Study On The Crystal Structure And Aging Characteristics Of Pueraria Lobata Starch By Nuclear Magnetic Resonance

Study on the structural properties and the aging process under different conditions of kudzu starch have profound implication for its application in food processing and management.This research be of great benefit to understand the different degree of aging of the kudzu starch under different storage conditions.The main objective of this paper were to study on the crystal structure properties?crystal,relative crystallinity,relative amount of double helix?of kudzu starch by ¹³C CP/MAS,and determine the effects of different concentration and additives on the aging process of kudzu starch by low-filed Nuclear Magnetic Resonance.The main conclusions are as follows:1.The results of the thermodynamics properties of kudzu starch showed:The initial gelatinization temperature was 64.32?,the finial gelatinization temperature was 80.00?,respectivelly.while the gelatinization enthalpy was 1.77Jg^-1.2.The results of microscopic observation of kudzu starch granules showed:That the morphological characteristics of kudzu starch were characterized by smooth and mostly polygonal or semi-elliptical shapes.The distribution pattern of the particle size of kudzu starch was bimodal.While the internal structure of kudzu starch granules which observed under laser confocal electron microscopy performed high intensity fluorescence existed in the surface of the kudzu starch granules,present a weak fluorescence in the interior of most granules.And the polarized cross where found near the center of the kudzu starch.3.The results of the structural characteristics of kudzu starch crystals show that:the C₁ region?chemical shift is from 94 to 110nm?was contain two peaks after peakfit and generated two sub-peaks indicated that kudzu starch was Cb-type crystal.coherently.Distinct C-type signature doublets emerged at 2?=15.3°,17.2°,17.5°,demonstrating the credible evidences to ensure the conclusion.The relative degree of crystallinity detected through ¹³C CP/MAS and XRD is 28.7%and 19.18%,respectively.¹³C CP/MAS showed that relative amount of double helix exits in Kudzu starch is 41.21%.4.The aging characteristics of kudzu starch were observed by using low-filed NMR showed that the longer aging time,higher the degree of aging.The additives such as glyceroll,citric acid,glucose slow down the aging of kudzu starch solution,the various of additives had different effects on the aging of kudzu starch solution.