Specific operation steps of processing technology of bagged fresh chestnut kernel

Chestnut belongs to Fagaceae and has been cultivated in China for more than 3000 years. At present, there are 26 provinces in China, with an annual output of 600000 tons, accounting for about one third of the world's total output. Chestnut is one of the "Woody grains" with high nutritional value. Each 100g contains 60g-70g of sugar and starch, 5g-10g of protein, 3g-7g of fat, and contains a variety of vitamins, inorganic salts, unsaturated fatty acids and amino acids. It is 1.5 times that of corn, flour and rice. In addition, it is also rich in vitamin A, vitamin B1, vitamin B2, vitamin C, carotene, riboflavin, a small amount of phenolic substances and minerals such as calcium, phosphorus, iron and potassium. Traditional medicine believes that chestnut has the effects of strengthening the waist and kidney, strengthening the spleen and stopping diarrhea, preventing cancer, promoting blood circulation and hemostasis.

After harvest, chestnut is easy to mold, lose water, breed insects, and then sprout. The loss rate usually exceeds 30%. The processing of Canned Chestnuts in bags is an effective way to solve this problem.

1. Processing technology of bagged chestnut

Raw material selection → shelling and peeling → color protection → hardening → water drainage, water drainage → packaging → drying → sugar liquid canning → vacuum packaging → sterilization → finished products.

2. Key points of operation

(1) The selection of raw materials requires the use of fresh and full chestnuts with normal flavor, no moth, no mildew and no germination as raw materials.

(2) Shelling and peeling can be carried out mechanically in the process of industrial production, and manual peeling can be used for a small amount of processing. After peeling, immediately soak the chestnuts in the color protection solution to prevent the oxidation and discoloration of the chestnuts.

(3) Browning of color preserving chestnut kernel is mainly divided into enzymatic browning and non enzymatic browning. In order to prevent chestnut kernel browning, it was first treated with inactivating enzyme, and then treated with color protecting solution.

① Inactivate enzyme treatment. The peeled chestnut kernel was soaked in hot water at 95 ℃ ~ 98 ℃ for 3 minutes to kill surface microorganisms and enzyme activities. It needs to be cooled immediately after scalding. Add 0.3% phytic acid, 0.3% ascorbic acid, 0.7% citric acid and 1% sodium chloride to the inactivated enzyme hot water, and adjust the pH to 3 with phosphoric acid. Adopt the step cooling method. First, cool it with 50 ℃ ~ 60 ℃ water for 1min, then cool it with room temperature water for 1min, and then fully cool it with 0 ℃ cold water.

② Color protection liquid color protection. Put the cooled chestnut kernel into the color protection solution (the formula of the color protection solution is: 0.3% ascorbic acid, 0.7% citric acid, 0.3% phytic acid, 1% sodium chloride), soak it for 30 minutes and then take it out.

(4) Hardening: harden chestnut fruits with 0.15% calcium chloride solution for 5 minutes, which can reduce fruit cracking and soup mixing during sterilization.

(5) Dry the precooked chestnuts, rinse them quickly with water to remove the sugar liquid on the surface. The surface moisture of chestnuts is dried under 65 ℃ and sandblasting conditions.

(6) Soak the processed chestnut in 1% chitosan glacial acetic acid solution for 1min-2min, take it out, put it into a tray, bake it at 68 ℃ -70 ℃ for 8min-10min, and dry the chestnut surface.

(7) Fill with sugar solution

① Preparation of sugar solution. Generally, heat the sugar and dissolve it in a small amount of water in the jacketed pot to form a clear and viscous syrup. Remove the floating impurities on the top and filter it, and then add a certain amount of water. Edta-2na with a mass fraction of 0.02% was added to the sugar solution as a color retention agent, and the sugar solution was boiled for later use.

② Fill with high-temperature cooking bags and add sugar.

(8) Vacuum packaging is packaged and sealed under the pressure of 0.09mpa to ensure product quality. Packaging materials should choose packaging bags with good barrier property, high mechanical strength and good heat resistance.

(9) Sterilize immediately after vacuum packaging sterilization. The sterilization method is to sterilize at a high temperature of 121 ° C for 25 minutes.

(10) The finished products can be stored indoors at a temperature above 25 ° C for 7 days. After passing the quality inspection, they can be shipped as finished products without expansion bags or deterioration.

3. Product quality standard

(1) Sensory indicators

① Chestnuts are orange yellow, no discoloration, no turbidity, and the syrup is transparent;

② The original flavor of chestnuts can be well maintained, with moderate sweetness and no peculiar smell;

③ The chestnuts in the can are basically the same size, and the fruit is soft and hard. Moderate, the cleanliness of chestnut is not less than 70%; According to the refractive index, the concentration of sugar water is 50%.

(2) Physical, chemical and microbiological indicators

① The total number of miscellaneous bacteria is not more than 150/g, and the coliform group is not more than 30/100g, so pathogenic bacteria cannot be detected.

② The content of tin in the product shall not exceed 200mg/kg, the content of copper shall not exceed 10mg/kg, and the content of Lead shall not exceed 2mg/kg.

The above is the specific operation steps of the processing technology of bagged fresh chestnut kernel. If you have other questions, please consult us!