# Integrated Quality Assessment and Metabolomic Analysis of Dezhou Donkey Meat During Extended Chilled Storage

## TL;DR

This study examines how Dezhou donkey meat quality and chemical composition change during chilled storage, revealing factors affecting tenderness and color loss.

## Contribution

The study provides the first comprehensive metabolomic analysis of donkey meat during storage, identifying biomarkers for freshness and quality.

## Key findings

- Extended storage improved tenderness but reduced color stability after 14 days.
- Metabolomics revealed accumulation of lysophospholipids and amino acids linked to membrane breakdown and proteolysis.
- Depletion of antioxidants like acetyl-L-carnitine and cysteinylglycine correlated with color deterioration.

## Abstract

Donkey meat is valued for its nutritional quality, yet maintaining its freshness during chilled storage is challenging, particularly with respect to color stability, the underlying mechanisms of which remain unclear. To address this, the present study investigated changes in meat quality and metabolite profiles of Dezhou donkey meat stored at 0–4 °C for 21 days. While extended storage significantly improved tenderness due to muscle fiber degradation, it markedly reduced color stability, especially after 14 days. Using untargeted LC-MS/MS metabolomics, we observed an accumulation of compounds associated with membrane breakdown, proteolysis, and energy metabolism. Concurrently, key antioxidants were progressively depleted, which correlated with color deterioration. Pathway analysis further highlighted significant alterations in glycerophospholipid, amino acid, and glutathione metabolism. These findings provide a scientific basis for developing improved preservation strategies aimed at maintaining the color and overall quality of donkey meat.

This study aimed to elucidate the dynamic changes in meat quality attributes and metabolomic profiles of Dezhou donkey longissimus lumborum (LL) during extended chilled storage. Donkey longissimus lumborum (LL) muscles (n = 4) were vacuum-packaged 24 h post mortem and stored at 0–4 °C for 0, 7, 14, or 21 days, followed by a 5-day aerobic display. Meat quality parameters and microstructural characteristics were evaluated, and untargeted metabolomics was performed using liquid chromatography-tandem mass spectrometry (LC-MS/MS). Extended storage significantly improved tenderness (shear force decreased from 76.40 to 27.84 N; p < 0.05), concurrent with progressive muscle fiber degradation. However, color stability deteriorated markedly, with accelerated declines in redness observed beyond 14 days. Metabolomics analysis demonstrated that storage resulted in a substantial accumulation of lysophospholipids, free amino acids, and nucleotide degradation products, indicative of membrane deterioration, proteolysis, and ATP catabolism. Notably, acetyl-L-carnitine, cysteinylglycine (Cys-Gly), and nicotinamide exhibited progressive depletion, correlating with diminished antioxidant capacity and color deterioration. KEGG pathway enrichment revealed significant alterations in glycerophospholipid, amino acid, and glutathione metabolism. This study provides the first comprehensive metabolomic characterization of donkey meat during chilled storage, identifying potential biomarkers for freshness assessment and offering a scientific foundation for developing targeted preservation interventions.