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Orange Peel Valorization Through Citric Acid Extraction: Linking Process Conditions to Structural and Functional
Brian Macias-Frotto1, Magdalena Rostro-Alanis1, Jorge Welti-Chanes1
1Escuela de Ingeniería y Ciencias, Tecnológico de Monterrey, Monterrey 64849, Mexico.
Molecules (Basel, Switzerland)
|June 26, 2026
Summary
Optimizing orange peel pectin extraction using citric acid reveals distinct fractions. Extraction conditions significantly impact pectin yield, galacturonic acid content, and degree of esterification, leading to varied functional properties.
Area of Science:
- Food Science
- Biochemistry
- Chemical Engineering
Background:
- Citrus processing generates substantial peel waste, a valuable source of pectic polysaccharides.
- Valorization of pectin from orange peel residues offers an eco-friendly approach to waste management and resource utilization.
Purpose of the Study:
- To investigate the influence of citric acid extraction parameters on pectin yield, composition, and functional properties from orange peel.
- To characterize pectin fractions optimized for yield, galacturonic acid (GalA) content, and degree of esterification (DE).
Main Methods:
- Utilized a central composite design (CCD) to study the effects of pH, temperature, and time on pectin extraction.
- Analyzed pectin yield, GalA content, and DE under varying extraction conditions.
- Characterized structural, thermal, rheological, and functional properties of optimized pectin samples.
Main Results:
- Maximum pectin yield (26.5%) achieved at 96 °C, 70 min, pH 1.46.
- Maximum GalA content (84.1%) obtained at 74 °C, 42 min, pH 2.17, with low recovery (5.6%).
- Maximum DE (67.0%) observed at 50 °C, 70 min, pH 1.46.
- GalA-optimized pectin exhibited superior gel hardness and viscosity compared to yield-optimized pectin.
Conclusions:
- Extraction conditions critically determine the characteristics of pectin obtained from orange peel.
- Optimizing for yield, GalA, or DE results in structurally distinct pectin fractions with unique functional properties.
- No single extraction condition yields optimal results for all desired pectin attributes, highlighting the potential for tailored pectin production.
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