Research On Preparation And Properties Of Resveratrol-riched Germinated Peanut Oil

Cardiovascular disease is the majority public health problem in China.Resveratrol has been proven to protect the cardiovascular system in medically.In addition to veratrum grandiflorum,polygonum cuspidatum and grape,peanut is the fourth plant that contains natural resveratrol.As one of the most important oil crops in China,peanut has the advantages of abundant resource,lower price,popularity and edibleness.However,there is a small amount of resveratrol in natural peanut.So how to increase resveratrol in peanut has caused wide public attention.Except for biotic and abiotic inductions,germination is an effective way to increase resveratrol in peanut.Recently,it has been reported that abiotic induced germination could enrich the resveratrol in peanut.However,there is limitation to the enrichment of resveratrol in single abiotic induction.Accordingly,Yueyou13 were selected to investigate the single and compound effects of the three abiotic induction of Phe,UV and US on the enrichment of resveratrol in peanut sprout.Defining the key factors of induction with enzymatic mechanism and obtaining the optimal induction method.Oil properties,lipid-solube nutrients,afaltoxin B₁,oil quality and oxidation stability of the prepared resveratrol-riched germinated peanut oil were further analyzed to provide theoretical basis and technical guidance.The detailed research contents and results were presented as follows:Firstly,the induction of Phe,UV and US promoted the enrichment of resveratrol in peanut sprout appropriately.The compound induction of UV-Phe and US-Phe showed synergistic effects on the enrichment of resveratrol in peanut sprout,while the compound induction of UV-US showed antagonistic effects.These phenomenona were related to the activities of the enzymes in resveratrol synthesis.The induction of Phe increased the activities of PAL,C4H,4CL and 3-O-GT.The induction of US increased the activities of C4H and RS.The induction of UV effectively increased the activities of PAL,C4H,4CL,RS,3-O-GT and?-D-G.Compared with the single induction,the compound induction of UV-Phe and US-Phe could further improve the corresponding enzymes activities,so it has synergistic effects on the enrichment of resveratrol.The compound induction of UV-Phe was the best method for enrichment of resveratrol in peanut sprout.The optimal condition was that Phe concentration of 0.6 mmol/L,UV intensity of 120?W/cm² and UV irradiation time of 45 min.After 7-day darkness germination in 25°C under this condition,the content of Res increased first and then decreased while the content of Pd showed continuous rising trend.The content of TR increased first and then decreased,reaching its maximum value on the 4^th day.The contents of Res,Pd and TR were 2.88±0.12,1.68±0.11 and 4.56±0.17?g/g,respectively.The content of TR in peanut sprouts was 7.24-fold that of peanut.Compared with the single induction,the compound induction of UV-US significantly reduced the activities of PAL,C4H,4CL and RS,so it has antagonistic effects on the enrichment of resveratrol in peanut sprout.Secondly,fat content,fatty acid composition,lipid-solube nutrients and afaltoxin B₁were analyzed during 4-day darkness germination in 25°C under the normal and optimal condition.The result showed the fat content still contained about 46.73±0.75%until the 4^thh day of germination.The values of UFA/SFA and O/L had no significant changes,indicating that germination did not change the high-quality fatty acid composition of peanut.Compared with normal germination,induced germination could further increase the lipid-solube nutrients of tocopherols,phytosterols and polyphenols in peanut sprout.The result showed that the amount of total tocopherols,total phytosterols and total polyphenols increased significantly by 1.39,1.31 and 1.70-fold respectively,which enriched the nutrition of peanut oil.The content of aflatoxin B₁ in the peanut sprouts were not detected?MDLs for 1?g/kg?,for supporting the edibility of peanut sprouts.In summary,peanut sprouts have the feasibility and potentiality for oil processing.Finally,RPO was successfully prepared through cold-pressed process using the 4^thh induced peanut sprout.The Res content of RPO was 0.98±0.03?g/g,which was 5.16 and5.16-fold that of SO and PO,respectively.The Pd content of RPO was 0.54±0.03?g/g,which was 2.70 and 3.61-fold that of SO and PO,respectively.The TR content of RPO was1.52±0.04?g/g,which was 3.90 and 4.47-fold that of SO and PO,respectively.The moisture,acid value,peroxide value and iodine value of RPO complied with the standard.RPO showed the rich flavor because of the added flavor components.2,3-butanediol,benzaldehyde and ketones were detected in RPO,which could enrich sweet and roasted flavor in peanut oil.Both the primary oxidation products and secondary oxidation products produced by RPO were both lower than SO and PO in Schaal oven storage test,indicating the quality and oxidation stability of RPO.The results of Rancimat and Raman showed the oxidation stability of oils ranked as RPO>SO>PO.In other words,the enrichment of resveratrol and other lipid-solube nutritients played good role in protecting the peanut oil,which could resist the oxidation and extend the shelf life in oil.The preferential oxidation of tocopherols and polyphenols protected resveratrol and reduced its loss during the oxidation of peanut oil.Therefore,after 30 days of accelerated oxidation,the contents of Res,Pd and TR in RPO was0.56±0.04,0.22±0.22 and 0.78±0.06?g/g respectively.The loss rate in RPO was lower than SO and PO.