# Energy Processes During Rigor Mortis in the Adductor Muscle of the Lion’s Paw Scallop (Nodipecten subnodosus): Effects of Seasonality and Storage Temperature

## TL;DR

This study examines how storage temperature and season affect energy changes in scallop muscles after death, influencing their quality and shelf life.

## Contribution

The study reveals how moderate refrigeration can delay rigor mortis and improve scallop quality during storage.

## Key findings

- Storage at 0 °C caused rapid ATP depletion and accelerated energy collapse in scallop muscles.
- Moderate refrigeration at 5 and 10 °C delayed rigor mortis and preserved muscle texture and appearance.
- Seasonality significantly influenced metabolite levels, with winter showing higher initial ATP concentrations.

## Abstract

The lion’s paw scallop (Nodipecten subnodosus) is a high-value mollusk species cultivated in northwestern Mexico, but its postmortem biochemical changes during storage are still poorly understood. This study investigated the effect of seasonality, storage temperature, and transportation on energy-related metabolites associated with rigor mortis in the adductor muscle. Scallops were stored at 0, 5, and 10 °C for 48 h across all four seasons, and the concentrations of ATP, ADP, AMP, glycogen, arginine phosphate, and arginine were quantified. The adenylate energy charge (AEC) was also determined in freshly harvested and transported scallops. The results showed that ATP depletion and AEC decline were strongly affected by storage temperature and seasonality, with significant implications for the postharvest quality and shelf life of this species.

The lion’s paw scallop (Nodipecten subnodosus) is a commercially valuable pectinid whose postharvest quality strongly depends on storage and handling conditions. This study investigated the combined effects of seasonality, postmortem time, and storage temperature on energy metabolism in the adductor muscle, focusing on metabolites associated with rigor mortis and freshness. Adult scallops (~10 cm shell height) were harvested in four seasons (spring, summer, autumn, winter), transported under commercial conditions for approximately 2 h, and stored at 0, 5, and 10 °C for 48 h. Muscle samples were collected every 8 h and analyzed for ATP, ADP, AMP, glycogen, arginine phosphate (Arg-P), and free arginine using HPLC and enzymatic assays. In addition, the adenylate energy charge (AEC) was determined in freshly harvested and post-transport specimens. Initial ATP concentrations ranged from 4.2 to 6.5 µmol/g, with higher levels in winter, while Arg-P varied from 3.1 to 4.8 µmol/g. Seasonality significantly influenced all metabolites except arginine, and transport markedly reduced ATP and AEC, particularly in spring and autumn. Storage at 0 °C resulted in rapid ATP depletion (<1.0 µmol/g within 12 h) and AMP accumulation (>3.0 µmol/g), indicating accelerated energy collapse. In contrast, scallops stored at 5 and 10 °C maintained ATP levels above 2.5 µmol/g for up to 24 h, delaying rigor mortis, reducing postmortem contraction, and preserving muscle texture and appearance. Overall, these findings demonstrate that moderate refrigeration represents a physiologically suitable and technologically advantageous strategy to optimize scallop postharvest handling, extend shelf life, and enhance product quality for the fresh seafood market.