Search for and Development of Novel Antioxidant Proteins from Tuna Cooking Drips and Heart

Tuna processing generates a significant amount of waste and by-products that are mostly used as animal feed stuff or disposed of. The study was performed on tuna cooking drips and heart. We found crude protein factions (TPs) with antioxidant activity from cooking drips (TP1) and heart (TP2) of the tuna. TP1 yielded more than 10 protein bands, ranging from 10 to 80 kDa. TP2 separated more clearly than TP1 and yielded more than 15 protein bands that appeared between 10 to 100 kDa. The TP antioxidant activities were measured by assessing the degree of DPPH radical scavenging through its electron-donating ability. TP1 antioxidant activity indicated a proportional increase of up to 0.7 mg/mL, with a constant value of 33% ± 0.5% above 0.7 mg/mL. TP2 exhibited 48 ± 0.8% DPPH radical scavenging activity at 1.0 mg/mL, which was more potent than TP1. These results indicate that TPs possess potential antioxidant activity and can be utilized as a natural antioxidant.