ПЕРЕРАБОТКА ВТОРИЧНЫХ ПРОДУКТОВ, ОБРАЗУЮЩИХСЯ ПРИ ПЕРЕРАБОТКЕ ЯБЛОК

УДК 664

Abstract

This article presents the results of experimental studies on the processing of apples and their secondary products, including apple peels. It was determined that due to the impact of microorganisms on fruits, improper storage conditions, and mechanical damage occurring during harvesting, transportation, and storage, approximately 35÷40 % of fruits, including apples, were lost during 2023-2024. During the research, scientific studies conducted by local and foreign scholars, as well as statistical data from international organizations related to the field, were analyzed. Existing problems and their possible solutions were summarized, and a technological processing scheme for apples and their secondary products was developed. Experimental results demonstrated that, for pectin production from apple peels, the residual moisture content should be reduced to 8÷12 %. It was also established that the obtained product can be utilized in the production of natural beverages, ingredients for baby food, and for expanding the assortment of confectionery products.

Аннотация

В данной статье отражены результаты экспериментальных исследований по переработке плодов яблока и их вторичных продуктов, в частности яблочной кожуры. Установлено, что вследствие воздействия микроорганизмов, неправильной организации условий хранения, а также механических повреждений при сборе, транспортировке и хранении плодов в 2023-2024 годах наблюдались потери фруктов, в том числе яблок, в объёме 35÷40%. В ходе исследования были изучены научные работы отечественных и зарубежных учёных по данной тематике, а также статистические данные международных организаций, относящиеся к отрасли. На основе проведённого анализа обобщены существующие проблемы и предложены пути их решения, а также разработана технологическая схема переработки плодов яблока и их вторичных продуктов. Экспериментально доказано, что для получения пектина из яблочной кожуры необходимо снизить остаточную влажность сырья до 8÷12%. Кроме того, установлено, что полученный продукт может быть использован для расширения ассортимента натуральных напитков, ингредиентов для детского питания и кондитерских изделий.

Keywords: apple, peel, drying, freezing, pressing, critical temperature, heat transfer agent.

Ключевые слова: яблоко, кожура, сушка, замораживание, прессование, критическая температура, теплоноситель.

Introduction

As the world’s population continues to grow, the demand for high-quality food products is increasing in parallel. Extensive research is being conducted worldwide to meet this demand by improving production processes and developing modern technological systems and equipment characterized by high efficiency and automated control. In this regard, particular attention is being paid to scientific and practical studies focused on the efficient organization of food production processes, the implementation of waste-free technologies, and the reduction of energy consumption. An analysis of scientific publications and statistical data related to the research topic revealed that 35÷40 % of the apples grown in the Namangan region were lost during 2023–2024. Therefore, improving apple processing technologies to minimize such losses and reduce the production cost of food products in both domestic and international markets is considered a priority objective. [1, 2, 3, 4, 5].

As research objects, the Golden Delicious apple variety was selected, as well as the production processes at “Fruits dried inno tech” LLC and “Sunny land products” LLC, including the existing problems encountered in these processes.

Literature Review. The issue of recycling and utilizing waste generated in the fruit and vegetable storage and processing industry has been widely studied worldwide, and numerous scientific investigations have been conducted in this field. In particular, A.M. Rustamov and M.A. Qudratov, in their research, analyzed existing approaches to reducing and recycling food industry waste and identified the innovations necessary to improve the economic efficiency of these processes. Their studies highlighted the importance of applying environmentally friendly technologies, introduced new mechanisms for waste management, and discussed the socio-economic impacts of developing waste recycling practices [6, 7, 8, 9, 10].

Research methodology

In this research, methodological foundations were selected based on modern scientific research approaches to study the economic and environmental aspects of the integrated processing of waste generated in the fruit and vegetable storage and processing industry, as well as its efficient utilization. Scientific studies conducted by local and foreign researchers on the subject, along with statistical data from international organizations related to the field, were reviewed, and existing problems and their possible solutions were analyzed and generalized. The results obtained through the applied research methodology serve as a scientific basis for developing recommendations aimed at improving waste management practices, producing value-added products from waste, and ensuring environmental sustainability in the food industry of Uzbekistan.

