Effect Of Inulin On Physicochemical Properties And In Vitro Digestion Of Wheat Starch

In the food processing industry,the application of starch and non-starch polysaccharide complex system was widely used.Starch and non-starch polysaccharide with a certain mixing ratios could overcome some disadvantages of native starch and improve processing performance by change pasting properties and control flowability.Using wheat starch and inulin as material,we measured the effect of inulin with different chain length on physicochemical properties and in vitro digestion of WS by in vitro digestion model of improved method Englyst and analysis of rheological,gelatinization and thermal properties.The results are follows:1.With the increase ratio of inulin,the transparency of different WS-inulin complex system were all raised.Among them,WS-HSI system increased the most obviously.With the ratio in WS-HSI and WS-GR mixtures of 9.5: 0.5,the dehydration rate decreased to some extent,the resault demonstrated that the freeze-thaw stability was improved.With the increase ratio of HSI and GR,the dehydration rate no longer drop but gradually increased even higher than the native starch.The dehydration rate of WS-HPX system was higher than the native starch as the freeze-thaw stability decreased.Comparing the gelatinization properties of different systems,the peak temperature of WS-HSI system was the highest among the WS-inulin blends.Gelatinization temperature raised with increasing inulin additive amount.After stored a period of time,retrogradation degree was reduced by addition of inulin,and this trend raised with increasing additive amount.2.The results of rheological properties analysis showed that the liquidity index of different WS-inulin systems were less than one and the multiple correlation coefficient is above 0.99.The systems were consistent with the power-law model and called as pseudoplastic fluid,the pseudoplastic of wheat starch paste coulde be reduced by additon of inulin in some degree,and this trend raised with increasing additive amount.At the same inulin addtion amount,the pseudoplastic of WS-HPX system is the weakest.The dynamical viscoelastic experiment resaults suggested that the paste of WS-inulin systems were weak gel,the addtion of inulin makes systems shows more viscous fluid properties.3.Amyloglucosidase,porcine pancreatic ?-amylase and pH were selected in single-factor experiments.Based on the single-factor experiments,orthogonal experiments were applied for the optimization of in vitro digestion reaction conditions of WS.Then the data was analyzed by orthogonal software,the resaults as follows: Amyloglucosidase 20 U/mL,porcine pancreatic ?-amylase 320 U/mL and pH 5.0.Under optimum reaction conditions,the digestibility in vitro of WS was 79.32%.4.The results of in vitro digestion showed that all the three inulin could inhibit the extent and speed of starch hydrolyzation to some extent,and the inhibiton increased with increasing inulin additive amount.The hydrolysis index(HI)and estimated glycemic index(eGI)all dcreased with increasing inulin additive amount.At the maximum HSI additive amount hydrolysis degree,HI and eGI decreased to 68%,59.00 and 72.10 respectively compared with 79.32%?69.16 and 77.68 of native starch.