Little is known about how combining probiotics affects the storage survival and functional performance of individual probiotics when incorporated into non-dairy drinks. Viability of Lacticaseibacillus rhamnosus GG (LG), Limosilactobacillus reuteri ATCC 55730 (LR), Bifidobacterium animalis subsp. lactis BB-12 (Bb), and Propionibacterium jensenii 702 (PJ), either alone or in multi-species combinations included in orange juice (OJ), were assessed during storage in refrigerated conditions and compared with bottled water (BW). The tolerance of probiotics included in refrigerated OJ to simulated gastrointestinal conditions was also examined. LG and LR viabilities were significantly higher in OJ than in BW (p ≤ 0.001), while the reverse was evident for PJ. Bb maintained high viability in both drinks. LG-PJ in both drinks and Bb-PJ in BW resulted in greater viabilities among the paired combinations compared to their respective monocultures when incorporated separately (p ≤ 0.001). The viability of LG in the LG-Bb-PJ combination improved significantly in BW compared with LG alone (p ≤ 0.001). OJ did not alter bacterial tolerance to simulated gastric juice but diminished tolerance to simulated intestinal juice (SIJ). In all combinations, tolerance of LG and LR to SIJ was improved, whereas tolerance of PJ declined significantly compared with respective monocultures (p ≤ 0.001). In conclusion, probiotic storage stability and gastrointestinal transit tolerance were species-dependent and affected by carrier type and combinations. These effects should be considered when formulating probiotic products.

Lutein is an important antioxidant that quenches free radicals. The stability of lutein and hence compatibility for food fortification is a big challenge to the food industry. Encapsulation can be designed to protect lutein from the adverse environment (air, heat, light, pH). In this study, we determined the impact of mixed biopolymer systems based on bovine and caprine caseins, yeast β-glucan, and maltodextrin as wall systems for microencapsulating lutein dispersed in emulsified lipid carriers by spray drying. The performance of these wall systems at oil/water interfaces is a key factor affecting the encapsulation of lutein. The highest encapsulation efficiency (97.7%) was achieved from the lutein microcapsules prepared with the mixed biopolymer system of caprine α_s1-II casein, yeast β-glucan, and maltodextrin. Casein type and storage time affected the stability of lutein. The stability of lutein was the highest (64.57%) in lutein microcapsules prepared with the mixed biopolymer system of caprine α_s1-II casein, yeast β-glucan, and maltodextrin, whereas lutein microcapsules prepared with the biopolymer system of bovine casein, yeast β-glucan, and maltodextrin had the lowest (56.01%). The stability of lutein in the lutein microcapsules dramatically decreased during storage time. The antioxidant activity of lutein in the lutein microcapsules was closely associated with the lutein concentration.

Plant-based diets are associated with both positive health outcomes and a diverse gut microbiome. Such diets alter the microbiome’s metabolic outputs, including increasing phenylalanine-derived phenols associated with beneficial health outcomes (hippuric acid and 3-phenylpropionate), while decreasing tyrosine-derived phenols considered uremic toxins (phenol sulfate and p-cresol sulfate). The mechanisms linking plant eating to these phenol metabolites are not known. Plant-based foods are fiber and phytochemical rich. They also contain proteins that are resistant to host digestion and thus reach the gut microbiome. Here, we show that fiber and digestion-resistant protein work in concert to shift the phenol profile by altering gut microbiome nutrient supply. Through isotope-tracing studies, we reveal that host secreted proteins are a source for phenol sulfate and p-cresol sulfate, while digestion-resistant dietary protein is the source for hippuric acid and 3-phenylpropionate. Fiber decreases bacterial digestion of host secreted proteins (e.g., mucins) and thus suppresses tyrosine-derived phenol sulfate and p-cresol sulfate, whose levels correlate with the mucin-digesting bacterial family Oscillospiraceae. Digestion-resistant dietary protein increases bacterial access to phenylalanine and thereby boosts phenylalanine-derived hippuric acid and 3-phenylpropionate. Thus, digestion-resistant plant protein modulates microbiome metabolism and, together with fiber, supports healthy metabolite profiles associated with plant-based diets.