Study On The Oxidation Stability And Degumming Process Of Wild Walnut Oil(Carya Cathayensis)

China is a big oil and fat consuming contury,and the per capita consumption of vegetable oil is higher than the world's average level.However,oil and fat selt-sufficiency rate in our country still count on importation partly.In contrast,a large number of natural oil and fat resources are not exploited.Wild walnut(Carya cathayensis)is a kind of walnut and it distributes in many provinces and cities in China.Different walnut in our country is discrepant no matter in appearance and interior.Wild walnut kernel's oil content is very high and oil quality is very good,some research has been show that long-term consumption wild walnut oil could lower blood lipid and antioxidant etc.But wild walnut oil still not be payed enough attention and application.This experiment studied physicochemical indexes,quality indexes and nutritional components etc.of Chongqing wild walnut oil and kernel,and appling principal component analysis(PCA)and cluster analysis study 11 varieties wild walnut oil in China.Because wild walnut oil is easily to oxidate and deteriorate,this experiment studied the oxidation stability of wild walnut oil.Finally,the hydration degumming and membrance degumming process of wild walnut oil were studied,and comparison two methods' influence to wild walnut oil.The main conclusions of this experiment are as follows:(1)This experiment studied physicochemical indexes,quality indexes and nutritional components etc.of wild walnut oil and kernel.The value of wild walnut kernel's compenent result showed moisture and volatile matter content was 6.04�0.24%,crude fat content was 56.76�0.17%,protein content was 25.24�0.16%,crude fiber content was 1.90�0.10%,carbohydrate content was 10.06�0.41%;Main trace elements level in wild walnut kernel as follow: Fe 24.2mg/kg,Cu 14.8mg/kg,Mn 21.5mg/kg,Zn 46.6mg/kg,Mg 8.6 mg/kg;the physicochemical indexes of wild walnut oil were determined and result shows that acid value 0.28 � 0.02mg/g,peroxide value 1.02�0.01mmol/kg,iodine value 156.99�0.05g/100 g,saponification 190.03�0.15KOH/(mg/g);The main fatty acid composition and content of wild walnut oil is as follow: oleic acid content was 23.156�0.100%,linoleic acid content was 61.223�0.133%,saturated fatty acid content was more than 95%.Vitamin E in wild walnut oil is consisted by ?-Vitamin E and ?-Vitamin E,and content was 28.9mg/kg and 400.7mg/kg,with total content being 429.7mg/kg.Phytosterol content was 2288.3mg/kg.(2)By using principal component analysis(PCA)and cluster analysis method investigated 11 different varieties' 20 indexes of wild walnut.PCA shows that overall scores highest variety was Yunnan 3,it's quality was optimal.cluster analysis shows that rigion was an important factor affecting the quality of wild walnut oil.(3)The oxidation stability of wild kernel oil was studied,result shows when there is no antioxidant in wild walnut oil,shelf life was 69 days;when there was same amount single antioxidants in wild walnut oil and additive amount,antioxidant effect ranking as;TBHQ>PG>BHT>tea polyphenols>vitamine E.,and when there was more additive there was more great antioxidant effect.When there was compound antioxidants in wild walnut oil,100mg/kg TBHQ+100mg/kg has the highest TP shows that the combination was the best.(4)Hydrated degumming and membrance degumming to the influence for raw wild walnut oil was researched.After the optimal test of single-factor experiment and response surface method,the degumming rate of hydrated degumming and membrance degumming was compared.Results indicated that phosphorus content decreased from 755.6 mg/kg to 36.2mg/kg by using hydrated degumming,with phospholipids removal rate being 95.21% and phosphorus content decreased from 755.6 mg/kg to 16.3 mg/kg by using hydrated degumming,with phospholipids removal rate being 97.85%.Furthermore,the oil obtained by membrane degumming contained more Vitamin E and phytosterol,exhibited more stable according to the induction time.In conclusion,membrance degumming was a better way to remove the gum in the wide walnut oil.