Effect of pre-treatments and defatting of seabass skins on properties and fishy odour of gelatin

The impact of different pretreatments and defatting processes of seabass skins onfishy odor and other properties of gelatin was investigated. Skin pretreated with0.05 M citric acid, followed by defatting using 30% isopropanol (G-Ci-Def) hadthe lowest residual phospholipid content (P < 0.05). Nevertheless, G-Ci-Def had alower yield and gel strength, compared to those from skins pretreated with aceticacid (G-Ac) or citric acid (G-Ci) (P < 0.05). All gelatins contained a-chains as thepredominant component as indicated by SDS-PAGE. G-Ci-Def showed the highestL* value and the lowest a*, b*, DE* and DC* values, compared to the other gelatins(P < 0.05). All gelatins were sponge or coral-like in structure but varied in patternsas evaluated by scanning electron microscopy. The lower fishy odor associated withlower amounts of most volatile compounds was found in G-Ci-Def, compared toother gelatins. Therefore, gelatin with negligible fishy odor could be prepared fromcitric acid pretreated and isopropanol defatted skin.PRACTICAL APPLICATIONSSeabass skins are potential raw materials for production of collagen, gelatin andbioactive protein hydrolysates. Pretreatment and defatting of seabass skin plays asignificant role in the reduction of lipids, especially membrane phospholipids.Pretreatment using citric acid and defatting using isopropanol of skin prior to gelatinextraction could lower lipid oxidation, volatile compounds, and fishy odor. Gelatinprepared could be widely used in foods with minimal effect on sensory attributes