Modified atmosphere packaging for fruits and vegetables
Modified atmosphere packaging for fruits and vegetables:Key technologies for modified atmosphere packaging of fruits and vegetables:
A qualified composite controlled atmosphere fresh-keeping packaging machine has two key technical indicators that must meet the corresponding requirements.
These two indicators are: first, the gas replacement rate must be high, and second, the gas mixing accuracy error rate must be low. Whether the quality of composite modified atmosphere fresh-keeping packaging equipment is qualified or not needs to be judged by these two key indicators. Controlled atmosphere preservation gas is generally composed of carbon dioxide (CO2), nitrogen (N2), oxygen (O2) and a small amount of special gases.
Carbon dioxide has the effect of inhibiting the growth and reproduction of most bacteria and molds and slowing down the metabolism of fresh fruits and vegetables. It is the main antibacterial component in fresh-keeping gas;
Oxygen has the function of inhibiting the growth of most anaerobic bacteria, maintaining the color of fresh meat, maintaining aerobic respiration of fresh fruits and vegetables, and maintaining freshness;
Nitrogen is an inert gas and has no effect on food. As a filling gas, it forms a composite preservation gas with carbon dioxide, oxygen and special gases. Different foods, fruits and vegetables require different compositions and proportions of fresh-keeping gases.
Food, fruits and vegetables use composite modified atmosphere packaging equipment for fresh-keeping packaging, which requires reasonable requirements for gas mixing accuracy error and gas replacement rate. In the standards of advanced composite modified atmosphere preservation packaging equipment in developed countries, the gas replacement rate is required to be above 98%, and the preservation gas mixing accuracy error rate is less than 2%. This is because the above two indicators play a vital role in the preservation of food, fruits and vegetables.
Examples are as follows:
Example 1: When packaging lychees with controlled atmosphere, the mixing ratio of the preservation gas is: oxygen (O2) concentration ratio 4% to 6%; carbon dioxide (CO2) concentration ratio 3% to 5%, damage concentration 8%; the rest is filling gas Nitrogen (N2); if the O2 concentration is low, anaerobic respiration will occur, causing fermentation of the lychee fruit and tissue necrosis; the O2 concentration is high or the CO2 concentration is low, inhibiting the metabolism of lychees and shortening the shelf life; the CO2 concentration is high ( >8%), it will cause damage to the peel and fruit and accelerate the deterioration of lychees.
Advantages of modified atmosphere packaging for fruits and vegetables over other preservation methods:
Commonly used methods for preserving food are:
1. Chemical preservation.
2. Freeze and keep fresh.
3. Vacuum and high-temperature sterilization to ensure quality.
4. Vacuum and fill with nitrogen to preserve freshness.
5. Composite controlled atmosphere preservation.
6. Natural biological preservation.
Among the above six modified atmosphere packaging technologies for fruits and vegetables, chemical preservation uses chemical agents to prevent corrosion and inhibit bacteria, but consumers are restricted due to concerns about the side effects of preservatives; the shortcoming of frozen preservation is that the taste and taste of food change after freezing; vacuum high-temperature sterilization The disadvantage of bacteria is that it damages the unique taste, texture and nutrition of food; nitrogen-filled packaging can better maintain the taste, taste and nutrition of food, but the shelf life is very short. If you need to extend the shelf life, you need to use high temperature after packaging Sterilization, the taste changes greatly. Composite controlled atmosphere preservation is a brand new preservation technology developed on the basis of the above traditions. It has certain requirements for the packaging environment. Its characteristic is that it does not require high-temperature sterilization. Therefore, composite controlled atmosphere preservation can ensure the taste, taste and nutritional content of the original food. , truly guaranteeing the original juice, flavor and appearance of the food.
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