Quick frozen fruits and vegetables are a new type of fruit and vegetable processing product that has developed in modern times. They can maintain the color, aroma, taste, and freshness of fruits and vegetables well, and are easy to consume. However, sometimes the quality and taste of frozen fruits and vegetables may deteriorate after processing. What is the reason for this? Let's take a look:

Discoloration:

① Light colored fruits and vegetables or sliced fruits and vegetables turn red or black in color on the cut surface;

② The green color of green fruits and vegetables gradually fades away and turns into grayish green;

③ Fruit and vegetable products lose their original color or deepen their original color.

The main reason is that fruits and vegetables contain polyphenol oxidase enzymes, which oxidize phenols into red and black quinone compounds under the action of oxygen, and chlorophyll enzymes oxidize and decompose chlorophyll.

Odor change:

① Fruits and vegetables with a pungent odor transmit the odor to mildly flavored fruits and vegetables, causing the product to cross taste;

② The cold odor in the cold storage can cause food to taste bad;

③ The process of quick freezing fruits and vegetables is not standardized, such as raw materials being frozen or excessively slow frozen or insufficient blanching, freezing or temperature fluctuations, repeated freezing causing changes in fruit and vegetable tissue, and odor changes caused by the loss of cytoplasm;

④ The taste change of fruits and vegetables containing protein and fat after oxidation. The latter two types of flavor changes are often accompanied by a decrease in taste. Taste change often occurs during the frozen storage stage.

Taste deterioration:

The deterioration of taste mainly refers to the hardening, growth, and fibrosis of the product,

① It occurs during freezing storage, mainly due to the hardening of protein texture after freezing denaturation, viscosity caused by fat oxidation, water evaporation, and fiber aging caused by oxidation;

② Occurred during the consumption stage, due to improper consumption methods such as slow thawing causing juice loss, causing changes in cell structure and fibrosis, resulting in a feeling of lettuce after cooking.