Postrigor mortis changes of texture, chemical and sensory properties in rainbow trout (Oncorhynchus mykiss) reared at two different temperature conditions (8 and 12 °C) were examined to better understand how differ-ent stunning methods, i.e. electroshock (E) and asphyxia with carbon monoxide (CO), can influence their evolution during refrigerated storage. Seven days after rigor resolution (TRR7), considering ATP catabolites (K- and K1-values), the freshness remained well preserved regardless of the stunning method applied and water temperature. During refrigerated storage fillets from fish reared at 8 °C maintained significantly higher (P < 0.001) pH at the day of rigorresolution (TRR0), whereas at the end of the storage time (TRR7), 8 °C-reared fish showed a significantly lower pH value (P < 0.05). CO treatment was effective in ensuring a more intense red colour of the fillet and high chroma, whereas E treatment exhibited the lowest a*, b* and chroma values. The texture profile analysis showed a significant effect of the stunning method (S), water temperature (T) and S × T interaction on fillet cohesiveness. TBARS values were significantly lower (P < 0.05) in fish stunned by CO when compared to E group in the first 76 h post mortem(TRR0). At the end of the storage period (TRR7), no TBARS value difference was detected between treatments. The stunning method had a relevant impact on fillet sensory traits, revealing that CO fillets were the juiciest (P < 0.05) and presented the lowest saltiness (P < 0.05), aroma (P < 0.05) and odour (P < 0.01) intensity. Rearing temperature, instead, had a moderate effect on fillet sensory traits and indicated that the water temperature of 12 °C enhanced juiciness (P < 0.05) and tenderness (P < 0.05) attributes. Overall results suggested that CO is a suitable stunning method for trout that, coupled with 12 °C water temperature, are able to preserve fillet freshness, enhance col-orimetric characteristics which are maintained during refrigerated storage, and provide desirable sensory traits.
Rainbow trout (Oncorhynchus mykiss) farmed at two different temperatures: Post rigor mortis changesin function of the stunning method / Antonella Dalle Zotte, Anna Concollato, Giulia Secci, Marco Cullere, Giuliana Parisi. - In: CZECH JOURNAL OF ANIMAL SCIENCE. - ISSN 1212-1819. - STAMPA. - 65:(2020), pp. 354-364. [10.17221/144/2020-CJAS]
Rainbow trout (Oncorhynchus mykiss) farmed at two different temperatures: Post rigor mortis changesin function of the stunning method
Anna Concollato;Giulia Secci;Giuliana Parisi
2020
Abstract
Postrigor mortis changes of texture, chemical and sensory properties in rainbow trout (Oncorhynchus mykiss) reared at two different temperature conditions (8 and 12 °C) were examined to better understand how differ-ent stunning methods, i.e. electroshock (E) and asphyxia with carbon monoxide (CO), can influence their evolution during refrigerated storage. Seven days after rigor resolution (TRR7), considering ATP catabolites (K- and K1-values), the freshness remained well preserved regardless of the stunning method applied and water temperature. During refrigerated storage fillets from fish reared at 8 °C maintained significantly higher (P < 0.001) pH at the day of rigorresolution (TRR0), whereas at the end of the storage time (TRR7), 8 °C-reared fish showed a significantly lower pH value (P < 0.05). CO treatment was effective in ensuring a more intense red colour of the fillet and high chroma, whereas E treatment exhibited the lowest a*, b* and chroma values. The texture profile analysis showed a significant effect of the stunning method (S), water temperature (T) and S × T interaction on fillet cohesiveness. TBARS values were significantly lower (P < 0.05) in fish stunned by CO when compared to E group in the first 76 h post mortem(TRR0). At the end of the storage period (TRR7), no TBARS value difference was detected between treatments. The stunning method had a relevant impact on fillet sensory traits, revealing that CO fillets were the juiciest (P < 0.05) and presented the lowest saltiness (P < 0.05), aroma (P < 0.05) and odour (P < 0.01) intensity. Rearing temperature, instead, had a moderate effect on fillet sensory traits and indicated that the water temperature of 12 °C enhanced juiciness (P < 0.05) and tenderness (P < 0.05) attributes. Overall results suggested that CO is a suitable stunning method for trout that, coupled with 12 °C water temperature, are able to preserve fillet freshness, enhance col-orimetric characteristics which are maintained during refrigerated storage, and provide desirable sensory traits.File | Dimensione | Formato | |
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