Research and preserve fruits after harvest

Currently, in the Mekong Delta, only a few large enterprises and supermarkets have a method of storing fruits in cold temperatures. The rest, the majority of fruit collecting shops as well as farmers harvest and sell fruits according to practices, without post-harvest preservation process. This has a significant impact on product quality and economic efficiency. To overcome this situation, Can Tho University has been implementing a number of research projects on preserving fruits after harvest . These studies will contribute to opening the new development direction for the fruit market in the Mekong Delta.

Song Hau farm currently has 150,000 Hoa Loc mango trees, on average, each household has 80-100 trees. With an annual output of up to thousands of tons of mango products, the farm aims at the process of harvesting and preserving mangoes of a scale of a regular classification, packaging and preservation of fruits. The farm cooperated with the Biotechnology Research and Development Institute and the Food Technology Department, Can Tho University and the Southern Fruit Research Institute to successfully research the post-harvest mango preservation process. By modern technology, ensuring good quality, helping to prolong the storage time, meeting the requirements of export and domestic consumption. This process was accepted by Can Tho City Department of Science and Technology in early 2007.

Dr. Ha Thanh Toan, Director of the Institute of Biotechnology Research and Development, Can Tho University, said: 'If consumed in the country, after harvesting, mangoes are classified, packaged and transported. and distribute to consumers. If exported, after sorting, it will take steps to process and store (for long distance transport), ripen,

Pink mandarin fruits are preserved in PE bags with 5 holes per hole, each with a diameter of 1mm.Photo document of Can Tho University.

packing, then transporting and distributing to consumers' . Cat Hoa Loc mango has a thin shell so it is difficult to preserve and transport long distances, making it difficult for export. Dr. Toan and his colleagues studied the above limitation by treating blanching of hot water to prevent anthracnose and fruit flies. This measure helps ensure quality products according to the requirements of plant quarantine for fruit trees. Then, the fruit is dipped in Chitosan solution, creating a thin film covering to prevent moisture loss, reduce weight loss and extend storage time. Through experiments, mangoes are best stored at cold temperatures between 10-12 ^o C. Dr. Ha Thanh Toan concluded: 'Through the process and storage, mangoes are best preserved. in 4 weeks, even 6 weeks, can be transported and distributed far away '. According to Master Le Van Bang, Chairman of the Fruit Production Service Club of Song Hau Farm, when finding a stable export market, the farm will build factories and invest in equipment for preservation. Mango according to the technological process studied.

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In 2006, Associate Professor Dr. Le Van Hoa, Deputy Head of the Department of Agriculture and Applied Biology, Can Tho University and colleagues conducted research on post-harvest preservation of fruits: mandarin tangerine , Nam Roi pomelo, orange blossom, orange honey and orange. This is a research topic carried out at the request of the Department of Science and Technology of Hau Giang province. It is expected that the project will be checked and accepted in 2009. Associate Professor Dr. Le Van Hoa said: 'We study towards the production of clean fruits, so we should implement biological control methods before and after harvest. . Toxic chemicals are restricted to use, instead use non-toxic substances such as antagonistic fungi to treat disease, lime, Chlorine solution (which is commonly used in domestic water treatment). . Currently, we have completed the post-harvest preservation process of sugar mandarin fruits; are continuing to study the process of preserving other fruits'.

Through many experiments, scientists have developed a process to preserve mandarin fruit with storage time up to 8 weeks. It is left preserved by covering the chitosan film at 0.25% concentration combined with Polyethylene (PE) bags with 5 holes of diameter per 1 mm hole and re-seaming with a press. After that, store at a temperature of 12 ⁰ C. With this method, the inner quality of fruits such as sugar content, vitamin C content . is always stable, low weight loss rate, shell color The fruit is even and beautiful. In addition to citrus fruits, scientists also studied the process of preserving pink tangerines by storing in PE bags (but only 3 holes, 1 mm per hole) and stored at cold temperatures. (15 ⁰ C). This process allows a storage period of up to 9 weeks.

Associate Professor Dr. Le Van Hoa said: 'Using PE bags to limit water evaporation, reducing the intensity of respiration and ethylene biosynthesis . helps to prolong the shelf life. Fruit bags with PE bags have been used quite popular on many different fruits, in many parts of the world and achieved good results. Preserving fruit in low temperature makes fruits ripen more slowly, fruits in the fruit are maintained longer, limiting the growth of pathogens, fruit peels are less wrinkled . However, each type of fruit can withstand different temperature thresholds. Therefore, research to find the best temperature threshold for each type of fruit is essential '.

Before the research topic of Associate Professor Dr. Le Van Hoa, Associate Professor Dr. Nguyen Bao Ve, Head of Department of Crop Science, Department of Agriculture and Applied Biology, Can Tho University and colleagues carried out the project 'Research on fresh preservation, prolonging the shelf life of gourmet orange, mandarin orange and Nam Roi pomelo in Can Tho' The project carried out many measures to preserve fruits such as: storing at cold temperatures, using herbal extracts to prevent fungal diseases, using PE bags, Chitosan film bags . Expected, at the end of 2007, The subject will be checked and accepted.

According to the scientists, the research of preserving fruits after harvest can be widely applied in supermarkets because it has cold rooms and necessary conditions for long-term fruit preservation. In addition, when the fruit of Vietnam is directed to the export market, the preservation of fruits after harvest to prolong the storage time during transport is a mandatory requirement. Therefore, the current research on preservation of fruits after harvest is essential, contributing to improving the commercial value of fruits in the domestic and foreign markets.

CAT DANG