Effect of gutting on microbiological, chemical and sensory properties of Urechis unicinctus stored in ice and at chill temperature

Abstract

This study investigates the effect of gutting on quality characteristics of Urechis unicinctus, stored in ice and at chill temperature (4℃), in terms of sensory assessment, total volatile basic nitrogen, biogenic amines and microbial changes. The gutted and ungutted groups were kept in ice (T1-gutted, T2-ungutted) and at chill (4℃) temperature (T3–gutted, T4-ungutted). The study revealed that gutting worsened the sensory quality (as indicated by hardness, cohesiveness, springiness and chewiness) of all samples and that samples kept at 4°C scored lower than those kept in ice. Total Volatile Basic Nitrogen registered the highest values in gutted samples, exceeding the acceptable limit after 1 day for the T3, and 12 days for T1 samples, respectively. For ungutted samples the threshold value of 30 mg/L has been exceeded after 4 days for T4, and 14 days for T2 samples. In the present study, eight biogenic amines were analyzed; tryptamine and histamine were not detected all the time. The total concentration of biogenic amines in gutted U. unicinctus was significantly higher in comparison with ungutted groups starting from the 8th day, for samples stored in ice, and from the 3rd day for samples kept at 4℃ (p < 0.05). However, the concentration of biogenic amines did not reach the allowable limit, even the samples were unacceptable due to high values of total viable count. Therefore, limits of biogenic amines available for fish are not suitable for U. unicinctus. Sensory scores were significantly correlated with Total Volatile Basic Nitrogen and Total Viable Count in all four groups (p < 0.05). Combined results of this study indicated that shelf life of T1, T2, T3 and T4 were 6, 7, 1 and 4 days, respectively. Gutting had a little effect on the storage of U. unicinctus stored in ice, but obviously shortened the shelf life of samples when stored at 4℃.