Method for ultra-rapid freezing preservation of litchi fruits by utilizing liquid immersion

Abstract

The invention discloses a method for ultra-rapid freezing preservation of litchi fruits by utilizing liquid immersion. The litchi fruits are tropical precious fruits which are originally produced in China and have excellent color, smell and taste and abundant nutrition, but the litchi fruits are very fast to become brown, decay and deteriorate after harvesting, very difficult to keep fresh and short in shelf life. The low-temperature modified atmosphere storage, the general freezing process and the like, which are currently widely applied have greater defects. By adopting the method, the defects in other current litchi fruit preservation methods and technologies can be thoroughly overcome, and the preparation steps comprise the selection of litchi fruit raw materials, packaging, ultra-rapid freezing, freeze preservation and thawing. The preservation period of the obtained rapid-frozen litchi fruits is greatly prolonged, which is above 6 times of that of the current best preservation method, the browning rate after thawing is low, the split fruits are few, the drip loss is low, the color, the smell and the taste are excellent, the texture is good, and the taste is fresh, thereby realizing quality leap of the rapid-frozen litchi fruits, being low in production energy consumption, being high in benefits, realizing appreciation of the litchi fruits and driving the development of the tropical fruit industry, such as the litchi fruits and the like.

Description

technical field [0001] The invention relates to a fresh-keeping method for litchi, in particular to a fresh-keeping method for litchi by liquid immersion ultra-fast freezing technology, which belongs to the field of food storage and fresh-keeping. Background technique [0002] Litchi is a rare tropical fruit native to China. It has a long history of cultivation. Because of its beautiful color, aroma and taste, it is well-known both at home and abroad, and is known as the king of fruits. Lychee pulp is rich in nutrients such as sugar, acid, vitamin C, and protein. Litchi is rich in hot and humid summer, and the production period is short. After harvest, litchi breathes very vigorously. It is difficult to store, transport and keep fresh after harvest, and the internal consumption of nutrients is fast. The color changes in one day, the taste changes in two days, and the color and fragrance are all gone in three or four days.” This natural attribute leads to a small sales radi...

AI Technical Summary

Problems solved by technology

[0003] At present, there are two main methods of preservation of litchi widely used. One is the cold storage method of low-temperature controlled atmosphere combined with preservatives. By reducing the temperature of the storage environment and controlling the proportion of gas components, the post-harvest respiration and microbial reproduction of litchi can be inhibited to a certain extent. , to delay the process of corruption and deterioration, the highest shelf life is about one month, which is far from meeting the market demand, and the browning rate of lychees is high, and sulfur fumigation, preservatives and other treatments will also cause drug residue problems

The second is the freezing method, which uses cold air as a refrigerant for quick freezing of lychees. This method has certain advantages, but due to the slow freezing speed and long freezing time, the rate of cracking of lychees is high, and browning and juice loss are often accompanied by thawing. , it is difficult to obtain high-quality fresh-keeping effect and meet the requirements of litchi export, so there is almost no application in production