A Matcha Tea Formulation Containing Lachancea thermotolerans: Phytochemical Profile After In Vitro Digestion and Effects on Intestinal Epithelial Function

Background/Objectives: Matcha tea is widely recognized for its antioxidant and anti-inflammatory properties; however, its health-promoting benefits depend on the gastrointestinal bioaccessibility of its phytochemicals. This study evaluated the impact of combining matcha tea with the probiotic yeast Lachancea thermotolerans DiSVA322 on bioactive stability and intestinal epithelial protection. Methods: Formulations of matcha tea alone (M), matcha tea combined with the probiotic yeast (M + P), and the probiotic alone (P) were subjected to in vitro gastrointestinal digestion. Probiotic survival, total antioxidant capacity, and polyphenol profiles were analyzed. The biological effects of the digested fractions were tested on inflamed Caco-2 cell monolayers to assess epithelial barrier integrity and gene expression profiles. Results: The digested M + P formulation exhibited a significantly higher polyphenol content compared to M alone, including a 322% increase in gallic acid alongside a 40.5% reduction in caffeine content. Both M and M + P digests protected the intestinal barrier against inflammatory damage, preventing the decline in TEER values. However, only the M + P formulation successfully mitigated the compensatory upregulation of the Claudin-1 gene, while significantly downregulating the pro-inflammatory transcription factor NF-κB and the mitochondrial antioxidant SOD2. Furthermore, L. thermotolerans DiSVA322 demonstrated significantly higher survival when co-ingested with Matcha tea (35.15% viability) compared to mineral water (14.95% viability). Conclusions: Enriching matcha tea with the probiotic yeast L. thermotolerans DiSVA322 improves its chemical composition: the tea matrix serves as a protective vehicle that enhances probiotic survival, while the yeast modulates and optimizes the phytochemical bioactive profile and enhances the nutrigenomic responses in the intestinal mucosa.