Yogurt volatile compounds as affected by processing and compositional factors: A review

Background: Yogurt is one of the most widely consumed fermented dairy products in the world with high nutritional value, health impact and high taste and flavor acceptance. The peculiar flavor pattern of yogurt is the result of the complex combination of qualitative properties of the milk, process conditions and that biochemical transformations leading to the formation of both non-volatile and volatile aroma compounds. Changes in raw materials and formulation, processing and microbiota occurred over time contributed to obtain products with higher nutritional and quality properties, by also enhancing the consumer's sensory acceptability. Scope and approach: This review will provide an overview of the most recent literature on the impact of various factors (raw material, microbial composition, formulation, processing) on flavor and volatile aroma compounds in fermented milk and yogurt products. The biochemical activity of lactic acid bacteria (LAB) to produce flavor chemicals (e.g. glycolysis, proteolysis, and lipolysis), the impact of chemical components (protein, fat, prebiotics etc.), as well as fat replacer factors on yogurt's aroma have been discussed. Key findings and conclusions: Besides raw materials and processing, LAB, depending on the species used for yogurt fermentation, heavily influence the flavor-related qualities of yogurt, and new biotechnological approaches have been developed to guide and gain more control over the flavor-forming procedure. To fully understand, regulate, and drive flavor development in yogurt-making processes—while also considering process innovations and novel raw materials—further advancements in, and the application of omics-based methodologies and artificial intelligence will be essential.