Analysis Of Main Polyphenols Of Cerasus Humilis And The Inhibition Of Proanthocyanidins On Potato Starch Digestion

In recent years,the inhibition of polyphenols on starch digestion has become more and more a focus of researchers.Researchers have found that the inhibition of polyphenols from different sources on starch digestion is different.Polyphenols can inhibit starch digestion by acting on the active site of ?-amylase,and polyphenols can also change the structure of starch molecules by interacting with starch,so as to slow starch digestion.European plum is a kind of fruit rich in polyphenols.In recent years,the planting area in Ningxia has been increasing.Potato is the main characteristic industry in Ningxia.In this study,the effect of proanthocyanidins on potato starch digestion inhibition was studied,which is helpful to develop potato slow digestion food.Firstly,the polyphenols were extracted and the main components were analyzed.Secondly,the effect of proanthocyanidins on the digestion of potato starch was studied.The main research contents and results are as follows:(1)Analysis of main polyphenols in Prunus humilisThe results showed that the main polyphenols in the fruit were catechin,epicatechin,proanthocyanidin B1,proanthocyanidin B2,proanthocyanidin B3,myricetin,quercetin,isorhamnetin,geranium-3-glucoside,chlorogenic acid,chlorogenic acid,chlorogenic acid,chlorogenic acid,chlorogenic acid,chlorogenic acid,chlorogenic acid,chlorogenic acid,chlorogenic acid,etc Cyanidin-3glucoside.According to the literature,the content of proanthocyanidins and catechins in Prunus humilis is relatively high.The content of proanthocyanidins and catechins in Prunus humilis is determined by HPLC.The results show that the content of proanthocyanidins and catechins is 10.03 mg/g and 0.31 mg/g,respectively.(2)Analysis of starch structure and GI value of Ningxia potato(Qingshu No.9)Scanning electron microscopy(SEM)was used to observe and compare the microstructures between the potato slices and the slices.It was found that the internal structure of Shengxianqing No.9 was loose and contained a lot of potato starch granules.The starch granules showed clear and regular oval shape.After maturation,the cell wall of Cyanopsis 9 was destroyed,the intermediate lamina was disintegrated,and the starch granules were expanded and gelatinized,which exposed the binding site of enzyme and starch,and the starch was easily digested.Secondly,it was found that the starch digestibility was high and the highest GI value reached 106.42.(3)Effect of proanthocyanidins on starch structure and digestion in potatoEffects of Proanthocyanidins from Prunus humilis on the structure of potato starch:Proanthocyanidins from Prunus humilis were extracted and added to potato starch.The effects of proanthocyanidins on the structure of potato starch were observed by X-ray diffraction(XRD),infrared spectroscopy(FT-IR)and scanning electron microscope(SEM).The results showed that the structure of potato starch with proanthocyanidins changed greatly,and the structure became more compact than that without proanthocyanidins.This is because proanthocyanidins are composed of many hydroxyl structures and macromolecules,such as benzene rings,which are interwoven with potato starch and form many netlike structures.The long distance crystal structure of potato starch is destroyed,resulting in loose starch structure and smaller molecular space,which will affect the contact between amylase active center and starch substrate.In addition,proanthocyanidins can occupy the active center of amylase,inhibit the activity of amylase and decrease the degree of hydrolysis of amylase.With the increase of proanthocyanidins,these effects were more obvious.Effects of proanthocyanidin on the digestion of potato starch:The digestibility of potato starch before and after the addition of proanthocyanidin was compared by simulated digestion experiment in vitro.The results showed that the digestibility of potato starch added with proanthocyanidins was lower than that without.The first reason is that the structure of potato starch becomes irregular and compact after the addition of proanthocyanidin,and the contact between potato starch and ?-amylase active center is blocked,which leads to the slow hydrolysis of potato starch.Secondly,due to the covalent binding of proanthocyanidins and ?-amylase-related active sites,the amino acid side chain of ?-amylase central active site was closed,which decreased the activity of ?-amylase,and finally led to the low digestibility of potato starch and the low GI value.