How to prevent browning of fruits and vegetables by fruit and vegetable processing equipment

Fruit and vegetable processing is through the processing of various fruit and vegetable processing equipment , so that fruits and vegetables can be preserved for a long time, not bad for a long time, and ready for use. We all know that fruits and vegetables are prone to browning, so how to prevent browning during processing?

1, blanching color protection

The blanching treatment is also called pre-cooking, and the pre-treated fresh fruits and vegetables are placed in boiling water or hot steam for a short period of time. The main function of blanching is to inactivate enzymes, reducing oxidative discoloration and loss of nutrients. Usually, the peroxidase activity in the fruit vegetables is completely destroyed. Peroxidase activity can be tested by mixing 0.1% guaiacol or benzidine alcohol solution with 0.3% hydrogen peroxide, and peroxidase is inactivated at 90~100 °C for 5 min.

Therefore, the blanching treatment can prevent browning of raw materials of fruits and vegetables, reduce the oxidation loss rate of VC, and separate the cytoplasmic wall of proteins in fruits and vegetables, and increase the dehydration speed of dried fruit and vegetable processing, and accelerate the candied fruit. Infiltration of sugar into the interior of tissue cells.

2, the color of the acid solution

The acidic solution can reduce the pH value of the fruit and vegetable products, inhibit the enzyme activity, and reduce the solubility of oxygen. Some acids have antioxidant effects. Commonly used acids are citric acid, malic acid or ascorbic acid, which are usually soaked in a mass fraction of 0.5% to 1% citric acid.

3, sulfur treatment

The SO: and sulfite solution have a good inhibitory effect on PPO under slightly acidic (pH about 6) conditions, and the hydrazine is reduced to phenol, and the carbonyl compound is added to prevent polymerization. The sulfur treatment method obtained in the actual production test is applicable to the color protection effect of various fruit and vegetable raw materials processing. When the sO: volume fraction is 1×10, the browning of the raw materials of fruits and vegetables can be reduced by 20%, and the fruits and vegetables can be guaranteed completely. Discoloration.

4, the treatment of salt solution

Salt (Nacl) can reduce dissolved oxygen in water, and the osmotic pressure of the salt solution can inhibit the activity of the enzyme. Short-term color protection generally uses 1% to 2% salt solution, and high quality scores will increase the difficulty of desalination. In order to enhance the color protection effect, 0.1% citric acid can also be added thereto; in order to improve the boiling resistance, it can also be immersed in a calcium chloride solution, because calcium chloride has both color protection effect and the same hardness of the pulp.

5, vacuum processing network

The vacuum method is used to extract the air in the fruit and vegetable tissue to reduce O: to prevent the browning of fruits and vegetables. Fruit and vegetable varieties that are prone to discoloration during the production and processing of fruit and vegetable products use 2% salt + 0.2% citric acid + 0.02% ~ 0.06% partial sodium sulfite solution as vacuum mother liquor; non-easy browning fruit and vegetable products vacuum mother liquor consists of 2% salt solution The general fruit and vegetable varieties use sugar water as the vacuum mother liquor, and after 5 to 10 minutes of treatment under the vacuum of 87-93 kPa, the fruit and vegetable flesh color is more beautiful.