Sensory and Nutritional Properties of Matcha Infusions Enriched with Qassim Blackberries: Effects of Thermal Processing on Phenolic Profile, Color, and Antioxidant Activity

Abstract

Matcha is recognised for its rich phytochemical composition, while blackberries are abundant in anthocyanins and phenolic compounds. This study evaluated the sensory properties, phenolic profile, colour dynamics, and antioxidant potential of pure matcha (MT) and a matcha beverage formulated with 15% Qassim blackberry powder (BL) at three extraction temperatures (5 °C, 70 °C, 100 °C). Sensory evaluation used a 9-point hedonic scale with 50 panelists. Colour parameters (L, a, b, chroma, hue, ΔE) were measured via chromameter. Total phenolics (TPC), flavonoids (TFC), anthocyanins, vitamin C, and individual phenolic compounds were quantified by spectrophotometry and HPLC. Antioxidant activity was assessed by DPPH and ABTS assays. The 15% blackberry formulation achieved the highest sensory acceptability (8.43–8.45). BL exhibited acidic pH (3.60–3.82) versus MT (6.20–6.30). TPC reached 71.07 mg GAE/100 mL in BL at 100 °C (25% higher than MT). Anthocyanins were detected only in BL and decreased with temperature (69.14→27.12 mg/100 g). Vitamin C was highest at 5 °C (140.94 mg/100 g). BL demonstrated superior antioxidant activity, with IC₅₀ (half-maximal inhibitory concentration) values of 169.9 μg/mL (DPPH) and 226.1 μg/mL (ABTS) at 100°C, representing 60–70% improvement over MT. Strong correlations (r > 0.94) between phenolic content and antioxidant activity were observed. Incorporating 15% blackberry powder into matcha yields a functional beverage with enhanced sensory appeal, improved phenolic profile, and potent antioxidant capacity.