Evaluation of FAAs and FFAs in yogurts fermented with different starter cultures during storage

Free amino acid (FAA) and free fatty acid (FFA) profiles influence the nutritional and biological value and desired flavour of yogurt. The differences in FAA and FFA profiles of three types of yogurts fermented with different and common lactic acid bacteria (LAB) combinations, as well as their variations during storage, were elucidated. The FAAs and FFAs were determined using an automatic amino acid analyzer and GC–MS, respectively. The profiles of FAAs and FFAs of the yogurts were significantly different and various LAB combinations resulted in differences in the changes in FAAs and FFAs during yogurt storage. The unsaturated fatty acids content in probiotic yogurts were higher in comparison with the common one, further confirming the greater health potential of probiotic yogurt. Storage of yogurt had the potential of increasing total free amino acids and short-chain fatty acids content and decreasing saturated fatty acids and medium-chain fatty acids contents. The appropriate storage condition has a positive impact on yogurt quality. This study is of relevance to both academia and the dairy industry.