Development of fish freshness indicator with red cabbage and turmeric extracts

Abstract

Fish freshness indicators were developed using pH sensing red cabbage and turmeric extracts. Chitosan films entrapped with the natural extracts were evaluated for their efficiency in detecting fish freshness during storage. The films act as visual colorimetric sensors inside fish package, changing colour with the rate of spoilage. The colour change indicates the degree of fish freshness. The pH chart developed in pH buffer gradient solutions with the extracts were correlated with the headspace pH. Biochemical, microbial and sensory quality of the fish were estimated during storage. The colour change of the film was measured using colorimeter. The red cabbage film turned from purple to green and the turmeric film turned from yellow to orange. The study reveals that the smart films can be effectively used as visual fish freshness detectors.