Effect of a Polyphenol-Vacuum Packaging on Lipid Deterioration During an 18-Month Frozen Storage of Coho Salmon (Oncorhynchus kisutch)

A packaging system combining a polyphenol-rich film and vacuum (PPRF-VP) was applied to farmed coho salmon (Oncorhynchus kisutch) muscle for an 18-month storage (-18 degrees C). For it, two different concentrations of polyphenol compounds (namely, p-coumaric and ferulic acids) obtained from a barley husk extract were applied (PPRF-VP conditions) and compared to vacuum packaging without polyphenol presence (vacuum control; VP condition) and to packaging in the absence of vacuum and polyphenols (control; CP condition). The study was addressed to lipid hydrolysis and oxidation development and to lipid changes related to nutritional value. Both PPRF-VP conditions provided an inhibitory effect (p<0.05) on conjugated diene and fluorescent compound formation in frozen salmon. Compared to CP condition, vacuum packaging (PPRF-VP and VP conditions) led to lower (p<0.05) peroxide and anisidine values and to an inhibitory effect (p<0.05) on alpha- and gamma-tocopherol losses. No effect (p>0.05) of polyphenol presence and vacuum packaging could be inferred on free fatty acid formation (hydrolysis development) and on polyunsaturated fatty acid retention (polyene index assessment). A low rancid odour development was observed in all kinds of fish samples, this being lower (p<0.05) in fish kept under vacuum (PPRF-VP and VP) conditions.