Long-acting fresh-keeping method of litchi based on low-temperature rapid micro-freezing

Abstract

The application discloses a long-acting fresh-keeping method of litchi based on low-temperature rapid microfreezing, and belongs to the technical field of agricultural product preservation. The method comprises the following steps: raw material pretreatment, precooling, low-temperature rapid microfreezing, packaging, dormant storage and thawing for marketing. In the low-temperature rapid microfreezing step, the temperature of the microfreezing liquid is controlled to be-6 to-2 DEG C, the immersion time is 8 to 15 minutes, the instantaneous cooling rate of the litchi peel is controlled to be 5 to 10 DEG C / min, the temperature of the litchi core is reduced to-1.5 to-0.5 DEG C at a rate of 0.5 to 2 DEG C / min, and the cells enter a dormant critical point. The method has the advantages of simple process and low cost, the instantaneous cooling rate of the peel and the cooling rate of the core are accurately controlled, the litchi rapidly passes through a maximum ice crystal generation zone, damage of cell membranes caused by large ice crystals is avoided, and the cells enter a stable supercooled dormant state. After thawing, the litchi juice loss rate is less than or equal to 3%, the vitamin C retention rate is greater than or equal to 89%, and the preservation period can reach 12 months.

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