TIAN Yu-xia1, QIAO Shu-tao2, QIU Nong-xue1*, DENG Hong1, GUO Yu-rong1
(1 College of Food Engineering and Nutritional Science, Shaanxi Normal University, Xi′an 710062, Shaanxi, China; 2 College of Mechanical Instrumental Engineering, Xi′an University of Technology, Xi′an 710048, Shaanxi, China)
Abstract:
Five ultrafiltration membranes in different molecular weight cut-off(MWCO) were applied to isolate apple pectin.The rheological properties and effect of concentration, shear rate, temperature, pH value, sucrose and salts on viscosity of apple pectins were studied. The results showed that apple pectin solution exhibited a shear-thinning behaviour. When the concentration of apple pectins increased, the viscosity increased too. The viscosity of apple pectins solution was in direct ratio with molecular weights and in inverse ratio with solution temperature. pH value affected the apparent viscosity of apple pectin gum remarkably. The viscosity of the pectin solutions increased in the presence of sucrose, but decreased in the presence of salts.
KeyWords:
apple pectin; rheological properties; influences factors