Comparative study of the biochemical changes and volatile compound formations during the production of novel whey-based kefir beverages and traditional milk kefir

►Most of the lactose present in milk was metabolized within 48 h. ►Volatile compounds were important to the flavours of these novel beverages. ►Higher alcohols increased from the beginning until the end of the fermentation. ►Ethyl acetate was detected during milk, CW and DCW fermentations by kefir grains. ►The use of DCW in kefir fermentation can be considered as a new whey valorisation strategy.