Synergistic phenolic extraction from Schinus molle–tomato binary mixture with RSM optimisation and DPPH antioxidant activity

Synthetic antioxidants BHT and BHA face increasing regulatory scrutiny due to potential carcinogenic effects, necessitating the development of safer plant-based alternatives. Despite individual studies on Schinus molle L. and tomato ( Lycopersicon esculentum Mill.), no prior study has investigated their binary combination for synergistic phenolic extraction. This study optimised phenolic antioxidant extraction from a Schinus molle –tomato binary mixture using response surface methodology (RSM). A face-centered central composite design examined temperature (25–60 °C), time (40–180 min), and fruit ratio (0:100 to 100:0 w/w) across 20 experimental runs. The RSM model (R 2 = 0.9896) predicted maximum yield of 50.07% at 55 °C, 110–132 min, and 47.6:52.4 w/w ratio, experimentally validated at 49.71 ± 0.10% (MAPE = 0.71%). The optimised extract yielded IC₅₀ = 0.428 mg/mL, total phenolics of 2.4–154 mg GAE/g and total flavonoids of 66–284 mg QE/g. The 50:50 binary mixture outperformed individual fruit extractions by up to 14%, attributable to complementary pH effects and enhanced mass transfer. These findings present the validated, protocol for synergistic natural antioxidant extraction from the S. molle –tomato system.