The objective of this work was to evaluate different solvents and times in the ultrasound-assisted extraction of polyphenols, in order to quantify the total phenolic and flavonoid contents in and the antioxidant activity of mate (Ilex paraguariensis) leaves. The experiment was carried out in a completely randomized design, in a 8x3 (solvent x time of extraction) factorial arrangement. The solvent extractors were distilled water and aqueous solutions of ethanol, acetone, and methanol, acidified or not with hydrochloric acid, and the time of ultrasound-assisted extractions were 15, 30, and 45 min. All extractions were finished with a mechanical agitation of 30 min. Samples treated with acidified hydroalcoholic solvents resulted in higher values of total phenolics and flavonoids and antioxidant activity. The extraction using acidified hydroethanol solvent was not affected by the time in the ultrasound. The contents of total phenolics and flavonoids were highly correlated with each other and with the antioxidant activity, especially when it was determined by the ferric-reducing antioxidant power method. Acidified hydroethanol solvent in ultrasound for 15 min is the most suitable extraction condition for the quantification of the contents of total phenolics and flavonoids in and the antioxidant activity of mate leaves.

Ultimamente estudam-se as ervas aromáticas e especiarias para tratamento e prevenção de doenças, tornando o uso destas em alimentos uma fonte importante des...

Beehive products, including honey, are valuable environmental indicators, as bees transport compounds in the environment by transferring them to the hive. Environmental pollutants can reduce the quality of honey and represent a risk for consumers. In this work, we characterised honey samples of Apis mellifera from different cities of the Rio Grande do Sul state (southern Brazil), sold without any inspection. A total of 23 honey samples were collected from 11 cities of Rio Grande do Sul. We carried out Lugol’s and Lund’s tests, analysed the electrical conductivity (EC), pH, and acidity of the honey samples, and determined their moisture, ash, reducing sugar, apparent sucrose, hydroxymethylfurfural (HMF), and diastase contents. Energy-dispersive X-ray fluorescence analysis was performed to determinate the mineral profile of the samples. Principal component analysis (PCA) was applied to the physicochemical data in order to differentiate the honey samples based on their origin. The analysis of the physicochemical parameters indicated that seven samples (30.4%) showed deviations from the reference values. PCA accounted for 90.03% of the variance with the first four principal component variables. Most samples were separated by the city of origin, supporting the possibility of using honey as an environmental marker.

Oak (Quercus spp.), traditionally used for aging alcoholic beverages, is not native in many countries, which increases production costs and environmental impact. During the aging process of alcoholic beverages, complex physical and chemical transformations occur that determine their chemical composition and sensory quality, many of which are unique depending on the type of wood used in the process. In this context, Maclura tinctoria (Tajuva), a native Brazilian species rich in phenolic compounds, was evaluated based on its phenolic composition and extraction behavior as a sustainable alternative for beverage aging. Wood chips were subjected to three toasting levels (untoasted, medium, and high) and aged for up to 360 days in two hydroethanolic model systems (10% and 14% v/v ethanol). The total and individual phenolic compounds were determined using the Folin–Ciocalteu method and HPLC–DAD/LC–MS/MS analysis. Results showed that toasting level, ethanol concentration, and aging time significantly influenced phenolic extraction. Untoasted Tajuva released the highest amounts of phenolic acids and flavonoids, particularly gallic and caffeic acids, and quercetin, respectively; while medium toasting favored the formation of thermally derived aromatic compounds, such as vanillic acid. The 14% ethanol system enhanced extraction efficiency for most analytes. Overall, Tajuva wood exhibited higher phenolic yields than French oak under comparable conditions, highlighting its chemical richness and extraction reactivity. These findings support the use of M. tinctoria as an eco-efficient and functional alternative to oak for the maturation of alcoholic beverages.

Ilex paraguariensis, a native plant to southern Brazil, has great socio-economic importance in this region. The quality of their leaves and new branches to “mate” or teas, also for pharmaceutical and cosmetics industries, can be affected by ecophysiologic stresses, especially when in monoculture, for being a climax plant, which in its natural habitat develops into a sheltered microenvironment by superior tree fragments. Obtaining greater productivity, with high concentration of beneficial health phytochemicals, as the phenolic compounds and antioxidants, with differentiated prices, is a result of the environment condition. So, the cultivation and management practices must be suited to the different micrometeorological conditions from the time of year and the degree of the plant exposure, in order to minimize possible stresses by excessive levels of solar radiation, temperature and wind speed. Thus, the objective of this work was evaluate the phenolics and antioxidants concentration as a function of stress caused by the increase of the wind speed in yerba mate leaves partially shaded and with plant remains coverage of the soil. The experiment was conducted in field conditions with young yerba mate plants, in a completely randomized bifatorial design with three repetitions in Santa Maria-RS. The factors tested were the wind speed (natural mitigated » 0 m/s, and 2, 4 and 6 m/s artificial wind) and shading (18 and 35%), consisting of 12 plants p/ plot of progeny "Cambona". After the periods of forced ventilation, applied in summer and autumn, 20 sheets of each experimental unit were collected and frozen. Alcoholic extracts were prepared and then determined the polyphenols and flavons contends by spectrophotometry with reading of UV-visible absorption. The antioxidant capacity was determined by iron reduction method (FRAP) and acid radical (ABTS). It was verified that the application of forced ventilation of 6 m/s or more altered the phytochemical composition expressed in phenolic and flavonoids compounds and antioxidant capacity, especially in summer. It was concluded that the yerba mate leaves have greater accumulation of phenolic compounds and flavonoids and better antioxidant capacity in places sheltered from wind, with partial shading of 35% and soil surface covered with plant waste.