Epidemiological evidence has correlated consumption of sorghum with reduced incidences of gastrointestinal (GI) tract cancer, especially esophageal cancer. There is little evidence on how phenols of sorghum may affect chemoprevention. Seventeen sorghum varieties were screened for phenolic profiles and antioxidant capacity. The ability of crude sorghum extracts to induce NAD(P)H:quinone oxidoreductase (QR, a phase II protective enzyme), and inhibit proliferation of colon (HT-29) and esophageal (OE33) carcinoma cells using the MTT (3-(4,5-dimethylthiazol-2-yl)-2,5- diphenyltetrazolium bromide) and PicoGreen assays, were determined in vitro. 3- Deoxyanthocyanidins, apigeninidin, luteolinidin and their methoxylated derivatives were also investigated for antioxidant capacity, QR inducing and antiproliferative potential. Tannin sorghum generally showed higher antioxidant capacity than non-tannin sorghum varieties. Sorghum varieties containing extractable condensed tannins did not show any significant QR inducing potential; on the other hand, non-tannin sorghums increased QR activity by 1.5-2.7 times; black sorghum (Tx430) was most potent (doubled QR activity at 25 mg/mL, 2.7-fold increase at 100 mg/mL). All sorghum extracts showed relatively strong antiproliferation activity with IC50s (the concentration needed to inhibit cancer cell growth by 50%) of 49.7-883 mg/mL. Tannin-containing sorghums had stronger cancer cell proliferation inhibitory potential (IC50s 49.7-131 mg/mL) than non-tannin sorghums (IC50s 141-883 mg/mL). Total phenol content and antioxidant capacity of crude sorghum extracts positively correlated with their antiproliferative potential (r2 0.71-0.97). Among tested 3-deoxyanthocyanidins, methoxylation on A-ring improved QR inducing potency. 5,7-Dimethoxyluteolinidin had the greatest QR inducing potency (4.3- fold at 100 mM). Methoxylation also improved their antiproliferation potential; the IC50s trend was di-methoxylated (8.3-105 mM) > mono-methoxylated (40.1-192 mM) > apigeninidin and luteolinidin (81.5-284 mM). This study provides information for how phenolic compositions of sorghum and 3-deoxyanthocyanidin structure affect their capacity to induce QR activity and inhibit GI tract cancer cell proliferation. The information is useful to promote the utilization of sorghum in functional foods, beverages, dietary supplements, and other health-related industries. Further study will focus on, fractioned and isolated sorghum phenols, the effect of food processing on their chemopreventive potential, as well as cellular mechanisms involved.

O vinho tinto é rico em compostos fenólicos com atividade antioxidante, capazes de inativar espécies reativas de oxigênio, minimizando danos celulares oriundos do estresse oxidativo, proporcionando uma redução de risco para doenças crônicas não transmissíveis. Assim, os objetivos desta pesquisa foram identificar associações entre a atividade antioxidante in vitro e fatores relacionados ao tipo de uva, região de produção, perfil sensorial, safra, valor comercial e concentração de compostos fenólicos de vinhos tintos produzidos no Brasil, Chile e Argentina. Inicialmente, os vinhos brasileiros (n=29) foram avaliados em relação à atividade antioxidante (ORAC e DPPH), cor instrumental e compostos fenólicos majoritários, no intuito de verificar qual classe de fenólicos estaria associada com a atividade antioxidante. Verificou-se que tanto os compostos fenólicos totais como os flavonóides totais, com destaque aos flavonóides não-antociânicos, se associaram significativamente (p<0,05) com a atividade antioxidante. Em um segundo passo, as características sensoriais, a cor, o valor comercial e a atividade antioxidante das 80 amostras de vinhos Sul-Americanos, distribuídas em Merlot (n=9), Pinot Noir (n=17), Malbec (n=11), Syrah (n=12), Cabernet Sauvignon (n=24), e vinhos de uvas americanas (Vitis labrusca) (n=7) foram avaliados usando estatística multivariada, objetivando-se verificar se a qualidade sensorial das amostras estaria associada