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The quantification of protein bound Maillard reaction products (MRPs) is still a challenge in food chemistry. Protein hydrolysis is the bottleneck step: it is time consuming and the protein degradation is not always complete. In this study, the quantitation of free amino acids and Amadori products (APs) was compared to the percentage of blocked lysine by using chemometric tools. Eighty thermally treated soybean samples were analyzed by mass spectrometry to measure the concentration of free amino acids, free APs and the protein-bound markers of the Maillard reaction (furosine, Nε-(carboxymethyl)-L-lysine, Nε-(carboxyethyl)-L-lysine, total lysine). Results demonstrated that Discriminant Analysis (DA) and Correlated Component Regression (CCR) correctly estimated the percent of blocked lysine in a validation and prediction set. These findings indicate that the measure of free markers reflects the extent of protein damage in soybean samples and it suggests the possibility to obtain rapid information on the quality of the industrial processes.

In this study, an artichoke stem powder (ASP) was used at three concentrations (3%, 6% and 9%) in the formulation of new breads. The bioaccessibility of polyphenols and cynaropicrin from the ASP-enriched breads was evaluated in vitro by using a digestion model combined to high resolution mass spectrometry analysis. The overall total antioxidant capacity of the bioaccessible and unsolubilized fractions obtained during the intestinal steps and the potential ability to modulate alpha-glucosidase activity were tested. Data showed that 82% of totally bioaccessible polyphenols and 74% of cynaropicrin were released during the duodenal digestion whereas 88% of caffeic acid was released in the colon step. The antioxidant capacity and the alpha-glucosidase inhibitory activity of the duodenal extract correlated with the amount of ASP in the bread. Data demonstrated that ASP might be a valuable functional ingredient to create a reducing environment in the intestine and to partially modulate glucose metabolism.