Introduction. Low-temperature freezing technology extends the shelf life of perishable fruits as it causes a sharp slowdown in the biochemical and microbiological processes in frozen products. However, it cannot provide complete destruction of microorganisms. The present research featured the reaction of apricot microbiota to the technological techniques of shock freezing. The research objective was to study the effect of low-temperature freezing modes (t = –25, –30, and –35°C), storage time (3 and 9 months), methods, and defrosting modes (in air at t = 5 and 22°C; in water at t = 5, 16, and 22°C; under the effect of microwave irradiation) on the surface microflora of apricots. Study objects and methods. The experiment featured apricots of the varieties Uzden, Untsukulskiy Pozdniy, Honobah, Krasnoshchyokiy, and Shalakh. The microbiological profile of defrosted apricots was based on the State Standard. Results and discussion. Fast freezing at t = –25°C provided a better inhibition of epiphytic microflora than at t = –30 and –35°C: aerobic-mesophilic and optionally anaerobic microorganisms – by 65.2–68.6%, yeast – by 61.5–69.0%, and mold – by 59.3–68.4%, compared to their initial content on fresh apricots. During the initial period of refrigeration storage, the number of microorganisms decreased, while the subsequent nine-month storage (t = –18°C) led to a slight increase in microbiota. After nine months of storage, the number of microorganisms on defrosted fruits, depending on the variety, was the following: aerobic-mesophilic and optionally anaerobic microorganisms – 1.2×103–2.0×103 CFU/g, yeast – 14–26 CFU/g, and molds – 75–108 CFU/g. Defrosting of apricots by microwave irradiation resulted in a greater destruction of microorganisms than after traditional thawing in air and water. Conclusion. The results of microbiological studies indicate that the shock freezing technology ensures the production of quick-frozen apricots that meet the requirements of Technical Regulations of the Customs Union No. 021/2011.
New functional foods based on local vegetal raw materials can accelerate the implementation of the Strategy for Improving Food Quality in the Russian Federation through 2030. The present research aimed at developing formulations and technology for new functional quick-frozen fruit-and-berry desserts. The study featured four dessert mixes: apricot-persimmon-buckthorn, apricot-feijoa-sloeberry, apricot-persimmon-cornel, and apricot-feijoa-currant. The quality of the finished products was evaluated using conventional methods according to the mass concentration of sugars, solids, pectin, titrated acids, vitamin C, β-carotene, and minerals. The desserts were tested for toxic elements based on the atomic absorption method. The microbiological safety parameters were determined after six months of refrigeration storage (t = –18°C) using standard methods. The physicochemical data made it possible to design formulations where all components complemented each other’s beneficial properties. To stabilize the quality and obtain the optimal structural and mechanical properties, the formulations were completed with a sugar-pectin solution (380 g per 1 kg) with 30% sugar and 1.3% pectin. The mass concentration of some biologically active substances made the desserts functional: 250 g of each product satisfied the daily intake of pectin substances by 51.9–61.3%, vitamin C – by 42.9–123.4%, β-carotene – by 22.5–47.5%, iron – by 8.9–20.5%, and iodine – by 13.3–30.0%. The new quick-frozen functional fruit-and-berry desserts proved to have advanced organoleptic indices and met the safety requirements provided by Technical Regulations of Customs Union TR TC 021/2011.
Недостаточные объемы производства и небольшой ассортимент натуральных продуктов питания из экологически чистого местного растительного сырья, низкий уровень потребления населением свежих фруктов из-за сезонности их выращивания – актуальные проблемы народного хозяйства. Плоды абрикоса (Prunus armeniaca L.) по питательному индексу мякоти стоят на первом месте среди косточковых культур. Разработка технологических режимов низкотемпературного консервирования абрикосов, обуславливающих высокую сохранность их пищевых свойств в течение длительного хранения, способствует решению проблемы круглогодичного обеспечения населения этими фруктами. Экспериментально обоснованы оптимальные режимы шоковой заморозки (t=-30°С) и длительного хранения (t=-18°С) абрикосов сортов Краснощекий, Уздень, Унцукульский поздний, Хонобах и Шалах при изучении сохраняемости их компонентов химического состава, определении органолептических и микробиологических показателей качества. В абрикосах общепринятыми методами определяли массовые концентрации титруемых кислот, витаминов С и Р, фенольных и пектиновых веществ. Дегустационная оценка давалась по 5-ти балльной шкале. Быстрое замораживание и последующее длительное хранение абрикосов при t=-18°С способствовали высокой сохранности нутриентов: после 9 месяцев хранения витамин С в них, в зависимости от сорта, сохранился на 78,4–84,6%, а витамин Р на 77,4–83,9%. Стабильность титруемых кислот варьировала от 78,7 (Хонобах) до 86,5% (Шалах). Сохранность фенольных и пектиновых соединений в среднем составила 80,1 и 97,2 %. Наиболее стабильным после шоковой заморозки и 9-ти месяцев холодового хранения оказался химический состав абрикосов сортов Краснощекий, Унцукульский поздний и Шалах. Различия в изменении концентрации нутриентов в исследованных абрикосах при шоковой заморозке (t=-25°С; t=-30°С; t=-33°С; t=-35°С) и длительном хранении (t=-18°С) зависели от их сортовой принадлежности.
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