Previous gutting was applied to fresh kutum (Rutilus frissi kutum) to study the effects of cold smoking on the changes of rancidity and fatty acid (FA) content of the gutted and ungutted smoked kutum stored at room temperature (25 ± 2C) for 60 days. To do so, proximate (protein, ash, moisture and lipid), chemical (peroxide value [PV], thiobarbituric acid-index [TBA-i], total volatile basic nitrogen [TVB-N] and FA profile) and pH analyses were carried out. The ungutting of kutum before smoking resulted in a higher degree of bacterial spoilage and oxidation during storage at room temperature, based on the results obtained from PV, TBA-i, TVB-N and FA content analyses. Moreover, pH as a critical factor on food spoilage showed a less decrease in smoked ungutted kutum during the 60-day storage. It is concluded that the gutting of kutum before cold smoking is recommended as a pretreatment for storage at room temperature.

Practical Applications

The results of this study can be applied to improve the existing methods of kutum processing. The findings show that the previous gutting has a proper effectiveness on the chemical quality, content of polyunsaturated fatty acids and nutritional value of cold-smoked kutum. These findings can be used by researchers as well as manufacturers in the economical preparation of cold-smoked fish products. Based on these results, suitable methods of smoking and preservation techniques can be developed to improve the shelf life of cold-smoked kutum in Iran.