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

Changes in the Physicochemical and Bioactive Properties of Yerba Mate Depending on the Brewing Conditions

Yerba Mate drink made from dried and crushed leaves and twigs of Paraguayan holly (Ilex paraguariensis A. St.-Hil.), which is a valuable source of bioactive substances, in particular antioxidants. The available literature lacks data on changes in the content and profile of bioactive compounds such as tannins, caffeine, the phenolic acid profile of flavonoids and carotenoids, as well as total polyphenol content and antioxidant activity in Yerba Mate infusions depending on different brewing conditions, and how different brewing conditions affect the physicochemical properties of these infusions. Therefore, this study evaluated the physicochemical properties of dried and Yerba Mate infusions prepared via single and double brewing processes at 70 °C and 100 °C. The organoleptic evaluation, as well as the instrumental color measurement, showed significant changes in the total color difference (ΔE) and the L*a*b* chromatic coordinates of dried Yerba Mate samples and their infusions. Moreover, the research showed higher contents of tannins (mean 1.36 ± 0.14 g/100 g d.m.), caffeine (mean 17.79 ± 3.49 mg/g d.m.), carotenoids (mean 12.90 ± 0.44 μg/g d.m.), phenolic acids (mean 69.97 ± 7.10 mg/g d.m.), flavonoids (mean 5.47 ± 1.78 mg/g d.m.), total polyphenols (mean 55.26 ± 8.51 mg GAE/g d.m.), and antioxidant activity (mean 2031.98 ± 146.47 μM TEAC/g d.m.) in single-brewed Yerba Mate infusions compared to double-brewed (0.77 ± 0.12 g/100 g d.m., 14.28 ± 5.80 mg/g d.m., 12.67 ± 0.62 μg/g d.m., 57.75 ± 8.73 mg/g d.m., 3.64 ± 0.76 mg/g d.m., 33.44 ± 6.48 mg GAE/g d.m. and 1683.09 ± 155.34 μM TEAC/g d.m., respectively). In addition, infusions prepared at a lower temperature (70 °C) were characterized by a higher content of total polyphenols and higher antioxidant activity, in contrast to the tannin and carotenoid contents, the levels of which were higher at 100 °C than at 70 °C. Considering the high amount of bioactive ingredients, in particular antioxidants, and a wide range of health benefits, it is worth including Yerba Mate in the daily diet.

Yerba Mate (Ilex paraguariensis) Processing and Extraction: Retention of Bioactive Compounds

Ilex paraguariensis is a native tree from South America known for the presence of bioactive compounds, and its processed leaves are consumed as hot and cold infusions. After harvest (step 1), the leaves are subjected to flame blanching to inactive the enzymes (step 2), followed by drying and milling (step 3). The impacts of I. paraguariensis processing on leaf composition were investigated by extracting the major compounds (chlorogenic and isochlorogenic acids (3-CQA, 4-CQA, 5-CQA, 3,4-DQA, 3,5-DQA and 4,5-DQA), p-coumaric acid, caffeine and rutin) using different ratios of ethanol and water as extraction solvent (EW 25:75, 50:50, and 75:25 (w/w)). The solvent ratio of EW 50:50 was more effective in extracting the chlorogenic acids isomers, with retention of chlorogenic acids of 3463, 9485, and 9516 µg mL- 1 for steps 1, 2, and 3, respectively. Rutin and p-coumaric acid exhibited similar behavior with the increment of processing steps; however, p-coumaric acid was only detected in steps 2 and 3 for the solvent ratios EW 50:50 and 25:50. The caffeine extraction from I. paraguariensis varied from 936 to 1170 µg mL- 1 for all processing steps, with emphasis on its concentration extracted in step 1. The evolution of processing steps led to a higher retention of phenolic compounds from I. paraguariensis, which was not observed when using different solvent ratios, and the solvent ratio EW 50:50 was more effective for the extraction of chlorogenic acids. The successful extraction of chlorogenic acids from I. paraguariensis in this study proved to be a promising alternative for the use of yerba mate beyond the cuia cup.

