Research On The Flavor Enhancement And Quality Of Cold-pressed Peanut Oil By The Flavor Substance Being Prepared By Deep Eutectic Solvents

In the whole process of preparation of cold-pressed peanut oil(CPO),low temperature processing can retained the fat-soluble nutrients of the peanut kernel,but there was no Maillard reaction(MR)in the processing,so that CPO has a weak flavor.It is imperative to explore a processing method of peanut oil with richer flavor and higher quality,which can effectively retain the fat-soluble accompanying nutrients of peanut,and inhibit the high-temperature oxidation of unsaturated fatty acids to produce associated chemical hazards.A large number of studies have found that deep eutectic solvents(DES)can be used to accelerate the Maillard reaction(MR)at lower temperatures,which can produce characteristic flavor substances of food grade.Therefore,this dissertation would enhance the flavor of CPO by DES.High quality peeling peanut was used as raw material to prepare peanut meal enzymatic hydrolyzed powder(PMP).Different DES were discussed to accelerate the MR,which could be used to produce the characteristic flavor substances of peanut oil.The effects,which was DES on MR of PMP and flavor enhancement of CPO,were investigated.The flavor of CPO was enhanced by MR catalyzed by suitable DES.Investigated the changes of basic physical and chemical indexes,fatty acid relative content,fat-soluble nutrient concomitant content,fat-soluble chemical hazard content,free radical scavenging ability and oxidation stability of CPO with flavor enhancement.The stability of storage,unsaturated fatty acid,volatile flavor substance and fat-soluble nutrient were evaluated by Schaal oven accelerated oxidation test.The research contents and results were presented as follows:(1)Effect of different DES on flavor enhancement of CPOPMP was prepared with high quality peeling peanut as raw material.The MR of PMP was catalyzed by choline chloride and glucose DES,choline chloride and xylose DES,choline chloride and L-ascorbic acid DES,malic acid and glucose DES,malic acid and xylose DES,betaine and glucose DES,betaine and L-ascorbic acid DES,respectively.The CPO is enhanced by flavor substances prepared by MR.According to the MR intermediates content and Browning degree of MR and the sensory evaluation,HS-SPEM-GC-MS detection and electronic nose detection results of peanut oil,combined with the OAV,PCA analysis and Kmeans clustering analysis of the experimental data,it was found that choline chloride and Lascorbic acid DES,betaine and L-ascorbic acid DES were most suitable for the flavor enhancement of CPO,meeting the requirements of flavor enhancement.CLO represents the flavor improved CPO by choline chloride and L-ascorbic acid DES.BLO represents the flavor improved CPO by betaine and L-ascorbic acid DES.CLO mainly showed fruity,toasted and nutty,while BLO was green and burnt fragrance.(2)Research on quality of cold-pressed peanut oil enhanced by flavorBased on the above research,CLO and BLO were selected to continue research.The basic physical and chemical indexes,fatty acid relative content,fat-soluble nutrient concomitant content,fat-soluble chemical hazard content,free radical scavenging ability and oxidation stability of self-made CPO,self-made hot-pressed peanut oil(HPO),sold CPO,sold HPO,CLO and BLO were detected.It was found that the moisture content,acid value and peroxide value of CLO and BLO were within the scope of first-grade HPO standard.There was no significant difference in the relative contents of fatty acids,and contained much oleic acid and linoleic acid.The content of α-tocopherol,δ-tocopherol,phytosterol,resveratrol and polydatin were increased.The content of γ-tocopherol,stigmasterol and β-sitosterol of CPO was retained,but the content of squalene was decreased.This may be due to the adsorption effect of DES on squalene,leading to the decrease of the content of squalene in peanut oil.The free radical scavenging ability was improved and the shelf life was delayed.Compared with self-made and sold HPO,the content of 2-monochloropropane-1,3-diol fatty acid esters,3-monochloropropane-1,2-diol fatty acid esters,glycidol fatty acid esters and benzo(a)pyrene were less,and betaine and L-ascorbic acid DES had the least promotion effect.What’s more,the content of glycidol fatty acid esters were lower than the European limit standard.The content of benzo(a)pyrene was lower than the national limit standard.(3)Research on the stability of cold-pressed peanut oil enhanced by flavorAccording to the accelerated oxidation experiment by Schaal oven test,it was found that the storage stability of CLO and BLO was better than that of self-made and sold CPO,but weaker than that of self-made and sold HPO.The oxidation rate of unsaturated fatty acids was slower than that of self-made and sold HPO,and faster than that of self-made and sold CPO.CLO and BLO could improve the stability of tocopherol,phytosterol,squalene and plant polyphenol,and its effect was better than that of self-made and sold CPO.However,resveratrol was less stable,which was consumed a lot in the 30-day accelerated oxidation test.The content of fat-soluble nutrients and flavor activity value of CLO and BLO were in accordance with the characteristics of first-order reaction kinetics equation,which belonged to first-order reaction.Combined with half-life analysis,it was found that fat-soluble nutrients and flavor substances of CLO and BLO had better stability.In particular,the stability of fat-soluble nutrients in BLO was similar to that of sold CPO,better than that of sold HPO,and the stability of flavor substances in BLO was better than that of self-made HPO.