Comparison and optimisation of headspace methods for the analyses of oxidation related off-flavour compounds in plant protein concentrates and infant formula

The aim of this study was to develop an effective and fast method for key-marker compound analysis of available oxidation related off-flavours, both in dry protein powder and in protein powder dispersed in water. Four different headspace techniques (static headspace (HS), dynamic headspace (DHS-ITEX), and solid phase microextractions (HS-SPME, HS-Arrow)) were compared under different extraction conditions. HS-Arrow in combination with true capillary cold trapping showed to be most sensitive and an efficient extraction technique for a wide range of oxidation related HRGC-MS analyses. Although HS-Arrow in combination with GC-MS is a relative fast technique for the analyses of the key aroma compounds of plant protein related products and infant formula, still some key aroma compounds could not be detected. Especially 2,4,7-decatrienal, an important key compound to detect “fishy” off-flavours in products with added DHA like infant formula, is missed by these four headspace techniques.