| Alpha-amylase inhibitor（α-AI）is a type of biologically active substances that takesα-amylase as its target and can block the decomposition of starch in high-starch food effectively,thereby reducing weight and blood sugar.In recent years,α-AI have been isolated from various beans,and proved that this kind ofα-AI had a good inhibitory activity onα-amylase.The Northeast snap bean series bred in Heilongjiang University are new beans with the good taste and high yield.For research the activity ofα-AI in these snap bean seed resources and provide data support for the extension of the northeast snap bean industry chain,this study selected 8 snap bean seeds as raw materials forα-AI extraction,and the optimal snap bean variety was selected based on the inhibitory activity ofα-AI on amylase.Method:The raw material for this experiment is Heida purple crown bean seeds.Optimize the extraction conditions ofα-AI by adjusting different soy flour particle size,material-to-liquid ratio and salting time.Based on these optimized conditions,the other7 snap bean seeds were used as raw materials,and the unit activity or the half inhibitory concentration（IC50）was used as the evaluation index to screen superior snap bean variety with highα-AI activity.And its inhibitory kinetics on porcine pancreaticα-amylase were analyzed to clarify its action mode.The susceptibility ofα-AI to temperature,p H and simulated gastrointestinal environment was studied.Finally,α-AI embedded wall material is sodium alginate-sodium carboxymethylcellulose.To evaluate the stability ofα-AI microcapsules.The results showed that:Univariate test and response surface method for optimizing the conditions for extraction of theα-AI.Optimum extraction conditions:Flour particle size 180-250μm,material-liquid mass-volume ratio 1:12（g/m L）,and salt-dissolving time7.80.Under these conditions,the unit activity(IC50)ofα-AI was maximal（27.036±0.235μg/m L）.8 snap bean varieties were screened,and the results showed that theα-amylase inhibitor activity(IC50)extracted from Jinguan seeds was maximal,with IC50 at 5.68±0.12μg/m L.When the concentration of porcine pancreatic amylase was 2 mg/m L,Increasing inhibitor concentration and the reaction time can advance the inhibitory activity ofα-AI.Analyzed by a double reciprocal plot of the curve of the inhibitor is a reversible inhibition noncompetitive inhibition.Stability studies showed that the inhibitor was stable when the temperature ranged from 30 to 70℃and in simulated intestinal juice.While theα-AI was vulnerable in simulated gastric juice.α-AI microcapsule formulations using single factor and orthogonal.The optimized formula of microcapsules is 0.6%sodium alginate,0.2%CMC and calcium chloride concentration 0.20 M.After optimization,the embedding rate ofα-AI by the microcapsules was 85.72±2.25%.. |
