NMR-based foodomics of common tubers and roots.

Common roots and tubers such as arracacha, Asterix potato, cassava, potato, sweet potato, taro, and yam are consumed by millions of people. These foods are an integral part of the diet in developing countries and are nutritionally important as energy reserves due to their carbohydrate content. Although many studies have been performed on these foods, comparative chemical profiles have been still poorly evaluated. In this work, we applied nuclear magnetic resonance (NMR) analysis associated with chemometrics to evaluate the chemical composition of extracts obtained in deuterated water from roots and tubers that are commercially consumed in Brazil and the rest of the world. From the 31 metabolites characterized in the extracts, 22 were quantified. Multivariate analyses showed 8 metabolites which were primary responsible for the distinction between samples, including choline, γ-aminobutyrate (GABA), glutamine, asparagine, isoleucine, fructose, glucose, and sucrose. Thus, our work shows important information on the chemical composition in addition to the mere carbohydrate content of these food matrices. This knowledge can provide information about food safety and beneficial nutritional values of the studied tubers and roots, which can be useful to consumers and the food industry.

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 â†’ 4)-ß-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.