Increasing the antioxidant power of tea extracts by biotransformation of polyphenols

Green tea (Camellia sinensis) and yerba mate (Ilex paraguariensis) are rich in polyphenolic compounds, which are thought to contribute to the health benefits of tea. The aim of this study was to evaluate the potential antioxidant properties of green tea and yerba mate extracts before and after the enzymatic biotransformation reaction catalysed by the Paecilomyces variotii tannase. The antiradical properties of the tea extracts, as well as the standards of chlorogenic acid and EGCG, were assessed using the ORAC and DPPH assays before and after the tannase biotransformation. The antioxidant power of enzyme-treated green tea and yerba mate increased by 55% and 43%, respectively, compared with that of untreated teas. The antioxidant power of the standards was also highly increased by enzyme treatment. These results provide relevant data about the potential of the tannase application on various polyphenol sources and to increase the antioxidant power of two widely consumed beverages.     

Aqueous extracts of yerba mate (Ilex paraguariensis) as a natural antimicrobial against Escherichia coli O157:H7 in a microbiological medium and pH 6.0 apple juice

Ilex paraguariensis is popularly used in the preparation of a tea infusion (yerba mate), most commonly produced and consumed in the South American countries of Uruguay, Paraguay, Argentina, and Brazil. In this study, aqueous extracts of commercial tea, derived from the holly plant species I. paraguariensis were evaluated for their ability to inhibit or inactivate Escherichia coli O157:H7 in a microbiological medium and modified apple juice. Dialyzed, lyophilized aqueous extracts were screened for antimicrobial activity against E. coli O157:H7 strains ATCC 43894 and 'Cider' in tryptic soy broth (TSB) and apple juice (adjusted to pH 6.0 to allow for growth of the bacterium). A mixture of the two strains was used as the inoculum when apple juice was used as the medium. MBCs were determined to be ca. 5 and 10 mg/ml for ATCC 43894 and 'Cider', respectively, in TSB. Higher concentrations of the extract were required to inactivate E. coli O157:H7 in pH-adjusted apple juice. An approximate 4.5-log reduction was observed for E. coli O157:H7 treated with 40 mg/ml extract. It was concluded that aqueous extracts from commercial yerba mate have potential to be used as antimicrobials in foods and beverages against pathogenic E. coli O157:H7.     

LC/MS characterization of phenolic constituents of mate (Ilex paraguariensis,St. Hil.) and its antioxidant activity compared to commonly consumed beverages

Mate is a tea-like beverage widely consumed in South America, prepared from the dried leaves of Ilex paraguariensis, St Hil. The total polyphenols (PP) and antioxidant activity of mate infusions and acid–methanol/acetone extracts were determined in three commercial brands, and compared to commonly consumed beverages like green and black teas, red, rosé and white wines, and orange juice. Mate had a PP content comparable to tea and orange juice, and, when normalized for the PP content of beverages, mate had an antioxidant activity slightly higher than wines, orange juice and black tea, but lower than green tea. LC/MS analysis of mate extracts showed that caffeoylquinic and dicaffeoylquinic acid isomers were the major components of the phenolic fraction of mate. Mixed mono-, di- and tri-esters of quinic acid and other hydroxycinnamates were also detected. Several quercetin and kaempferol glycosides were identified. Consumption of mate infusions would significantly contribute to the overall antioxidant intake, providing high amounts of caffeoylquinic acid derivatives, with biological effects potentially beneficial for human health.     

保健酒认知与消费行为分析——以山东市场为例

为研究消费者对保健酒的认知情况和消费行为,在山东省进行调查并进行实证分析。结果显示,认知方面,部分消费者在保健酒所属范畴、适用对象上存在误区,48.20%的消费者认为保健酒发展前景较好,仅19.97%的消费者文化认知水平较高。饮用行为方面,43.53%的消费者为长期忠实顾客;大部分消费者饮用频率很低,并能理性消费;基于调理身体、亲人朋友聚餐等原因,主要在家庭和酒店饮用。整体来看,饮用满意度评价为一般,且大部分消费者更偏爱国产品牌。购买行为方面,51.73%的消费者购买比较频繁,其目的主要为孝敬长辈和保健自饮。大部分消费者更青睐中低价位的知名品牌,81.13%的消费者选择在实体商超购买。影响购买决策的主要因素包括组织与产品、功效作用、包装配送、文化资质。     

