Comparative Chemical Characterization of Yerba Mate, Green Tea, and Lemongrass Infusions Under Different Sugar Concentrations

Tea is a beverage made from aqueous plant infusions that exhibits various health benefits, being considered the second most consumed beverage in the world. The benefits of its consumption involve anti-inflammatory, antioxidant, relaxing, and digestive properties, depending on the substrate used and the extraction conditions, which can vary according to sugar concentration, for example. Some of the commonly consumed plants include yerba mate, a plant native to the South American flora that features various bioactives such as polyphenols and methylxanthines, being beneficial to health; the species Cymbopogon citratus, known as lemongrass, native to India and commonly used for preparing beverages, essential oil, displaying antimicrobial properties; in addition to green tea, obtained from the Camellia sinensis plant, a rich source of phenols and alkaloids, widely used in the pharmaceutical industry. With the objective of understanding the composition of these beverages, this study uses HPLC and HS-GC-MS methods for the identification of phenolic compounds, organic acids, volatile, and semi-volatile compounds, as well as benchtop methods (Folin-Ciocalteu and aluminum chloride) for the quantification of total phenolic and flavonoid compounds (TPC and TFC), also comparing the effect of sugar concentration on the extraction of these molecules. For this purpose, infusions of 10 g/L of yerba mate, green tea, and lemongrass were prepared in aqueous solutions containing 0, 60, and 100 g/L of sucrose for 10 minutes, in triplicate. In the chromatographic analyses, yerba mate stands out due to the high presence of various phenolic compounds in its composition—molecules with anti-inflammatory and antioxidant properties, highlighting kaempferol, rutin, and quercetin, while featuring the presence of caffeine and butyric acid as a distinctive factor. In contrast, green tea and lemongrass beverages show a high presence of terpenes, molecules found in plants responsible for aromas, widely studied for their anticancer and antidiabetic properties. However, their substrates differ in phenolic and acid composition: while green tea is rich in catechins and gallic acid, uniquely featuring succinic acid and benzyl acetate, lemongrass shows a low occurrence of phenolic compounds, a predominance of malic acid, and characteristic aromatic molecules, such as citronellol. When evaluating the effect of sugar concentration on the extraction of these compounds, it was observed that in green tea and lemongrass beverages the increase in sucrose concentration in the aqueous medium interferes with solubility and molecule entrainment, as evidenced by a reduction of about 15% in the final concentration of TPC and TFC. However, for yerba mate, this change was not significant, which may occur due to the leaf structure not suffering interference from the sucrose concentration in the medium. This research was supported by CNPq/MCTI. The funder had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.