Formation of Lentil Protein-tannic Acid Complexes Limits in Vitro Peptic Hydrolysis and Alters Peptidomic Profiles of the Protein

Food protein interaction with other biopolymers, such as tannic acids, within a food matrix can alter their structure and functionality. In this study, the nature of lentil protein-tannic acid (LPTA) interaction and itseffect on in vitro peptic hydrolysis were investigated. InLPTA mixtures containing 1% w/v LP and 0.001%–0.5% TA, a twenty-fold increase in particle size was observed in LPTA 0.5% compared to LPI, indicating aggregation. Static quenching of tryptophan residues within the protein hydrophobic folds were observed.Increasing TA content caused an overall increase in α-helix fractions. A 56.79% reduction in free aminonitrogen of LPTA 0.5%, relative to LPI, was observed after digestion. High molecular weight hydrolysates from LPTA 0.5% recorded slightly different amino acidprofile. This study showed that 0.5% w/v TA inducedprotein aggregation, reduced lentil protein digestibilityby hindering accessibility of pepsin to protein networkand modified amino acid pro