Submitted:
06 February 2026
Posted:
09 February 2026
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Abstract
The valorization of citrus peel waste represents a fundamental pillar for developing a circular bioeconomy within the agri-food sector. This study comprehensively evaluated the biorefinery potential of ten citrus varieties, encompassing mandarin (Citrus reticulata criolla, Citrus nobilis Loureiro, Citrus tangerina, Citrus unshiu), lemon (Citrus aurantifolia swingle, Citrus limonia, Citrus limonum, Citrus latifolia), and grapefruit (Citrus paradisi, Citrus paradisi Macfad) from the Bolívar province of Ecuador. The residual biomass was characterized through proximate and elemental analyses, revealing significant variability in moisture, ash, and volatile solids content among varieties. Essential oil extraction was optimized using fractional distillation, systematically evaluating the effect of maceration time at two levels. Results demonstrated that Citrus nobilis Loureiro exhibited the highest extraction yield, while grapefruit varieties showed the most pronounced response to extended maceration time. Gas chromatography coupled with mass spectrometry confirmed limonene as the predominant component across all varieties, with grapefruit essential oils achieving exceptional purity exceeding ninety percent. The chemical profiles revealed statistically significant intervarietal differences in monoterpene distribution, establishing distinctive chemotaxonomic patterns. The principal scientific contribution of this work lies in the advanced kinetic modeling approach, wherein seven mathematical models were rigorously evaluated to describe extraction dynamics. The Monod model demonstrated superior predictive capacity with coefficients of determination exceeding 0.99, providing mechanistically meaningful parameters for process optimization and industrial scaling. This integrated analytical framework, combining compositional characterization with predictive kinetic modeling, positions these agro-industrial residues as sustainable sources of high-quality essential oils for food, pharmaceutical, and cosmetic applications under circular economy principles.
