Effects of Precooling with Slurry Ice on the Freshness of Farmed Perch (<i>Lateolabrax japonicus</i>) during Logistics Process
Weiqing Lan, Wanjun Zhang, Jiali Liu, Jing Xie
Abstract
The effects of precooling with slurry ice on quality changes of fresh farmed perch (Lateolabrax japonicus) during circulation were investigated. The basic component (ash, moisture, crude fat, and protein content), microbial (total viable counts, TVC), physicochemical (total volatile basic nitrogen, TVB-N), water-holding capacity (WHC), color difference indexes, and sensory evaluation were analyzed periodically. Scanning electron microscope (SEM) and low field nuclear magnetic resonance (LF-NMR) were measured in the experiments. The results showed that it took only 25 min for fresh perch to be chilled to 0°C with slurry ice (SI), which was one half of the time for samples treated with crushed ice. For the quality analysis, TVC and TVB-N in farmed perch muscle treated with SI were lower, and samples precooled with SI kept the color and sensory quality of fish muscle from day 4 better than that of crushed ice (P < .05). Meanwhile, the WHC and bound water content (T22) in muscle of slurry-iced samples were higher than that of crushed-iced samples. The results of SEM also confirmed that precooling with SI could keep the structural stability of muscle tissue. Therefore, SI is an efficient method for precooling and could be worthy of further study in short-distance transportation.