不同酯化度果胶钙的结构特征与体外消化稳定性

Structural Characteristics and in Vitro Digestion Stability of Pectin Calcium with Different Esterification Degrees

为探究不同酯化度(DE)果胶形成的果胶钙的结构特征与消化稳定性,采用5种DE值的果胶与氯化钙反应获得5种DE的果胶钙,比较其产率、钙含量,红外、X衍射(XRD)、电镜(SEM)等结构特征与体外模拟消化稳定性。结果表明:果胶钙产率为50%~87%;DE=10%的果胶与Ca^(2+)反应形成的果胶钙(DE10-CaP)的钙含量最高(88 mg/g),DE59-CaP钙含量最低(43.6 mg/g);果胶钙中Ca^(2+)与羧酸根的结合形式为单齿配位结合型,并可分为3种结合区域,进一步完善了果胶钙的结合模式;XRD表明低酯果胶钙比高酯果胶钙多一处2θ=21.5°的衍射峰;SEM表明低酯果胶钙的表观结构更紧密,呈块状,高酯果胶钙则呈薄片状。体外模拟胃肠消化试验表明,高酯果胶钙的钙释放率及释放量更高。本研究有助于了解果胶钙的微观结构及应用性能。

In order to explore the structural characteristics and digestion stability of pectin calcium formed by pectin with different degrees of esterification(DE),this article used five different pectin with different DE to react with calcium chloride to obtain five different pectin calcium with different DE.And its yield,calcium content,infrared,X-ray diffraction(XRD),electron microscopy(SEM)et al.,structural features and its stability in vitro simulated digestion were compared.Results showed that the yield of pectin calcium was 50%-87%.Pectin calcium formed by the reaction of pectin with DE=10% and Ca^(2+)(DE10-CaP)had the highest calcium content(88 mg/g).DE59-CaP had the lowest calcium content(43.6 mg/g).The binding form of Ca^(2+)in calcium pectinate and carboxylate was single monodentate coordination binding type,with three binding regions intermolecular and intramolecular,which further improved the binding mode of pectin calcium.XRD showed that low-ester pectin calcium had a 2θ=21.5°diffraction peak more than that of high-ester pectin calcium.SEM showed that the apparent structure of low-ester pectin calcium was more compact and massive,and high-ester pectin calcium was in the form of flakes.It can be obtained by the in vitro simulated gastrointestinal digestion test that the calcium release rate of high-ester pectin calcium was higher.This research is helpful for in-depth understanding of the microstructure and application properties of pectin calcium.