Application of the hottest vacuum packaging techno

2022-08-16
  • Detail

Application of vacuum packaging technology in Deastringency and freshness preservation of persimmons

persimmons are rich in nutrition and have important medical value and health care functions. However, the traditional persimmon production areas in China are almost all astringent persimmons, and the representative variety is Mopan persimmon. The content of soluble tannin in astringent persimmon fruit is high, and it has a strong astringent taste. Therefore, it is an urgent task for China's persimmon industry to explore the astringent and fresh-keeping technology of persimmon fruit

1. Current situation of domestic vacuum packaging technology

at present, the processing and preservation of grain, oil, fruits, vegetables, livestock, poultry and aquatic products are basically in a low-level and extensive state, and China's refrigeration conditions cannot be compared with the United States, Japan and other developed countries, resulting in a large loss of agricultural products and a waste of resources. Persimmon fruit loss accounts for 20% of China's annual output. Vacuum packaging persimmon fruit can maintain the quality and nutritional components of persimmon fruit, which is highly valued by the persimmon industry

2. Basic principle and characteristics of vacuum packaging

in addition to controlling the external temperature and sterility, vacuum packaging is more important to control the appropriate gas environment of persimmon fruit to achieve the expected purpose of fresh-keeping. The main methods are mechanical extrusion, straw degassing and other methods. In either way, the air in the packaging bag should be extracted and then heat sealed. Its main features are: reduce the oxygen content in the bag, inhibit the growth and development of mold and aerobic bacteria, control the deterioration of persimmon fruit, and achieve the purpose of fresh preservation and quality assurance. At the same time, the environment in which persimmon fruit produces carbon dioxide through anaerobic respiration can effectively reduce the respiration of persimmon fruit, reduce ethylene production and nutrient consumption, remove strong astringency, and finally, it is both astringent and fresh-keeping. In addition, persimmon fruit can resist mechanical pressure and reduce vibration after vacuum packaging, which is not only conducive to long-distance transportation, but also conducive to sales

3. Persimmon fruit harvesting and grading

(1) the friction coefficient of plastic film is a major goal. Harvesting and grading fruits should be handled with care; Ensure the integrity of sepals, because sepals are important respiratory organs of persimmon fruit; The requirements for maturity are the same. Picking at maturity in August and September, the maturity is different, and the Deastringency and freshness of persimmon fruits are also inconsistent; After picking, select the fruit, remove the pest fruit, injured fruit and the fruit that is too large and the standard is that the upper space is stretched too small

(2) single fruit packaging because the size of the packaging bag involves the area of gas penetration, which affects the final gas proportion in the bag and relates to the storage life of persimmon fruits

4. Persimmon vacuum packaging equipment and materials

chamber type vacuum packaging machine is used. When packaging, the selected persimmon fruit is packed in a plastic bag and placed in the vacuum chamber. The mouth is closed for air extraction. After reaching the predetermined vacuum degree, the heat sealing device is closed and the mouth of the bag is sealed. If vacuum inflatable packaging is required, the gas is filled before sealing. This vacuum packaging machine has a high vacuum degree, which can be adjusted according to needs. It is a kind of vacuum packaging machine that is widely used at present. Most of the materials used for vacuum packaging are plastic films. Because the films have good barrier property, safety, chemical stability, mechanical toughness and temperature resistance, they are convenient for printing, and some have certain transparency and shading. Plastic is divided into single film and composite film. Persimmon vacuum packaging generally uses single film

relevant studies have shown that using low-density polyethylene (LDPE) plastic film vacuum packaging technology to treat astringent persimmons, persimmons are in the disgust of low oxygen and high carbon dioxide. Powerful calculation and mathematical statistics functions replace the anaerobic respiration in the complex working oxygen environment in the past, producing ethanol and acetaldehyde. Acetaldehyde condenses with soluble tannins in persimmons, which can transform soluble tannins into insoluble tannins to achieve the purpose of astringency removal. Because LDPE has certain air permeability, and persimmon fruit produces carbon dioxide during anaerobic respiration, so the carbon dioxide in the bag will exchange with the outside air. When the exchange of internal and external gas reaches equilibrium, the gas in the bag will maintain a certain proportion. Through the selection of packaging materials, the proportion of gas can be suitable for persimmon fruit Debittering and fresh preservation

5. This is a new intelligent loading equipment in the aluminum profile industry in China. The mobile intelligent material handling system. The vacuum degree of persimmon fruit packaging

the vacuum degree determines the initial oxygen content in the bag, affects the degree of anaerobic respiration of persimmon fruits, and thus affects the length of time required for persimmon fruit debittering

millstone persimmon packaged in 0.1mm LCPE single fruit vacuum takes 7 days to remove astringency at room temperature, and can remain crisp for 50 days without softening. During storage, the content of vitamin C, the color of fruit surface and the flavor of fruit basically have no change, and there is no peculiar smell. However, when the persimmon fruit is completely softened, the vitamin C content in the persimmon fruit decreases, and ethanol is produced in the packaging bag. At this time, eating it has a slightly alcoholic taste. The control persimmon fruit without any treatment at room temperature completely softened after 20 days. And the persimmon fruit is still not completely astringent after softening. It can be seen that vacuum packaging technology has played a role of killing two birds with one stone in Deastringency and crispness preservation of astringent persimmon fruits

Copyright © 2011 JIN SHI