Effects of rainbow trout freshness on n ‐3 polyunsaturated fatty acids in fish offal

Abstract

Effects of rainbow trout freshness on n-3 polyunsaturated fatty acids in fish offalThe effects of rainbow trout cold storage on the quality of offal left after fish processing to fillets with skin were determined. The intact farmed rainbow trout were kept at 2 7C in ice for 0, 4, 7, and 14 days of storage. The offal was, immediately after processing, frozen at 220 7C and analysed after a month-long frozen storage; fillets (non-frozen) were analysed as well. Non-protein nitrogen, volatile bases, trimethylamine, lipid oxidation (peroxide value, anisidine value, UV-VIS spectra, and fluorescence) and fatty acid composition were determined. The offal consists in 15% of protein and in about 20% of chloroform/methanol-extractable lipids, with n-3 polyunsaturated fatty acids (n-3 PUFA) accounting for 20.37 6 1.25% of the fatty acids. The fish storage duration was found to exert a significant (p = 0.05) effect on the changes in lipids and nitrogen compounds. No losses of long-chain n-3 PUFA in the offal were detected during the 2 wk of storage in ice plus 1 month at 220 7C. The rainbow trout offal is a valuable -rich and stable -source of n-3 PUFA.

Lipid damage in farmed rainbow trout (Oncorhynchus mykiss) after slaughtering and chilled storage

“…Values for these constituents did not provide significant differences (p .0.05) as a result of the icing conditions, nor as a result of the icing time. The lipid content was found to be similar to the one reported for the same species obtained from wild conditions [13], but lower when compared to previous research on farmed fish individuals [13,19,20,36]. According to a known inverse ratio between moisture and lipid matter [1], a higher moisture content was obtained in the present study than in previous research on farmed rainbow trout [19,20,36].…”

Evaluation of Allium paradoxum (M.B.) G. Don. and Eryngium caucasicum trauve. Extracts on the shelf‐life and quality of silver carp (Hypophthalmichthys molitrix) fillets during refrigerated storage

“…The antioxidant property of A. paradoxum and E. caucasicum extracts is associated with sulfur, limonene and linoleic acid compounds (Corzomartinez et al, ; Dehghanzadeh et al, ). The maximum acceptable limit of PV value for foodstuffs is considered to be 10–20 meq O 2 kg −1 oil (Kotakowska, Domiszewski, Kozlowski, & Gajowniczek, ). In this study, the PV value of the control reached the upper limit of 20 meq O 2 kg −1 oil on day 6 while it took 9 days for the E. caucasicum (2%) and the A. paradoxum (2%) samples to reach the same level.…”

“…Fish fillet is probably the most susceptible to oxidation mainly due to its high level of unsaturated fatty acids (Sullivan & Budge, 2012) and its shelf-life is limited by microbial and enzymatic activity The maximum acceptable limit of PV value for foodstuffs is considered to be 10-20 meq O 2 kg 21 oil (Kotakowska, Domiszewski, Kozlowski, & Gajowniczek, 2006). In this study, the PV value of the control reached the upper limit of 20 meq O 2 kg 21 oil on day 6 while it took 9 days for the E. caucasicum (2%) and the A. paradoxum (2%) samples to reach the same level.…”

Evaluation of antioxidant and antimicrobial effects of shallot (Allium ascalonicum L.) fruit and ajwain (Trachyspermum ammi (L.) Sprague) seed extracts in semi-fried coated rainbow trout (Oncorhynchus mykiss) fillets for shelf-life extension

“…Peroxide value (PV). Rainbow trout is rich in polyunsaturated and monounsaturated fatty acids (26 and 50%, respectively) (Kotakowska, Domiszewski, Kozlowski, & Gajowniczek, 2006). It is, therefore, very sensitive to lipid oxidation that limits its shelf life.…”