Aroma profile development of intermediate chocolate productsI. Volatile constituents of block-milk

Block-milk or white crumb is an intermediate product used in the manufacture of white chocolate and milk chocolate and it is produced from a mixture of concentrated milk and sugar. Volatile compounds of block-milk samples at different stages in the manufacturing process were investigated by dynamic headspace GC–MS. The changes in aroma profiles during processing were evaluated using similarity indices and a multidimensional scaling technique. These methods allow a better use of the information contained in the GC data. The results clearly point out the short intense heating step as the key step in the formation of the aroma profile of block-milk. During this step many volatiles are formed due to autoxidative and Maillard reactions. This is consistent with a decrease in the lactose level concomitant with an increase in the lactulose level following the heat treatment, as evaluated by HPLC analysis.