| Kudzu starch and glutinous rice starch are commonly used as a nutritious food in East Asia,however,its impact on glycemic response is unclear.The objective of this study is to investigate its susceptibility to digestive enzymes and its potential impact on glycemic response.The main purpose of this paper is the sensitivity of main starch digestive enzymes kudzu starch and glutinous rice starch in the human body.Using the purified the kudzu starch and glutinous rice starch and pasting kudzu starch and glutinous rice starch as the main research object,by using of advanced technology,changes of sample size,the particle size,crystallinity and enzyme kinetics properties and hydrolysis index are analyzed,the results are as follows:1.The laser scattering particle size analyzer,according to the results of analysis that natural granularity of kudzu starch respectively between 5 and 50 microns,natural granularity of glutinous rice starch is 5-120 microns.Scanning electron microscope?SEM?shows that,the kudzu root starch crystal configuration of polygon,that smooth and has a concave part;and the glutinous rice starch crystal configuration for irregular stones,and its uneven distribution granularity.2.By X-ray diffraction?XRD?to observe the crystallinity changes of two starches,the crystallinity of kudzu root starch was increased with enzyme solution time;kudzu root starch granule crystallinity was 34.8%,after the enzyme solution 20 min crystallinity was48.4% and the crystallinity increased to 53.6% after 120 min.The crystallinity of the glutinous rice starch was 49.8%,after the enzyme solution 20 min crystallinity was 51.2%and the crystallinity increased to 63.4% after 120 min.3.Using a first-order enzyme kinetics model,we figured the k value of the granular kudzu root starch and pasting state kudzu root starch was 7.0×10-4min-1and 7.7×10-3min-1respectively;the k value of the granular glutinous rice starch and pasting state glutinous rice starch was 2.0×10-3min-1and 1.1× 10-2min-1respectively.Obtained byLinewever-Burk figure,we worked out the Michaelis constant Km and the maximum reaction rate Vm of the granular kudzu root starch was 16.78mg/mL and 0.69mg/m L·min respectively;the value of the pasting state kudzu root starch was 2.08mg/mL and7.93mg/m L·min;the value of the granular glutinous rice starch was 10.35 mg/mL and 0.52mg/m L·min;the value of the pasting state glutinous rice starch was 9.92mg/mL and 2.23mg/m L·min?4.Through the in vitro digestion experiment the rapid digestion starch?RDS?,slowly digest starch?SDS?and resistant starch?RS?content in granular Kudzu root starch we observed was 5.66%?21.88% and 72.46% respectively;the RDS,SDS and RS content in pasting state kudzu root starch was 18.79%?29.83% and 51.38%,compared with the granular kudzu root starch,RDS and SDS content increased by 232% and 36.33%respectively,while the content of RS is down by 29.09%.Then the RDS,SDS and RS content in granular glutinous rice starch was 8.92%?21.52% and 69.56%;the RDS,SDS and RS content in pasting state glutinous rice starch was 18.47%,29.75% and 51.78 %,compared with the granular glutinous rice starch,RDS and SDS content increased by 107.06% and 38.24% respectively,while the content of RS is down by 25.61%. |
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