بر حفظ کیفیت و افزایش عمر انیارمانی چیکو انجام شد. میوه‎ها به‎مدت 2 دقیقه در محلول‎های فنیل‎‌آلانین (8 میلی‌مولار)، گلوتاتیون (0.05 درصد)، ملاتونین (0.5 میلی‌مولار) و ال‌آرژنین (1 میلی‌مولار) در مقایسه با شاهد (آب مقطر) غوطه‎ور شده و سپس در محیط خشک شدند. پس از اعمال تیمار، میوه‎ها در سردخانه با دمای 1±8 درجه سلسیوس و رطوبت نسبی 5±90 درصد نگهداری شدند. آزمایش به‌صورت فاکتوریل در قالب طرح کاملا تصادفی با سه تکرار انجام شد و ارزیابی کیفیت میوه‎ها در در پنج زمان انبارمانی (صفر، 10، 20، 30 و 40 روز) صورت گرفت. پس از پایان دوره، میوه‌ها به‎مدت یک روز در دمای محیط (25 درجه سلیسیوس) نگهداری شدند تا تغییرات کمی آنها بررسی شود. نتایج نشان داد که تیمار فنیل‎آلانین توانست به‎میزان 9.37 درصد از کاهش وزن میوه در 40 روز نگهداری جلوگیری کند و در نهایت، سفتی بافت میوه چیکو در تیمارهای ملاتونین و گلوتاتیون نسبت به شاهد به‎ترتیب 22.31 و 19.95 درصد در پایان آزمایش افزایش یافت. همچنین، تیمار گلوتاتیون سبب افزایش 56.79 درصدی میزان اسید آسکوربیک نسبت به شاهد در 40 روز نگهداری میوه شد. در پایان 40 روز آزمایش، تیمارهای آرژنین، ملاتونین و گلوتاتیون به‌میزان 6.98، 6.60 و 6.41 درصد نسبت به شاهد سبب کاهش مواد جامد محلول در میوه چیکو شدند. افزون بر این در پایان زمان نگهداری، تیمار آرژنین توانست به‎میزان 32 درصد اسید قابل تیتر میوه را افزایش دهد. این مطالعه نشان داد که تیمارهای مورد استفاده در این تحقیق می‎توانند به‎طور موثری بر بهبود کیفیت و حفظ خصوصیات تغذیه‎ای میوه چیکو در طول دوره نگه‌داری موثر باشند. این نتایج پتانسیل استفاده از این ترکیبات را به‎عنوان راهکارهایی برای افزایش عمر مفید و حفظ کیفیت میوه‎ها تاکید می‌کند.

maintaining the quality of chico fruit (manilkara zapota) during storage using amino acids (phenylalanine, glutathione, and l-arginine) and growth regulator (melatonin)

introductionsapodilla is a tropical fruit well-known for its sweet taste and soft texture. it is a fruit that continues to ripen naturally after being harvested. therefore, the fruit harvesting time must be chosen carefully to ensure that the fruit reaches a stage of ripeness where it has the desired flavor and quality. sapodilla continues to ripen naturally after harvest, so selecting the right time for picking is crucial for ensuring optimal flavor and quality. proper post-harvest handling, such as controlling temperature and humidity, can extend its shelf life. using edible coatings or suitable packaging also helps preserve its freshness and delay spoilage. maintaining quality and reducing post-harvest fruit deterioration is one of the significant challenges in the agricultural supply chain, requiring effective protective methods. the spoilage of sapodilla fruit is due to its sensitivity to temperature conditions and water loss. application of amino acids can help preserve its quality and extend its shelf life. in this study, phenylalanine, glutathione, melatonin, l-arginine, and control (distilled water) were applied to evaluate post-harvest quality of sapodilla over five storage periods with three replications.materials and methodsfirst, sapodilla fruits were harvested from an orchard located in rodan city at the stage of commercial maturity in the second half of july. immediately after harvesting, the fruits were transported to the horticultural science laboratory at the faculty of agriculture, university of hormozgan. the harvested fruits were healthy and free from pests and diseases. they were selected based on uniform shape and weight. after being washed, the fruits were disinfected in a 1% sodium hypochlorite solution for 2 minutes. following disinfection, the fruits were dried in ambient air.the fruits were treated with four amino acids (phenylalanine (8 mm), glutathione (0.05%), melatonin (0.5 mm) and l-arginine (1 mm)) and control (distilled water) for 10 minutes.  after the treatment, they were transferred to the cold room with a temperature of 8 ± 1 c° and a relative humidity of 90 ± 5 %. the factorial experiment was conducted in five storage times (0, 10, 20 30 and 40) in three replications as a completely random design and the quality and biochemical factors of sapodilla were measured. results and discussionin this study, the weight loss of sapodilla fruit increased with storage time, while the treatments helped prevent weight loss. at the end of the 40-day storage, the phenylalanine treatment prevented 37.9% of the weight loss compared to the control. phenylalanine treatment prevented 92.33% of the weight loss relative to the control. the fruit firmness decreased over time, whereas treatments helped increase this parameter. the highest and lowest firmness values at the end of the experiment were observed in the melatonin and glutathione treatments (97.67 and 66.66 n, respectively), with the control having the lowest firmness (57.55 n). soluble solids content increased over time. the highest and lowest soluble solids were found in the control and the treatments with arginine, melatonin, and glutathione, respectively. at the end of the 40-day experiment, the arginine, melatonin, and glutathione treatments reduced soluble solids content, compared to the control by 6.98%, 6.60%, and 6.41%, respectively. the greatest and least increases in soluble solids were observed in the control and the treatments with l-arginine and glutathione, respectively. after 40 days of storage, the l-arginine and glutathione treatments reduced the decay percentage by 45.81% and 41.43%, respectively, compared to the control. glutathione treatment increased the ascorbic acid content of sapodilla fruit at most storage times. at the end of storage (40 days), glutathione treatment increased ascorbic acid content by 56.79% compared to the control. an increase in antioxidant activity was observed in sapodilla fruit over time. on day 30 of storage, phenylalanine treatment increased antioxidant activity by 28.67%, and on day 40, melatonin treatment showed a 30.61% increase. this increase in antioxidant activity is considered a defense response to environmental and physiological stress during storage. at the end of 40-day storage period, catalase activity increased. the highest and lowest catalase activities were observed at 33.06 and 25.22 units/mg fresh weight, respectively. by day 40, catalase activity was increased to 31.08% in the arginine treatment compared to the control. conclusionin conclusion, using these treatments, particularly phenylalanine, melatonin, and glutathione, can serve as effective strategies for preserving the quality of sapodilla fruit during long-term storage and mitigating the negative effects of physiological and environmental stress. these treatments not only reduce weight loss, maintain firmness, and prevent decay, but also improve the nutritional properties and health benefits of the fruit by enhancing antioxidant activity and defense enzyme levels. in the future, further research could focus on identifying the precise mechanisms by which these compounds influence the biochemical processes in sapodilla and other fruits. furthermore, studying the long-term effects of these treatments, as well as their interactions with various environmental and physiological factors in real-world storage conditions, could pave the way for wider adoption of these strategies in the fruit storage and packaging industry. these investigations could enhance fruit preservation methods, minimize food waste, and prolong the shelf life of fruits and decresing postharvest loss.