超滤法分离苹果果胶及其理化性质

 【目的】对苹果果胶超滤法分离条件和不同相对分子质量的果胶与其结构及性质的关系进行研究。【方法】采用5种不同截流分子量的超滤膜分离苹果果胶,通过傅立叶变换红外光谱仪和气相色谱仪分别测定不同相对分子质量苹果果胶的结构和单糖组成。【结果】在跨膜压差为0.08 MPa,料液浓度为1 g?L-1,50℃条件下,获得6种不同相对分子质量的果胶。相对分子质量与其理化性质有着对应的关系,果胶半乳糖醛酸含量、酯化度和胶凝度随相对分子质量增大而增大,单糖组分也随相对分子质量增大而增多。同时,超滤对果胶液的脱色有良好作用。【结论】本研究可作为苹果果胶深度开发的新方法。

Study on the Properties of Apple Pectin Isolated by Ultrafiltration

【Objective】 Separation conditions of ultrafiltration for apple pectin were investigated. The relationship between different molecular weights of apple pectin and their structures and properties were also determined. 【Method】 Five ultrafiltration membranes in different molecular weight cut-off were applied to isolate apple pectin. FT-IR and GC were developed to determine the structures and monosaccharide composition of apple pectin with different molecular weights. 【Result】 Under ultrafiltration conditions of temperature 50℃, pressure 0.08 MPa and concentration 1 g?L-1, six kinds of pectins with different molecular weights were obtained. Meanwhile, molecular weight of pectin was related to its physicochemical properties. The larger the molecular weight of pectin was, the more its galacturonic acid content and degree of esterification and gelatination were. In addition, ultrafiltration contributed to the decolouring of pectin extract. 【Conclusion】 Ultrafiltration could isolate apple pectin well and it could be a new method of purification, separation and development for apple pectin.