Steam explosion‐assisted grinding improves the functional properties and antioxidant activity of Java tea‐leaf powders (Clerodendranthus spicatus)

Abstract BACKGROUND Java tea is widely consumed and has multiple health effects. This study established a steam explosion (SE) pretreatment method to prepare Java tea‐leaf powders. The physicochemical, functional properties, phenolic extraction, and antioxidant activity of Java tea‐leaf powders produced by simple and SE‐assisted milling methods were investigated. RESULTS In comparison with simple milling, SE pretreatment broke the cell wall effectively and reduced the particle size of Java tea‐leaf powders. Steam explosion‐treated powders showed higher values for sensory signals, bulk and tap density, and for the water solubility index. After SE treatment, the adsorption capacities to glucose, soybean oil, and cholesterol of leaf powders were increased by up to 55, 95, and 80% respectively. The extracts from SE‐treated powders also showed higher total polyphenol content and antioxidant activity. CONCLUSION Steam explosion treatment is helpful for the improvement of functional properties and antioxidant activity, which can benefit the development and application of Java tea‐leaf powders. © 2024 Society of Chemical Industry.