| Excessive intake of diet and low exercise have caused a dramatic increase in the number of people with diabetes.How to prevent and control diabetes through diet has become the focus of attention.Studies have shown thatβ-glucan has the potential to inhibit starch digestion.Hericium Erinaceusβ-glucan(HEBG)and wheat starch were selected in this study.And the effect of HEBG on the in vitro digestion of wheat starch was studied and its influencing mechanism was explored.It provided a theoretical basis for the development of low glycemic index starch foods.The main contents and results are as follows:1.The high molecular weight HEBG(HEBG-0)was obtained by hot water extraction and ethanol precipitation with a yield of 0.51%.Medium and low molecular weight HEBG(HEBG-5,HEBG-10)was prepared by hydrolyzed with hydrochloric acid.The analysis of HEBG by high performance liquid chromatography,infrared spectroscopy,and ion chromatography confirmed that HEBG-0,HEBG-5,and HEBG-10 were allβ-glucans,and the average molecular weights were 7.504×10~5,3.177×10~5 and 2.184×10~5 Da,respectively.And they are all composed of glucose.2.The Englyst method was used to determine the characteristics of HEBG’s inhibition of wheat starch digestion.The experiment showed that the inhibitory effect of adding 20%HEBG is optimal.With the increase of the molecular weight of HEBG,the inhibitory effect of the in vitro digestion of starch was better,the mass percentage of slowly digestible starch and resistant starch were increased.But the in vitro digestibility,the mass percentage of rapidly digestible starch and the prediction of the predicted glycemic index were decreased.At the same time,it was found that HEBG had an inhibitory effect on the glucose diffusion rate,and the larger the molecular weight was,the better the inhibitory effect obtained.3.The interaction between HEBG and wheat starch was investigated by differential scanning calorimetry,rapid viscometry,rheometry,X-ray diffraction,determination of leaching amylose content,confocal laser scanning microscopy.It was found that the endothermic enthalpy,gelatinization temperature and peak viscosity of wheat starch and HEBG were higher than that of wheat starch,and increased with the increase of molecular weight,indicating that a stable structure was formed between HEBG and starch chains.After the addition of HEBG,the elastic modulus and the viscous modulus of the mixed gel system increased,the apparent viscosity was greater,and it increased with the increase of the molecular weight,indicating that the HEBG and the starch were cross-linked to each other and the network structure of the gel system was enhanced.The addition of HEBG significantly reduced the crystallinity of the system,and decreased with increasing molecular weight,indicating that HEBG might limit the movement of water molecules around the starch particles,making the water molecules unable to participate effectively in the gelatinization process of starch granules(p<0.05).With the increase of the molecular weight of HEBG,the content of leached amylose in the system decreased,which may be because HEBG coated on the surface of starch granules,thereby prevented the further diffusion of starch in the whole system.Laser confocal microscopy showed that HEBG coated starch,and the high molecular weight HEBG-0 coated the starch more completely than the medium and low molecular weight(HEBG-5,HEBG-10).4.The enzymatic reaction kinetics was used to study the interaction between HEBG and digestive enzymes.The results showed that HEBG had inhibitory effects onα-amylase and was non-competitive inhibition with inhibition rate of 29.76%.Fluorescence microscopy showed thatα-amylase was distributed on the surface of HEBG.HEBG has no inhibitory effect on amyloglucosidase.It was demonstrated that HEBG interacts with theα-amylase in the digestive enzyme and does not interact with the amyloglucosidase. |
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