Application of Hot Water Extraction Techniques and the Principal Component Analysis to Study the Influence of Cultivation of Commercial Yerba Mate Samples on Their Mineral Profiles

Consumption of organic food has grown much around the world in the last 20 years. Change in the profile of consumers who have increasingly sought a healthy diet is the major contributor to this phenomenon. In scientific literature, some studies have already shown the nutritional superiority of organic food in the individual evaluation of metabolites. However, few studies have assessed interaction among metabolites, especially the one between minerals and the food matrix. This information may have great relevance in determining the extractability of minerals, especially in food consumed through infusion, such as yerba mate, since this interaction can directly influence their solubility. Thus, this study aimed to use hot water extraction techniques (infusion and decoction) and the principal component analysis (PCA) to evaluate the differences between organic and conventional cultivation systems in absorption and availability of Ca, Mg, Fe, Mn, and Zn in yerba mate leaves and stems. The PCA showed that cultivation influences total mineral contents found in both leaves and stems. Results of extractability only showed differences in conventional leaf samples, from which all minerals under study were better extracted. Results point out a different interaction between minerals and the matrix, depending on the cultivation, and to the stronger interaction between the matrix and minerals in organic samples, a fact which leads to low availability of minerals for consumption.

Fractionated extraction of polyphenols from mate tea leaves using a combination of hydrophobic/ hydrophilic NADES

A new methodology for the selective extraction of antioxidants from mate tea leaves (and decaffeinated mate tea leaves), using different natural deep eutectic systems (NADES), is reported in this paper. A fractionated extraction was carried out and the optimization of the extraction conditions such as solid/liquid ratio, temperature, time, stirring and the use of ultrasound assisted extraction (UAE) technology was performed. The results demonstrate that a sequential extraction using, in a first step, an hydrophobic system Men:Lau (2:1) and, in a second step, an hydrophilic lactic acid-based NADES, leads to two distinct extracts: the first one rich in pigments and the second one rich in polyphenols.

NADES systems were able to extract 30% more of the polyphenolic components of the mate tea leaves matrices, when compared with traditional solvents/techniques. Moreover, it has been shown that the incorporation of the extract in the NADES, compared to the same extract in aqueous medium was beneficial for the stabilization of the antioxidants. It maintains their functionality at least for three months, reaching 41% more versus the extracts obtained by traditional solvents/techniques. The absence of caffeine in the extracts did not shown to have any effects on the stability results.

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NADES proved to be more effective extraction solvent compared to conventional techniques.

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Fractionated extraction method using different classes of NADES as extraction medium.

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Novel technique to extract the major compounds of mate tea leaves.

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The extract incorporated in the NADES is beneficial for the stabilization of the antioxidants.

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Final product is 100% natural.

Mate (Ilex paraguariensis) tea preparations: Understanding the extraction of volatile and non-volatile compounds upon variations of the traditional consecutive infusions

Common variations of traditional consecutive infusions of mate (Ilex paraguariensis) tea were studied. Effects of tea grinding type and water temperature on the extraction of volatile and non-volatile compounds were elucidated. Extraction behavior was determined mainly by grinding type and to a minor extent by water temperature. The extraction behavior along the series of infusions is mostly driven by the way the water can access and flow through the tea mass. This processes are impaired by the formation of clogging layers which are more intense upon the increasing abundance of tea particles of sufficiently small size and high water temperatures.

Effect of flaxseed (Linum usitatissimum L.) flour and yerba mate (Ilex paraguariensis) extract on physicochemical and sensory properties of a gluten free corn-based snack

Flaxseed (Linum usitatissimum L.) and yerba mate (Ilex paraguariensis) are particularly interesting as functional ingredients due to their high content of essential omega 3-fatty acids and antioxidant properties, respectively. The objective of this work was to formulate a corn snack enriched with flaxseed flour and yerba mate extract and evaluate its physicochemical and sensory properties. Flaxseed flour, added at three levels 1, 3 and 5%, increased the water activity, moisture content and cohesiveness, and decreased the hardness and plastic deformation of the samples. The flour also changed the superficial colour and made the microstructure more compact. On the contrary, yerba mate extract (1 and 3%) decreased the water activity, moisture content and cohesiveness, counteracting the effect of flaxseed flour. Yerba mate increased the plastic deformation and the antioxidant activity of the snacks. The colour was not modified and the microstructure was more fragmented in the presence of yerba mate. Sensory evaluation suggested that flaxseed flour and yerba mate affected the flavour but did not modify the colour and crunchiness of the product.

