Retention of trans-anethole by single and double layered films based on gelatine

Abstract

The present work investigated the retention of trans-anethole by single and double layered films based on gelatine. In the case of double layered films, gelatine was the base component whereas gellan was the upper layer. The gelatine layer was always carrying the aroma compound. Films were formed under varying drying conditions. Aroma release was determined by hexane extraction. For some double layered films the aroma present in the headspace above the film was determined by static headspace analysis. Experimental conditions were of great importance. Longer extraction time, lower drying temperature and shorter drying time resulted in greater extraction yields. Longer extraction treatment did not compensate for the volatile losses during drying at high temperatures. Moreover, regardless the film composition or the drying conditions, no significant difference in the air/film partition coefficient was observed. In addition, when comparing single and double layered films under the same experimental conditions, the extraction yield was always higher for the double films. Thus, the double layered gelatine-gellan films are effective as aroma barriers.