Milk fat content is an important factor affecting the flavor of fermented dairy products. The effects of milk fat concentration (0–90) g·L−1 on
the changes of flavor-related compounds in the milk base fermented by Lactobacillus casei GBHM-21 were investigated. The amount of
some of the free fatty acids (FFAs) and free amino acids (FFAs) increased as the fat concentration increased, accompanied by a concomitant
increase of the quantities and intensities of volatile compounds (VCs). A substantial increase in long-chain fatty acids was observed,
whereas no significant effect on short-chain fatty acids was observed. The amount of the total FFA was linearly and positively correlated
with the total FAA. The most abundant group of VCs was ketones for low-fat samples and carbonyl acids for high-fat samples. The level of
FFA-derived ketones increased dramatically first and then reached a plateau, while FFA-derived carbonyl acids continuously increased.
These results provided valuable informative utilization of milk fat in the fermented industry.
Keywords: fermented milk base; free fatty acid; free amino acid; volatile compound; Lactobacillus casei