Litchi fresh-keeping method

Abstract

The invention discloses a litchi fresh-keeping method, and belongs to the technical field of storage and fresh-keeping of fruits and vegetables. The litchi fresh-keeping method comprises the following steps: soaking cleaned litchis in Sportak, then performing soaking in sodium nitroprusside, spraying a vegetable gum solution on the surfaces of the litchis, then carrying out heat treatment, and storing the litchis in a low-temperature closed environment. According to the fresh-keeping method, the low-temperature storage time of the litchis is prolonged to the maximum extent, loss of moisture of the litchis is reduced, generation of malonaldehyde and hydrogen peroxide in the litchis is reduced, the activity of superoxide dismutase in the litchis is improved, rotting and browning of the litchis are effectively prevented, the fresh-keeping effect is good, chemical substances such as sulfur are not contained, the preserved litchis are good in taste, green and environment-friendly, and the preservation process is simple and easy to popularize.

Description

technical field [0001] The invention relates to the technical field of storage and preservation of fruits and vegetables, in particular to a method for preservation of litchis. Background technique [0002] Litchi (Litchi chinensis Sonn) is the most abundantly planted in Guangdong and southern Fujian. At the same time, litchi is one of the world-famous Chinese specialties. It is a subtropical fruit with bright color, unique flavor and rich nutrition. It is the best fruit in Lingnan. However, lychee is one of the most difficult fruits to keep fresh and store. Browning, qualitative change and decay will occur soon after picking, and the physiological and metabolic activities of lychee after picking are very vigorous, and the most important physiological activity is respiration, which consumes a lot of energy. Water, soluble sugar and organic acid cause the loss of water and nutrients in the fruit, which leads to browning and aging of litchi fruit. The freshness of lychees has...

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Problems solved by technology

[0003] The methods for keeping litchi fresh in the prior art are mainly based on low temperature preservation, controlled atmosphere preservation, chemical agent preservation, heat treatment and film preservation. Respiration, but the temperature requirements for low-temperature storage are relatively strict. If the local temperature is not properly controlled, it is easy to cause chilling injury or the local temperature is too high to achieve the expected fresh-keeping purpose. Therefore, the requirements for cold storage equipment are high, resulting in high low-temperature preservation costs. Moreover, the shelf life of low-temperature stored fruit at room temperature is shorter than that of unrefrigerated fresh fruit, the browning rate is faster, and the flavor is poor. However, to achieve longer storage, other methods are needed to achieve it; controlled atmosphere preservation is based on litchi fruit. The principle of respiration and inhibition, aiming at the characteristics that the fruit respiration process is inhibited by the content of carbon dioxide and oxygen, controls the respiration by adjusting the content of each gas in the microenvironment, and then achieves the purpose of preservation; chemical agents generally use antiseptic drugs such as fencarb, Litchi fruits are soaked in medicinal solutions such as benomyl and benomyl, or treated with sulfur fumigation or sulfite to achieve the purpose of preservation, but the use of chemical agents will leave a certain degree of toxicity, which poses a threat to people's health; heat treatment is through high temperature To inactivate polyphenol oxidase, thereby preventing fruit browning, but if the temperature is not well controlled, it will affect the flavor of lychee; coating preservation is to coat a layer of polymer liquid film on the surface of the fruit, and it becomes a very uniform layer after drying The film can isolate the fruit and the air for gas exchange, thereby inhibiting the respiration of the fruit, preventing the consumption of nutrients, and reducing the rot caused by the infection of pathogenic bacteria. The current film coating agent uses some biodegradable high-quality materials such as vegetable glue. Molecular materials are the main raw materials. These raw materials are polysaccharide polymer compounds, which are easily degraded by microorganisms, which makes the preservation effect not durable enough.

And how to prevent and treat the phenomenon of rot and deterioration in the fresh-keeping process of litchi, prolong the storage time and normal temperature storage time of litchi, keep the original mouthfeel of litchi, and avoid using toxic chemicals to become a difficult problem to be solved urgently by those skilled in the art

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