Effect of Different Factors on the Quantity of Gelatin and Oil Extracted from Tuna Fish

Gelatin and oil from three species of tuna fish, Thunnus albacares (yellow-fin tuna), Thunnus tonggol (long-tail tuna), and Katsuwonus pelamis (skipjack tuna) were extracted to study the factors affecting yield. Factors studied included organ (fin or skin), catch location (Chah bahar, Bushehr, Bandar-e abbas), season (summer or winter) and species (the three species). To extract gelatin and oil, an alkali treatment and a solvent method, were used. respectively, The highest amount of gelatin extracted from the skin of K. pelamis was 17.5 &plusmn; 0.3% and the lowest from the fin of T. tonggol, 7.9 &plusmn; 0.4%. The highest and lowest amount of oil extracted were from skin of T. tonggol (7.5 &plusmn; 0.3%) and its fin (3.7 &plusmn; 0.8%), respectively. The organ and species showed significant effects on gelatin and oil extracted (p < 0.05), but not seasons and location (p > 0.05).