| Peanut is one of the most important oil crop and food raw materials in the world,which is rich in essential fatty acids,protein,fat-soluble vitamins,polyphenols,mineral elements and other beneficial ingredients.According to the color of seed coat,peanut is divided into red peanut and black peanut.The content of anthocyanin in black peanut is significantly higher than that in red peanut.After germination,not only the nutrients of peanut such as vitamins,amino acids and minerals are improved,but also the contents of resveratrol and other phenolic compounds are significantly increased.Phenolic compounds have antioxidant,anti-inflammatory and anti-cancer effects.With the development of economy and the change of people's consumption concept,people's demand for food has changed from quantity to quality.In recent years,black food and sprouts are favored by more and more consumers due to their rich nutrition.Therefore,it is of great significance to excavate and utilize the characteristic nutrient quality of peanut and its by-products to meet people's consumption needs and promote industrial upgrading.The concrete research content is as follows:1.Establishing an accurate quantitative determination method for 10 metabolites in the phenylpropane pathwayA rapid and accurate LC-HRMS method was developed for the determination of 10 metabolites in the phenylpropane pathway.The 10 compounds studied included L-phenylalanine,p-coumaric acid,caffeic acid,isoliquiritigenin,ampelopsin F,p-hydroxybenzaldehyde,pterostilbene,resveratrol,daidzein and formononetin.By optimizing the pretreatment condition,2 mL acetonitrile: methanol: water(2:2:1,v/v/v)was selected,and 75-min ultrasound was used to improve the extraction efficiency of the targeted metabolites.The linearity,recovery and precision of the method were verified.The interday and intraday accuracy ranged from 1.2-8.7% and 1.2-8.5%,respectively.The average recovery was 87.3-117.8%.The results showed that the method had high sensitivity and good repeatability.2.Studing the effects of three kinds of exogenous additives on the content of phenolic compounds during the germination of peanutsPeanut was germinated by adding L-tyrosine,malonic acid and acetic acid.The content of phenolic compounds during germination was detected by triple quadrupole mass spectrometry.The results showed that the contents of resveratrol in peanut sprouts were significantly increased by providing L-tyrosine,malonic acid and acetic acid at a certain concentration in the early stage of peanut germination.The contents of 2-hydroxycinnamic acid and p-coumaric acid in peanut sprouts were increased by adding L-tyrosine of 0.4,0.8 and 1.0 mmol/L.From the first day to the third day,the addition of 0.1,0.2,0.4,0.8 and 1.0 mmol/L of L-tyrosine could increase the content of ferulic acid in peanut sprouts.3.Analyzing differential compounds between peanuts and peanut sprouts based on LC-HRMS non-targeted metabolomicsThe differential metabolites between peanut seeds and peanut sprouts were compared by full spectrum analysis based on LC-HRMS non-targeted metabonomics.PCA,OPLS-DA and cluster analysis showed that there were significant differences between peanut seeds and peanut buds,which covered 21 metabolic pathways and 358 metabolites.There were 83 different metabolites in peanut seed group and peanut bud group(P<0.05).The results make a systematic analysis on the change between peanut seeds and peanut sprouts,which provide strong support to the evaluation of nutritional function of peanut sprouts.4.Screening different phenolic compounds between black peanut and red peanut based on LC-HRMS targeted metabolomicsEighteen different kinds of black peanuts and red peanuts were selected,and the differential phenolic compounds between black peanuts and red peanuts were compared by full spectrum analysis based on LC-HRMS targeted metabonomics.21 phenolic compounds were screened.PCA,OPLS-DA and T-test analysis showed that there were significant differences between black peanut group and red peanut group.The contents of caffeic acid,biochanin A,quercetin,coniferyl aldehyde,salicylic acid,hesperidin,catechin,epicatechin,daidzin and syringic acid in red peanuts were significantly higher than those in black peanuts,while the content of anthocyanin in black peanut was significantly higher than that in red peanut. |
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