Impact of ternary NADES prepared from proline, glucose and water on the Maillard reaction: Reaction activity, Amadori compound yield, and taste-enhancing ability

This study employed proline, glucose, and water to prepare natural deep eutectic solvents (NADES) through heating and stirring. The Maillard reaction was then performed, producing a high yield of Amadori rearrangement product (ARP) and physicochemical properties of NADES were examined for impacts on the reaction. Water had a dual function by promoting the formation of hydrogen bonding networks within the NADES when present at less than 15%, and also working as a diluting agent that could potentially disturb its structure when exceed 15%. These changes further affected the subsequent Maillard reaction, especially the ARP accumulation (reached the highest when water content was 15%). Correlation analysis shows strong positive viscosity-ARP and negative water activity-ARP correlations within a range. Moreover, the product (rich in ARP) remarkably enhanced umami and saltiness. This finding provides insights into modulating the Maillard reaction by adjusting NADES properties, demonstrating feasibility of this approach for flavor enhancer development.