Factors Affecting Extraction Efficiency and Establishing Quality Standards for Pomelo Peel Essential Oil: A GC-FID Approach

Background: Pomelo is a key fruit crop in the Mekong Delta, Vietnam, offering economic value not only from its pulp but also from its peel. Pomelo peel essential oil is rich in limonene, which exhibits antibacterial, antioxidant, and hair growth-stimulating properties. Objectives: This study investigates the factors influencing extraction efficiency, validates the analytical method for limonene quantification, and establishes quality standards for Pomelo peel essential oil using gas chromatography-flame ionization detection (GC-FID). Methods: Pomelo peel essential oil was extracted using the hydrodistillation method. The extraction process was optimized by evaluating key factors, including the raw material-to-solvent ratio (X1), extraction time (X2), distillation rate (X3), material size (X4), and Pomelo variety (X5). The limonene quantification method was validated following ICH and AOAC guidelines, and the quality standards for Pomelo peel essential oil were established based on ISO 3053:2004. Results: This study identified the optimal extraction conditions as a raw material-to-solvent ratio of 1:4, an extraction time of 120 minutes, a distillation rate at level 5-high, ground material size, and the use of Citrus maxima, resulting in an extraction yield of 2.6%. Validation results confirmed that the GC-FID method met system suitability requirements, selectivity, high precision (RSD < 2%), and accuracy (95.0 - 105.0%). The established quality standards for Pomelo peel essential oil define it as a colorless, volatile liquid with a characteristic Pomelo aroma, a density of 0.854 ± 0.191, a refractive index of 1.475 ± 0.266, an optical rotation of 93.360, a residue after evaporation of 1.623 ± 0.163%, and a limonene content of 84.178 ± 0.916% for C. grandis and 97.960 ± 0.013 for C. maxima. Conclusions: This study optimized the extraction process and established quality standards for Pomelo peel essential oil from Vinh Long, providing a solid foundation for its broader application in the pharmaceutical, cosmetic, and related industries.