The preparation of chitosan−based material for the preservation of posthaverst fruits and vegetables

Abstract

Mass and quality reductions of fresh fruits and vegetables occur in the post−harvest stage. This loss due to damage can be as high as 20-80%. After harvesting, the fruit remains composed of living cells and continues respiratory and metabolic activities through various transformation processes. These transformations lead to rapid ripening, aging, softening, etc., resulting in spoilage if special measures are not applied to slow down these processes. Currently, toxic and high-dose chemical agents are being used for their effectiveness in controlling the quality of harvested fruits and vegetables, which seriously threatens human health. The use of modern methods such as irradiation and the cells alive system are expensive, area-specific, and limited to particular fruits, such as exported fruits. Therefore, the development of new biodegradable materials with low cost, safe and healthy properties, high efficiency, and in accordance with fragmented farming practices in Vietnam is necessary. Chitosan, a natural polysaccharide derived from chitin, has shown promising potential material for food preservation because of its film−forming properties, antimicrobial actions, lack of toxicity, biodegradability, and biochemical properties. It has been proven that chitosan can control numerous pre and post-harvest diseases of fresh fruits. Covering the surface of fruits and vegetables with chitosan film could limit the weight loss and slow down the water loss, which helped prolong the self−life of fresh fruits and vegetables. This paper presented the synthesis of a chitosan−based material and the evaluation of its effectiveness in preserving postharvest fruits and vegetables. The obtained results indicated that the storage time of certain harvested agricultural products covered by a material with 75 % chitosan content could be extended to 3−6 weeks, depending on the applied temperature. The weight loss of the products during storage was found to be below 10%.