Qualitative And Quantitative Analysis Of Phenolic Compounds In Different Colors Of Highland Barley And Germinated Highland Barley And Their Antioxidant Activity

Colored highland barley is a very high quality and special germplasm resource,and its nutritional function and nutritional quality are strongly correlated with its natural color.At the same time,the development and production of bud products are still very deficient in China.Therefore,the research on highland barley of different colors and germinated barley is of great significance.In this study,four different colors of highland barley were used as raw materials,and the yellow highland barley was germinated for 12,24 and 36 hours.The germinated highland barley was dried in the infrared and oven,and then polyphenols,flavonoids and anthocyanins were extracted from the samples with organic solvents.The crude extracts of polyphenols,flavonoids and anthocyanins were qualitatively and quantitatively analyzed by liquid chromatography-mass spectrometry(LC-MS)and internal standard analysis;The antioxidant capacity of different colored highland barley and germinated highland barley was studied by various evaluation methods of antioxidant activity;At the same time,a preliminary metabolic analysis was performed on the polyphenols in the barley.The main results are as follows:Among four different colors(black,yellow,blue and white)highland barley,the polyphenol and flavonoids in black barley are the most abundant,and their content is also significantly higher than that of yellow,blue and white highland barley.The antioxidant experiment results show that the white highland barley polyphenols and flavonoids extract have the strongest antioxidant capacity,while the blue highland barley polyphenols and flavonoids extract have the weakest antioxidant capacity.LC-MS detection was performed on the crude anthocyanin extracts of highland barley of four different colors(black,yellow,blue and white)highland barley.Proanthocyanin,geranium pigment,centaurus pigment,delphinium pigment,peony pigment and malva pigment and their glucosidated derivatives were detected.Proanthocyanidins were selected for verification,and internal standard quantitative method was used to conduct quantitative analysis of proanthocyanidins in highland barley of four different colors.The results showed that the content of procyanidins in blue highland barley is the highest,while the content of procyanidins in white highland barley is the lowest.Antioxidant experiments show that the crude anthocyanin extract from black highland barley has the strongest antioxidant capacity.Different germination time and different drying methods will have a great influence on the type and content of active components in highland barley.The results of LC-MS showedthat the types and content of polyphenols and flavonoids in the germinated samples increased,among which,the varieties and content of polyphenols and flavonoids in the barley dried in the oven were the most and the highest after 24 h germination.The antioxidant experiment results show that the antioxidant capacity of the germinated highland barley is significantly different from that of the ungerminated highland barley,and the antioxidant capacity of the infrared dried samples is generally lower than that of the samples after drying in the oven,which may be because the infrared drying will damage the activity of polyphenols and flavonoids to a certain extent.In germinated highland barley,proanthocyanidins and geranium pigment,centaurus pigment,delphinium pigment,paeonia lactiflora pigment and malva pigment are common anthocyanins and their glucosidated derivatives have been detected.Proanthocyanidins were selected for verification,and the internal standard quantitative method was used for quantitative analysis of proanthocyanidins in germinated highland barley.The results showed that the content of procyanidins in highland barley increased after germination,and the content of procyanidins in highland barley germinated for 36 h and dried in the oven was the highest.Antioxidant experiment results showed that after germination,the antioxidant activity of anthocyanin in highland barley increased.The heat maps of four colored highland barley and germinated highland barley were analyzed,and the phenolic compounds(polyphenols,flavonoids and anthocyanins)were analyzed by hierarchical cluster analysis(HCA),and two main clusters were obtained.The metabolic pathways of phenolic compounds were analyzed.The results showed that the phenolic metabolites enriched in the biosynthetic pathway of flavonoids and flavonols were the most important and the change trend was the most obvious,and these phenolic compounds had important physiological activities and biological significance.Therefore,this metabolic pathway can be used as the metabolic pathway for transgenic reference in subsequent experiments.The method of high resolution mass spectrometry for the detection and analysis of phenolic substances and their derivatives in metabolomics has been effectively established,which provides a research basis for the subsequent experiments and detection.