Effect of ultrasound pretreatment and Maillard reaction on structure and antioxidant properties of ultrafiltrated smooth-hound viscera proteins-sucrose conjugates

- LMW peptides were elaborated by UF of smooth hound viscera hydrolysates.
- MRPs were elaborated using LMW peptides-sucrose conjugation.
- Physical changes of MRPs were proportional to the heating time increase.
- US pre-treatment was found to accelerate the MR rate.
- US-treated MRPs exhibited good sensory scores and antioxidant capacities.

The effect of ultrasound (US) pre-treatment on the evolution of Maillard reaction (MR), induced between low molecular weight (LMW) peptides and sucrose, was studied. LMW peptides (<1 kDa) were obtained by the ultrafiltration of smooth hound viscera protein hydrolysates, produced by Neutrase, Esperase and Purafect. MR was induced by heating the LMW peptides in the presence of sucrose for 2 h at 90 °C, without or with US pre-treatment. During the reaction, a marked decrease in pH values, coupled to the increase in colour of the Maillard reaction products (MRPs), were recorded. In addition, after sonication, the glycation degree was significantly enhanced in Esperase-derived peptides/sucrose conjugates (p < 0.05). Moreover, results showed that thermal heating, particularly after US treatment, reduced the bitter taste and enhanced the antioxidant capacities of the resulting conjugates. Hence, it could be concluded that US leads to efficient mixing of sugar-protein solution and efficient heat/mass transfer, contributing to increase the MR rate.

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