Method and device for color protection and freshness retaining of litchis

Abstract

The invention belongs to the field of fruit and vegetable fresh-keeping, and discloses a method and device for color protection and freshness retaining of litchis. The method comprises the following steps: picking and selecting fresh litchis, feeding the pre-cooled litchis into a plasma treatment device for plasma treatment, then immersing the litchis in a composite preservative prepared from chitosan and VC for soaking treatment, the fresh picking, blow-drying the litchis with cold air, and then packaging or refrigerating the litchis. The device comprises a tray, a plasma treatment device, acomposite preservative soaking device and an air drying device which are sequentially arranged along a conveyor belt; the tray is in sliding connection with the conveyor belt, the plasma treatment device is arranged above the conveyor belt, the composite preservative soaking device is arranged below the conveyor belt, and the air drying device is arranged above the conveyor belt. According to theinvention, by combining plasma treatment with a coating fresh-keeping technology, the color and nutritional components of the litchis can be well maintained, so that the shelf life of the litchis is prolonged, and the edible and production value of the litchis are improved.

Description

technical field [0001] The invention belongs to the field of fresh-keeping of fruits and vegetables, and in particular relates to a method and device for color protection and fresh-keeping of litchi. Background technique [0002] Litchi is rich in nutrition, rich in carbohydrates, proteins, amino acids, vitamins and folic acid, fresh and juicy, sweet and delicious. However, the ripening period of litchi is relatively concentrated, and the pericarp is prone to dehydration, and is subject to the infringement of microorganisms, and under the action of endogenous enzymes, such as polyphenol oxidase and peroxidase, it is prone to browning, and then rots and deteriorates. It is said that "the color changes in one day, the fragrance changes in two days, the taste changes in three days, and the color and fragrance are gone in four days." These adverse changes have seriously affected the edible and production value of lychees. [0003] The technologies currently used in litchi prese...

AI Technical Summary

Problems solved by technology

Among them, cryopreservation can achieve the purpose of long-term preservation, but during the freezing process of litchi, larger ice crystals are more likely to be formed in the fruit, causing damage to pulp cells and loss of juice, which eventually leads to adverse changes in taste and quality.

Controlled atmosphere technology includes spontaneous controlled atmosphere and controlled atmosphere controlled atmosphere. The effect of spontaneous controlled atmosphere treatment is poor, and the effect of controlled atmosphere controlled atmosphere is better than spontaneous controlled atmosphere. However, because the gas source is required, the cost of application is high, and it is difficult to carry out large-scale chemical production

However, chemical preservation is faced with the safety hazards of some reagent residues.

In short, the current storage and fresh-keeping technologies cannot match the unique postharvest physiological properties of litchi, so it is urgent to explore new technologies to supplement and improve the deficiencies caused by the above technologies

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