Insights into the quality changes of edible sea urchin (Echinus esculentus) gonads during ice storage

Abstract

The study aimed to assess the quality changes of E. esculentus gonads during 14-days of ice storage. Microbial quality and community composition succession were examined using both culture-dependent and independent methods. Additionally, the chemical profile, including spoilage metabolite production, proximate composition, fatty acids and amino acids distribution, was investigated. Colorimetric and texture parameters were also assessed. Microbial counts were relatively stable until day 4, followed by rapid growth, reaching 7.3 ± 0.1 log CFU/g on day 8 for psychrotrophic counts. Pseudomonas emerged as the primary specific spoilage organism, followed by Photobacterium and Psychrobacter. Concurrently, inosine, hypoxanthine and biogenic amines formation correlated with the rapid microbial proliferation. The fresh gonads' lipid consisted of 29.4 ± 1.0% SFA, 18.7 ± 1.0% MUFA and 46.5 ± 2.7% PUFA, with no significant changes up to day 8 of ice storage. The initial ratio of essential to non-essential amino acids was 62.3 ± 1.8% and declined during storage, while the concentration of free amino acids significantly increased after 4 days of ice storage. Notable shifts in the lightness and texture parameters coincided with the water content reduction. Overall, the results indicated satisfactory gonad quality for up to 4 days of ice storage, beyond which significant degradation and spoilage processes were initiated. This study could offer insights to enhance comprehension and prolong the quality stability of gonads.