Antioxidant activities of hydrolysed collagen from salmon scale ossein prepared with the aid of ultrasound

Summary Hydrolysed collagen with antioxidant activity from salmon scale ossein as influenced by ultrasound pretreatment and prior thermal treatment were investigated. Ultrasound pretreatment of scale ossein at 70% amplitude for 30 min with intensity power of 750 W, followed by heating at 55 °C for 6 h resulted in the highest release of collagenous materials from ossein. Hydrolysed collagen from aforementioned scale ossein prepared using Alcalase had higher degree of hydrolysis and recovery than those from ossein with other pretreatments. 2,2′‐Azinobis(3‐ethylbenzothiazoline‐6‐sulphonic acid) (ABTS), 1,1‐diphenyl‐2‐picrylhydrazyl (DPPH) radical scavenging activities and ferric reducing antioxidant power (FRAP) increased as Alcalase concentration increased. Higher proportion of low molecular weight (MW) peptides was observed after gastrointestinal digestion, in which peptides with MWs of 347 and 219 Da exhibited the highest ABTS radical scavenging activity and FRAP, respectively. Therefore, ultrasound pretreatment of ossein along with subsequent thermal treatment could increase yield and antioxidant activities of hydrolysed collagen.