Liquid nitrogen quick-freezing preservation method for fresh bamboo shoots

A method for preserving fresh bamboo shoots by quick-freezing with liquid nitrogen, comprising, in order, the steps of:

• 1) Cleaning and draining fresh bamboo shoots;
• 1a) cutting the fresh bamboo shoots into a plurality of bamboo shoot sections;
• 1b) selecting bamboo shoot sections free from mechanical damage except for sectioning cuts;
• 1c) immersing the selected bamboo shoot sections in an aqueous coating solution, wherein the coating solution consists essentially of 10-15% of sodium alginate, 0.3-0.5% of Kappa-Selenocarrageenan, 1.5-2.5% of Leucobryum glaucum extract, and 3.2-4.5% of Pyrrhobryum spiniforme extract;
• to obtain coated bamboo shoot sections;
• 2) Cooling the coated bamboo shoot sections to a treatment temperature of 0-4° C. to obtain cooled bamboo shoot sections;
• 2a) exposing the cooled bamboo shoot sections to 450-500 W of ultrasonic power for a first treatment period of 5-8 seconds in an ultrasonic vessel to obtain partially treated cooled bamboo shoot sections;
• 2b) removing the partially treated cooled bamboo shoot sections from the ultrasonic vessel and allowing the partially treated cooled bamboo shoot sections to stand for 10-15 min;
• 2c) placing the partially treated cooled bamboo shoot sections to an ultrasonic vessel and then treating the partially treated cooled bamboo shoots at 550-650 W for a second treatment period of 3-5 seconds;
• 2d) repeating steps 2b)-2(c) for a total of three times to obtain fully treated cooled bamboo shoot sections;
• 3) Immersing the fully treated cooled bamboo shoot sections from step 2d) in a preservative solution to obtain preserved bamboo shoot sections;
• wherein the preservative solution consists essentially of the following raw materials in parts by weight:
• 15-25 parts of water-soluble chitosan, 5-8 parts of serum protein, 1-3 parts of aspartic acid, 1-3 parts of vitamins, 20-40 parts of konjac gluocomannan degradation products, and 100-200 parts of water;
• 4) Putting the preserved bamboo shoot sections from step 3) into a container and adding liquid nitrogen to the container to obtain frozen preserved bamboo shoot sections;
• and
• 5) storing the frozen preserved bamboo shoot sections from step 4) in a cold storage facility.