Analysis and results

The processing of apples and their secondary by-products was carried out according to the technological scheme presented in picture 1 below.

Picture 1. Technological scheme for processing apple fruit and its secondary products

Convective and sublimation methods were selected for drying the secondary mass of apples, namely the apple peel.

By processing apple secondary raw materials without waste, it is possible to obtain food and pharmaceutical products with high nutritional value. In particular, it contributes to the expansion of the assortment of natural pure beverages, baby food ingredients, and confectionery products, as well as ensuring a healthy lifestyle for future generations. Depending on the temperature of the drying agent, the drying time is presented in Table 1.

Table 1. Apple peel cutting sizes, drying temperature, and drying duration

In freeze-drying (lyophilization), the optimal temperatures depending on raw material size and product sample shape range from −15 to −35 °C.

The drying temperature varies depending on the particle size of the product; the highest temperature of the heat agent is applied at the initial stage, while the lowest temperature is used at the final stage of the drying process. The solubility of the obtained dried products is 80÷85%. Vacuum drying allows moisture to be removed from the final product while preserving its quality characteristics and structure. This is because drying is carried out at lower temperatures compared to atmospheric conditions. During vacuum drying, the rate of moisture evaporation from the product increases, as the removal of water vapor from both the product surface and the surrounding chamber is accelerated. The efficiency of this technology also increases due to the absence of heat loss with exhaust air. During vacuum drying, heat required for moisture evaporation is mainly supplied through contact, and treatment with ascorbic acid further intensifies the moisture evaporation process within the product.

Treatment with citric acid prior to the freeze-drying (sublimation drying) process accelerates the drying process. In cyclic changes of pressure, the drying process depends on the nature and condition of the material being dried, as well as on the assimilation parameters, and the efficiency of the cooling and vacuum systems. In freeze-drying technology, the main process is carried out in a cylindrical drying chamber. The chamber is equipped with a desublimator and connected to a vacuum pump. In its lower part, through a vacuum lock, the chamber is connected to a discharge screw conveyor. The drying process regime is monitored and controlled. During drying, the samples are processed under deep vacuum, and moisture in the frozen state is removed through sublimation. Research results show that treating the material with ascorbic acid during the drying process and using freeze-drying provides high efficiency. In the conducted studies, it was found that short-term treatment with ascorbic acid, applied after washing the product and before the freezing stage, is appropriate. In conventional freeze-drying technology, preliminary treatment is usually applied to materials before freezing, especially when thermal processing is involved. The reason is that any treatment after freezing causes the moisture in the frozen product to convert back into liquid water.

When carrying out freeze-drying (sublimation drying), it is also possible to develop pre-treatment regimes using ascorbic acid and citric acid depending on the specific properties of the product being dried. In this case, adjustments are made based on the chemical composition of the product, particularly the cellulose content within carbohydrates. This involves increasing or decreasing the concentration of ascorbic acid and modifying thermal capacity in order to optimize the process. Before processing and drying, the raw materials are sorted and inspected according to their structure, variety, and degree of ripeness.

The cleaned products are cut into standard-sized pieces using a knife. Then they are blanched in a locally prepared solution of powdered ascorbic acid dissolved in hot water at a temperature of 85÷90°C for 3÷5 minutes. In the food industry, they are processed in a freezing chamber, then immersed in a 0.7 % citric acid solution for 3÷5 minutes, removed and drained, and placed on trays. The trays are loaded into a drying cabinet and dried at 95÷105°C for 4÷6 hours. Under local conditions, the apple is trimmed at the stem and calyx using a knife. In industrial processing plants, the peel is removed using special cutting machines. The cleaned apple secondary mass is washed, inspected, and treated in a 0.5÷0.7% ascorbic acid solution for 3÷5 minutes. It is then drained, placed on trays, and dried in a drying cabinet at 50÷75°C for 4÷5 hours.

