Chemical and nutritional characterization of raw and hydrothermal processed jambu (Acmella oleracea (L.) R.K. Jansen).

Jambu (Acmella oleracea (L.) R.K. Jansen) is a neglected plant native to the Amazon Biome. Although it is very consumed in the north of Brazil, little is known about its chemical and nutritional composition. Thus, this study aimed to characterize jambu and to evaluate the effects of the boiling process on its chemical composition. The proximate composition, minerals, total amino acids, fatty acids levels, and phytosterols were determined. In comparison with conventional vegetables jambu presented higher levels of protein (24.01%), ash (10.92%), total fiber (62.61%) some mineral such as Ca (2551.56 mg/100 g), Mg (734 mg/100 g) and Cu (2.09 mg/100 g), and amino acids such as asparagine (32.01 mg/g), glutamic acid (28.26 mg/g), valine (14.55 mg/g) and isoleucine (14.19 mg/g). A significant reduction was observed in carbohydrates, total dietary fibers, minerals, unsaturated fatty acids, and in some amino acid levels after the boiling process, with an increase in ash content, protein, and saturated fatty acids in the heat-treated jambu. Lipids, phytosterols, and some amino acid levels were not significantly affected by the hydrothermal process. Thus, this study has shown that raw and processed jambu may be good alternatives for conventional vegetables, even with nutrients losses during boiling.

Chlorogenic acids and flavonoid extraction during the preparation of yerba mate based beverages.

This study determined the content of chlorogenic acids (CA) and rutin during successive aqueous extraction of yerba mate for tererê and chimarrão from four yerba mate types (smooth, native, traditional and coarse ground). Aqueous extracts were prepared aiming to simulate homemade procedure by partially (chimarrão) or completely (tererê) immersing the herb into hot (chimarrão) or cold (tererê) water (30 times consecutively). The content of CA and rutin in the aqueous extracts was compared to those in methanolic extracts (exhaustive extraction). Tererê aqueous extracts gave higher amounts of all phenolic compounds (2.5 to 6 times higher than chimarrão). Among chimarrão, course-ground aqueous extracts had on average 15% more PC (phenolic compounds). By comparing the content in aqueous and methanolic extracts, after 30 successive extractions, on average 14% of the total amount of CA in yerba mate leaves and 9% of rutin were transferred to the chimarrão extracts, whereas tererê achieved between 40% and 100% of transference. Thus, this study shows that CA and rutin are continuously extracted during the preparation of aqueous extracts of chimarrão and tererê, favoring a high intake of these antioxidant species by consumers.

Optimization of the Preparation Conditions of Yerba Mate tea Beverage to Maximize Chlorogenic Acids Extraction.

The beverage obtained from the yerba mate tea, besides being the most consumed in Brazil, has high concentrations of chlorogenic acids. In this study, a central composite design was employed to establish the best infusion time, temperature and water volume to maximize the extraction of chlorogenic acids 5-caffeoylquinic (5CQ), 3.4-dicaffeoylquinic (3.4 DQ), 3.5-dicaffeoylquinic (3.5 DQ) and 4.5-dicaffeoylquinic (4.5 DQ), from the leaves and stems of yerba mate tea (beverage ready for consumption). Analyses were performed by high-performance liquid chromatography and the optimum conditions were obtained through the use of the desirability function of Derringer and Suich. The maximum chlorogenic acids content in the beverage was obtained when the infusion was prepared with 2 g of mate tea, in 300 mL of water at 95 °C, under infusion for 16 min. The optimal conditions were applied for the preparation of beverages from 15 commercial samples of yerba mate tea, and it was observed that the sum of the concentration of the four compounds showed variation of up to 79 times between the average of the samples, which can be attributed to climatic conditions of cultivation of the plant and/or of processing.