Dietary fiber chemical structures and physicochemical properties of edible Pouteria glomerata fruits, native from Brazilian Pantanal.

Pouteria glomerata is a native species from the Brazilian Pantanal, whose fruit is edible and still underexploited. The objective of this study was to carried out the chemical, nutritional and antioxidant properties of this tropical fruit, as well as to isolate e characterize the chemical strucutre of their dietary fibers. DPPH and ORAC methods were used to determine the antioxidant capacity. Minerals were quantified using inductively coupled plasma optical emission spectrometry. Soluble and insoluble dietary fiber fractions were obtained by the standard enzymatic-gravimetric method and chemically characterized by monosaccharide composition, gel permeation and NMR spectroscopy. Results showed that P. glomerata fruits presented high antioxidant capacity and high levels of vitamin C, minerals, insoluble dietary fiber, and malic acid. The soluble dietary fiber was mainly composed of uronic acids, arabinose, and galactose, and NMR analysis indicated the presence of highly methylesterified homogalacturonan, arabinan and/or arabinogalactan as pectic polysaccharides. Hemicelluloses present in insoluble dietary fiber fraction were solubilized by alkaline treatment, and characterized as (1 → 4)-β-D-xylan. The results brings new chemical information about this native fruit and may open new opportunities for using it as a potential ingredient for health improvement by human comsumption.