Changes in Freshness during Frozen Storage of Farmed Coho Salmon: Effect of Replacement of Synthetic Antioxidants by Natural Ones in Fish Feeds

Abstract

The addition of antioxidants to the diets for salmonids is crucial to prevent or delay deterioration of fish muscle. Most of the antioxidants used in these diets are synthetic, and their safety is more and more being questioned. The aim of this research was to compare the effects of substituting synthetic antioxidants with natural ones on selected biochemical freshness indicators of frozen coho salmon Oncorhynchus kisutch muscle. Three different feeds were tested: a conventional diet with the synthetic antioxidants butylated hydroxytoluene and ethoxyquin (diet 1) was supplied to farmed coho salmon in parallel with two different diets that included natural antioxidants (a tocopherol isomer‐rich mixture [diet 2] and a tocopherol isomer–rosemary extract mixture [diet 3]). Five individuals of each group were analyzed every 3 months during frozen storage. The biochemical indicators measured were total volatile basic nitrogen (TVB‐N), dimethylamine content, formaldehyde content, and tissue pH. Levels of TVB‐N were significantly different between the three diets; TVB‐N content was the lower for salmon fed diet 3 than for those fed diet 1, a result that was attributed to the antimicrobial action of the rosemary extracts. Formaldehyde content was similar among the salmon fed diets with different antioxidants, and pH values were always lowered to maximum limits allowed by international legislation. These results support the use of natural antioxidants in the diet of Chilean coho salmon for export.

Rapid Assessment of Fish Freshness and Quality by 1H HR-MAS NMR Spectroscopy

“…This observation is consistent with the literature data were DMA has been reported as a possible Fig. 3 Changes in the concentration of ATP breakdown products of brown trout stored at 0°C in ice indicator of freezing in salmon stored at −40°C (Castejón et al 2010;Ortiz et al 2012). The DMA marker could be of significant importance when it has to be proven that a fish sample has not been frozen for extended periods of time.…”

Lipid and sensory quality of canned Atlantic salmon (Salmo salar): Effect of the use of different seaweed extracts as covering liquids

“…Total volatile basic nitrogen (TVB‐N) was determined according to a trichloroacetic precipitation method modified by Ortiz et al , based on the precipitation of salmon muscle proteins with a solution 5 g/100 mL of trichloroacetic acid (CCl 3 COOH; Merck) in water, followed by the separation of volatile bases of other nitrogen compounds present in the sample by steam distillation at alkaline pH‐value, in a distillation unit (Büchi B‐323 Labortechnik, Flawil, Switzerland) using magnesium oxide (MgO; Reutter, Santiago, Chile) as alkalizing agent. Then, TVB‐N is collected in a solution 4 g/100 mL of orthoboric acid (H 3 BO 3 ; Winkler, Santiago, Chile) in water, and quantified by means of titration with 0.01 mol/L hydrochloric acid (HCl; Merck).…”

“…At present, farming of salmonids has a crucial role in worldwide economy; and Chile is one of the major players in the market of these fish species . Canned salmon is one of the major fish products in countries like UK and USA.…”

Classical Single Factor Optimisation of Parameters for Phenolic Antioxidant Extraction from Tamarind Seed (Tamarindus indica)

“…Though the use of synthetic additives are effective in maintaining the shelf life of processed foods, the need of substituting synthetic additives with natural antioxidants are gradually increasing day by day considering the food safety they offer (Ortiz et al, 2012;Karre et al, 2013). The biotechonomy frame and liability of modern food industries towards maintaining a sustainable environment are leading towards imposing greater emphasis on valorising food by products as a source of antioxidant in food formulations.…”