Quality Changes during the Steaming Process of Different Cut-Up Parts of Low-Salt Brined Grass Carp (Ctenopharyngodon idellus)

To investigate the effects of different steaming durations on the eating quality of different cut-up parts of brined grass carp (Ctenopharyngodon idellus) with 1.5% (m/m) salt and to assess its suitability for thermal processing.

The different cut-up parts of grass carp namely back, abdomen, belly and tail were brined at a 1.5% salt concentration for 30 min. After being steamed at 2100 W for 6, 9 and 12 min, each part was evaluated for cooking yield, color, sensory score, adenosine triphosphate (ATP)-related compounds, protein digestibility and molecular mass distribution of the digested products.

Compared to those steamed for 6 and 12 min, back and abdomen meat steamed for 9 min had significantly higher protein digestibility (P < 0.05). In comparison to steaming for 12 min, steaming for 6 min imparted tail meat higher overall sensory score and inosine monophosphate (IMP) content (P < 0.05). As the steaming time increased, the overall sensory score of tail meat significantly decreased, the color significantly deteriorated, becoming excessively red or yellow (P < 0.05) and the eating quality significantly declined. The redness (a*) and yellowness (b*) values of abdomen and belly meat steamed for 12 min were significantly higher than those of back and tail meat steamed for the same time (P < 0.05), and the eating quality notably decreased. Furthermore, the protein digestibility of belly meat significantly increased when steamed for 9 min compared to 6 min (P < 0.05). In summary, belly meat had better color and higher protein digestibility when steamed for 9 min.

The optimal steaming duration varies among different cut-up parts of low-salt brined grass carp. Prolonged steaming should be avoided to prevent color deterioration, reduction in protein digestibility, and loss of IMP.