Consumer preferences for the color of unprocessed animal foods

Consumer choices for food products are often based on appearance; one important aspect being product color. We systematically review the literature on consumer preferences for the color of raw beef, pork, poultry, bee honey, cow milk, and chicken eggs to inform future food technology and marketing research; a total of 40 studies were identified. Consumer preferences for pork color vary widely globally and can depend on other demographic factors. A trend toward light and bright beef was observed in six out of eight studies. A pink color was preferred in chicken by consumers in Northern Ireland and Brazil; muscle color uniformity was also related to higher acceptance. Contrarily, a diverse selection of honey colors is preferred; dark golden, yellow, and amber products were liked by consumers across the globe. One study observed a preference for white (over yellowish) milk. Worldwide, white and brown eggshells are preferred nearly equally with considerable differences between continents and regions. Our review highlights the heterogeneity of color preferences for animal products, worldwide; research methods should focus on quantifying colors associated with preferences so that food producers can accurately market their diverse products in regions with corresponding color preferences.     

Flavour characteristics of Ilex paraguariensis infusion,a typical Argentine product,assessed by sensory evaluation and electronic nose

Sensory evaluation and electronic nose (E‐nose) technology were applied to study two formulations of a new product intended to have organoleptic characteristics similar to those of Ilex paraguariensis (Saint Hilaire) infusions. Infusions prepared from I paraguariensis, called ‘yerba mate’ in South America, possess distinct sensory properties that were described by trained panellists using a lexicon of 17 terms. The two commercial products were formulated by combining various flavour components and processed as instant powders for infusion. Results from the sensory panel showed that it would be necessary to change the product formulation in order to achieve desirable yerba mate characteristics. Odour, mouthfeel and sweetness intensities would have to be improved. The E‐nose had an array of 32 sensors which were able to discriminate between infusions prepared from yerba mate and from the instant powders. Using stepwise discriminant analysis, the group of sensors that contributed to this classification was identified. The response of these sensors correlated (P < 0.05) with yerba mate odour, mouthfeel and sweetness attributes. Comparison of the results obtained by the two methodologies enabled the E‐nose procedure to be improved and showed that this methodology is suitable for food product development and is a good complement to sensory evaluation. Copyright © 2004 Society of Chemical Industry     

An investigation on the appropriateness of chocolate to match tea and coffee

The aim of this study was to provide some recommendations for selecting a befitting tea and coffee to match chocolate with different cocoa contents. Three coffee samples (chocolate flavored, vanilla flavored and unflavored coffee), four tea samples (black tea, green tea, vanilla flavored tea and citrus flavored tea) and three chocolates (30%, 70%, and 99% cocoa) were hedonically rated by eighty regular chocolate consumers. The beverages were then paired with each chocolate, and the consumers were asked to indicate the hedonic liking of the resulting pairings, and to indicate whether the chocolate or beverage flavor dominated the pairing flavor. This study showed that liking of chocolate and coffee pairings and chocolate and tea pairings significantly varied (p < 0.001) across samples. Consumers preferred pairings with 30% cocoa and 70% cocoa chocolate to pairings with 99% cocoa chocolate. Overall, coffee is significantly (p < 0.001) preferred to tea as a chocolate partner.Chocolate and beverage pairing liking was biased by the liking of the beverage tasted alone, the liking of chocolate tasted alone, beverage type, chocolate type and the level of flavor match between chocolate and tea or coffee in a given pairing. When chocolate and beverage flavor balanced out in a given pairing, chocolate and coffee/tea pairings were significantly preferred by the consumers. A significant decrease in acceptance was observed when beverage or chocolate flavor dominated the flavor of the pairing, much more so when the chocolate flavor dominated the pairing flavor. However consumers don't enjoy any preferred chocolate with any preferred tea or coffee because some flavors match better than do others. Indeed, consumers formulate their hedonic responses taking into consideration what flavors go well together more than they rely exclusively on their hedonic judgments of the chocolates, the teas, and the coffees tasted alone.     

HPLC determination of caffeine in tea,chocolate products and carbonated beverages

Different brands of mate and black tea, chocolate products and carbonated beverages available on the Brazilian market were analysed for caffeine by high-performance liquid chromatography with a UV-vis detector at 254 nm. The column was a reverse phase C18 and the mobile phase consisted of methanol–water (30:70, v/v), acetonitrile–water (10:90, v/v) and methanol–water (25:75, v/v) for tea, chocolate products and soft drinks respectively. Caffeine content ranged from 1.05 to 15.83 mg per cup in mate tea, from 32.21 to 36.23 mg per cup in black tea, from 0.14 to 0.95 mg g⁻¹ in chocolate products from 2.73 to 7.49 mg per can in guaraná-type soft drinks and from 19.81 to 45.89 mg per can in cola soft drinks. These data indicate that the levels of caffeine in Brazilian teas, chocolates and soft drinks are within the ranges reported for similar products in other countries. © 1999 Society of Chemical Industry     

