Auxiliary fresh-keeping technology of the hottest

2022-08-09
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Auxiliary fresh-keeping technology of fruits and vegetables before storage (I) precooling is to pre cool the fruits and vegetables before storage or shipment, so as to remove the field heat of fruits and vegetables and reduce the heat and decay of fruits and vegetables during storage and transportation

the precooling efficiency before storage is different for different kinds and varieties of fruits and vegetables. Only when a certain kind of fruits and vegetables is completely precooled as far as possible before the respiratory peak occurs after harvest can the ideal storage effect be obtained. Generally, fruits and vegetables that have been pre cooled should not be put back to normal temperature, otherwise the physiology and biochemistry of fruits and vegetables will change

(II) mildew prevention and corrosion prevention

under suitable storage conditions, the use of preservative agents can effectively inhibit the loss. Especially for fruits and vegetables with higher storage temperature, such as tropical and subtropical fruits such as citrus, banana, litchi and mango, as well as vegetables such as tomato, sweet pepper, cauliflower and cucumber, the combination of anti-corrosion and fresh-keeping agents under suitable low-temperature storage can greatly improve the quality of products and prolong the storage life

1. the tri Mack mixed panel of antiseptic and bactericide is manufactured by robot injection molding unit: in the early 1970s, carbendazim and methyl tobuzin 2.4-D imported from Japan were used in China to prevent citrus decay and peeling, and the effect is obvious. Small medicine bags made of sodium bisulfite and sodium bisulfite plus silica gel are mixed with grapes, and the mildew proof effect is also very significant. Subsequently, many new drugs, such as phenlaite, terketol, imazole, etc., were introduced in succession. Tektor, phenylette, etc. have also been successfully copied in China

in recent years, the high-efficiency and low toxicity fungicides used are mainly carbendazim, tobujin, methyltobujin, phenylette, imazalzole, terketol, thiabendazole (TBZ), carbendazim, SEC butylamine series, etc., which have a significant effect on preventing the decay of citrus, apple, banana, peach and tomato, cucumber and other vegetables. Using ethoxyquine or diphenylamine emulsion to spray wrapping Apple paper has a significant effect on preventing the tiger skin disease of apple. In grape storage, the use of an appropriate amount of sulfur dioxide gas, or the use of sodium bisulfite, potassium pyrosulfite (sodium) and grape fresh-keeping tablets can inhibit the activities of microorganisms and have the effect of preservative and fresh-keeping

2. Drugs to prevent physiological aging:

(1) ethylene remover: removing the ethylene released by the fruit during storage can delay its maturity aging process and prolong its storage life. The commonly used ethylene remover is to adsorb saturated potassium permanganate on vermiculite, perlite, carbon molecular sieve, zeolite or broken brick and other carriers, put them into plastic bags, tie several small holes in the plastic bags, and put them into fruits and vegetables

(2) deoxidizer: it has long been used to consume oxygen in packaging containers through pharmaceutical chemical reactions to prevent oxidation and deterioration of fatty foods such as peanut, biscuits, candy, etc. Applying it to fresh persimmon debittering is the experiment of researchers in recent years, which is quite characteristic. The method is to put the crispy persimmon, which is free of pests and mechanical injuries and has turned color, into an airtight plastic film bag and seal it together with the deoxidizer. It can remove astringency for 4 ~ 6 days at room temperature of 20 ℃ ~ 30 ℃, and keep it crisp and hard; If stored in 0 ℃ cold storage, it can be stored for 1 ~ 2 months, and the astringency is gradually removed and remains crisp and hard

preparation components of deoxidizer: 100 parts of iron powder (10 mesh ~ 50 mesh) plus 1 ~ 10 parts of salt mixture such as sodium chloride and 5 ~ 20 parts of calcium hydroxide, etc., which are fully mixed to make small packages. In addition, P (HB – HV) has piezoelectric properties. The general dosage is 0.1% - 1.0%

(3) carbon dioxide absorbent: excessive carbon dioxide accumulation in the storage environment of fruits and vegetables will often cause physiological damage to fruits and vegetables. For example, too much carbon dioxide will browning the pulp and core of apples, pears and other fruits. Therefore, to remove carbon dioxide from the environment in production, air conditioners or silicon windows can be used. The application of carbon dioxide absorbent is also an effective method

preparation of carbon dioxide absorbent: calcium hydroxide, sodium hydroxide, calcium oxide, etc. are mainly used to make powder, which is put into breathable bags, and then mixed with fruits and vegetables in membrane bags. The addition amount is generally 1% - 3%

(III) high carbon dioxide treatment

experiments and practice have proved that good fresh-keeping effect can be achieved by pretreating fruits and vegetables with high carbon dioxide before storage. Due to the short-term high carbon dioxide treatment, it can effectively reduce the respiratory intensity of fruits and vegetables, inhibit the release of ethylene, delay the hydrolysis of pectin, inhibit the disintegration of chloroplasts, delay and inhibit the emergence of the peak respiratory period of fruits and vegetables, and have a good effect on prolonging the storage period of fruits and vegetables. For example, treating strawberries with 20% - 25% carbon dioxide can prolong the storage period by about 15 days. For different kinds of fruits and vegetables in long-distance logistics conditions, first of all, they should be advanced and have the word "grounding" or grounding mark to conduct tests to find out the most suitable concentration and time of treatment, so as to avoid injury

(IV) drying treatment

the purpose of drying treatment before storage is to effectively inhibit the respiration and water emission of fruits and vegetables, so as to minimize the nutritional components consumed by fruits and vegetables due to physiological activities after storage, so as to maintain the freshness and quality of fruits and vegetables during storage as much as possible. For example, the peel of Citrus contains more water after harvesting. After drying, some water is lost from the peel of citrus, which makes the peel elastic and reduces mechanical damage

when carrying out drying treatment, the degree of drying treatment should be mastered, and the time of drying treatment should be determined according to the temperature and wind speed during drying treatment

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