Effect of different conching processes on the functional properties of chocolate: contribution of maillard reaction products and polyphenols

The aim of this study was to evaluate the evolution upon processing of the functional properties and the development of non enzymatic browning reactions in chocolate samples produced by two conching processes characterized by different time/temperature combinations, a Long Time Conching (LTC) and a Short Time Conching (STC). Aqueous extracts were used in order to evaluate the TEAC and the FRAP values, indices of the antiradical and reducing properties, respectively. The aqueous extracts were then submitted to both SPE separation, to obtain the phenolic fraction (PF) and the non-phenolic fraction (NPF), and to dialysis (DIAL). In order to unravel the contribution of the fractions obtained to the overall TEAC and FRAP properties, the content in total polyphenols and melanoidins as well as the radical scavenging and reducing properties were determined. The development of browning reactions was quite limited in both the conching processes based on the NPF content, whilst the content in total polyphenols increased upon processing, especially in the LTC samples, likely due to the formation of high molecular weight polymers. A similar result could be observed for both the antiradical and reducing properties of the aqueous extracts which increased upon LTC process. The contribution of the NPF to the functional properties resulted to be rather limited and accounted for a very low percentage (