Development of novel functional fermented beverages with psychobiotic potential from whey

Depression and anxiety are mental disorders with an increase in prevalence that affect millions of people worldwide reducing their life quality, and the economic state of entire regions. Psychobiotics are defined as probiotics that confer mental health benefits to the host when consumed in a particular quantity through the interaction with commensal gut bacteria. Among their action mechanisms is the production of psychoactive compounds, such as gamma-aminobutyric acid (GABA), which is a primary neurotransmitter that is essential for many brain processes. Thus, the use of psychobiotics promises a novel approach to preventing and treating mental disorders. In the state of Jalisco, big amounts of whey are produced, posing an environmental problem, so using it as the base of a food product is a promising way of revalorizing this by-product. Furthermore, due to an increase in the demand of functional products, new sources of functional ingredients should be explored. In this sense, the main objective pursued during this thesis project was to develop a novel functional probiotic fermented beverage from whey with potentially psychobiotic microorganisms and other functional ingredients obtained from raspberry and Mexican hawthorn fruit. To achieve this, whey was characterized, and its safety was ensured. Next, the psychobiotic potential, fermentation capacity, and in vitro digestion survival in whey of microorganisms isolated from an artisanal kefir and certain commercial strain were characterized, followed by the formulation and characterization of novel fermented beverages using Mexican hawthorn fruit and raspberry as sources of functional ingredients. Finally, the physicochemical, functional, and preliminary sensory parameters of the formulations were assessed through a 21-day shelf-life study and after an in vitro digestion assay. Results showed that 4 different fermented and functional potentially psychobiotic beverages were successfully formulated using GABA-producing commercial and kefir-isolated strains. All formulations were widely accepted by panelists, and beverages behaved stably in all parameters through the 21-day shelf analysis, except for the levels of anthocyanins that decreased over time. Furthermore, the formulations exhibited an increase in the bioaccessibility of phenolic contents and GABA after the in vitro digestion while preserving its load of fermentative microorganisms. In conclusion, the development of novel functional fermented beverages with psychobiotic potential from whey was feasible.