Odour compounds in thermo-mechanically processed food based on pulse ingredients

This study investigates the effect of pulse flours (chickpea, lentil, lupin, yellow and green pea) on the formation of key volatiles with likely impact on the odour of sponge cakes compared to a wheat reference. Twenty molecules with an odour activity value of five or higher were determined from a wide variety of volatile compounds identified using headspace-solid phase microextraction/gas chromatography-mass spectrometry (HS-SPME/GC-MS) and quantified by internal isotope standards. While the majority of these originated from lipid oxidation, the remaining compounds were generated through Maillard reaction. Principle component analysis revealed that the lipoxidation-derived volatiles typically possessing green, fatty odours were mainly related to cakes made with lentil, chickpea, yellow and especially green pea flour. Among these, hexanal was assumed to be of substantial sensory importance based on its outstanding odour activity values. 3-Methylbutanal (malty, chocolate notes) was identified as most odour-active compound in all formulations and might have contributed to the overall flavour, in particular in wheat, green pea and yellow pea cakes. Moreover, lentil formulas were associated with 2-ethyl-3,5-dimethylpyrazine, which is known to be responsible for an earthy aroma. From these results it can be concluded that the raw material determines the potential to generate odour-active compounds during product development and mastering the reactions likely to occur might offer an opportunity to tailor the global flavour quality of food.