New Method for Extracting and Purifying Dihydromyricetin from Ampelopsis grossedentata

Dihydromyricetin (DMY) is a kind of flavone. It has a variety of physiological effects, and its content in Ampelopsis grossedentata is as high as 35%. There are two shortcomings in the traditional batch extraction process commonly used in a laboratory: long extraction time and low extraction rate. In this study, a new chelating extraction method was proposed, that is, Zn2+ was introduced into the extraction and purification process to chelate with DMY, and the yield and purity were taken as evaluation indices for a comparative study with the traditional batch extraction method. In addition, 1H NMR, single-crystal X-ray diffraction, IR, and UV were used to analyze the product structure; thermogravimetry and differential thermal analysis was utilized to examine the thermal stability of DMY. The results were shown as follows. Compared with the batch extraction method, the chelation extraction method could effectively avoid the oxidation of DMY by air during the extraction and purification process, and the yield of the DMY also increased. Furthermore, this method was time-saving. Through investigating the extraction process and characterizing the structure and thermal stability of DMY, the chelating extraction method could be considered to provide a reference for commercial applications of DMY.

In vitro evaluation of hydroxycinnamoyl CoA:quinate hydroxycinnamoyl transferase expression and regulation in Taraxacum antungense in relation to 5-caffeoylquinic acid production

Chlorogenic acids (CGA; including 5-caffeoylquinic acid and its regio-isomers) in Taraxacum antungense Kitag. have antioxidant and anti-inflammatory properties and exert other pharmacological effects. T. antungense hydroxycinnamoyl-CoA quinate hydroxycinnamoyl transferase (TaHQT)1 and TaHQT2, which belong to the BAHD acyltransferase family, are candidates for synthesizing 5-caffeoylquinic acid and that have not been extensively characterized. In this study, we cloned the TaHQT1 and TaHQT2 genes and analysed the properties of the expressed enzymes both in vitro and in vivo. Quantitative reverse transcription PCR analysis revealed that TaHQT1 was highly expressed in the root, whereas the strongest TaHQT2 expression was observed in T. antungense leaves. In Nicotiana benthamiana leaf cells, TaHQT1 and TaHQT2 were localized at the cell periphery as well as in the cytoplasm and nucleus. The 5-caffeoylquinic acid concentrations in T. antungense calli were reduced by TaHQT1 and TaHQT2 knockdown relative to the control. Conversely, inoculation of T. antungense plants tissues with recombinant TaHQT1 and TaHQT2 increased 5-caffeoylquinic acid levels in situ. These in vitro and in vivo findings demonstrate that both HQTs are involved in regulating 5-caffeoylquinic acid biosynthesis in T. antungense, which can be exploited to increase 5-caffeoylquinic acid production in plants for medicinal or other beneficial purposes.

Caffeine in the Diet: Country-Level Consumption and Guidelines

Coffee, tea, caffeinated soda, and energy drinks are important sources of caffeine in the diet but each present with other unique nutritional properties. We review how our increased knowledge and concern with regard to caffeine in the diet and its impact on human health has been translated into food-based dietary guidelines (FBDG). Using the Food and Agriculture Organization list of 90 countries with FBDG as a starting point, we found reference to caffeine or caffeine-containing beverages (CCB) in 81 FBDG and CCB consumption data (volume sales) for 56 of these countries. Tea and soda are the leading CCB sold in African and Asian/Pacific countries while coffee and soda are preferred in Europe, North America, Latin America, and the Caribbean. Key themes observed across FBDG include (i) caffeine-intake upper limits to avoid risks, (ii) CCB as replacements for plain water, (iii) CCB as added-sugar sources, and (iv) health benefits of CCB consumption. In summary, FBDG provide an unfavorable view of CCB by noting their potential adverse/unknown effects on special populations and their high sugar content, as well as their diuretic, psycho-stimulating, and nutrient inhibitory properties. Few FBDG balanced these messages with recent data supporting potential benefits of specific beverage types.