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Characteristics and antioxidative activity of gelatin and gelatin hydrolysate powders from scale of spotted golden goatfish using maltodextrin as a carrier agent at different ratios [1:0, 2:1, 1:1 and 1:2 (w/w)] were investigated. Gelatin hydrolysates with 40 % degree of hydrolysis exhibited the highest antioxidative activity. With increasing maltodextrin proportions, the resulting powders showed an increase in yields, total sugar content and whiteness with coincidental decrease in [Formula: see text], [Formula: see text]-values and browning intensity. Solubility of gelatin powder increased with increase in maltodextrin proportion. Gelatin powder was spherical with smooth surface of hydrolysate varied, regardless of maltodextrin levels. Gelatin hydrolysate powder form, uniform agglomerates when maltodextrin was incorporated. DPPH and ABTS radical scavenging activities and ferric-reducing antioxidant power of gelatin and gelatin hydrolysate decreased when maltodextrin was used as a carrier agent. Thus, maltodextrin levels directly affected characteristics and antioxidative activity of gelatin and gelatin hydrolysate powders.

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Gelatins from the scales of spotted golden goatfish were extracted under different conditions and characterized. The gelatin yield, when extracted at 45, 60 and 75C (for 6 or 12 h), was 2.3–2.6%, 8.6–9.3% and 9.9–10.1% on dry weight basis, respectively. All the gelatins had β‐ and α‐chains as the dominant components, and had high imino acid contents (182–192 residues/1,000 residues). Gel strength of the gelatin decreased and the gelatin solution became more turbid with increasing temperature and time of extraction. The gelling and melting temperatures of gelatin were 18.7–20.1 and 26.4–28.0C, respectively, and these decreased with extraction temperature and time. The results suggest that the scales of spotted golden goatfish have potential to serve as the collagenous raw material for gelatin extraction. Practical Applications Spotted golden goatfish (Parupeneus heptacanthus) is used in the manufacturing of frozen fish fillets in Thailand, and the scales with low market value are generated as byproducts. Large amounts of scales could potentially serve as raw material for gelatin production. However, the proper extraction conditions need to be determined experimentally, considering both yield and properties of the resulting gelatin.