Cold Pressing And Refining Process Of Tea Seed Oil And Its Nutrition Components

Tea seed oil (Camellia Sinensis O.Ktze) is an important advanced cooking oil resource to bedeveloped. A specific extraction technique is necessary because the traditional pressing methodwith seed shells causes deep color, bad flavor, and other undesirable chemicals in the crude oil,and subsequently causes increased refining cost and losing of nutrients in the refining process.Pressing method directly using tea seed kernels leads to low oil extraction rate. We therefore usedrice husk instead of seed shell mixed with kernels to press, the results showed an effective way toimprove quality of the crude tea seed oil and the oil extraction rate. The main results are asfollowing:（1）After30days storage, the total oxidation value was increased by64.50%. Content of Oleicacids was decreased by51.46%. Content of squalene was decreased by15.06%, and content of teapolyphenols was decreased by28.16%. High temperature storage was not conducive to tea seedquality, the total oxidation value at37℃storage increases0.23%compared to22℃after30daysstorage. High moisture content was also not conducive to tea seed quality during storage, the totaloxidation values at3%and5.0%moisture content storage increased6.9%,8.0%, respectively,compared to1.0%moisture content storage.（2）Hot air drying was a proper way for seed drying before pressed. The best conditions of thehot air drying was90℃for8h that could reach an oil extraction rate of73.23%。Content of Oleicacids were increased by6.8%and2.5%, increased by6.1%and6.2%of tea polyphenols, andincreased by4.2%and3.0%of squalenes when compared to the conditions at70℃/8h,90℃/12h,respectively. The average hole area on the seed cross-section was41.506μm2which was by33.1%of the total hole area.（3）The proper proportion of tea seed kernel and rice husk of the mixtures was15-18:1. The oilextraction rate was87.02%which were47.8%and19.4%higher than these of pressing with seedshells and pressing directly using seed kernels, respectively. The lovibond value was38.01whichdecreased by33.1and increased by4.9when compared to the pressing with seed shells, andpressing directly using seed kernels, respectively. The total oxidation value was increased by5.2%and decreased8.0%, respectively. （4）The parameters of main refining steps of filtration, degumming, deacidification, washing, anddecoloration (or bleaching) were studied. Results indicated that the proper refining parameterswere: filtration with140meshes polypropylene clothes could reach a better filtration rate of31.3g/100g; the degumming rate of combined hydration degumming and phosphate degummingwas2637.1mg/100g. The best conditions of alkali deacidification were temperature at40℃, alkaliconcentration of10%,0.30%excess of alkali, stirring rate at200rpm. The de-soap rate was68.13%in washing process under the best conditions of water temperature at60℃, stirring rate at200rpm,and amount of water added at15%of oil weight. The proper bleaching agent for tea oil bleachingwas a mixture of activated clay and activated carbon, the amounts of activated clay and activatedcarbon used were2.0%and1.5%of oil weight, respectively. The lovibond values was R1.3Y20.0,and the oil yield was up to92.8%.（5）The quality of the final refining tea seed oil met to the national standard of China.