Postmortem biochemical and textural changes in the sea cucumber Stichopus japonicus body wall (SJBW) during iced storage

Abstract

Biochemical, chemical and textural changes in postmortem Stichopus japonicus body wall (SJBW) were evaluated during iced storage for 8 days. Triphosphate (ATP) and its breakdown products, K-value, total volatile basic nitrogen (TVB-N), microbiological,pH, water-holding capacity (WHC), texture, protein degradation and cathepsin activities were monitored. K-value increased linearly from 4.83 ± 0.57% at day 0–18.85 ± 2.09% at day 2, 28.15 ± 2.05% at day 4, and 48.16 ± 1.91% at day 8. Spoilage indicator TVB-N (mg/100 g) increased from 4.03 ± 0.28 to 12.68 ± 0.56 during the same time span. Textural parameters (e.g., hardness, chewiness, springiness and adhesiveness) all followed a declining trend over the storage duration. The WHC decreased from 67.71 ± 4.03% at day 0–54.60 ± 6.14% at day 2 and 48.57 ± 12.68% at day 8. SDS-PAGE results indicated that actin was degraded at day 6. Both cathepsin B and L increased throughout the iced storage, suggesting that cathepsin B and L played important roles in the deterioration of SJBW quality. The overall results indicated that SJBW was suitable to be consumed raw within the first 2 days, and to be processed in no more than 4 days.