Key Points and Detailed Operation Methods of Lily Whitening Processing Technology
Lily is one of the important health vegetables. The traditional processing method is to blanch the harvested lily and then dry it in the sun. Lily dried by this method still has a relatively high moisture content, is not resistant to storage, and is prone to discoloration. In the past, people used sulfur fumigation to maintain the whiteness of lily, but lily processed by this method is harmful to people's health. Now the dehydration method is used to dry lily, the moisture content is low, and after color protection, blanching and dehydration, discoloration is not likely to occur, which better solves the quality and safety problem of lily caused by sulfur fumigation.
1. Process flow. Fresh lily bulbs -> material selection -> cleaning -> scale separation and color protection -> hot blanching to deactivate enzymes -> cold water rinsing -> draining surface water -> tray loading and cart loading -> hot air circulation drying -> sorting and grading -> packaging -> sealing -> warehousing -> finished product.
2. Material selection and cleaning. Select lily with a bulb weight of more than 150 g, plump individuals, fresh, without discoloration, without insect damage, without breakage, and of good quality as raw material. Then use clean water to wash away the mud, sand and impurities on the surface of the bulbs.
3. Scale separation and color protection. Manually remove the outer withered and old scales and the stem base, then separate the scales, grade the scales according to different sizes, and promptly put them into the color protection solution to protect the color, avoiding the scales turning brown due to exposure to sunlight.
4. Hot blanching to deactivate enzymes. Hot blanching to deactivate enzymes is carried out in a tilting stainless steel open pot. The amount of added water is generally 4 times that of the scales. The amount of material put in at one time should not be too much, otherwise hot blanching will not be uniform. Turn on the steam fully to boil the water in the pot, put in the scales (the scales are best pre-loaded into 1 specially made bamboo container or stainless steel container), mix well, and when the water in the pot is observed to boil for the 2nd time, the scales should be immediately removed, reaching the standard of initially cooked but not mushy. The operation of hot blanching to deactivate enzymes must be well controlled. If the hot blanching temperature and time are insufficient, oxidative browning will occur during the drying process; if hot blanching is excessive, the scales will be boiled mushy, and after drying the scales will easily break or form fish-scale-like pieces, and the color will deepen, affecting the appearance quality of the product.
5. Cold water rinsing. Immediately put the well-blanched scales into flowing cold water and rinse until cold, then remove and drain the surface water.
6. Hot air drying. Pour the scales with surface water drained into the drying tray, spread them evenly, load them onto the drying cart, push them into the drying equipment, and carry out hot air circulation drying. The temperature is controlled at 60-70°C, and the cart is turned and the material is stirred once every hour. Dry until the moisture content of the scales reaches about 10%, and the scales feel crisp when touched, which means the dehydration process is completed.
7. Cooling and grading. After the dried lily slices are cooled to room temperature, manually select and grade the slices. Those that are white in color, intact, large and thick are Grade I products, small slices and fragments are Grade III products, and the rest are Grade II products.
8. Sensory indicators. White or slightly yellow, the flesh is slightly early transparent; scale-like, dry, the flesh is slightly tough, with the unique taste and smell of lily; moisture not more than 14%, impurities controlled below 0.5%, sulfur dioxide greater than or equal to 30 mg/kg, arsenic (calculated as As) less than or equal to 0.5 mg/kg, lead (calculated as Pb) less than 1.0 mg/kg.
9. Packaging and warehousing. After grading, immediately package and seal to prevent moisture absorption and bacterial contamination. Place in a ventilated and cool warehouse to prevent insect damage and mildew.