When apple peel is treated with ascorbic acid, its color and structure are well preserved, and it has been found that the treated product samples demonstrate high resistance to heat agents. In addition, the secondary raw material was processed using two different methods.

In the first method, the raw materials were mechanically processed; that is, they were initially cut into various shapes, treated with ascorbic acid, then frozen and placed into a vacuum freeze-drying chamber for drying. The secondary raw materials, after cutting, were treated with concentrated solutions of citric acid and ascorbic acid as shown in pictures 3 and 4.

Ascorbic acid treatment of raw material is carried out either by immersion or spraying using 0.5÷0.7% and 0.4÷0.5% citric acid solutions. In the treated product samples, the process that occurs during freezing begins from the outer layer of the raw material. In the frozen mass, under deep vacuum conditions, a new interface forms between the frozen region and the dried region. Over time, the boundary between the dried and frozen zones changes, and the frozen volume of the product becomes thinner while the volume of the dried region increases.

Conclusion

Based on the study of scientific works, monographs, research articles, and patents of Uzbek and foreign scholars related to the research topic, I have reached the following main conclusion. A number of scientific studies have been conducted on improving the techniques and technologies for the integrated processing of waste generated during the storage and processing of fruits and vegetables. The analyses show that if these wastes are not properly managed, they can cause environmental pollution, the spread of unpleasant odors, and sanitary and hygienic problems. At the same time, through their processing, it is possible to obtain biogas, compost, feed additives, and other useful products. In conclusion, a deep study of the main characteristics of fruit and vegetable waste serves as an important scientific basis for developing and implementing efficient processing technologies. This, in turn, enables rational use of resources, ensures environmental sustainability, and increases economic efficiency.

References:

1. M.F. Meliboev. Use of highly efficient combined methods in drying plums. Dissertation of the Doctor of Philosophy in Technical Sciences, - Tashkent: TKTI, 2022, 104 p
2. T.L. Khudaiberdiev. Technology and equipment for drying agricultural products, textbook. - Tashkent: "Mukhr press" publishing house, 2022, - 232 p.
3. Z. Salimov. The main processes and devices of chemical technology.: Textbook for students of higher educational institution. T.1. - T: Uzbekistan, 1994. – 366 p.
4. Z. Salimov. Basic processes and devices of chemical technology, T.2. Metabolic processes: a textbook for higher educational institutions. - T: Uzbekistan, 1995. – 238 p.
5. N.R. Yusupbekov, X.S. Nurmuhamedov, S.G. Zokirov. Chemical technology basic processes and devices. - T.: "Science and technology", 2015, 848 p.
6. Pospelova I.G. Development technology of sublimation dried fruits and ovoshchey s ispolzovaniem SVCh-i UZ . // Autoref . ... candy. tech . science - Izhevsk, 2009. - S. 20.
7. M. Meliboev, Sh.M. Mamatov, M. Aripov, B. Shamsutdinov. Advantages of quick-freezing technology of cherry // International journal of innovative technology and exploring engineering (IJITEE) (Hindiston). ISSN: 2278-3075, Volume-9, Issue-3 January 2020 3254-3256 б.
8. Mansurov O.A., Igamberdieva D.A., Khamdamov A.M. Systems analysis of the drying process of agricultural products // Universum: technical sciences: electronic scientific journal. 2021. 11(92). URL: https://7universum.com/ru/tech/archive/item/12535 (date of access: 14.12.2022).
9. Study of the process of freeze-drying of plum fruits // Universum: technical sciences: electronic scientific journal. Ergashev O.K., Egamberdiev A.A., Khamdamov A.M., Mallaboev O.T. 2022. 12(105). URL: https://7universum.com/ru/tech/archive/item/14806 (access date: 02/26/2023).
10.  Saifitdinov Anvar Sadritdinovich. Interfaol tamoillardan foidalanib tekhnologik ta'limini ўqitish // Economy and Society, ISSN: 2225-1545, 01 (104) 2023.