Emulsifying properties, in vitro digestive characteristics, and ß-carotene bioaccessibility of mandarin peel pectin emulsions prepared with different carrier oil phases.

Mandarin peel pectin (MPP) emulsions were prepared with different oil phase loadings with or without ß-carotene, and their emulsifying characteristics, digestive properties and ß-carotene bioaccessibility were investigated. Results revealed that all MPP emulsions exhibited good loading efficiency for ß-carotene, while their apparent viscosity and interfacial pressure (π) of MPP emulsions increased significantly after the addition of ß-carotene. Emulsification of MPP emulsions as well as digestibility were significantly dependent on the kind of oil. MPP emulsions prepared with long-chain triglycerides (LCT) oil (soybean, corn, and olive oil) exhibited higher volume average particle size (D4,3), apparent viscosity, π values, and bioaccessibility of carotene compared to those prepared with medium-chain oils (MCT). MPP emulsions with LCT rich in monosaturated fatty acids (olive oil) had the highest ß-carotene encapsulation efficiency, bioaccessibility, etc. than from other oils. This study provides a theoretical basis for the efficient encapsulation and high bioaccessibility of carotenoids with pectin emulsions.

Extraction of Pectin from Satsuma Mandarin Peel: A Comparison of High Hydrostatic Pressure and Conventional Extractions in Different Acids.

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.

Potential low-calorie model that inhibits free fatty acid release and helps curcumin deliver in vitro: Ca2+-induced emulsion gels from low methyl-esterified pectin with the presence of erythritol.

Our previous study showed that pectin de-esterified by high hydrostatic pressure assisted enzymatic method (HHP-pectin) had better Ca2+-induced gel performance and more stable emulsion than those from conventional enzymatic and alkaline methods. In this study, Ca2+-induced emulsion gels were further prepared by HHP-pectin in the presence of erythritol, and their texture properties, moisture distribution, the release of free fatty acids (FFAs) and curcumin were investigated. Results showed that gel strength, gel elasticity, and water cut-off capacity of the prepared emulsion gels significantly increased with Ca2+ concentration increasing. Compared with emulsions, HHP-pectin emulsion gels can significantly decrease FFAs and curcumin release in vitro digestion, especially for samples with better texture properties (higher Ca2+ concentration). This study indicated that Ca2+-induced HHP-pectin emulsion gels prepared with erythritol may provide a new choice for low-calorie foods preparing, and may become a potential alternative model that inhibiting FFAs release and helping fat-soluble nutrients (curcumin) deliver.

Structural and Emulsifying Properties of Citric Acid Extracted Satsuma Mandarin Peel Pectin.

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.