Different parts from the whole red beet (Beta vulgaris L.) valorization with stimulatory effects on probiotic lactobacilli and protection against gastrointestinal conditions

This study evaluated the effects of freeze-dried red beet (Beta vulgaris L.) root (FDBR) and stem/leaves (FDBSL) on the growth and metabolic activities of the probiotics Lactobacillus acidophilus La-05, Lacticaseibacillus casei 26, and Lismosilactobacillus fermentum 296, as well as on their survival and physiological states when exposed to simulated gastrointestinal conditions (SGIC). The changes in the contents of phenolic compounds and antioxidant activity of FDBR and FDBSL when exposed to SGIC were also evaluated. FDBR and FDBSL had high contents of soluble (5.25 and 11.10 g/100 g) and insoluble fiber (21.43 and 37.03 g/100 g), pectins (8.45 and 9.51 g/100 g), betalains (3.36-28.99 g/100 g), and a variety of phenolic compounds. FDBR and FDBSL stimulated the growth of the probiotic strains with high viable counts (>9 log CFU/mL), the production of acetic, butyric, lactic, and propionic acids, and alterations in the contents of phenolic compounds during 72 h of cultivation. FDBR and FDBSL had positive prebiotic activity scores on the tested probiotics (>= 0.17) linked to selective stimulatory effects. FDBR and FDBSL increased the survival and maintenance of active physiological functions in the probiotic during exposure to SGIC. The contents of phenolic compounds and the antioxidant activity of FDBR and FDBSL increased after exposure to the stomach conditions, while the antioxidant activity decreased after exposure to intestine conditions. The stimulatory and protective effects of FDBR and FDBSL on probiotic strains could be associated with their dietary fiber and phenolic compound contents, which could be exploited in the formulation of functional foods or dietary supplements.