Effect of acidulants on some properties of a gelatin dispersion

Abstract

Three gelatin dispersions of 1.5% concentration were prepared. Two of the dispersions were acidified with fumaric and citric acids up to a concentration of 0.05 N. The third containing no acid, served as'the control The pH and the relative viscosity of the sols and the strength and liquifying time of the gels were determined for the three variables. The sol containing fumaric acid had the lowest pH, highest viscosity and its gel was the weakest as indicated by the greatest depth of penetration. The same gel also had the shortest liquifying time compared to the other two variables. The dispersion containing citric acid had a slightly higher pH and a lower relative viscosity than the one containing fumaric acid The gel containing citric acid required more time to liquefy and had a lower depth of penetration of the cone than the gel containing fumaric acid. The pHof the control sample was close to neutrality. This sol with no added acid had the lowest relative viscosity, and its gel had the least depth of penetration and required the longest time for liquefaction indicating a greater strength of the gel compared to those of the other two gels. From these observations it can be concluded that besides providing the desired tartness, acidulantsvlso affect the other properties of a gelatin dispersion. Of the two acidulants tested in the present investigation fumaric acid appears to make the gelatin gel more weak compared to citric acid.