Synergistic Effects of Nanoselenium and Environmental Factors on the Quality, Antioxidant Activity, and Gut Health Benefits of Matcha

This study investigated the synergistic effects of nanoselenium foliar fertilization, cultivar, altitude, and light exposure on matcha quality and functionality. Among 16 different cultivation treatments, the best quality matcha was found in the selenium-enriched, high-altitude shaded cv. Fuyun No. 6 group, which exhibited the highest theanine content, the lowest polyphenol-to-amino acid ratio, and the best sensory score. Simulated gastrointestinal digestion showed that selenium-enriched matcha had higher 2,2-diphenyl-1-picrylhydrazyl scavenging activity compared with regular matcha. In vivo selenium biofortification enhanced glutathione peroxidase activity and reduced the malondialdehyde content in the liver and kidneys. It also increased the expression of intestinal barrier proteins Claudin-1 and Occludin, protecting gut integrity. Additionally, selenium-enriched matcha reshaped the gut microbiota by promoting beneficial bacteria such as Ligilactobacillus (family Lactobacillaceae). These findings highlight the optimal cultivation conditions for selenium-enriched matcha and demonstrate its potential as a functional food with enhanced antioxidant and gut health benefits.