Antioxidant capacity of Maillard reaction products in the digestive tract: An in vitro and in vivo study

The release of biscuit Maillard reaction products (MRP) with antioxidant capacity was compared by in vitro and in vivo studies. Antioxidant determinations were performed by DPPH, FRAP and ICRED. Results indicated that an intense heat treatment on biscuits increases the amount of MRP with antioxidant capacity (p < 0.05). Besides, a low amount of antioxidant compounds was obtained after enzymatic digestion, whereas the highest proportion was released by colonic bacteria. Moreover, a high amount of non-released antioxidant compounds remained in faeces of Wistar rats; this was only predicted by in vitro ICRED determination. In addition, an increase in the stool amount and in the cecum weight/body weight ratio was observed in animals fed with a diet enriched in MRP (p < 0.05), which indicated a possible prebiotic activity. In conclusion, the in vitro digestion/fermentation procedure combined with ICRED determination would be a useful methodology to predict the release of antioxidant MRP in vivo.