Characterization of carp (Cyprinus carpio) skin gelatin extracted using different pretreatments method

Abstract

The influence of pre-treatment method on the characteristics and gel properties of gelatine from Cyprinus carpio L. skin was studied. Gelatine was extracted from the carp skin using three methods: (I) NaCl pre-treatment, (II) NaOH and ethanol pre-treatment and (III) NaOH, H2SO4, C6H8O7 pre-treatment. The chemical composition and functional properties of gelatine were investigated. The gelatines had high protein (75.86–82.44%) and relatively high fat contents (3.99–10.02%). Electrophoresis showed that gelatines I and III contained α- and β-chains as the predominant components, while in gelatine I the distinctive bands corresponding to the main components of collagen were not observed. Amino acids analysis revealed high proline and hydroxyproline content in all the gelatines.The gel strength of gelatine III was higher than gelatines I and II. Gelatine I remained in a liquid state during the experiment. Moreover, the pre-treatment of carp skin significantly affected the colour, pH as well as foam-forming, amino-acids composition, water-binding and fat-binding properties. Gelatine III was the only gelatine with properties sufficient for industrial applications. The results indicate that C. carpio L. skin by-products can be utilised to extract gelatine with potential industrial application as an alternative source to the mammalian gelatine.