Interaction of peptides obtained from the enzymatic hydrolysis of soybean meal with cyclodextrins: an evaluation of bitterness reduction

Enzymatic hydrolysis improves the functional and nutritional characteristics of soybean meal proteins. However, the presence of hydrophobic peptides can cause an intense bitterness to the hydrolysate, which is deleterious in terms of final product taste. In this paper we evaluate the interaction of peptides employed for the enzymatic hydrolysis of soybean meal with alpha-, beta- and gamma-cyclodextrins, aiming to reduce the bitter taste. Each cyclodextrin was added in mass fractions of 1.5, 2.0 and 2.5% in a hydrolysate of soybean meal prepared with enzyme Alcalase(A (R)) 2.4 L at 1% concentration (protein/protein). In order to identify possible interactions between the components, several instrumental techniques were employed. NMR H-1 spectra evidenced strong interactivities between the peptides' aromatic and aliphatic regions and the cyclodextrins' internal cavities. Analysis by an electronic tongue system showed that the addition of alpha- and beta-cyclodextrins to the hydrolysate, at concentrations 1.5 and 2.0% (w/w), respectively, induced the greatest difference with regard to control hydrolysate. The difference was also sensory perceptible to untrained tasters in a bitterness ranking test, and reveal that the treatment was efficient in reducing bitterness compared to the control samples, indicating this method as a suitable approach for masking bitterness in soybean hydrolysates.