A functional approach to cheese production: Boosting gamma-aminobutyric acid content with Kluyveromyces marxianus

This study aimed to investigate the exploitation of Kluyveromyces marxianus FM09 to enhance gammaaminobutyric acid levels in cheese. Cheese samples were manufactured using a commercial starter of Lacticaseibacillus casei (CC) as the control and a mixed starter culture of CC and K. marxianus FM09. Cheeses were analyzed for GABA content and the concentration of succinic acid. Moreover, the expression of genes related to GABA metabolism was evaluated. A stronger proteolysis and a higher pH characterized cheeses obtained with the mixed-starter culture. Significant increases in cheese GABA content were measured within cheeses obtained with K. marxianus, which reached 512 mg/kg after 30 days, representing an 81 % increase compared with the control. GAD gene expression and GABA accumulation reached their maximum value after 20 days. The sensory analysis revealed that the cheeses obtaiened with K. marxianus showed increased fruity, floral, creamy notes. The obtained data suggested that K. marxianus FM09 could be used for the production of GABA-enriched cheeses featuring improved sensory quality. This work supports K. marxianus as a promising candidate in developing functional fermented dairy products with potential health benefits.