关键词: 苹果果胶, 超滤膜, 红外光谱, 气相色谱

Abstract:

【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.

Key words: apple pectin, ultrafiltration membrane, FT-IR, GC