Comprehensive study of matcha foam formation: Physicochemical composition analysis and mechanisms impacting foaming properties

Tea foam is crucial for new food and drink innovations. This study examined nine types and grades of matcha, identifying Longjing 43 as a high-quality raw material for matcha with good foaming properties. Foam scanning, particle electrophoresis and biochemical analysis revealed that pH (≈6.0), catechins (such as EGCG), amino acids (such as valine), pectin, soluble proteins and lipids enhanced foam formation. These components affected matcha's foaming through inter-component complexation, hydrophobic interaction of groups and intermolecular hydrogen bonds. EGCG had the greatest impact on foaming ability (1.89-fold), while amino acids primarily stabilized the foam. At the molecular level, phenolic hydroxyl groups close to each other promoted foaming, whereas alcoholic hydroxyl groups had the opposite effect. Phenol (5.17-fold) and n-propanol (8.03-fold) were the most effective foam promoters among phenols and alcohols. This study enhances our understanding of tea foam's biochemical mechanisms, driving innovation in food and beverage products.