The effects of refining steps on Kilka (Clupeonella delicatula) fish oil quality

Kilka fish are known as the main industrial and pelagic species of Iran that are captured abundantly in the southern Caspian Sea. This study was conducted to survey the effectiveness of refinement steps on Kilka (Clupeonella delicatula) crude oil quality and fatty acid profiles. Neutralization, bleaching, winterization and deodorization were performed on crude oil with deodorization done under two different conditions of A: at ۱۸۰˚C for ۱۲۰ min and B: at ۱۴۰˚C for ۲۴۰ min. During refinement, peroxide value (PV) significantly decreased from ۷.۶۶ meq/kg in crude oil to ۰.۵ in deodorized oil A and to ۰.۲۱ in deodorized oil B (p<۰.۰۵). Significant reduction in free fatty acids (FFA) was recorded from ۰.۸۶% oleic acid in crude oil to ۰.۱۵% in deodorized oil A and to ۰.۳۳% in deodorized oil B (p<۰.۰۵). N-۳ fatty acids content and fatty acids composition were determined by GC-FID and n-۳ fatty acids content increased from ۱۸.۷۴% in crude oil to ۲۱.۵۸% in deodorized oil A and to ۲۱.۷۵% in deodorized oil B. The red color in oil significantly decreased from ۵.۴ to ۰.۴ and ۰.۵ in deodorized oil A and deodorized oil B, respectively (p<۰.۰۵). Results confirm that refinement steps improved oil quality and raised n-۳ PUFA concentration and n-۳/n-۶, properly. Deodorization at ۱۸۰˚C for ۱۲۰ minutes (A) was more effective than deodorization at ۱۴۰˚C for ۲۴۰ minutes (B) in removing off flavors.

Keywords:

Clupeonella delicatula , Fish oil , Refinement , Deodorization , N-۳ fatty acids , Oxidation