In this study,collagen hydrolysates were prepared by autoclaving or its combination with enzymolysis.After it,the digestion pattern and antioxidant activity were estimated in vitro gastrointestinal digestion.Three MW(...In this study,collagen hydrolysates were prepared by autoclaving or its combination with enzymolysis.After it,the digestion pattern and antioxidant activity were estimated in vitro gastrointestinal digestion.Three MW(HMW-CH,10-100 kDa;MMW-CH,1-10 kDa;LMW-CH,<1 kDa)of collagen hydrolysates were obtained.After digestion,MW of these samples decreased to some extent,while their total MW composition still show a similar tendency to the undigested samples,i.e.HMW-CH>MMW-CH>LMW-CH.From gastric to intestinal phase,DPPH radical scavenging of HMW-CH increased from 5.45%to 35.19%.However,MMW-CH and LMW-CH increased from 47.35%to 52.90%and 49.84%-64.40%in the gastric phase,and then decreased to 27.94%and 21.69%in the intestinal phase,respectively.Meantime,the reducing power of these samples was lower in the gastric phase,but increased within 15 min of intestinal phase.After,the differences decreased and the final was LMW-CH(1.030)>MMW-CH(0.914)>HMW-CH(0.872).These results indicate that the lower the MW,the higher the antioxidant activity.In addition,the binding mode of them to tannins was analyzed by thermody-namic parameters.The results suggest that the main mode of interaction between HMW-CH and MMW-CH and tannins was hydrogen bonding,whereas LMW-CH and tannin was hydrophobic.Overall,these results are helpful for us to better understand absorption process of collagen hydrolysates and provide some theoretical and technological support for collagen consumed in food and medicine.展开更多
Investigations of runoff and sediment yield changes and their relationships with potential driving factors provide good insights for understanding the mechanisms of hydrological processes.This study attempted to prese...Investigations of runoff and sediment yield changes and their relationships with potential driving factors provide good insights for understanding the mechanisms of hydrological processes.This study attempted to present a comprehensive investigation on the spatiotemporal variations of sediment yield in the Loess Plateau using continuous observed data at 46 hydrological stations during 1961-2016,and its responses to changes of precipitation,land use/cover and vegetation cover were analyzed by using the Partial Least Squares-Structural Equation Model(PLS-SEM).The results indicated that sediment yield reduced pro-nouncedly during 1961-2016 in the Loess Plateau,and 77.9%of this variation was explained by the combined effects of precipitation,land-use change,vegetation dynamics and runoff reduction.Indirect effects of precipitation,land-use change,and vegetation cover on sediment yield were 0.242,-0.528 and-0.630(P<0.05),respectively,and direct effect of runoff on sediment yield was 0.833(P<0.05).According to the Pearson Correlation Coefficient,the strongest positive correlation existed between annual sediment yield and runoff(r=0.88,P<0.05),followed by vegetation cover(r=-0.47,P<0.05)and land-use change(i.e.forest land and grassland)suggesting their significant trapping effects on soil erosion.However,lower correlations were examined between sediment yield and precipitation indices(-0.14<r<0.34),and a relatively higher relationship was examined between sediment yield and heavy rainfall(P_(25))(r=034).Overall,changes in runoff and land-use/vegetation cover well explained varia-tions in sediment yield in the Loess Plateau.The findings are expected to provide scientific and technical support for future soil and water conservation planning in the Loess Plateau,and are valuable for sus-tainable water resources and sediment load management in the Yellow River Basin.展开更多
基金supported by the National Nature Science Foundation of China(32172249)the Research Innovation Project for Post-graduate Students of Tianjin,China(No.2022BKY136).
文摘In this study,collagen hydrolysates were prepared by autoclaving or its combination with enzymolysis.After it,the digestion pattern and antioxidant activity were estimated in vitro gastrointestinal digestion.Three MW(HMW-CH,10-100 kDa;MMW-CH,1-10 kDa;LMW-CH,<1 kDa)of collagen hydrolysates were obtained.After digestion,MW of these samples decreased to some extent,while their total MW composition still show a similar tendency to the undigested samples,i.e.HMW-CH>MMW-CH>LMW-CH.From gastric to intestinal phase,DPPH radical scavenging of HMW-CH increased from 5.45%to 35.19%.However,MMW-CH and LMW-CH increased from 47.35%to 52.90%and 49.84%-64.40%in the gastric phase,and then decreased to 27.94%and 21.69%in the intestinal phase,respectively.Meantime,the reducing power of these samples was lower in the gastric phase,but increased within 15 min of intestinal phase.After,the differences decreased and the final was LMW-CH(1.030)>MMW-CH(0.914)>HMW-CH(0.872).These results indicate that the lower the MW,the higher the antioxidant activity.In addition,the binding mode of them to tannins was analyzed by thermody-namic parameters.The results suggest that the main mode of interaction between HMW-CH and MMW-CH and tannins was hydrogen bonding,whereas LMW-CH and tannin was hydrophobic.Overall,these results are helpful for us to better understand absorption process of collagen hydrolysates and provide some theoretical and technological support for collagen consumed in food and medicine.
基金supported by the National Natural Science Foundation of China(Grant Nos.U2243211,42177323,42077076,41671279).
文摘Investigations of runoff and sediment yield changes and their relationships with potential driving factors provide good insights for understanding the mechanisms of hydrological processes.This study attempted to present a comprehensive investigation on the spatiotemporal variations of sediment yield in the Loess Plateau using continuous observed data at 46 hydrological stations during 1961-2016,and its responses to changes of precipitation,land use/cover and vegetation cover were analyzed by using the Partial Least Squares-Structural Equation Model(PLS-SEM).The results indicated that sediment yield reduced pro-nouncedly during 1961-2016 in the Loess Plateau,and 77.9%of this variation was explained by the combined effects of precipitation,land-use change,vegetation dynamics and runoff reduction.Indirect effects of precipitation,land-use change,and vegetation cover on sediment yield were 0.242,-0.528 and-0.630(P<0.05),respectively,and direct effect of runoff on sediment yield was 0.833(P<0.05).According to the Pearson Correlation Coefficient,the strongest positive correlation existed between annual sediment yield and runoff(r=0.88,P<0.05),followed by vegetation cover(r=-0.47,P<0.05)and land-use change(i.e.forest land and grassland)suggesting their significant trapping effects on soil erosion.However,lower correlations were examined between sediment yield and precipitation indices(-0.14<r<0.34),and a relatively higher relationship was examined between sediment yield and heavy rainfall(P_(25))(r=034).Overall,changes in runoff and land-use/vegetation cover well explained varia-tions in sediment yield in the Loess Plateau.The findings are expected to provide scientific and technical support for future soil and water conservation planning in the Loess Plateau,and are valuable for sus-tainable water resources and sediment load management in the Yellow River Basin.
