Fermentation of carob juice for the production of innovative low-alcohol beverages with high health benefits

Fermentation of fruit juices from minor species, such as carob (Ceratonia siliqua), is an attractive proposition for the development of innovative products. This fruit has a unique composition that includes high levels of bioactive compounds, sugars and polyphenols. This study describes a biotechnological approach to enhance this species, with great potential for food innovation in the fermented beverage market. Carob juice was fermented with the two starter strains of wine-derived Saccharomyces cerevisiae. At the end of the fermentation process in the obtained juice, the following were quantified: 1) the content of total polyphenols, 2) the antioxidant capacity, 3) the content of sugars and organic acids, and 4) the presence of volatile compounds. The juice was also analyzed with untargeted analytical technologies using an 80 MHz NMR and an E-nose GC-FID for liquid and VOCs components, respectively. The results obtained indicate that the fermentation process enhances the functional properties of carob juice particularly in total polyphenol content and antioxidant capacity. Chemical analysis showed specific metabolic differences between the two strains, which may influence the organoleptic profile of fermented carob juice. The high concentrations of esters, alcohols, acids and phenols in the fermented juices revealed the complex aroma and sensory profile of the final product suitable for specific food applications. Fermentation of carob juice has been shown as an optimal approach to develop functional low-alcohol beverages enriched with prebiotic and antioxidant compounds. This bio-technological approach might lead to the enhancement of local biodiversity to create typical regional products using sustainable technologies to enhance these minor species and expand offerings in the fermented beverage market.