com o valor comercial, cor, e à atividade antioxidante. De uma forma geral, os vinhos chilenos e argentinos apresentaram maior atividade antioxidante, valor comercial, intensidade de odor, qualidade sensorial, índice de acidez e taninos, ao passo que os vinhos brasileiros obtiveram os menores valores para os atributos sensoriais. Os vinhos de uvas americanas apresentaram menores valores para todas as variáveis. As varietais Syrah, Malbec e Cabernet Sauvignon apresentaram maior capacidade antioxidante e melhores características sensoriais, sendo que esse resultado foi independente da safra e de procedência. Como última etapa, as amostras de vinhos produzidas com uva V. vinifera (n=73) foram classificadas, usando análise hierárquica de agrupamentos, de acordo com o valor comercial, qualidade sensorial e capacidade antioxidante medida por ORAC e DPPH, e os grupos foram caracterizados em relação à sua composição fenólica. Os resultados indicaram que a atividade antioxidante se correlacionou positivamente com o conteúdo de fenólicos totais, flavonóides totais, ácido gálico, quercetina, catequina, ácido ferúlico, miricetina, caempferol, e rutina, sendo que apenas os conteúdos de miricetina, ácido gálico e quercetina foram diferentes (p<0,05) entre os grupos. Nenhum composto fenólico avaliado nesse estudo associou-se com a as diferenças sensoriais dos grupos de vinho. / Red wine is rich in phenolic compounds with antioxidant activity, being able to buffer reactive oxygen species, thus decreasing the risk of non-transmissible chronic diseases. In this regard, the objectives of this research aimed at identifying associations between the in vitro antioxidant activity and factors related to grape varietal, region of production, sensory profile, vintage, color, commercial value, and concentration of phenolic compounds of red wines produced in Brazil, Chile, and Argentina. Initially, the Brazilian red wines (n = 29) were assessed in relation to antioxidant activity, instrumental color, and major phenolic compounds with the objective to verify which phenolic class was associated with the antioxidant activity. Both the total phenolic compounds and total flavonoids, with special attention to non-anthocyanin flavonoids, were significantly associated with the antioxidant activity. In a second step, the sensory characteristics, color, commercial value, and antioxidant activity of the 80 red wine samples, which were distributed in Merlot (n=9), Pinot Noir (n=17), Malbec (n=11), Syrah (n=12), Cabernet Sauvignon (n=24), and table wines (Vitis labrusca) (n=7) were evaluated using multivariate statistical techniques, with the aim to verify how the overall perception of quality of wines was related to commercial value, color and antioxidant activity. In a general way, te Chilean and Argentinean red wines displayed a higher antioxidant activity, commercial value, intensity of odors, sensory perception of quality, acidity level, and tannin level, whereas the Brazilian samples obtained the lowest values for the sensory attributes. The table wines presented the lowest values for all response variables. Syrah, Malbec and Cabernet Sauvignon varietals presented the highest antioxidant activity and most favorable sensory features, and this result was independent of wine\'s vintage and origin. As a last step, the wines produced with V. vinifera grapes (n=73) were classified, using hierarchical cluster analysis, in relation to commercial value, sensory quality and antioxidant activity measured by ORAC and DPPH assays, and the groups were characterised in relation to the phenolic composition.The results showed that the antioxidant capacity correlated to the total contents of phenolic compounds, flavonoids, gallic acid, quercetin, catechin, ferulic acid, myricetin, kaempferol, and rutin, where only the contents of quercetin, gallic acid, and myricetin were different (p < 0.05) whithin clusters. None of the phenolic compounds analysed in this research was associated with sensory differences within clusters.

