Title: The quality changes in smoked and dried fresh water sardine (Rastrineobola argentea) and marine pelagic fish (capelin) as influenced by processing methods
Abstract
Lipid oxidation changes can result in production of repugnant flavour, destruction of valuable nutrients and even production of toxic compounds. The effects of different drying and smoking methods on lipid oxidation and microbial growth of fresh water sardine and marine pelagic fish (capelin) during processing and storage were investigated. The level of lipid oxidation resulting in formation of fluorescent compounds, free fatty acid and other primary, secondary and tertiary oxidation products was tested to assess the quality of sardine and capelin after processing and during storage. In addition to lipid oxidation measurement, microbial quality was analysed. The results showed that cold smoking of capelin accelerated lipid oxidation observed by increases in lipid hydroperoxides (PV) and free fatty acid (FFA) as well as in the development of fluorescence compounds (δFor and δFaq). Hot smoking was found to be good in destroying and limiting microbial growth in both capelin and sardine after processing and during storage. However, storage time had no effect on salt and water content; rather affected positively the microbial growth and lipid oxidation. For the same processing method, ungutted capelin influenced positively microbial growth and FFA after processing and during storage. This study also revealed high rate of lipid oxidation and microbial growth to sardine locally dried on rocks and sands, indicating poor quality of the product.