Collection and processing of tea oil

1. Harvest: there are many varieties of Camellia oleifera, and the fruit ripening period is generally from October to early November. The mature fruit has the following characteristics: bright color, redness or yellowing, glossy fruit, peel hair off, fruit base hard and thick, fruit shell slightly cracked, seed shell blackened and shiny, seed kernel showing oil. Tea fruits should be harvested as soon as they are ripe. Different varieties of tea fruits should be picked first, then ripe and then picked, and the mature tea fruits of the same variety should also be harvested within nearly 7 days. The harvested tea fruits should be put in the indoor compost for 6 days and 7 days, so that the tea seeds can play the role of ripening and increase the oil content. Then seize the sunny day, spread out and turn in the sun, and after 3 or 4 days, the tea fruit will crack naturally, and the tea seeds of most fruits can be separated, and the unseparated ones can be stripped off manually, then sifted and dried intermittently, usually for 12 days, so that organic matter such as starch and soluble sugar can be fully converted into oil. The soil or bamboo mat for drying tea seeds is better than cement, which can improve the oil yield and the quality of tea oil. If the tea seeds cannot be dried in time on cloudy and rainy days, the tea seeds should be spread on a dry and ventilated floor, about 20 cm thick, and be turned over once or twice a day to prevent fever, mildew or sprouting, and turn in time in case of sunny days. The weight ratio of Camellia oleifera seeds dried to fruit shell is 1 ∶ 2. The dried Camellia oleifera seeds should be stored in a ventilated and dried place. When the oil content of camellia seeds reaches the highest after 1 to 2 months, the oil yield is high and the oil quality is good.

Second, oil extraction: tea oil is extracted from tea seeds by pressing method at present. The traditional oil pressing tool in rural areas of our country is wood press, which has high labor intensity and low oil production rate. It will be gradually replaced by hydraulic presses and screw machines. Before pressing, it needs to be crushed and steamed and fried: ① crushing: the camellia seed is shelled. In order to avoid the difficulty of shelling and breaking too much kernels, the moisture content of the tea seed must be controlled within 5%-6%. After shelling, it is processed into powder by a grinder. If the stone mill is used, it must be screened several times in the rolling process in order to get fine and uniform, no coarse grain, and get a higher oil yield. ② steaming and stir-frying: the purpose of steaming and frying is to turn the raw meal into clinker, to deepen the color of the billet, and to be in the most suitable state for oil shunt, which is a key process before pressing. The traditional steaming and frying is steamed with wood retort and stir-fried in iron pan. The raw meal is first moistened by steam or spray water before frying, which is called "wet steaming"; without wetting, it is called "dry steaming". Generally, it is better to "wet steaming and frying". The moisture and temperature of steaming and frying vary according to the type of machinery used. With hydraulic press and wood press, the frying temperature is generally 110-120 ℃, and the water content after steaming and frying is 7%-8%. The stir-frying temperature of the screw press is generally 130-140 ℃, and the water content after steaming and frying is 3%-4%.