Physicochemical and Functional Properties of Gelatin Extracted from Goat (Capra hircus) Skin Using the Partial Acid Hydrolysis Method

Abstract

Gelatin is a high molecular weight polypeptide derived from the partial hydrolysis of collagen tissue of animals. The commonly used gelatin are gelatin that is derived from porcine and bovine. Porcine gelatin is absolutely forbidden for every Muslim, otherwise, bovine gelatin is halal (permitted, allowed). Unfortunately, the source of bovine gelatin is limited and relatively expensive, so that alternative sources in producing halal gelatin are still needed. One of the animals that have not been explored as a source of gelatin is goat. The objectives of this research were to extract and characterize the properties of gelatin from goat (Capra hircus) skin. In order to obtain gelatin from goatskin, the process begun by pre-treating goatskin with 4% hydrochloric acid for 24 h and extracting with distilled water at a temperature of 60 °C for 9 h. The physicochemical and functional properties of goat gelatin were evaluated. The results of the evaluation exhibited the following properties: moisture of 7.9%, ash content of 0.26%, pH of 4.96, fat content of 0.03%, protein content of 98.97%, sulfide content of 5.22 ppm, lead and copper were not detected, zinc content of 0.061 ppm, and the gel clarity of 56.4%. All of these physicochemical properties indicated that goatskin gelatin met the defined requirements of a good gelatin. The results of functional properties revealed that the emulsion activity index, foaming properties, and the gel strength are 57.42 m2/g, 152.67%, and 219.65 gbloom, respectively. Therefore, goatskin gelatin could be applied as emulsifying agent, foaming agent, and gelling agent in the food, pharmacy, and cosmetics product. This study showed goatskin gelatin had a high potential to be used as a gelatin alternative.