Modified atmosphere packaging is the best choice for food preservation

Zhejiang Mingwei Machinery Co., Ltd. is also known as lightly processed or micro-processed fruits and vegetables for fresh-cut fruits and vegetables. After grading, sorting, cleaning, cutting, pitting, peeling, trimming, packaging, etc. Remaining fresh, consumers can cook or eat these products without any processing after purchasing them. With the acceleration of the pace of modern life and the improvement of living standards, people's demand for fruit and vegetable consumption is getting higher and higher. Fresh-cut fruits and vegetables are favored by more and more people for their freshness, convenience, nutrition, and other characteristics, especially in In Europe, America, Japan, Thailand and other regions, consumers have become very common in the consumption of fresh-cut fruits and vegetables.

Fresh-cut fruits and vegetables have a certain convenience, so the public catering industry is in great demand. However, fresh-cut fruits and vegetables must undergo peeling, pitting, cutting, slicing and other processes, and these processes are all factors that lead to the rapid reduction of the shelf life of such semi-processed fruits and vegetables, because fresh fruits and vegetables will be subjected to certain processes during these processes. degree of mechanical damage, thereby making it more susceptible to microbial infection and resulting in poor quality. Therefore, for fresh-cut fruits and vegetables, it is particularly critical to find a reasonable packaging machine. Fortunately, the current modified atmosphere packaging technology has been effectively applied in the preservation of fresh-cut fruits and vegetables.

Modified Atmosphere Packaging

Modified atmosphere packaging is a fresh-keeping packaging technology that reduces the respiration intensity and ethylene content of fruits and vegetables by changing the gas environment in the packaging, thereby delaying the ripening and aging of fruits and vegetables and the decline of nutritional quality. It is mainly divided into spontaneous modified atmosphere packaging and controlled modified atmosphere packaging.

1. Spontaneous modified atmosphere packaging

The working principle of spontaneous modified atmosphere packaging is to use the respiration of fresh-cut fruits and vegetables and the selective permeability of packaging films to achieve gas exchange. When the consumption rate of O2 in the package is equal to the infiltration rate, and the production rate of CO2 is equal to the exudation rate. , the package can form a low O2 high CO2 controlled atmosphere equilibrium concentration, so as to achieve the purpose of preservation. However, this gas environment has only been proven effective in the preservation of fresh-cut fruits and vegetables such as garlic moss, carrots, lotus roots, and apples. Most fresh-cut fruits and vegetables are more suitable for controlled atmosphere packaging.

2. Controlled atmosphere packaging

The working principle of controlled atmosphere packaging is to fill certain gases into the packaging according to a certain controllable ratio, and obtain the best gas ratio suitable for maintaining the quality of fruits and vegetables through screening, so as to achieve the purpose of preservation. Under normal circumstances, 5% to 10% CO2 and 2% to 5% O2 are used for controlled atmosphere packaging, because this proportion of gas environment can significantly reduce the respiration rate of fresh-cut fruits and vegetables and effectively inhibit the deterioration of fruits and vegetables caused by enzymatic reactions. , This gas ratio has been confirmed to have a positive effect on the preservation of fresh-cut fruits and vegetables such as kiwi fruit and longan. In addition, some inert gases such as Ar, N2, NO2, etc. are also considered to be ideal gases for the control of modified atmosphere packaging. At the same time, some high-oxygen gases can effectively inhibit the growth of aerobic bacteria and are also good for fresh-cut fruits and vegetables to control modified atmosphere packaging. s Choice.

Modified atmosphere storage is a more advanced method of preservation and storage of fruits and vegetables. On the basis of refrigeration, it increases the adjustment of gas components. By controlling the temperature, humidity, carbon dioxide, oxygen concentration and ethylene concentration in the storage environment, it inhibits the respiration of fruits and vegetables, delays their metabolic process, and better maintains the freshness of fruits and vegetables. degree and commerciality, prolong the storage period and sales shelf life of fruits and vegetables. Usually, modified atmosphere storage can prolong the storage period by 2-3 times than ordinary refrigeration.

In order to make the air-conditioning warehouse reach the required gas composition and keep it relatively stable, in addition to the air-tight warehouse that meets the requirements, there must also be a system composed of corresponding gas regulating equipment, pipelines and valves, that is, the air-conditioning system. The entire air conditioning system includes deoxidizer or nitrogen production system, carbon dioxide removal system, ethylene removal system, temperature, humidity and gas composition automatic detection and control system.

The air-conditioning warehouse equipment is mainly composed of the following parts: refrigeration equipment (ammonia system, freon system and ethylene glycol system, etc.) humidification equipment in the warehouse, frosting in the warehouse and cooling water equipment for refrigeration units, electrical control equipment, gas Adjustment equipment (nitrogen generator, carbon dioxide remover, ethylene remover and sulfur dioxide generator, etc.), other equipment (air-conditioning warehouse door, observation window safety device, air storage bag and other ancillary equipment), ethylene is fruit and vegetable in ripening and A gas produced and released by itself in the process of post-ripening is a plant that promotes respiration and accelerates post-ripening, and has a ripening effect on fruits stored after harvest. In the storage of ethylene-sensitive fruits, ethylene should be removed. Therefore, in the storage of fruits and vegetables, it is necessary to try not only to suppress the production of ethylene, but also to accumulate ethylene in the storage warehouse. The main function of the detection and control system in the controlled atmosphere warehouse is to check and measure the temperature, humidity, oxygen, and carbon dioxide gas in the controlled atmosphere warehouse in real time. Display to determine whether it meets the requirements of air-conditioning technical indicators, and perform automatic (manual) adjustment to make it in a state of better air-conditioning parameters. It can be said that modified atmosphere packaging is both a challenge and an opportunity for my country's food preservation and processing market. It is believed that with the increasingly mature and rational market demand, China's modified atmosphere food preservation packaging will flourish in a short period of time and become the mainstream of consumers' purchase of food.