The goal of the research was to develop a method whereby high-quality pectin could be extracted from orange albedo. Pectin was acid extracted from early Valencia orange albedo using rapid microwave heating under pressure. The extraction times ranged from 3-60 minutes, at a constant temperature. The pectin was then characterized for molar mass (M), radius of gyration (Rgz), and intrinsic viscosity (IVw). The characterization was obtained by High-Performance Size-Exclusion Chromatography with online light scattering and viscosity detection. The molar mass, radius of gyration, and intrinsic viscosity were the highest at the lower heating times, particularly at 3 minutes. The molar mass was 480,000 Daltons, the Rgz was 40.9 nm, and the IVw was 8.1 dL/g. As heating times increased the percentage of pectin recovered increased, whereas the M, Rgz, and IVw all decreased. Analysis of the Mark-Houwink plots showed that the pectin extracted at lower heating times was more compact and spherical. As heating times increased the pectin structure fragmented and became less compact.
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