PRODUCTION PROCESS OF CANNED LONGAN

Longan is a specialty fruit of Vietnam. In this article, we will go into detail about the process of producing light sirup canned longan, a product with high export value in recent years.

Cleaning

Eliminate impurities such as sand, and dust, and reduce the number of microorganisms attached to the shell as well as residues of pesticides.

Peel and remove seeds

After the washing process, remove the unusable parts such as peel, stalk, pulp, seeds, etc. to obtain the flesh of longan.
Soak in 5% CaCl2 solution
Longan's flesh is immediately soaked in 0.5% CaCl2 solution for about 10-15 minutes. The flesh needs to be soaked to avoid darkening due to exposure to air, to create hardness for the fruit, remove part of the dirt and impurities on the surface of the fruit.

Heat treatment

Longan's flesh is soaked with hot steam at 100°C for 3-5 minutes. After, it should be cooled quickly to avoid loss of sensory value.
Purpose: Partially destroy microorganisms, inactivate enzymes, and suspend biochemical processes of raw materials. Limit the appearance of unsuitable odor colors for the product.

Packing longan's flesh on the can

Products before being packed into the can need to be drained and checked for the last time to remove any remaining unqualified products during the processing process. The weight of the product when packed into the can accounts for 55-80% of the net weight of the box.

Sirup Pouring

Pour sugar water into the can of packed longan’s flesh. During pouring step, the sugar water should have a temperature of 80-85°C and should be poured 7-10mm from the mouth of the can. If overfilled, during pasteurization, the lid can be opened (with iron cans) or popped (with glass jars).

Pasteurization

Purpose: Kill microorganisms in the product to the maximum extent allowed to no longer cause damage to the product, suspend enzyme activities. The high temperature also helps speed up the osmosis process.

After mixing with sirup, pasteurize immediately, not longer than 30 minutes, to avoid fermentation before pasteurization and reduce the initial temperature of canned goods.

The pasteurization temperature is usually 98°C for 10 to 25 minutes. After pasteurization, it is necessary to cool down to ensure the taste, color, and firmness of the box and to prevent the iron box from being corroded.

Recheck

After cooling, canned goods are washed and dried and then transferred to the finished product warehouse, arranged in trees to insulate the product for about 7-15 days and to check product quality. The purpose of this stage is to detect errors in the implementation stages.

Preserve

Canned longan must be stored in a dry, clean, and well-ventilated warehouse.