Shelf‐life enhancement of whole rainbow trout (Oncorhynchus mykiss) treated with Reshgak ice coverage

Abstract

The effect of ice coverage comprised of Reshgak extract and Reshgak essential oil on shelf‐life extension of chilled whole rainbow trout (Oncorhynchus mykiss) was evaluated. Chemical (peroxide value (PV), thiobarbituric acids (TBA), total volatile nitrogen base (TVB‐N), and free fatty acids (FFA)), microbiological (total viable count (TVC) and psychrotrophic viable count (PVC)), and sensory evaluations (texture, color, flavor, and general acceptance) were investigated every 4 days during a 20‐day storage period. Results revealed that the effect of both icing systems led to considerably lower bacterial counts and chemical indices in comparison with the traditional ice coverage without such phytogenic. According to sensory analyses, fish stored in ice containing Reshgak essential oil had a longer shelf‐life (>16 days) and those stored in ice medium included with Reshgak extract possessed a shelf‐life of 16 days, whereas lot stored in traditional ice showed a shorter shelf‐life of 12 days.

Effect of various postmortem processing times and blanching methods on quality of rainbow trout (Oncorhynchus mykiss) waste oil

“…Comparison of FFA contents of oil immediately obtained from blanched waste and stored blanched waste (all methods) shows that the storage process leads to a significant increase in FFA content. This result is in agreement with those of Abedi et al () and Tavakoli et al (). The highest increase in Free fatty acid is recorded in oil from stored pH shift‐treated viscera (0.698 ± 0.023).…”

“…Samples with a longer delay time for freezing present the highest mean levels (1.9 mg malondialdehyde/kg oil). The mean values of TBA content of extracted oil were considerably higher than those values reported in fish fillet by Abedi, Naseri, Ghanbarian, and Vazirzadeh, () and Tavakoli et al (); meanwhile, they are similar to those reported by Nazir et al () for tuna waste oils obtained using various extraction methods. Increasing TBA values during storage time are also reported in the oil extracted from Caspian white fish ( Rutilus frisii kutum ) and Nile perch ( Lates niloticus ) when freezing delay time becomes longer (Karungi et al, ).…”

“…In brief, about 50 g of fish waste was homogenized in a mixture of 200 ml chloroform, 200 ml methanol, and 150 ml distilled water. The mixture was filtered, and solvent was removed using rotary evaporator (Vacuum Rotary) at 40ºC and kept refrigerated until analyses in a dark screw‐topped bottle (Tavakoli, Naseri, Abedi, & Imani, ).…”

“…The mixture was filtered, and solvent was removed using rotary evaporator (Vacuum Rotary) at 40ºC and kept refrigerated until analyses in a dark screw-topped bottle (Tavakoli, Naseri, Abedi, & Imani, 2018).…”

“…Measurement of secondary lipid oxidation product content is an appropriate quality parameter to evaluate the chemical changes from various processing treatments (Tavakoli et al, 2018). In this sense, carbonyl formation during blanching is widely used (Binsi et al, 2014;Cerretani, Bendini, Rodriguez-Estrada, Vittadini, & Chiavaro, 2009;Cyprian et al, 2016).…”