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.

NMR-based approach reveals seasonal metabolic changes in mate (Ilex paraguariensis A. St.-Hil.).

Ilex paraguariensis (mate) is a species native to South America and is widely consumed in countries such Argentina, Uruguay, Paraguay, and Brazil. Mate consumption is associated with several phytotherapeutic functions, in addition to its cultural and regional importance. However, the harvest period can affect the properties of the mate, due to variations in the constituent proportions, as a consequence of seasonal changes. In this work, we employed nuclear magnetic resonance and chemometrics to evaluate the chemical variations in leaf extracts of I. paraguariensis over the four seasons of the year. We found significant changes in the levels of glucose, myo-inositol, caffeine, theobromine, and fatty acids. These changes can be related to resource allocation for the flowering period, or to responses to environmental stresses, such as temperature.