Study On Extraction, Refinding And Stability Of Blackberry Seed Oil

The blackberry output in China occupies11.9%in the world. With the growth of concentrated juice production, amounts of blackberry residues are produced, causing environmental pollution and resource wasting. With27.7%of oil content, which contains80.49%of unsaturated fatty acid, blackberry seed is a good kind of oil resources. So making use of blackberry seed oil is another direction of pomace utilization with great economic and social benefits. Blackberry seed oil was extracted by four methods of organic solvent extraction, supercritical fluid extraction, supercritical carbon dioxid extraction and subcritical extraction. The yield, properties, fatty acid compositions and the antioxidant capacity of blackberry seed oil were studied in this thesis.1. Extraction, properties, and fatty acid compositions of blackberry seed oilBlackberry seed oil was extracted after being dried in the shade and pretreatment. The yield of blackberry seed oil was27.14%being extracted for4h at temperature30℃with the ratio of4:1(v/w,petroleum ether to blackberry seed). When adopting supercritical carbon dioxide under the pressure of25MPa at temperature30℃, the highest extraction efficiency could be22.48%. Moreover, the yield was up to23.72%by using subcritical method under the pressure of0.8MPa. Blackberry seed oil belonged to semi-dry oil with iodine value of150.14g/100g, and needed further refining processing because of its high level of water content and free fatty acids. The gas chromatography-mass spectrum analysis showed that blackberry seed oil contained palmitic acid, stearic acid, oleic acid, linolic acid, eicosenoic acid, eicosatrienoic acid, and docosanoic acid mainly. The unsaturated fatty acid occupied80.49%, especially for polyunsaturated fatty acids.2. Refining of blackberry seed oilThe quality indexes of blackberry seed oil, including phospholipid, saponifiable content, acid value, water content, color and flavor, have met the qualification of hygienic standards for edible vegetable oil after hydrated degumming, deacidification with alkali, washing and drying. The optimum degumming parameters of water addition, hydration temperature, and time were10%,60℃, and30min respectively. And the optimal alkali refining parameters of time, initial temperature, exceed alkali quantity were50min,80℃, and0.3%respectively.3. The effects of antioxidants on the POV of blackberry seed oilThe effects of temperature and time on the anti-oxidation of blackberry seed oil and the effect of antioxidants on anti-oxidation ability of blackberry seed oil were studied by Schaal experiment according to POV of blackberry seed oil. The results showed that the POV of blackberry seed oil was affected remarkably by temperature and time. The TBHQ had good antioxidant effect on blackberry seed oil:TBHQ>BHT>VE. Compound antioxidant has better effect then single antioxidant, and Synergist’s effect is even more obvious. The Citric acid is better than Vc.0.015%TBHQ and0.005%BHT and0.01%Citric acid would extend the shelf life of blackberry seed oil from2months to11～13months at20℃.