Wenfu Hou,Yile Lin,Yujie Zhang,Tingting Liu,Juan Du,Yang Yi,Hongxun Wang
This study investigated the effect of 0.8% (m/v) kojic acid treatment on changes in the microstructure and myofibrillar protein of duck meat covered with oxygen-permeable polyvinylchloride (PVC) film (9 ± 0.5 µM) during superchilled storage (−1.65 ± 0.5°C). The superchilled samples exhibited wider gaps between muscle fibers at 5 weeks storage compared with kojic acid–treated groups. Based on the variation of water status, the water-holding capacity decreased significantly ( p < 0.05), and bound water and immobilized water were gradually converted into free water during superchilled storage. For kojic acid–treated samples, however, no major changes were observed with respect to muscle structure, water status, and protein degradation at 6 weeks. The 0.8% (m/v) kojic acid treatment increased the water-holding capacity, reduced carbonyl content and protein degradation, and decreased the α-helix contents loss of myofibrillar proteins. Kojic acid treatment effectively protected myofibrillar protein structure from being destroyed during superchilled storage, suggesting that this method was a good way to reduce protein oxidation and prolonged its shelf life.
The active coatings supplemented with epigallocatechin gallate (EGCG) (0.16 %, 0.32 %, and 0.64 %, respectively) combined with superchilling storage (−3 ± 0.2 °C) were used to reduce hydrogen peroxide (H 2 O 2 ) content, and inhibit lipid and protein oxidations of large yellow croaker during 42 days of superchilling storage. EGCG coatings delayed lipid and protein oxidations by inhibiting the generation of H 2 O 2 , malondialdehyde (MDA) and carbonyl groups, and maintaining a higher Ca 2+ -ATPase activity and sulfhydryl content. We also observed that EGCG treatments maintained myofibrillar organized secondary structure by keeping higher α-helix content, and also stabilized tertiary structure during superchilling storage. Low-field nuclear magnetic resonance (LF-NMR) revealed that EGCG treatments might improve the association of water molecules with protein for fixed water. In addition, sodium dodecyl sulfate–polyacrylamide gel electrophoresis (SDS-PAGE) and scanning electron microscope (SEM) images both showed that these treatments could delay the myofibrillar degradation of fresh fish. Overall, we report that the active coatings containing EGCG treatments protect the lipid and protein of large yellow croaker during superchilling storage.
The effect of gum tragacanth (GT) and sodium alginate (SA) active coatings incorporated with epigallocatechin gallate (EGCG, 0.16%, 0.32% and 0.64%, respectively) on the quality of large yellow croaker fillets was evaluated during superchilling storage at -3 ℃ for 42 days. The results revealed that the GT-SA-EGCG active coatings delayed the microbial spoilage via reducing the numbers of total viable counts, Pseudomonas spp. and psychrophiles bacteria, retarded degradation of the physical properties of water holding capacity, cooking loss, color, odor and texture. GT-SA-EGCG coatings could also maintain the fillets’ freshness by keeping lower total volatile basic nitrogen, K value and histidine content, inhibiting myofibrillar protein degradation during superchilling storage. These results suggested that the active coatings embedded with GT-SA-EGCG could be used as a preservative to enhance the quality of large yellow croaker and prolong the shelf life by 7-14 days during superchilling storage at -3 ℃.
危险品化学品经营许可证（带存储）