Effect of Stage of Rigor and of Freezing–Thawing Processes On Storage Quality of Refrozen Cod

Abstract

frawler-caught cod were frozen before and after rigor mortis in brine (23l, NaCl) and between refrigerated plates, thawed in circulating water at 7 C or in a conveyorized microwave oven, then processed into fillets which rvere packaged, plate-frozen, and stored at -18 C.All samples thawed satisfactorily in circulating water. Some overheating was encountered during thawing in microwaves. But the equipment was not developed sufficiently to permit assessment of the commercial potential of microwave thalving.Examinations of the fillets from the thawed fish for appearance, odor, and texture showed that freezing pre-rigor is preferable to freezing post-rigor and that thal,r'ing by means of microwaves is preferable to thawing by means of water. Freezing or thawing methods did not affect the /H of the thawed fillets.Results of organoleptic and chemical tests to determine the changes in quality of the refrozen fillets packaged and stored at -18 C for 12 months indicated that neither the average taste panel scores nor the chemical tests for moisture, total lipid, free fatty acids, and extractable protein nitrogen showed any difference attributable to state of rigor, freezing method, orthawing method. The taste panel slightly preferred the texture of fillets from fish frozen pre-rigor and from fish frozen in brine. Free fatty acids increased sharply as a result of thawing and refreezing, and the rapid increase continued during the first 2 months of. frozen storage. Taste panel scores correlated significantly with free fatty acids (l/6 level) and with extractable protein (5/6 level).

Physical and quality attributes of salted cod (Gadus morhua L.) as affected by the state of rigor and freezing prior to salting

“…Peters et al (1968) found that freezing pre-rigor was preferable to freezing postrigor with respect to the sensory properties while Love (1988; showed that the degree of gaping was least in thawed marine species when the fish had been frozen pre-rigor.…”

Thawing, Refreezing and Frozen Storage Effects on Muscle Functionality and Sensory Attributes of Frozen Cod (Gadus morhua)

“…Dyer et al (1962) reported accelerated deterioration for refrozen cod (Gadus morhua) fillets stored at Ϫ23ЊC but confounded any effects of thawing and refreezing with product form by using whole fish as once frozen controls. Peters et al (1968) compared refrozen fillets with once frozen fillets from the same batch but reported slight (sometimes non-significant) taste panel differences after 12 months at Ϫ18ЊC. The use of composite sensory attribute measurements, such as 'overall taste panel score' or 'overall taste/texture score', has also been common (Dyer et al, 1962;Peters et al, 1968) preventing evaluation of effects that thawing and refreezing might have on specific sensory attributes.…”

Current freezing and thawing scenarios employed by North Atlantic fisheries: their potential role in Newfoundland and Labrador’s northern cod (Gadus morhua) fishery

“…This binding occurs through the coupling of actin and myosin by consuming adenosine triphosphate as energy and results in the loss of muscle extension ( Yao et al, 2019 ). Peters et al (1968) found that freezing fish pre-rigour produced a higher quality product than freezing in- or post-rigour. However, Hedges (2002) noted that if thawing occurs before rigour is complete, the fish may complete rigour during the thawing process, which will result in excessive drip loss and damage to the flesh.…”