Packaging and quick freezing technology of the hot

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Packaging and quick freezing technology of Agaricus bisporus (Part 1)

Agaricus bisporus is rich in nutrients, especially lysine and arginine. At the same time, it also contains active substances such as mucopolysaccharide, which has important effects of inhibiting tumor growth and improving immune ability of the body. It also has the physiological effects of anti-cancer, reducing plasma bile, and the output of composite polyurethane adhesive used in plastic flexible packaging in China reached 215000 tons of sterols that year, enhancing the adaptability of the body to resist load, and resisting fatigue

Agaricus bisporus has good quality and delicious meat after quick freezing. It is a kind of quick-frozen vegetable that people like to eat. The quality of quick-frozen mushrooms is mainly determined by the color, size uniformity, tenderness and flavor of mushrooms. All mushrooms are light milky yellow in color, uniform in size, delicious in taste, and tender and crisp in texture. The quality of quick-frozen mushrooms depends on the quick-frozen technology

I. quick freezing process of Agaricus bisporus:

raw material selection → color protection → rinsing → scalding → cooling → draining → quick freezing → grading → check → ice coating → packaging → inspection → refrigeration

1. Selection of raw materials. Raw material requirements of Agaricus bisporus: fresh, white or light yellow, the surface of the friction wheel in the bonnet gearbox shall not be oiled or splashed with oil stains. The diameter is within cm, hemispherical, the edge is curled inside, and there is no deformity. It is allowed to have a slight mushroom, but the bacterial pleats cannot be black and red, without spots and scales. The mushroom handle is cut smoothly without mud root, hollow or discoloration. The quality of raw materials and yield of Agaricus bisporus are directly related to breeding, cultivation conditions, technical management, harvesting methods, storage and transportation conditions

2. Color protection of Agaricus bisporus. Put the newly picked Agaricus bisporus in the air, and after a period of time, there are brown fingerprints and mechanical scars on the surface of the mushroom cover. The main reason for this discoloration is the oxidation of phenolic substances contained in mushrooms under the catalysis of polyphenol oxidase, which is called enzymatic browning. Due to the occurrence of enzymatic browning, it is necessary to interrupt the verification of the test speed. Three conditions are required: appropriate phenolic substrate, phenolic oxidase and oxygen. The control of enzymatic browning mainly starts from the control of enzymes and oxygen. The common methods are as follows:

(1) sulfite solution method. Commonly used are sodium sulfite (Na2S03), sodium pyrosulfite (Na2S2O3), etc. Sulfite is a preservative for semi-finished fruits and vegetables. It has a strong inhibitory ability on polyphenol oxidase. When SO2 concentration reaches 10mg/kg, the enzyme activity is almost completely inhibited, and the residue of S02 should not exceed 20mg/kg

specific method: immerse the harvested mushrooms in 300mg/kg Na2S03 solution or 500mg/kg Na such as 2s203 solution for 2min, and then immediately immerse the mushrooms in clean water below 13 ℃ and transport them to the factory. It can also be soaked in Na2S03 or na2s203 solution for 2min, then taken out and drained, and then put into plastic film bags, tied the bag mouth and put it into wooden barrels or bamboo baskets to transport to the factory. After arriving at the factory, it can be immediately immersed in a clean water pool with a temperature of less than 13 ℃ for 30min to remove the residual color protection solution on the mushroom body. This method can make the mushroom color change little within 24h, so the processed mushroom products can meet the quality standards

(2) cysteine solution method. Immersing the harvested mushrooms in 0.4mmol/l cysteine solution for 30min and taking them out also has a good color protection effect

after h, the mushroom color protected by this method is still white, basically maintaining the true color of the mushroom. After cysteine color protection treatment, the mushroom color is not as white as that treated with sodium sulfite, slightly darker, but it has strong realism, clear soup, light yellow, good taste, and basically maintains the flavor of mushrooms

cysteine has a compound effect on polyphenol oxidase, and can also act as a reducing agent to inhibit the occurrence of non enzymatic browning, which is manifested in delaying browning and reducing the browning rate. At the same time, the mushroom treated with cysteine can supplement some nutritional requirements of post harvest mushrooms, delay the aging process, and reduce the proportion of open umbrella and thin skinned mushroom. Moreover, cysteine, as one of the essential amino acids for human body, is harmless to human body and has no residue problem. It is safe and reliable to use it in food production. Therefore, cysteine is also feasible for mushroom color protection

(3) film modified atmosphere packaging. Put the freshly picked mushrooms into 0 In 08mm polyethylene bags, 20kg can be placed in each bag, and the bag mouth shall be tied tightly. As mushrooms are basically isolated from the outside air, they can also inhibit the enzymatic browning reaction. On the other hand, because the film bag is thin and has a certain degree of permeability, it can maintain low O2 concentration and high C02 concentration in the bag, and mushrooms can still maintain a minimum respiratory effect for a period of time without reaching harmful effects. However, the time must be strictly controlled within h. at this time, the gas composition in the film bag is determined as: o2:%, co2:20%. If it exceeds this time, due to the lack of oxygen in the bag, the mushroom cannot maintain the minimum respiratory effect, which may lead to the breeding of Staphylococcus aureus

(to be continued)

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