Effects of ultrasound-assisted heating on aroma profile, peptide structure, peptide molecular weight, antioxidant activities and sensory characteristics of natural fish flavouring.

This study deals with the production of natural fish flavouring using ultrasound-assisted
24 heating process. The effect of ultrasound pretreatment at different amplitudes (0, 15, 30,
25 and 45%) on the Maillard reaction rate, antioxidant activities, flavour profile, and sensory
26 characteristics of fish flavouring was investigated. Results showed that sonication
27 markedly accelerated the Maillard reaction rate, as evidenced by the modification of
28 peptide structure, a decrease in pH value, free amino acid content coupled with a rise in
29 browning intensity. Also, ultrasound pretreatment significantly enhanced the antioxidant
30 activities of fish flavouring (p ≤ 0.05). Moreover, sonication increased the type and
31 content of aroma compounds significantly. Sensory analysis revealed that ultrasound
32 pretreatment increased the fish-like and toasty aroma as well as umami and mouthfulness
33 attributes coupled with the reduction of the bitter taste of the fish flavouring. This result
34 was consistent with the GC-MS, electronic nose, cluster, and Partial Least Squares
35 Regression analysis (PLSR), which clearly showed that ultrasound pretreatment enhanced
36 the fish-like aroma, which was associated with the increase in aldehydes, ketones,
37 alcohols, thiophenes pyrazine, and furans content. Thus, it could be concluded that
38 ultrasound pretreatment, coupled with the thermal process, could be a promising process
39 for the production of natural fish flavouring with higher antioxidant activities.