Comparative non-volatile composition, sensory quality, and ferroptosis-targeted anti-inflammatory activity of instant green tea powders from green- and purple-leaf cultivars

Instant tea powder is a convenient, shelf-stable product with growing global popularity, yet the impact of cultivar type on its composition and functionality remains underexplored. This study compared two instant green tea powders from green-leaf (ZYQ) and purple-leaf (ZY) cultivars in terms of metabolite profiles, sensory attributes, and anti-inflammatory effects. Metabolomics and sensory evaluation revealed distinct characteristics: ZYQ contained higher levels of epicatechin, proanthocyanidins, total flavonoids, etc., while ZY was enriched in anthocyanin glycosides and EGCG. ZYQ showed greater umami, sweetness, and harmony, whereas ZY exhibited stronger bitterness, astringency, and a purplish-red infusion. Both powders significantly alleviated LPS-induced inflammation in RAW 264.7 macrophages by inhibiting NF-κB and ferroptosis-related oxidative stress, reducing ROS, MDA, iron, and inflammatory mediators. ZY induced stronger upregulation of Nrf2 , Gpx4 , and Txnrd1 , indicating enhanced antioxidant defense. These findings demonstrate that cultivar selection shapes instant tea's flavour and bioactivity, with purple-leaf products offering distinctive functional advantages.