Protein-flavour interactions in relation to development of novel protein foods

Proteins are known to interact with relatively small molecules such as flavour compounds and saponins, and may thus influence the taste perception of food. In this study, the interactions of flavour volatiles with pea proteins, and the effects of heat on these interactions were investigated. The presence of saponins, which are non-volatile flavour compounds, was also explored. Saponins are known to contribute to the bitterness in pea and were found to interact with proteins. Pea proteins, legumin (11S) and vicilin (7S), were used for interaction studies with aldehydes and ketones using static headspace-gas chromatography (SH–GC). The binding of various flavour compounds as a function of concentration was studied at pH 7.6 and pH 3.8. Vicilin binds both aldehydes and ketones at pH 7.6 and pH 3.8. Legumin only showed binding to aldehydes at pH 7.6 and no binding to aldehydes or ketones at pH 3.8. The effect of heat on vicilin-flavour interactions was studied at pH 7.6. Heating of vicilin seemed to lead to a decrease in the binding of aldehydes and ketones to the protein. In addition, the presence of saponins in hulled pea flour was identified by high performance liquid chromatography and mass spectrometry (HPLC–MS) and three groups of saponins, A, B and DDMP saponins were found to be present, with group B saponins dominating.