Phytochemical Diversity and Antioxidant Potential of Indigenous Zimbabwean Fruits: Strychnos madagascariensis and Parinari curatellifolia as Underutilised Plant Resources

Introduction: Strychnos madagascariensis (Mutamba) and Parinari curatellifolia (Muhacha) are indigenous Zimbabwean fruits traditionally valued for their health benefits, yet quantitative phytochemical and antioxidant characterisation of their processed products remains unreported. This study provides the first assessment of total phenolic content, antioxidant activity, and syrup formulation feasibility for these underutilised species.
Methods: Fresh fruit pulps were macerated, heated (85°C, 20 min), filtered, and vacuum-concentrated to 68–72 °Brix. A 60:40 Strychnos: Parinari blend was evaluated. Physicochemical properties (pH, total soluble solids, viscosity) were measured; total phenolic content was determined by Folin‑Ciocalteu assay and antioxidant activity by DPPH radical scavenging. Sensory acceptability was rated on a 9‑point hedonic scale (30 semi‑trained panellists). Accelerated stability was assessed at 40 °C/75 % RH over 6 months.
Results: The syrup exhibited pH 3.8–4.2, total soluble solids 68–72 °Brix, and viscosity 800–1200 cP. Total phenolic content was 45 ± 3 mg GAE per mL syrup, and DPPH IC₅₀ was 45 ± 5 µg/mL. Mean overall acceptability was 7.5 ± 0.6. No significant changes in physicochemical or antioxidant parameters were observed after 6 months of accelerated storage.
Conclusions: The formulated syrup demonstrates high phenolic content and appreciable antioxidant activity, supporting its potential development as a functional food ingredient. Limitations include reliance on a single antioxidant assay, absence of nutritional profiling, and the need for real‑time stability validation. These findings establish baseline compositional data for future valorisation of these indigenous fruits.