| Prunus mongolica Maxim.seed oil content was more than 50%and it unsaturated fatty acid content reached 98%.P.mongolica seed oil was a rare oil tree species in desert areas,had high development and utilization value.In this paper,the aqueous enzymatic extraction and antioxidant properties of P.mongnlica seed oil was investigated.The main experimental results were as follows:(1)The results of water enzymatic extraction of P.mongnlica seed oil showed that the optimum conditions for cellulase extraction were:the amount of enzyme added was 1.0%(w/w),the enzymatic hydrolysis time was 4h,the enzymatic hydrolysis temperature and the pH were 50℃and5.0 respectively;The optimum conditions for extracting oil by pectinase enzymatic hydrolysis were:the amount of enzyme added was 0.7%(w/w),2.5h hydrolysis time,enzymatic hydrolysis optimal temperature and pH were 30℃and 2.5 respectively;The optimum conditions for extracting oil by neutral protease enzymatic hydrolysis were:enzyme addition amount was 5%(w/w),enzymatic hydrolysis time was 1.5h,enzymatic optimum temperature and pH were 50℃and 7.0.Under this optimized condition,the oil extraction rates were 54.98%,50.45%and60.61%respectively.The extraction rate of oil extracted by the combination of cellulase,pectinase and neutral protease was up to63.37%.The optimum temperature and pH for enzymatic hydrolysis were45℃and 4.5,the ratio of solid to liquid was 1:6,and the hydrolysis time was 3 h.(2)Antioxidant stability test results showed that the current extraction of P.mongnlica seed oil peroxide value was 165.0μmol/kg,which was a low peroxide value oil.The test results of long-term storage oil at room temperature showed that with the prolongation of storage time,the peroxide value and conjugated diene content of P.mongnlica seed oil increased gradually,but the content of conjugated triene did not increase significantly.During storage for 285d at room temperature,the P-anisidine value of P.mongnlica seed oil increased to 12.02,and the daily average increment was 0.032.After entering the propagation period,the P-anisidine value increased significantly,and the P-anisidine value increased to 27.25 at the 540th day.It indicates that the P.mongnlica seed oil had a long induction period and strong antioxidant stability.(3)The results of rancidity induced by high temperature treatment showed that the heat resistance and high temperature oxidation resistance of oil gradually deteriorated with the prolongation of storage time.After treatment at 100℃for 40 minutate,the oil conjugated diene and conjugated triene content increasement was not obvious.After treatment at 190℃for 40 min,the conjugated diene and conjugated triene value of the stored for 6 months oil was 0.885 and 0.305.The conjugated diene and conjugated triene value of the oil stored for 10 months were increased to 0.354 and 0.208,respectively.When treated at 220℃for 40 min,the conjugated diene value and the conjugated triene value of the stored 9months oil were 0.991 and 0.462;The conjugated diene value and the conjugated triene value of the stored in 10 months oil increased to 0.692and 0.448 respectively.It was shown that the secondary oxidation was more likely to occur at high temperatures as the storage time was extended.(4)The results of lipid free radical scavenging ability studies showed that the FRAP value of P.mongnlica seed oil was 391.09,superoxide anion radical,hydroxyl radical scavenging DPPH~·free radical and ABTS.~+free radical scavenging capacity reached 74.58%,87.13%,73.73%and 70.23%respectively.It showed that P.mongnlica seed oil had a strong free radical scavenging ability. |
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