Effects of whey protein edible coating on bacterial, chemical and sensory characteristics of frozen common Kilka(Cluponellia delitula)

The objective of the current study was to investigate the effects of whey protein coating on the quality of common Kilka during frozen storage. For this study, common Kilka was coated with 20% whey protein concentration. Non- coated Kilka also was used as a control. Coated and non-coated samples were then stored at -18 °C for six months. Bacterial, chemical and sensory properties of the samples were determined in each month. Results showed that Coliform, Escherichia coli and Pseudomonas bacteria contaminations were negative until the end of storage period in the covered samples. Total bacterial counts and Staphylococcus bacteria count were lower in the test samples compared with the control samples. Humidity, protein, lipid, ash and calorie contents were higher in test samples as compared with the control samples, while peroxide value, free fatty acids, thiobarbitoric acid, TVN and pH were lower in test samples. Taste, odor, color, tissue and overall acceptability were studied in the test and control samples. These specifications had a better quality in test samples compared with the control ones. These factors showed a significant difference in the uncoated samples (control) (p < 0.05). Significant decrease was observed in bacterial counts in the covered and control samples. According to the statistical analysis in sensory specifications, there was a significant difference between the covered samples and the control ones (p < 0.05). According to the results of experiments and statistical analysis, the covered samples had a favorable quality until the end of storage period but the control samples had lost their quality after three months.