Effect of factors on the status and rheological properties of gelatin extracted from catfish skin (Pangasius) in Vietnam

Abstract

This study investigates the influence of some factors, such as temperature, concentration of gelatin, salt (NaCl, CaCl₂) or sucrose, on the status and some rheological properties (viscosity, storage modulus) of gelatin solution extracted from catfish skin (Pangasius) in Vietnam. These are the technological factors that affect the applicability of gelatin in the food industry. The research results show that the gelatin solution can form a gel at a concentration of 0.7% at 5^oC, and the gelling temperature increases with increasing gelatin concentration. At temperatures above 20^oC, the viscosity of gelatin increases strongly at concentrations of gelatin above 4%. Sucrose helps to increase the viscosity and increase the gel-forming temperature of gelatin when the concentration of sucrose is above 10%; the viscosity increases about 4 times when the concentration of sucrose increases from 10 to 30%. Meanwhile, sodiumchloride or calcium chloride has the opposite effect; the gelling temperature and the viscosity of gelatin solution decreases when the salt content increases above 20 mM (NaCl), 10 mM (CaCl₂).