On the role of lactones in the overall aroma of milk chocolate and their formation during processing

The amount of milk powder used in the recipe of chocolate has a significant impact on the aroma. However, there was only little information which compounds cause the difference in the overall aroma compared to the dark chocolate (DC). By applying the Sensomics concept, odor-active compounds were identified in milk chocolate (MC) and DC. The development of new stable isotope assays for lactones allowed the verification that these compounds significantly influenced the overall aroma of MC even in subthreshold concentrations. Studies on the stability of lactones by NMR showed a clear degradation of delta-nonalactone to the corresponding hydroxy acid by contact with water; i. a. the determination of odor thresholds in water shows incorrect results.