Synergistic enhancement of matcha tea with strawberry (Qassim region) aqueous extracts: influence of extraction temperature on phytochemicals, vitamin C, and bioactivities

Introduction Matcha tea is renowned for its rich phytochemical profile; however, optimizing its bioactive potential through formulation and extraction conditions requires further investigation. This study tested the hypothesis that strawberry powder creates an acidic microenvironment that stabilizes matcha catechins during thermal extraction while contributing complementary bioactives. Methods Aqueous extracts from pure matcha (MT) and an 85:15 matcha–strawberry blend (ST) were prepared at 5 °C, 70 °C, and 100 °C. Total phenolics, flavonoids, anthocyanins, vitamin C, individual phenolic compounds (HPLC), and in vitro antioxidant (DPPH, ABTS) and anti-inflammatory activities were evaluated. Two-way ANOVA and a Synergistic Enhancement Index (SEI) were used to quantify formulation × temperature interactions. Results and discussion The ST blend exhibited a significantly lower pH (∼3.70) compared to MT (∼6.20–6.30), remaining stable across all temperatures. This acidic environment dramatically enhanced catechin recovery: at 70 °C, SEI = +24.8% (2631.18 vs. 2109.08 μg/g); at 100 °C, SEI = +28.9% (2042.11 vs. 1584.33 μg/g). Strawberry substitution introduced protocatechuic acid, cinnamic acid, and anthocyanins (13.89–35.14 mg/100 g). Antioxidant activity peaked at 100 °C for ST (80.21% DPPH, 81.34% ABTS), representing a 34.9% enhancement over MT. Anti-inflammatory activity was highest at 70 °C (85.52% inhibition). Vitamin C and anthocyanins were optimally preserved at 5 °C, with ST providing 2.5-fold higher concentrations. Two-way ANOVA confirmed significant formulation × temperature interactions for all major outcomes ( p < 0.01). Conclusion Strategic formulation with strawberry powder fundamentally alters the thermal extraction window of matcha. Brewing the blend at 100 °C maximizes antioxidant potential, while 70 °C optimizes anti-inflammatory effects, and cold brewing at 5 °C preserves heat-labile nutrients. These findings enable targeted functional beverage development through precise temperature control and synergistic ingredient blending.