Views: 0 Author: Site Editor Publish Time: 2022-11-21 Origin: Site
1. What is preservation and preservation
When people buy food, most of them pay attention to the shelf life, which actually guarantees the safety of food. However, with the improvement of people's living standards, people's requirements for food safety are far from enough. We also hope that the food we eat is fresh. So the concept of "fresh preservation" came into being. The so-called "fresh preservation" means that food can be guaranteed in terms of nutrition, color, texture and flavor on the basis of ensuring safety. Food can definitely keep the quality, but the food that keeps the quality does not necessarily keep fresh.
2. What gases need to be filled in the modified atmosphere packaging
1. Modified atmosphere fresh-keeping packaging is also called gas displacement packaging, and it is called MAP packaging (Modified Atmosphere Packing) internationally. The principle of the modified atmosphere packaging machine is to use mixed fresh-keeping gases (2-4 kinds of gases are mixed according to the ratio of food characteristics) to replace the air in the packaging box or packaging bag, and change the external environment of the food in the box (bag) to inhibit bacteria. The growth and reproduction of (microorganisms) slow down the metabolic rate of fresh fruits and vegetables, thereby prolonging the freshness or shelf life of food.
2. Modified atmosphere fresh-keeping gas is generally composed of carbon dioxide (CO2), nitrogen (N2), oxygen (O2) and a small amount of special gases. Carbon dioxide gas can inhibit the growth of most spoilage bacteria and molds, and is the main antibacterial component in the protective gas; oxygen can inhibit the growth and reproduction of most anaerobic spoilage bacteria, maintain the color of fresh meat and maintain aerobic respiration of fresh fruits and vegetables, and maintain The role of freshness; nitrogen is an inert gas, which has no effect on food, and is used as a filling gas to form a mixed fresh-keeping gas with carbon dioxide, oxygen and special gases. Different foods have different compositions and ratios of fresh-keeping gas.
Commonly used protective gases at home and abroad are CO2 (carbon dioxide), O2 (oxygen), N2 (nitrogen) and a small amount of special gases. The respective functions are:
(1) Usually the concentration of inhibiting bacteria is 30%.
(2) It has antibacterial effect on most aerobic bacteria, but not on anaerobic bacteria and yeast.
(3) Easily soluble in water and fat at low temperature;
(4) Good antibacterial effect is in the hysteresis period of the bacterial reproduction curve (inhibition bacteria index is about 100/100g);
O2: It works in three ways:
(1) Produce myoglobin with fresh meat to maintain the red color of fresh pork, beef and mutton;
(2) Maintain fresh fruit and vegetable metabolism and aerobic respiration.
(3) Inhibit the growth and reproduction of anaerobic bacteria;
N2: Inert gas, does not work with food, only used as filling gas for mixing fresh-keeping gas