Comparative study of various methods used for bitterness reduction from pea (Pisum sativum L.) protein hydrolysates

Pea protein hydrolysates (PPH), promising raw materials for health products, have not been well embraced by consumers because of their noticeable bitter taste. To solve this difficulty, this study examined the effects of three food-grade mild methods, including Flavorzyme, sec-butanol and β-Cyclodextrin (β-CD) at various concentrations on PPH debittering. Sensory evaluation, free amino acids (FAAs), molecular weight (MW) analysis revealed that PPH solutions (100 g/L) under subsequent treatment of sec-butanol (1:4, mL/mL) and β-CD (15 g/L) had the lowest bitterness score (0.3) and bitterness response value of electronic tongue (1.2), as well as the lowest contents of bitter FAAs and low molecular weight peptides (p < 0.05). As evidenced by FTIR and NMR spectra, the interaction of the hydrophobic region of hydrolysates with β-CD resulted in the formation of an inclusion complex. Furthermore, the observed loss of angiotensin-converting enzyme (ACE) and dipeptidyl peptidase-IV (DPP-IV) inhibition activities (p < 0.05) could be compensated for by increasing the amount of PPH. Thus, the combined debittering treatment offers a potential process for the production of PPH with acceptable bitterness intensity and ensured usability.