Study On The Effect Of Storage Environment On Lipid Oxidation Of Peanut

This paper investigated the effects of different storage temperatures and storage conditions on peanut lipid oxidation,and also analyzed the changes of different metabolites and metabolic pathways of peanut lipids under different storage conditions using non-targeted lipidomics,to explore the mechanism of peanut lipid oxidation during conventional storage,nitrogen gas storage and nitrogen unsealing storage,and to provide reference for the subsequent optimization of storage environment to ensure the storage safety of peanut The experiments were conducted with Wanhua 2 peanut as the experimental material.Peanuts of Wanhua 2 were stored at four storage temperatures(15℃,20℃,25℃and 35℃)and three storage methods(conventional storage,nitrogen gas conditioning storage,and nitrogen unsealing storage)for a period of 10 months.During storage,samples were taken every two months and lipid oxidation indexes(acid value,peroxide value,carbonyl value,p-anisidine value,thiobarbituric acid value),antioxidant indexes(vitamin E content,ABTS radical scavenging rate,DPPH radical scavenging rate),fatty acid composition,and oxidative stability index were measured;lipidomic analyses were also performed on peanuts from different storage methods at the end of storage.Lipidomic analysis was performed on peanuts at the end of storage.The results showed that:1.Comparison of four storage temperatures: with the extension of storage time,the degree of peanut lipid oxidation gradually increased;the antioxidant capacity of peanuts gradually decreased.The higher the storage temperature,the faster the rate of peanut oxidation and the weaker the antioxidant capacity;the decrease in peanut linoleic acid content increased,and the oxidative stability index(OSI)of the extracted peanut oil showed a decreasing trend.This is because the lower storage temperature can slow down the rate of peanut lipid oxidation,inhibit the generation of oxidation products,and maintain the good oxidative stability of peanuts.2.Comparison of the three storage methods: with the increase of storage time,the lipid oxidation index of peanuts under different storage conditions showed an increasing trend;antioxidant capacity,linoleic acid content,and oxidative stability index all showed a decreasing trend.At the end of storage,the lipid oxidation indexes of peanuts in nitrogen gas conditioning storage were significantly lower than those in nitrogen unsealed storage and conventional storage,except for carbonyl value;the vitamin E content was significantly higher than those in nitrogen unsealed storage and conventional storage,while the ability to scavenge ABTS and DPPH radicals was the same as that in conventional storage;meanwhile,the OSI values of peanut oil extracted from peanut in nitrogen gas conditioning storage were significantly higher than those in the other two storage methods.While the lipid oxidation index,vitamin E content,OSI value,and scavenging rate of DPPH radicals in nitrogen unsealed storage peanuts were basically the same as in conventional storage;the ability of nitrogen unsealed storage peanut lipids to scavenge ABTS radicals was significantly lower than conventional storage;the linoleic acid content of nitrogen unsealed peanuts was significantly higher than conventional storage.3.Differential metabolic analysis:(1)Conventional storage vs.Day 0 of storage:compared with day 0 of storage,phosphatidylcholine and phosphatidylethanolamine contents in glycerophospholipid metabolism of conventionally stored peanuts were significantly down-regulated;ceramide was up-regulated and glucose ceramide was down-regulated in sphingolipid metabolism,indicating that the prolonged storage time affected glycerophospholipid metabolism and sphingolipid metabolism.(2)Nitrogen storage vs.Conventional storage: compared with conventional storage,nitrogen storage of peanut triacylglycerol content was significantly up-regulated,indicating that glycerol ester metabolism in peanut lipids accumulated during storage;phosphatidic acid content was down-regulated,indicating that nitrogen environment can slow down the rate of glycerol phospholipid metabolism,and also reduce the rate of peanut lipid metabolism;lactose ceramide was down-regulated,demonstrating that nitrogen conditions can slow down the process of sphingolipid metabolism,and inhibit the conversion of ceramide to lactose ceramide.In summary,nitrogen storage can slow down lipid oxidative degradation by inhibiting glycerol ester metabolism,glycerophospholipid metabolism,and sphingolipid metabolism.(3)Nitrogen unsealed storage vs.Conventional storage: compared with conventional storage,1-acyl-sn-3-glycerophosphorylcholine,and ceramide were significantly up-regulated in nitrogen unsealed storage,indicating that glycerophospholipid metabolism and sphingolipid metabolism were more active in peanut after nitrogen unsealing.(4)Nitrogen unsealed storage vs.Nitrogen storage: ceramide content was significantly up-regulated in nitrogen unsealed storage compared with nitrogen storage,indicating a higher rate of sphingolipid metabolism in nitrogen unsealed storage;triacylglycerol content was significantly down-regulated,indicating that nitrogen unsealed storage promoted the glycerol ester metabolism of peanut lipids and accelerated the rate of triacylglycerol catabolism.