Effects of four multi‐compound freezing medium on the quality of red drum (Sciaenops ocellatus) during frozen storage

Abstract

Taking air freezing (AF) as the reference, the effects of four types of multi-compound freezing medium for cryogenic liquid quick-freezing (immersion freezing, IF) on the freezing rate, quality and myofibrillar protein (MP) denaturation of red drum (Sciaenops ocellatus) fillets during frozen storage (À18°C) from days 0 to 90 were studied. Samples were gathered on days 0, 15, 30, 45, 60 and 90 for analysis. The results showed that IF groups (IF-1: 20% ethanol, 30% propylene glycol, 10% sodium chloride aqueous solution; IF-2: 20% ethanol, 20% propylene glycol, 10% glycerol, 10% sodium chloride aqueous solution; IF-3: 20% ethanol, 20% propylene glycol, 10% polyethylene glycol, 10% sodium chloride aqueous solution; IF-4: 20% ethanol, 20% propylene glycol, 5% glycerol, 5% polyethylene glycol, 10% sodium chloride aqueous solution) significantly shortened the time to cross the formation zone of maximum ice crystals while the freezing rate was 6.13 times higher than the AF group after adding 30% propylene glycol as the freezing medium. Furthermore, compared with the AF group, the IF groups significantly reduced losses in the water-holding capacity, the myofibrillar fragmentation index, microstructure damage, texture characteristics, drip loss and water migration (P < 0.05). In addition, the MP of IF groups had higher maximum transition temperatures (T max1 and T max2 ), total sulfhydryl content, Ca 2+ -ATPase activity and relative a-helix content compared with the AF group. In conclusion, IF could significantly increase the freezing rate of red drum fillets, and slow down quality deterioration and denaturation of MP during frozen storage for 90 days (À18°C). In particular, IF-2 (20% ethanol, 20% propylene glycol, 10% glycerol, 10% sodium chloride aqueous solution) was found to be more suitable for the immersion freezing of marine fish among the four multi-compound freezing medium.

Effect of novel infrared–ohmic thawing method on the thawing rate and minced turkey breast quality

“…The size of ice crystals plays a significant role in the rate of thawing. Samples from snap freezing treatment have smaller ice crystals than those treated at −70 °C and −20 °C (Zhang et al ., 2022; Zhao et al ., 2022). Smaller ice crystals thaw faster, which reduces the overall thawing time.…”

“…Smaller ice crystals thaw faster, which reduces the overall thawing time. Similar studies have reported the effect of the freezing method on thawing rate and time (Zhang et al ., 2022; Zhao et al ., et al ., 2022). The fastest thawing time and highest thawing rate were observed in the snap freezing method with ohmic thawing and double‐sided IR pre‐treatment.…”

“…During freezing, the protein's spatial structure changes and sulfhydryl groups oxidise, gradually disappearing. The slow freezing method applies mechanical pressure on the cells, increasing protein denaturation and large ice crystal formation in the intermuscular space, resulting in more damage to proteins (Zhao et al ., 2022). In contrast, fast freezing forms smaller crystals that damage proteins less, leading to fewer small peptides.…”

“…In this wavelength range, carbon‐nitrogen and carbon–oxygen stretching vibrations in the protein skeleton create changes in Raman spectra. Protein secondary structures such as α‐helix, β‐sheet, β‐turn and random crimp appear, respectively, in the 1650–1660 cm −1 , 1665–1680 cm −1 , 1680–1680 cm −1 and 1665–1660 cm −1 (Zhao et al ., 2022; Hu et al ., 2023). Table 4 shows the ratio of different secondary structures of turkey meat protein.…”

A systemic study on the effect of egg white protein and isomalto‐oligosaccharide mixture on the functional and gelation properties of Culter alburnus myofibrillar protein during long‐term frozen storage

“…The decrease in Ca 2+ ‐ATPase activity is related to the irregular aggregation and rearrangement of myosin heads induced by the unfolding of myosin conformational sites (Fig. 2) (Zhao et al ., 2022). Meanwhile, the irregular aggregation of Mfp accompanied the production of carbonyl groups, resulting in the reduction of sulfhydryl groups and a subsequent decline in Mfp gel‐forming capacity, thus producing an adverse influence on the texture, flavour and sensory attributes of the final product (Nikoo et al ., 2019; Jing et al ., 2022).…”