Comparison of the Antioxidant Properties of Commonly Consumed Commercial Teas

The antioxidant properties of various commonly consumed commercial teas were screened and compared to check what the consumers get in commercial tea bags in the range of consume preparation conditions. It includes flavored black teas and green teas, as well as some fruit teas. Electron transfer-based assays, such as phenolic content by Folin-Ciocalteu method and cupric ion reducing antioxidant capacity (CUPRAC), were applied. Higher antioxidant activity values were obtained for green and black tea infusions in comparison to fruit teas. The correlation between FC total phenolic and CUPRAC assay for all studied teas was significant (R² = 0.871). The antioxidant power of tea infusions were also measured using cyclic voltammetry. The observed anodic waves were broadened in comparison with voltammograms of single flavonoids due to the response of several antioxidants with different oxidation potentials. The values of Trolox equivalents obtained by electrochemical approach were lower than in the CUPRAC assay; however, the increased order of the antioxidant capacity of tea infusions was the same.     

消费者Check-all-that-apply和喜好度测试在植物近水饮料感官评定中的应用研究

本研究采用check-all-that-apply（CATA）法与喜好9点标度法相结合的消费者快速感官评价方法,对马尾松、淡竹叶、桑叶、菊花、桂花、薄荷、紫苏、桦树汁露8种草本植物近水饮料的感官特征进行分析。消费者在19个口感和24个气味属性描述词中勾选,对8款近水饮料样品进行感官和喜好度评定。喜好度分析结果表明,消费者对8款植物近水饮料的喜好度存在差异,消费者对薄荷露和桂花露整体喜好度较高,两者差异不显著（P<0.05）。Cochran’s Q test分析结果表明,样品在41个感官属性中均存在显著性差异（P<0.05）。对应分析（Correspondence Analysis,CA）结果说明了8种植物近水饮料之间感官特征的差异,薄荷露感官特征突出,具有清凉、薄荷的特征属性;桂花露感官属性主要表现为桂花香、桃香、甜香;菊花露、紫苏露、桑叶露具有相似的绿茶、甘草、菊花等感官属性;马尾松与淡竹叶露感官特征相似;桦树汁露感官特征不明显。结合消费者李克特量表数据进行惩罚分析（Penalty Analysis,PA）,本研究发现注重健康人群并未对产品中草药气味表现出显著的不接受;有饮水添加助饮物习惯的人群更偏好甜香、清凉、金银花的感官特征。因此,消费者快速感官评价CATA法能够有效测试产品的感官属性和消费者偏好,并在新产品开发和市场调研方向展现出广阔的应用前景。     

The effect of the duration of infusion,temperature, and water volume on the rutin content in the preparation of mate tea beverages: An optimization study

The consumption of tea beverages has increased 30% over the last decade, mainly due to the presence of bioactive compounds. Mate tea, produced by infusing the leaves and stems of Ilex paraguariensis, is the most widely consumed beverage in Brazil. The present study employed a central composite experimental design to optimize the transfer of rutin from the leaves and stems to the beverage during the infusion process. The optimum condition was applied to three batches of mate tea beverages from five commercial samples. Analysis of the rutin content was performed by high performance liquid chromatography coupled to a photo diodo array detector. The maximum rutin content in the beverage was obtained when the infusion was performed using 2 g of mate tea added to 100 mL of water at 72 °C and infused for 9 min. The commercial tea beverages prepared under these conditions contained from 0.16 to 1.1 mg of rutin in the ready-to-drink product.     

Consumer preferences for iced coffee determined by conjoint analysis: an exploratory study with Norwegian consumers

The main aim of this study was to investigate consumer preferences for extrinsic attributes of iced coffee, explore consumers' coffee consumption habits, find new market opportunities and segment consumers based on similar products preferences. A sample of 101 consumers of iced coffee was recruited during 2012 in Norway. Twelve iced coffee products combining different levels of attributes such as coffee type, origin, calories and price were presented on screen and rated according to consumers' willingness to buy (WTB). Mixed model anova , principal component analysis (PCA) and partial least squares discriminant analysis (PLS‐DA) were applied to analyse data. Results show that the most preferred products for the consumer sample as a whole were low‐price low‐calorie products, while age has a significant effect on WTB for different iced coffee products. Four different consumer segments based on type of iced coffee and country of production preferences were identified and discussed.     

