Effects of Brining Conditions on Weight Gain in Herring (Clupea harengus) Fillets

Salted herring is an important product category in many European countries. Reduced need for salt as a preserving agent and the increased emphasis on less salt in the human diet has changed the basis for the traditional processing of these products. This has led to significant changes in the processing conditions and in the characteristics of the salted products. In this perspective, the effects of different brine concentrations (10.0%, 16.5%, and 25.5%), brining temperatures (3.5 °C and 17.5 °C), the presence of skin or not on the fillets, and brining time (1, 2, 3, 4, and 7 d) were investigated on the weight gain (%) and final salt content (%) of herring (Clupea harengus). A significant (P < 0.001) higher weight gain of the fillets were observed at the lowest brining temperature (3.5 °C) compared with at the higher temperature (17.5 °C), independently of brine concentration and brining time. Increased brine concentration and skinning of the fillets caused the weight gain to significantly decrease (P < 0.001) and increase (P < 0.001), respectively. After 1 d of brining, the weight gain was in the range of 10% to 12% for both brining temperatures, and at the lowest temperature, the weight gain increased significantly (P < 0.001) as a function of brining time. At the higher temperature, no further significant increase in weight was observed from 1 to 7 d of brining. It is concluded that the weight gain in herring fillets brined according to the present commercial practice is significantly affected by temperature, brine concentration, brining time, and the presence or not of skin on the fillets and that the weight gain may be of high magnitude.