Physicochemical characteristics and microbial diversity of sous vide scallops (Chlamys farreri) during chilled storage

Abstract

This study investigated the impact of sous vide (SV) cooking methods on the physical and chemical characteristics as well as the microbial composition of scallops (Chlamys farreri) over a 30 days period of refrigerated storage. Scallop treatments were divided into two groups: CS (scallops vacuum-packed and then steamed for 30 min at 75 °C) and CK (scallops steamed for 15 min at 100 °C). With the increase in refrigeration time, the total volatile basic nitrogen (TVBN), pH, cooking loss, microbial content, and malondialdehyde (MDA) content gradually increased, while the water-soluble protein extraction rate and the myofibrillar protein (MP) extraction rate of the CS and CK samples significantly decreased. Notably, the SV steaming treatment effectively reduced microbial degradation of proteins, improved water retention of scallop samples, and maintained high MP extraction as compared to CK samples (MP content ranged from 1.09% to 2.50% in the CK group and 1.75%–3.33% in the CS group). During the late stages of refrigeration, conventionally cooked scallops (CK) were dominated by Pseudomonas and Psychrobacter, with the ability to produce biogenic amines, while SV steamed scallops were dominated by Psychrobacillus. Furthermore, a link was discovered between the microbial community and the physicochemical parameters.