Assessment of dietary exposure to flavouring substances via consumption of flavoured teas. Part 1: occurrence and contents of monoterpenes in Earl Grey teas marketed in the European Union

Estimations of dietary exposure via the consumption of flavoured foods play a central role in the safety evaluation of flavouring substances. To assess uncertainties, actual data regarding the occurrence and concentration levels of flavouring substances were determined in commercially available flavoured foods, using Earl Grey tea as an example. The contents of the consistently occurring monoterpenes linalyl acetate, linalool, limonene, β-pinene and γ-terpinene were determined in 90 tea samples purchased in 10 European Union member states. Rather narrow frequency distributions were observed for the major compounds linalyl acetate and linalool. The factors (1) country of purchase, (2) source of the products (national/international brands versus private label brands versus speciality tea shops), and (3) enantiomeric purities of the flavouring substances had no significant impact on the contents of the flavouring substances. Only in teas sold as loose leaves were the median contents of linalyl acetate and linalool (66% and 39%, respectively) higher than in teas offered in tea bags. Significant losses of flavouring substances were observed on storage of teas, indicating an impact of the type of packaging and the flavouring technology on the contents of flavouring substances in the product finally consumed.     

Phytochemicals and bioactive properties of Ilex paraguariensis: An in-vitro comparative study between the whole plant,leaves and stems

The leaves, stems and whole plant of Ilex paraguariensis (yerba mate) were characterized in terms of their chemical composition and biological activities in order to determine which part of the plant is more interesting to develop bioactive formulations. The yerba mate samples contain at least five free sugars, five organic acids, eighteen fatty acids, one tocopherol, nine hydroxycinnamoyl derivatives and two flavonols. The leaf extract revealed the highest antioxidant activity, correlating with its highest levels of phenolic compounds. By contrast, the stem extract showed the highest anti-inflammatory potential and was also the most potent against MCF-7 and HepG2 cell lines, probably due to the presence of other phytochemicals. The absence of hepatotoxicity in the extracts was confirmed in porcine liver primary cells. Although the yerba mate extracts have been widely studied, this report shows for the first time the distinct potentialities of each individual part of the plant.     

Characterization of aroma-impact compounds in yerba mate (Ilex paraguariensis) using GC–olfactometry and GC–MS

The volatile compounds of 18 yerba mate (YM) commercial brands from Argentina, Brazil, P.araguay and Uruguay were extracted using a Likens–Nickerson simultaneous distillation–extraction (SDE) apparatus, and analyzed by gas chromatography–mass spectrometry (GC–MS). Results showed that a total of 35 major volatile compounds were identified by GC–MS; among them, norisoprenoid compounds. A principal component analysis (PCA) was carried out in order to ascertain the degree of differentiation between samples and which compounds were involved. The results showed three main groups of YM corresponding to the places where they are commercialized. The first group (samples from Paraguay and Argentina) correlated positively with 6-methyl-5-hepten-2-one, octanal and 1-octanol. The second group (YM marketed in Uruguay but produced in Brazil) correlated positively with α- and β-ionone, linalool, nerol, α-terpineol, (Z)-linalool oxide and the aliphatic hydrocarbons undecane, dodecane and heptadecane. The third group (YM produced and marketed in Brazil) correlated positively with 2,4-heptadienal isomers, (E)-linalool oxide and β-cyclocitral. Through a preference test, one commercial brand was selected to be analyzed by gas chromatography–olfactometry (GC–O). Sixteen odor active compounds were perceived by GC–O analysis. It seems that the norisoprenoid compounds and components produced by fatty acid degradation play a vital role in the special aroma of yerba mate.     

Authentication of yerba mate according to the country of origin by using Fourier transform infrared (FTIR) associated with chemometrics

This study deals with the development of a method for classification of yerba mate (Ilex paraguariensis) using attenuated total-reflectance Fourier transform infrared (ATR-FTIR) and multivariate analysis. Fifty-four brands of yerba mate from southern South America were analysed in order to classify the commercialised yerba mate according to the respective country of yerba mate processing. The yerba mate was ground in a cryogenic mill, and the reflectance was directly measured in the region ranging from 4000 to 650 cm^?1. Different pre-processing algorithms and three methods of multivariate analysis were investigated, including principal component analysis (PCA), partial least square discriminant analysis (PLS-DA) and support vector machine discriminant analysis (SVM-DA). The yerba mate classification was 100% correct when the reflectance spectra were pre-treated (derived at first order, normalised by standard normal variation, smoothed and mean centred) and analysed using the SVM-DA method.