Selection of Indigenous Lactic Acid Bacteria Strains to Enhance the Functional Properties of Fermented Opuntia sp. Fruit Juices

Currently, the trend in the development of fermented foods seeks to use indigenous strains of lactic acid bacteria that enhance their functionality. This study focused on the formulation of an indigenous LAB starter culture to be applied in the conducted fermentation of three different colored Opuntia sp. fruit juices and on the evaluation of their functional properties. Thus, after spontaneous fermentation of Opuntia sp. juices took place, bacterial strains of both Weissella cibaria B1 and Pediococcus pentosaceus B2 were isolated, biochemically characterized, and identified using MALDI-TOF mass spectrometry and partial 16S rRNA gene sequencing. Both strains were combined at the same proportion (1:1), and this mixture served as the starter culture in a juice fermentation process for 96 h at 30 °C. Variations in their total phenolic compound contents, betalains concentration, antiradical activity, and physicochemical parameters were evaluated after fermentation of juices of different colors of Opuntia fruits. Juice fermentation induced by these selected strains produced after 96 h increases in their phenolic compound contents (2–8 times), antiradical capacity (6–12 times), and a reduction in total soluble solids about 60%. This fermentative process induced by indigenous strains represents a viable alternative for taking advantage of Opuntia fruits, an underutilized natural resource, and provides a suitable technology to improve their physicochemical and antioxidant properties and to extend juice shelf life. Fermented cactus pear juices can be considered as potential functional beverages and are rich sources of health-beneficial phytochemicals.