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

The objective of current study was to investigate the effects of whey protein coating on the quality of common kilka during frozen storage period. For this study, common kilka was coated with 12% whey protein concentration. Also, non- coated kilka was used as a control sample. Coated and non-coated samples were then stored at -18 oC for six months. Bacterial, chemical and sensory properties of the samples were determined in each month. Results showed that total bacterial counts and Staphylococcus bacteria count were lower in the test samples compared to the control samples. Coliform, Escherichia coli and Pseudomonas bacterial contamination were negative till the end of the storage period in the covered samples. Chemical factors consisting of humidity, protein, lipid, ash and calorie were higher in the test samples compared to the control samples. Peroxide value, free fatty acids, thiobarbitoric acid, TVB-N and pH were lower in the test samples. Sensory tests had a better quality in the test samples compared to the control samples. No statistically significant decreases were observed in chemical factors in the covered samples compared to the control samples (p<.05). In sensory specifications, there was a significant difference between the covered samples and the control samples (p<.05). According to the results of experiments and statistical analysis, the covered samples had a favorable quality till the end of the storage period but the control samples had lost their quality.