**Abstract**

Lactic acid bacteria are of great importance in the production of yogurt worldwide, yet very little is still known about the mechanisms of aroma formation in foods subjected to lactic acid fermentation. However, advances in the Adolfsson development of instrument methods have made it possible to avoid some of the difficulties in extracting flavoring substances from the otherwise complex matrix of lactic acid products. In this chapter, we present recent developments related to the impact of yogurt starter cultures on the production of the aromatic components in yogurts. In addition, we examine and characterize the aromatic compounds based on the chemical structures and discuss modern analytical techniques for yogurt analysis. As described in this chapter, a large number of flavoring substances can be studied, isolated, and identified with the help of advanced instrument analysis such as synthetic fibers for solid-phase extraction (SPME) and gas chromatography combined with mass spectrometry (GC-MS). These techniques can help us reach a more advanced level of understanding of the importance of specific strains for obtaining the desired sensory qualities of fermented, lactic acid products. At a more advanced stage, these analyses could allow scientists to develop rapid methods for determining the quality and authenticity of lactic acid products based on the aromatic-metabolic profile of starter cultures in the final product.

**Keywords:** yogurt, volatile, aromatic flavor, *Lactobacillus bulgaricus*, *acetaldehyde*
