Satsuma mandarin peel pectin (MPP) was extracted by citric acid and its structure and emulsifying ability were evaluated. Structural characterization, including NMR, FTIR, monosaccharide compositions demonstrated that MMP showed lower DM value and higher Mw than commercial citrus pectin (CCP). In addition, MPP exhibited significantly better emulsification performance than CCP. When MPP concentration was increased to 1%, 1.5% (10 g/L, 15 g/L) and the pH was 3 (acidic condition), a stable emulsion containing 10% oil fraction could be obtained. The particle size of the obtained emulsion was ranging from 1.0–2.3 μm, its emulsifying activity ranged from 93–100% and emulsifying stability was 94–100%. Besides, MPP can better ensure the storage stability of higher oil ratio emulsions. The results demonstrated that the stable emulsifying properties of MPP may largely depend on the lower DM value and higher Mw. MPP could be used as a novel polysaccharide emulsifier, especially under acidic conditions, providing a promising alternative for natural emulsifiers that could be used in the food industry.

Satsuma mandarin peel pectin was extracted by high hydrostatic pressure-assisted citric acid (HHPCP) or hydrochloric acid (HHPHP), and the physiochemical, structural, rheological and emulsifying characteristics were compared to those from conventional citric acid (CCP) and hydrochloric acid (CHP). Results showed that HHP and citric acid could both increase the pectin yield, and HHPCP had the highest yield (18.99%). Structural characterization, including NMR and FTIR, demonstrated that HHPHP showed higher Mw than the other pectins. The viscosity of the pectin treated with HHP was higher than that obtained with the conventional method, with HHPHP exhibiting significantly higher viscosity. Interestingly, all the pectin emulsions showed small particle mean diameters (D4,3 being 0.2–1.3 μm) and extremely good emulsifying stability with centrifugation and 30-day storage assays, all being 100%. Satsuma mandarin peel could become a highly promising pectin source with good emulsifying properties, and HHP-assisted acid could be a more efficient method for pectin extraction.

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