[Objective]The aim was to clarify the chemical substance basis of hypoglycemic and lipid-lowering effects of Pu-erh Tea. [Method]Pu-erh Tea was extracted with 95% ethanol,followed by petroleum ether,chloroform,ethyl a...[Objective]The aim was to clarify the chemical substance basis of hypoglycemic and lipid-lowering effects of Pu-erh Tea. [Method]Pu-erh Tea was extracted with 95% ethanol,followed by petroleum ether,chloroform,ethyl acetate and n-butanol extraction,after the further purification and through the NKA-9 macroporous resin and many times of Sephadex column chromatography,two compounds were isolated,in the same time,the effect of Uracil and Gallic acid on α-amylase was studied. [Result]The Uracil and Gallic acid were isolated and identified respectively from Pu-erh Tea and the Uracil was firstly isolated from Pu-erh Tea; Gallic acid had strong inhibition on α-amylase. [Conclusion]It could provide some theories on the hypoglycemic and lipid-lowering effects of Pu-erh Tea.展开更多
A response surface method was employed to study the effect of α-amylase concentration, hydrolysis temperature and time on the production of high protein glutinous rice flour(HPGRF). The suspension of glutinous rice f...A response surface method was employed to study the effect of α-amylase concentration, hydrolysis temperature and time on the production of high protein glutinous rice flour(HPGRF). The suspension of glutinous rice flour(15%) that contained 6.52% protein was gelatinized and subsequently hydrolyzed by thermostable α-amylase. The hydrolysis yielded 0.144–0.222 g/g HPGRF with 29.4%–45.4% protein content. Hydrolysis time exerted a significant effect, while enzyme concentration and hydrolysis temperature showed insignificant effect on the protein content and production yield of HPGRF. The result of response surface method showed that the optimum condition for the production of HPGRF that contained at least 36% protein was treating gelatinized 15% glutinous rice flour suspension with 0.90 Kilo Novo α-amylase Unit(KNU)/g α-amylase at 80 oC for 99 min. By carrying out the predicted hydrolysis condition, HPGRF with 35.9% protein and 61.8% carbohydrates was resulted. The process yielded 0.172 g/g HPGRF. HPGRF contained higher amount of essential amino acids compared to glutinous rice flour. HPGRF had higher solubility and lower swelling power, and also showed no pasting peak compared with glutinous rice flour.展开更多
Backgrounds:Tannic acid(TA),as a plant-derived phenolic substance,is involved in regulating the activity of starch digestive enzymes,but its underlying mechanism remains unclear.Methods and Results:In the present stud...Backgrounds:Tannic acid(TA),as a plant-derived phenolic substance,is involved in regulating the activity of starch digestive enzymes,but its underlying mechanism remains unclear.Methods and Results:In the present study,inhibition rate and inhibition kinetics assays were performed and confrmed that TA had a strong inhibitory effect on bothα-amylase andα-glucosidase with IC50 values of 0.1585 mg/mL and 0.00542 mg/mL,respectively,through a mixed inhibition mode.The secondary structures of both enzymes were confrmed to be modifed by TA through circular dichroism(CD)spectra.Fluorescence quenching analysis revealed that the interaction between TA and two enzymes was a static process of pontaneous complex formation.Finally,molecular docking revealed that non-covalent bonds were the main interaction forces between TA and both enzymes.Conclusions:Thus,TA was a promising candidate for the inhibition of starch-digesting enzymes,and the present research provided insight into postprandial glucose regulation through polyphenols.展开更多
基金Supported by National Science and Technology Support Project(2007BAD58B04 )Special Fund Project of Modern Agriculture(Tea) Industrial Technology SystemYunnan Department of Education and Scientific Research Fund (07Y40163)~~
文摘[Objective]The aim was to clarify the chemical substance basis of hypoglycemic and lipid-lowering effects of Pu-erh Tea. [Method]Pu-erh Tea was extracted with 95% ethanol,followed by petroleum ether,chloroform,ethyl acetate and n-butanol extraction,after the further purification and through the NKA-9 macroporous resin and many times of Sephadex column chromatography,two compounds were isolated,in the same time,the effect of Uracil and Gallic acid on α-amylase was studied. [Result]The Uracil and Gallic acid were isolated and identified respectively from Pu-erh Tea and the Uracil was firstly isolated from Pu-erh Tea; Gallic acid had strong inhibition on α-amylase. [Conclusion]It could provide some theories on the hypoglycemic and lipid-lowering effects of Pu-erh Tea.
文摘A response surface method was employed to study the effect of α-amylase concentration, hydrolysis temperature and time on the production of high protein glutinous rice flour(HPGRF). The suspension of glutinous rice flour(15%) that contained 6.52% protein was gelatinized and subsequently hydrolyzed by thermostable α-amylase. The hydrolysis yielded 0.144–0.222 g/g HPGRF with 29.4%–45.4% protein content. Hydrolysis time exerted a significant effect, while enzyme concentration and hydrolysis temperature showed insignificant effect on the protein content and production yield of HPGRF. The result of response surface method showed that the optimum condition for the production of HPGRF that contained at least 36% protein was treating gelatinized 15% glutinous rice flour suspension with 0.90 Kilo Novo α-amylase Unit(KNU)/g α-amylase at 80 oC for 99 min. By carrying out the predicted hydrolysis condition, HPGRF with 35.9% protein and 61.8% carbohydrates was resulted. The process yielded 0.172 g/g HPGRF. HPGRF contained higher amount of essential amino acids compared to glutinous rice flour. HPGRF had higher solubility and lower swelling power, and also showed no pasting peak compared with glutinous rice flour.
基金the Institute of Science and Technology,Moutai Group(No.MTGF2021020),China.
文摘Backgrounds:Tannic acid(TA),as a plant-derived phenolic substance,is involved in regulating the activity of starch digestive enzymes,but its underlying mechanism remains unclear.Methods and Results:In the present study,inhibition rate and inhibition kinetics assays were performed and confrmed that TA had a strong inhibitory effect on bothα-amylase andα-glucosidase with IC50 values of 0.1585 mg/mL and 0.00542 mg/mL,respectively,through a mixed inhibition mode.The secondary structures of both enzymes were confrmed to be modifed by TA through circular dichroism(CD)spectra.Fluorescence quenching analysis revealed that the interaction between TA and two enzymes was a static process of pontaneous complex formation.Finally,molecular docking revealed that non-covalent bonds were the main interaction forces between TA and both enzymes.Conclusions:Thus,TA was a promising candidate for the inhibition of starch-digesting enzymes,and the present research provided insight into postprandial glucose regulation through polyphenols.
