Improvement of antioxidant activity of Morchella esculenta protein hydrolysate by optimized glycosylation reaction

Morchella protein hydrolysate (MPH) is produced from an edible and medicinal fungus, Morchella esculenta (L.), and exhibits antioxidant activity. In order to further improve the antioxidant activity of MPH, glycosylation of MPH was conducted by applying response surface methodology via the Maillard reaction (MR). Optimum glycosylation conditions were confirmed as: xylose/MPH mass ratio of 3.7:1, pH 11.80, and reaction time 60 min. The glycosylation of MPH under these optimized conditions was characterized by Fourier transform infrared spectroscopy, fluorescence spectroscopy, and scanning electron microscopy. In vitro antioxidant activity tests showed that glycosylated MPH had significantly enhanced antioxidant activities compared to the native MPH, heat-treated MPH, or a MPH–xylose mixture. Collectively, these results indicate that glycosylation by the MR can improve the antioxidant activity of MPH, making it a novel source of natural antioxidants with excellent developmental prospects as a functional food.