A kind of edible, medicinal and industrial oil obtained from the seeds of Camellia oleifera in the Theaceae family. Camellia oil is one of the main edible oils in southern China. Before the 3rd century AD, "The Classic of Mountains and Seas" recorded: "Yuanmu is an oily food in the south." Yuanmu is today's camellia oleifera tree. China currently has 4 million hectares of new and old Camellia oleifera forests, with an output of 462,622 tons of Camellia oleifera seeds in 1988.
Properties
Tea oil is a high-quality, shelf-stable edible oil. The seeds contain 31.3% oil, 4.3% ash, 1.4% crude fiber, 14.1% protein, and 48.9% non-nitrogen substances. The refractive index is 45231.4688, the saponification value is 191, the iodine value is 81~84.33, the ester value is 5.8, the acid value is 186.1, and the specific gravity is 0.90118~0.91890. Unsaturated fatty acids in tea oil account for about 90%, do not contain erucic acid, and have no harmful effects on the growth and myocardial health of humans and animals. Camellia oil is not easily contaminated by Aspergillus aflatoxin and is safe for consumption.
Raw material collection
It only takes more than 10 days from the time when the camellia oleifera fruit is fully matured to when the tea fruit cracks. When the camellia oleifera fruit becomes brighter in color, the red-skinned fruit turns red with yellow, the green-skinned fruit turns green with white, the hairs on the peel are all gone, the hairs at the base are hard and thick, and the color is dark, the tea fruit is slightly cracked, and the seeds are shiny. Dark brown, the seed kernel is white with yellow. When it appears oily, it is fully mature and can be harvested. Tea seeds can increase their oil content after retting, but the stacking time should not be too long. After 6 to 7 days, spread them out to dry, remove debris, and place them in a dry place for later use.
Processing methods
There are four types of processing methods: wood pressing, machine pressing, pre-pressing and leaching, and water substitution.
Wood pressing method
The tea seeds are roasted at about 70°C for 24 to 27 hours. After roasting, the tea kernels turn dark yellow and the moisture content does not exceed 5%. The roasted tea seeds need to be cleaned of insect shells, mites, soil and other debris, and then the tea seeds are shelled, passed through a windmill or sieve to separate the tea shells from the kernels, and then the kernels are ground finely. Steam the rice noodles for 50 to 60 minutes while the water in the pot is boiling. After the tea powder is steamed, press the cake while it is hot, and control the thickness to 20 to 25 mm. The moisture content of the prepared tea cakes is 10-13%. First, use a screw cake press to press out 40-50% of the oil content. Then put the tea cakes into an insulating box and control the temperature at 80-100°C. When the cake is put into the wooden press, it is necessary to press it in quickly, change the wooden wedges quickly, and press while it is hot. The pressing temperature is kept at 60°C and the indoor temperature is kept above 25°C. After the first pressing, you can press again.
Machine pressing method
Use a hydraulic oil press or screw oil press to press. Hydraulic oil presses are divided into two types: horizontal and vertical. The oil extraction process includes shelling, rolling, steaming, frying, cake making, pressing and other processes. ① Shelling: Use a wooden shelling machine or grinder, the shelling amount is generally controlled at 70 to 75%, and the kernel content in the shell does not exceed 2%. ② Rolling: First crush and then roll. Rolling requires fine, uniform and particle-free rolling. ③Steaming and frying: The embryo changes during the steaming and frying process, mainly because the attraction between oil molecules decreases, the surface tension decreases, the viscosity of the oil decreases, protein agglomerates, starch gelatinizes, and cellulose swells, resulting in cell membrane rupture. The cell contents are fused and compacted with each other, and the plasticity of the embryo is increased; the uniform dispersion system of oil in the embryo is destroyed, and non-hydrophilic oil is separated and gradually agglomerated; oxidation, saccharification and saccharification of oil occur. The proteins interact to produce melanin, which deepens the color of the blank. The stir-frying temperature is 110-120°C for wood presses or hydraulic presses, and the moisture content of the dough after steaming and stir-frying is 7-8%; for screw presses, it is 130-140°C, and the moisture content after steaming and stir-frying is 3-4%. Before pressing, the hydraulic press needs to make cakes to extract oil, but the screw press does not need to make cakes. The pressing temperature is required to be no less than 120°C, and the thickness of the cake is controlled at about 4 mm.
Pre-pressing and leaching method
After the tea seeds are shelled, separated from the kernels, crushed, rolled and steamed, they enter the pre-pressing machine for squeezing. The oil obtained by pre-pressing is called machine The oil is pressed, filtered and ready for consumption. The residual oil rate in the pre-pressed tea cake is more than 10%. Put the tea cake into the extractor and extract it with No. 60 soybean solvent oil. After evaporation and desolvation, the tea oil is extracted. After deodorization and deacidification, edible tea oil can be obtained. The leaching equipment includes tank-type and horizontal-type continuous leaching machines. Rural wood-pressed tea cakes can be soaked again with an extractor. Every 100 kilograms of cake can extract 5.5 to 6.5 kilograms of oil.
Water substitution method
Grind the Camellia oleifera seeds with a grinder, soak them in heated water, and shake them continuously to separate the oil and water, skim out the oil, boil it in a pot, and steam it. Remove the water and it becomes edible oil.
Uses
Consumption of tea oil will not increase serum cholesterol, is easily digested and absorbed by the human body, and is beneficial to health. Tea oil is one of the most ideal oils in the canning industry. In addition, it can also be used as machine lubricating oil, iron anti-rust oil, margarine, petroleum jelly, hair growth oil, soap, candles, fuel and medicine, etc.