Study of drying kinetics of salmon processing by-products at different temperatures and the quality of extracted fish oil

ABSTRACT

Samples of salmon processing by-products were minced, mixed, and partially dried to moisture content of 90 ± 5% (dry basis), at two different temperatures 60 and 100°C (using hot air-drying and oven-drying, respectively). Theoretical and semitheoretical drying models were used for modeling of the drying kinetics of salmon by-products mix, where Page model and logarithmic models were observed as the best models presenting the drying kinetics of salmon by-products at 60 and 100°C, respectively. Salmon by-product oil was extracted from the partially dried by-product through centrifugation and was compared with enzymatically extracted (enzymatic extraction method was considered as the control method) salmon oil, in terms of fatty acid profile of the oils. The oil content obtained through semidried samples and enzymatically treated samples ranged between 16.234 and 18.212 g/100 g of fresh sample, which were not significantly different. The fatty acid composition was similar in all the cases. The fatty acids predominantly observed in the salmon oils included oleic acid, linoleic acid, and palmitic acid. Other fatty acids included palmitoleic acid, stearic acid, vaccenic acid, gondoic acid, and myristic acid. Docosahexaenoic acid and eicosapentaenoic acid contents were between 1 and 2% of the oil extracted in all the cases, and DPA (Docosapentaenoic acid) content was approximately 1%. Hence, partial dehydration at both the temperatures was concluded as a potential processing method for increasing the storability of salmon by-products and obtaining salmon oil with high quality.

KEYWORDS:

• By-products
• drying
• drying model
• fatty acid
• salmon

Acknowledgments

This project was funded by Research and Development Corporation of Newfoundland and Labrador, Canada, Ignite R&D program and authors would like to thank the organization for their continuous support. Authors are grateful to Ms. Heather Manuel for her guidance during the project and her expertise. Authors would also like to thank Ms. Sheila Trenholm (Laboratory Technologist, CASD, Marine Institute), Ms. Julia Pohling (Marine Biotechnologist, CASD, Marine Institute) and Jennette Wells (Research Assistant, Aquatic Research Cluster, Memorial University of Newfoundland) for their expertise and support while conducting the research.