Effects of frozen storage temperature on the quality and oxidative stability of bigeye tuna flesh after light salting

Abstract

SUMMARY Effects of frozen storage temperature on the quality and oxidative stability of lightly salted tuna were investigated. The bright and vivid colour became totally brown after 4 weeks at −20 °C and 8 weeks at −30 °C, where the a*/b* value decreased from 1.35 to 0.38 and 0.58, respectively. Discoloration and lipid oxidation occurred concurrently in lightly salted tuna flesh, and it was speculated that the oxidation of oxymyoglobin to metmyoglobin exacerbated lipid oxidation and vice versa. Storage at −40 °C or lower temperatures effectively suppressed the discoloration and maintained the high water‐holding capacity and unique textural properties of lightly salted flesh. It was attributed to the reduction in the conformational changes and particularly hydrophobic interactions among proteins, protecting the myoglobin from oxidative damages during frozen storage. Considering the quality maintenance and energy savings, storage at −40 °C was appropriate for lightly salted tuna flesh.

Physicochemical and microstructural mechanisms for quality changes in lightly salted tilapia (Oreochromis niloticus) fillets during frozen storage

“…The decreased content of active sulfhydryl groups was likely due to the oxidation of the sulfhydryl groups into disulfide bonds, which led to protein aggregation and denaturation 36 . After 14 and 28 days of storage, the content of active sulfhydryl groups in S3 group was significantly higher than that in other groups ( P < 0.05), which was ascribed to the formation of protein network mainly via hydrophobic interactions, 4,16 protecting the sulfhydryl groups from oxidation.…”

“…3 Lightly salted fish fillets characterized by juiciness and unique texture are becoming increasingly popular, especially among young consumers. 4 In an industrial context the fillets are always soaked in phosphate solution before freezing to improve their waterholding capacity. An excessive intake of phosphate is, however, harmful to health, affecting the balance of calcium and phosphorus in the body and causing calcium deficiency, especially for children.…”

“…High drip loss, dry and fibrous mouthfeel, and an unappealing appearance are among the common problems faced by the producers and consumers of related fish products 3 . Lightly salted fish fillets characterized by juiciness and unique texture are becoming increasingly popular, especially among young consumers 4 . In an industrial context the fillets are always soaked in phosphate solution before freezing to improve their water‐holding capacity.…”

Effect of freezing-thawing on the quality changes of large yellow croaker treated by low-salt soaking during frozen storage

“…During frozen storage, the a* value of the SFS group was significantly ( P < 0.05) higher than that of the LSS group, which might be related to the decrease in myoglobin content caused by protein oxidation. Although the mechanism of post-salting meat discoloration is not clearly, this might related to the reduced antioxidant capacity of the tissue and the effect of salt on myoglobin stability ( 27 ). The b* values of the SFS group were significantly ( P < 0.05) higher than that of the LSS group after frozen storage.…”

Insight into mechanism of quality changes in tilapia fillets during salting from physicochemical and microstructural perspectives

“…Salting is a traditional technique used in the aquatic processing industries to prevent quality deterioration for some fish species ( Jiang et al, 2019a , Jiang et al, 2023 ). Since excessive sodium intake causes hypertension, cardiovascular disease, and other health problems ( He, Tan, Ma, & MacGregor, 2020 ), NaCl is primarily added at a relatively low level to improve the quality attributes (such as water-holding capacity, and springiness), and to modify the functionalities of muscle proteins with the general application of cryogenic technology to guarantee the shelf-life of aquatic products ( Inguglia et al, 2017 , Jiang et al, 2019b , Jiang et al, 2022 , Shen et al, 2020 ).…”