اثر تیمارهای پوترسین و آب گرم روی برخی خصوصیات بیوشیمیایی میوه‌ی توت‌فرنگی، رقم پاروس در طول انبارداری

توت‌فرنگی یکی از میوه‌هایی است که به‌دلیل داشتن مزه و عطر و طعم منحصر به فرد، موردپسند و علاقه فراوان مردم دنیاست. این میوه سرشار از مواد مغذی مانند آنتی اکسیدان‌ها، اسیدهای آمینه و ویتامین‌ها می‌باشد. در این تحقیق تاثیر غلظت‌های مختلف پوترسین و دماهای مختلف آب روی برخی از ویژگی‌های بیوشیمیایی میوه توت‌فرنگی رقم پاروس به ‌صورت آزمایش فاکتوریل (دارای دو فاکتور) در قالب طرح کاملاً تصادفی و در سه تکرار بررسی شد. فاکتور اول شامل 4 تیمار پوترسین (صفر شاهد، 0.5، 1 و 2 میلی‌مولار) و 4 تیمارآب گرم (25 شاهد، 45، 50 و 55 درجه سلسیوس) و فاکتور دوم نیز زمان انبارمانی (صفر شروع انبارداری، 3، 6، 9، 12 و 15 روز) بود. صفات اندازه‌گیری شده شامل اسیدیته قابل تیتراسیون، اتیلن، تنفس، ظرفیت آنتی‌اکسیدانی، مالون دی‌آلدئید و فنل کل بود. ارزیابی ویژگی‌های ذکر شده طی 15 روز انبارداری به شرح فوق انجام شد. نتایج نشان داد که افزایش تنفس، مالون دی‌آلدئید، کاهش مصرف اسیدهای آلی و افزایش اتیلن طی دوره انبارمانی در نمونه‌های تیمار شده به‌طور معنی‌داری کم بود. در نمونه‌های تیمار شده با پوترسین ظرفیت آنتی‌اکسیدانی ابتدا افزایش و سپس کاهش نشان داد. هم‌چنین پوترسین باعث افزایش فنل کل شد. افزایش تنفس، اتیلن، مالون دی‌آلدئید و کاهش مصرف اسیدهای آلی طی دوره انبارمانی در نمونه‌های تیمار شده با پوترسین به‌طور معنی‌داری کم بود. در نمونه‌های تیمار شده با آب گرم، میزان فنل کل و ظرفیت آنتی‌اکسیدانی طی دوره انبارمانی افزایش نشان داد.

the effect of putrescine and hot water treatments on some biochemical characteristics of strawberry fruit, cv. paros during storage

introductionstrawberry is a fruit with a short season of harvest. strawberry is well-known among people all over the world for its distinct flavour, nutritional value, and delicacy. while on the other hand, preserving strawberry and shelf life extension has been a huge difficulty due to their perishable nature. making effective and sustainable use of already available food processing and preservation technology needs time. researchers must use advanced techniques like a cool store, modified atmospheric packaging (map), cool store, controlled atmospheric storage (ca), various packaging methods, and a variety of chemical and physical treatments to retain commodities for a longer period due to strategic market sales following harvest. except for the preserving techniques, there is some polysaccharide-based edible coating which has a crucial role in delaying fruit softening, fruit decay, maintaining the increased levels of ascorbic acid and phenols, enhancing the activities of antioxidant enzymes, and reducing membrane damage. during the postharvest stages, there are numerous threats to keep in view regarding the safety and quality of strawberries. the beneficial effect of heat treatments on the storability of different fruits is well documented. the exposure to temperatures higher than 35 degrees celsius has caused ripening inhibition in different fruits. polyamines are a group of biomaterials which control ripening of fruits and, due to their aliphatic nitrogen structure, are among the compounds detected in animals, plants, and microorganisms. in plants, there is a competition in production of ethylene and polyamines of spermine, spermidine, and putrescine using the common precursor of s-adenosyl methionine, yet ethylene and polyamines act oppositely in ripening and senescence processes. application of polyamines had extraordinary effects on the quality of some fruits during storage. materials and methodsthis research was carried out in the laboratory and cold room of the department of production engineering and plant genetics, faculty of agriculture, razi university, kermanshah. strawberry fruits of paros cultivar with uniform sizes and similar conditions in the stage of commercial maturity (when more than 75% of their surface had turned red) were obtained from a sample garden in sanandaj and transferred to the laboratory in a short time. in this research, the effect of different concentrations of putrescine and different water temperatures on some biochemical characteristics of paros strawberry fruit was investigated in a factorial way in the form of a completely randomized design in three replications. the first factor in this research included putrescine at four levels of 0 (control), 0.5, 1, and 2 mm and water temperature at four levels of 25 (control), 45, 50, and 55 degrees celsius and the second factor was storage time. the measured traits included titratable acidity, ethylene, respiration, antioxidant capacity, malondialdehyde and total phenol. results and discussionincrease in respiration, malondialdehyde, decrease in consumption of organic acids and increase in ethylene production during the storage period were significantly less in the treated samples. in the samples treated with putrescine, the antioxidant capacity first increased and then decreased. also, putrescine increased total phenol. the increase in respiration, ethylene, malondialdehyde and decrease in consumption of organic acids during the storage period were significantly less in the treated samples. in the samples treated with hot water, the amount of total phenol and antioxidant capacity increased during the storage period. conclusionalthough the quality of the products after harvesting cannot be improved, the decrease in fruit quality can be controlled. for this purpose, various physical and chemical methods and treatments are used to maintain the quality of the products after harvesting. putrescine, that is naturally present in animals and plants in particular, belongs to the amine groups. it seems that putrescine of 2 mm concentration has tangible impact on strawberry fruits and it is recommended in strawberry store rooms. there is a competition in production of ethylene and polyamides of spermine, spermidine, and putrescine in plants, due to their common precursor namely s-adenosyl methionine, yet they act oppositely in ripening and senescence processes. the use of polyamines has been claimed to decrease ethylene synthesis in a wide range of plants by decreasing acc synthase (acs) and acc oxidase (aco) enzymes activities. application of polyamides and hot water had extraordinary effects on the quality of some fruits during storage. therefore, hot water treatment is recommended as a safe method to improve and increase the storage life of strawberries and a suitable alternative to chemical fungicides. based on the obtained results, it is recommended to use putresin and hot water treatment to maintain the quality of paros strawberry fruit after harvesting.