Properties of Fish Sausages Containing Common Carp (Cyprinus carpio) Roe Oil and Defatted Roe Protein Hydrolysate during Refrigerated Storage

Influence of emulsified or non-emulsified common carp roe oil (CRO) and carp defatted roe hydrolysate (CDRH) on properties of crucian carp (Carassius auratus) sausages was determined during 30-day storage at 4°C. Sausages containing CRO and CDRH were lighter and had better textural properties including hardness, gumminess, and chewiness. These textural attributes were significantly higher in the sample prepared with pre-emulsified CRO and 7 g/100 g CDRH (p < 0.05). The sausages fortified with CDRH also presented better microstructure, as evidenced by fewer voids and smaller oil droplets. When incorporated at 7 g/100 g, CDRH could significantly reduce microbial spoilage in sausages in terms of the total viable count and the psychrophilic bacterial count (p < 0.05); however, pre-emulsification had no significant effect on antibacterial activity of hydrolysate in the samples (p > 0.05). Sausages with pre-emulsified roe oil and 7 g/100 g hydrolysate were more resistant against lipid oxidation and had a higher level of polyunsaturated fatty acids, especially docosahexaenoic acid and eicosapentaenoic acid after 30 days of storage at 4°C. Furthermore, the sausages with pre-emulsified CRO and 7 g/100 g CDRH exhibited better organoleptic properties at day 30.