Rheological and microstructural properties of beef sausage batter formulated with fish fillet mince.

Rheological properties and microstructure of beef meat sausage batter, incorporated with different percentages of fish fillet mince (5 %, 20 %, 35 % and 50 %), were investigated and compared to the control (0 % fish). By increasing the proportion of fish fillet mince to the sausage formula up to 35 % and 50 %, hardness was increased by 40 % and 16 %, respectively, (P < 0.05), whereas, cohesiveness and springiness showed no significant differences (P > 0.05). In terms of temperature sweep test, storage modulus (G') of control sample faced a substantial slop from 10 °C to 58 °C, corresponding to the lowest magnitude of G' at its gelling point (~58°), but completed at around 70 °C, as same as the other treatments. Whereas the gelling point of batter sample with 50 % fish mince remained at nearly 42 °C, which was remarkably lowest among all treatments, indicating the better gel formation process. SEM micrographs revealed a previous orderly set gel before heating in all treatments whereas after heating up to 90 °C gel matrices became denser with more obvious granular pattern and aggregated structure, specifically in sample with 50 % fish mince. In conclusion, addition of fish mince up to 50 % into beef sausage formula, positively interacted in gel formation process, without diminishing its rheological properties.