| Mung beans have high nutritional value(proteins,carbohydrates,vitamins,minerals,polyphenols,etc.).Traditional chemical methods have been used to determine these nutrients for a long time.Therefore,it is a very meaningful work to quickly and efficiently determine its protein and starch content.Mung bean polyphenols have important physiological functions,such as antioxidant,anti-diabetic,and anti-inflammatory activities,etc.There are few studies on the differences in polyphenols component identification and functional activity among different varieties of mung beans.In addition,some researches on mung bean polyphenols mainly focus on the antioxidant activity in vitro,and there are few reports on the composition of mung bean polyphenols and their changes in the in vitro digestion process:In this study,a Fourier transform near-infrared spectrometer was used to establish a model of mung bean protein and starch.The nutritional components of six kinds of mung beans(Suheilv 1,Sulv 3,Sulv 4,Sulv 1,Sukang 3,Sulv 3074)were determined by the near-infrared model,and their antioxidant activities were compared.Liquid-phase mass spectrometry(UPLC-MS)was used to qualitatively analyze the composition and distribution of phenolic compounds in six mung beans.The changes in the content and antioxidant activity of mung bean polyphenols in the simulated digestion process in vitro,as well as the bioavailability of polyphenols were also determined.The specific research results are as follows:1.This study collected 101 near-infrared spectra of mung bean materials and created a near-infrared model of the protein and starch content of mung bean.The relevant indicators of the model are as follows: The RMSECV of protein and starch are 0.474 and0.732 respectively,and the coefficient of determination is 0.8725 and 0.9024,respectively.It was verified by an external inspection method to prove the accuracy of the model.2.The six mung bean varieties have significant differences in basic nutrients,total phenolics,total flavonoids and antioxidant activity.Suheilv 1 has the highest protein content(25.96%);Sulv 4 has the highest starch content of 47.93%;The phenolic,total flavonoids,DPPH free radical scavenging activity and ABTS free radical scavenging activity of Suheilv 1 mung bean were significantly higher than other tested varieties.3.UPLC-MS was used to qualitatively analyze the composition of various monomeric phenols in the phenolic extracts of mung bean,and a total of 76 compounds were identified,including isoflavones,flavanols,flavanones,flavonoids,flavonols,and anthocyanidin glycoside and so on.Isoflavones and flavonoids are compounds with a higher proportion of mung bean phenolic compounds;Suheilv 1 was identified to have the most phenolic compounds,and at the same time the most types of anthocyanins.4.There are significant differences in the total phenols,total flavonoids and antioxidant capacity of the six mung beans at different digestion stages.The content of total phenols and total flavonoids was significantly increased by digestion.Sulv 4 exhibited the highest total phenol content,which was 36.84±2.86 mg mg GAE/g.At the same time,Suheilv 1 showed to have highest total flavonoid content with 73.61±0.65 mg RE/g.Through the measurement results of the free radical scavenging ability of DPPH and ABTS,the antioxidant activity of mung bean polyphenols was significantly increased after digestion.Sulv 4 has higher content of total phenols and total flavonoids,antioxidant activity,Bioaccessibility and Bioaccessibility index. |
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