LC-ESI-QTOF-MS identification of novel antioxidant peptides obtained by enzymatic and microbial hydrolysis of vegetable proteins

•Wheat, emmer, lupine, pea flour were hydrolyzed by enzymes and lactic acid bacteria.•Fractions of hydrolysates enhanced the antioxidant activity of the substrates.•75 vegetable antioxidant peptides were identified by LC-ESI-QTOF-MS.•13 peptides were selected, synthesized and analyzed for antioxidant properties.•4 peptides were able to scavenge common radicals and to inhibit lipid peroxidation.

Bioactive antioxidant peptides are more and more attracting the attention of food manufacturers for their potential to transform food in functional food, able to prevent a variety of chronic diseases associated with oxidative stress. In the present study proteins extracted from different vegetable sources (KAMUT® khorasan wheat, emmer, lupine and pea) were hydrolyzed with commercial enzymes and Lactobacillus spp. strains. Hydrolysates were separated by size exclusion chromatography and purified fractions were analyzed for their antioxidant activity. Peptides from the fractions with the highest activity were identified by nanoLC-ESI-QTOF-MS and thirteen peptides were selected for synthesis on the basis of their sequence. Four peptides (VLPPQQQY, TVTSLDLPVLRW, VTSLDLPVLRW, FVPY) were found able to scavenge superoxide anion and hydroxyl radicals, organic nitro-radicals (ABTS, DPPH) and to inhibit lipid peroxidation. The impact of this work is targeted to add hydrolysed vegetable proteins to reformulated functional food or to produce health-promoting ingredients and nutraceuticals.