From Forest to Fuel: Exploring Uapaca Kirkiana (Wild Loquat) Extracts to Enhance Biodiesel Life
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Date
2026-01-12
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Publisher
Springer Nature
Abstract
Biodiesel is a renewable, low-emission fuel; however, its poor oxidative stability limits its practical use. Although synthetic antioxidants like Pyrogallol can improve stability, they raise toxicity concerns, prompting interest in safer, plant-based alternatives. This study evaluates the antioxidant potential of Uapaca kirkiana extracts, specifically from fruit peels, pulp, and root bark, for enhancing the oxidation stability of biodiesel. Methanolic extraction was employed to obtain the plant extracts, and the total phenolic content (TPC) was determined using the Folin–Ciocalteu (FC) reagent. Antioxidant activity was assessed using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assay, while oxidation stability of croton biodiesel was measured using the OXITEST method. Among the tested samples, fruit peel extracts exhibited the highest phenolic content and antioxidant activity. At a concentration of 1000 ppm, the fruit peel extract extended the biodiesel induction period from 3.02 h (control) to 16.25 h, compared to 14.18 h and 10.10 h for the pulp and root bark extracts, respectively. These results were benchmarked against Pyrogallol (PY), which extended the induction period to 18.30 h at the same concentration. Although PY demonstrated slightly higher effectiveness, the natural extracts, particularly from fruit peels, showed substantial potential. Notably, the fruit peel extract met and exceeded the minimum oxidation stability requirements of EN 14112 and ASTM D6751 (8 h) at just 500 ppm. These findings highlight the promise of Uapaca kirkiana extracts as eco-friendly, natural alternatives to synthetic antioxidants for improving biodiesel stability and shelf life.
Sustainable Development Goals
SDG-7: Affordable and Clean Energy
SDG-12: Responsible Consumption and Production
Keywords
Natural antioxidants, Wild loquat, Biodiesel, Oxidation stability, Underutilised African plant