1. process flow
Selecting materials → washing fruits → peeling and coring → rinsing → canning → adding sugar solution → exhausting → sealing cans → sterilization → cooling 2. Key points of production.
(1) Selection of raw materials
Longan varieties with large fruit, thick meat, fine meat and medium sugar content are better. The varieties suitable for processing are Yanfu, Shuizhang and Dawuyuan. Fruit maturity should be 89% mature, and rotten fruit, pests and diseases, broken fruit, cracked fruit and small fruit should be eliminated.
(2) Wash the fruit
Cut the fruit and pour it into the washing tank. Wash off the sediment and dirt with clear water.
(3) Peeling and coring
After manual peeling, use a seeder to remove the core. The core remover consists of a core piercing tube and tweezers. The diameter of the core tube is 1 1 ~ 14 mm, which is basically the same as the transverse diameter of the core. When removing the core, insert the puncture tube in the pedicel of the fruit, and rotate it gently to make the meat core separate for easy pulling out. If the stone can't be taken out, use tweezers to clamp out the stone and clamp off the lignified fibers and debris in the pit. After removing the core, the holes in the pulp should be kept intact, and cracks and cracks should be avoided as far as possible, and then the peel should be removed. Soak the pulp in an enamel dish containing 1% salt water according to its size and hardness. Salt water must submerge the pulp to prevent discoloration, then rinse it with clear water and can it.
(4) canning
When canning, the pulp size in the same can should be basically the same. Different canned models have different fruit contents. 8 1 13 canned pulp 280~290g, 78 1 canned pulp 150 ~ 160g.
(5) sugar solution
The sugar content of sugar solution should be adjusted according to the sugar content of canned pulp, so that the sugar content of longan meat and sugar solution can be balanced, and the sugar content after canning can reach the requirement of 14% ~ 18%. For example, the sugar content of canned pulp is 14%, and the sugar solution is 18%. 0.2% citric acid should be added to the sugar solution, and the pH value of the contents should be adjusted to 4.2. Adding 0.02% ~ 0.08% calcium chloride can increase the crispness of pulp. Heat that prepared sugar solution to 85 DEG C, and pour into a canned container filled with longan meat, leaving a gap at the top.
(6) Exhaust and tank sealing
Commonly used methods are vacuum exhaust and hot exhaust. Vacuum venting is carried out in a vacuum can sealing machine, and the vacuum degree is required to reach 0.4 ~ 0.5 bar, and the can is sealed immediately after venting; Hot exhaust is carried out in the exhaust box for 7m. Heat and exhaust with steam for 7 minutes to make the center temperature of the tank reach 70 ~ 75℃, and seal the tank immediately after exhaust.
(7) sterilization and cooling
Sterilization should be carried out as soon as possible after sealing, and sterilization should be carried out in boiling water at 100℃ under normal pressure. 78 1No. Tank sugar water net weight 32 1g, hot exhaust sterilization for 8min, vacuum exhaust sterilization for10 min; ; The net weight of tank 8 1 13 is 567g sugar water, which is sterilized 10min and 12min respectively. Immediately after sterilization, it is put into cold water and cooled to 37℃, which is the finished product of canned longan in sugar water. The finished cans are stored in the warehouse for 7 days, and then whether there is convex can phenomenon is checked. Unqualified cans are picked out in time, and qualified products can only leave the factory after being labeled.