A Detailed Guide to the Processing Method for Crispy Fried Walnut Kernels

  (1) Raw material preparation: peeled walnut kernels, starch, whole milk powder, white granulated sugar, honey, syrup, protein sugar, β-cyclodextrin, vanillin, sodium D-isoascorbate, sodium bicarbonate, citric acid, malic acid.

  (2) Process flow: Crispy syrup preparation process flow: starch, water → gelatinization → hot slurry (sweeteners, acidulants, sodium D-isoascorbate, whole milk powder) → cooling → blending (sodium bicarbonate, β-cyclodextrin, vanillin) → crispy syrup.

  Finished product manufacturing process flow: peeled walnut kernels → sugar coating → baking → cooling → sorting → bagging → sealing → inspection → boxing → storage.

Pictured: crispy fried walnut kernels

  (3) Key operating points

  Selection of walnut raw materials: requires no impurities, no contamination, no off-odors, clean and hygienic shell surface, large size, thin shells, uniform size, and a kernel yield of over 40%.

  Shelling: generally done by hand to minimize breakage of the walnut kernels.

  Walnut kernel selection: remove broken kernels, insect-damaged kernels, moldy kernels and other substandard kernels, and remove impurities.

  Peeling: use a solution of 0.4% sodium stearate and 0.2% sodium hydroxide to peel at 95~100°C for 10 minutes, then neutralize with 0.1% citric acid. The ratio of solution to walnut kernels is 3~4:1. Before neutralizing, first cool with water, and rinse to remove residual skin and residual alkali.

  Color protection: a solution composed of 0.1% citric acid, 0.15% zinc chloride and 0.1% sodium ascorbate is used at a ratio to walnut kernels of 1.5~2:1, and soaked for 20 minutes.

  Dehydration: use centrifugal dehydration at 2000 rpm for 15 minutes, so that the moisture content is ≤20%.

  Add water to starch and gelatinize: first boil water 10 times the weight of the starch, then mix the starch into a slurry with cold water, add it to the boiling water while stirring to gelatinize, then add milk powder, sugar, acid and sodium D-isoascorbate, stirring constantly to prevent local burning; after the starch is cooked, cool it promptly to 50°C.

  Sugar coating: at a ratio of peeled walnut kernels:crispy syrup of 2:3~4, stir evenly, the temperature can be raised from 50°C to 80°C; after treating for 1 hour, filter out the excess slurry, which can be reused.

  Baking: spread the sugar-coated walnut kernels evenly on a material drying tray, place in a drying oven, and bake at 110°C until the moisture content is ≤7%, then cool.

  Cooling and sorting: carry out cooling in an environment with a temperature below 20°C and a humidity below 70%, to prevent moisture absorption. After cooling to room temperature, sift through a 10~20 mesh vibrating screen; the portion on the screen is the finished product and can be packaged, while the portion below the screen is granular syrup, which can be added to the crispy syrup for reuse.

  Bagging: use 130 mm X 170 mm aluminum foil composite bags, avoiding foreign matter entering the bags.

  Sealing: use a vacuum gas-flushing packaging machine for sealing; first draw out the air in the bag. Filling with nitrogen can allow the product to be stored for more than 1 year; if non-gas-flushed packaging is used, it can also be stored for 8 months without discoloration or off-flavor. After sealing, promptly check whether the bag opening is tightly sealed.

  Boxing and storage: pack 50 bags per box, and remove bags with loose or insecure seals. The storage temperature for warehousing is below 20°C.