Characterization of antioxidant activity and volatile compounds of Maillard reaction products derived from different peptide fractions of peanut hydrolysate

Five peptide fractions isolated from peanut hydrolysate were purified by ultrafiltration and gel filtration chromatography. Their reaction degrees with glucose or lecithin in Maillard reaction were compared. Glucose consumption, oxygen radical absorbance capacity (ORAC) values and volatile compounds composition of peanut hydrolysate (PH) and its peptide fractions after thermal treatment and Maillard reaction were evaluated. Results revealed that the peptide fraction of 1–3 kDa showed the highest antioxidant activity. The peptides with smaller molecular weight showed a higher reaction degree to increase antioxidant activity and to produce more volatile compounds through Maillard reaction. Analysis of molecular weight distribution showed that peptide degradation and cross-linking simultaneously occurred during the Maillard reaction. In addition, lecithin addition to peptide–glucose system caused a significant increase of antioxidant activity possibly due to more nitrogen-containing compounds formed.

► Degradation and cross-linking occurred simultaneously during Maillard reaction.
► Peptides of 1–3 kDa showed the highest antioxidant activity.
► The shorter peptide chain showed the higher reaction degree in Maillard reaction.
► Small peptides increased significantly antioxidant activity in Maillard reaction.