Gelatin Preparation from Cow's Bone by Heat-Pressure Method

Abstract

The main sources of gelatin are pig skin, cow hide and fish bone or skin. The extraction of gelatin could be done by three different processes i.e., acid process, alkali process and heat-pressure process. The heat-pressure method to extract gelatin may produce a gelatin with a lower quality but the processing time is also low. In this study gelatin was extracted from cow's bone by heat-pressure process and some properties of the product was investigated. The cow's bone cured in a highpressure tank in boiling water for 5 h. Then the gelatin solution was filtered, defatted and the remaining solution was concentrated. This solution was dried at room temperature. The colour of the gelatin obtained was dark yellow with colorimetric indexes of L, a, b* of 57.5, 5.1, 24.7, respectively. The moisture content of gelatin was 9.6 % and the gelatin ash content is determined by pyrolysis at 900 °C that it was 2.4 %. The pH of solution (1 % w/v) was about 7. The viscosity of a 6.67 % solution at 25 °C was zero. The gelatin doesn't have good gel strength. The amino acid analysis of the produced gelatin exhibited that the high amounts of amino acids belong to glycine, glutamic acid and aspartic acid, respectively. Atomic absorption analysis also showed that elements such as Cu, Pb, Al, Ca and Zn are existed in the product.