O vinho tinto é rico em compostos fenólicos com atividade antioxidante, capazes de inativar espécies reativas de oxigênio, minimizando danos celulares oriundos do estresse oxidativo, proporcionando uma redução de risco para doenças crônicas não transmissíveis. Assim, os objetivos desta pesquisa foram identificar associações entre a atividade antioxidante in vitro e fatores relacionados ao tipo de uva, região de produção, perfil sensorial, safra, valor comercial e concentração de compostos fenólicos de vinhos tintos produzidos no Brasil, Chile e Argentina. Inicialmente, os vinhos brasileiros (n=29) foram avaliados em relação à atividade antioxidante (ORAC e DPPH), cor instrumental e compostos fenólicos majoritários, no intuito de verificar qual classe de fenólicos estaria associada com a atividade antioxidante. Verificou-se que tanto os compostos fenólicos totais como os flavonóides totais, com destaque aos flavonóides não-antociânicos, se associaram significativamente (p<0,05) com a atividade antioxidante. Em um segundo passo, as características sensoriais, a cor, o valor comercial e a atividade antioxidante das 80 amostras de vinhos Sul-Americanos, distribuídas em Merlot (n=9), Pinot Noir (n=17), Malbec (n=11), Syrah (n=12), Cabernet Sauvignon (n=24), e vinhos de uvas americanas (Vitis labrusca) (n=7) foram avaliados usando estatística multivariada, objetivando-se verificar se a qualidade sensorial das amostras estaria associada com o valor comercial, cor, e à atividade antioxidante. De uma forma geral, os vinhos chilenos e argentinos apresentaram maior atividade antioxidante, valor comercial, intensidade de odor, qualidade sensorial, índice de acidez e taninos, ao passo que os vinhos brasileiros obtiveram os menores valores para os atributos sensoriais. Os vinhos de uvas americanas apresentaram menores valores para todas as variáveis. As varietais Syrah, Malbec e Cabernet Sauvignon apresentaram maior capacidade antioxidante e melhores características sensoriais, sendo que esse resultado foi independente da safra e de procedência. Como última etapa, as amostras de vinhos produzidas com uva V. vinifera (n=73) foram classificadas, usando análise hierárquica de agrupamentos, de acordo com o valor comercial, qualidade sensorial e capacidade antioxidante medida por ORAC e DPPH, e os grupos foram caracterizados em relação à sua composição fenólica. Os resultados indicaram que a atividade antioxidante se correlacionou positivamente com o conteúdo de fenólicos totais, flavonóides totais, ácido gálico, quercetina, catequina, ácido ferúlico, miricetina, caempferol, e rutina, sendo que apenas os conteúdos de miricetina, ácido gálico e quercetina foram diferentes (p<0,05) entre os grupos. Nenhum composto fenólico avaliado nesse estudo associou-se com a as diferenças sensoriais dos grupos de vinho. / Red wine is rich in phenolic compounds with antioxidant activity, being able to buffer reactive oxygen species, thus decreasing the risk of non-transmissible chronic diseases. In this regard, the objectives of this research aimed at identifying associations between the in vitro antioxidant activity and factors related to grape varietal, region of production, sensory profile, vintage, color, commercial value, and concentration of phenolic compounds of red wines produced in Brazil, Chile, and Argentina. Initially, the Brazilian red wines (n = 29) were assessed in relation to antioxidant activity, instrumental color, and major phenolic compounds with the objective to verify which phenolic class was associated with the antioxidant activity. Both the total phenolic compounds and total flavonoids, with special attention to non-anthocyanin flavonoids, were significantly associated with the antioxidant activity. In a second step, the sensory characteristics, color, commercial value, and antioxidant activity of the 80 red wine samples, which were distributed in Merlot (n=9), Pinot Noir (n=17), Malbec (n=11), Syrah (n=12), Cabernet Sauvignon (n=24), and table wines (Vitis labrusca) (n=7) were evaluated using multivariate statistical techniques, with the aim to verify how the overall perception of quality of wines was related to commercial value, color and antioxidant activity. In a general way, te Chilean and Argentinean red wines displayed a higher antioxidant activity, commercial value, intensity of odors, sensory perception of quality, acidity level, and tannin level, whereas the Brazilian samples obtained the lowest values for the sensory attributes. The table wines presented the lowest values for all response variables. Syrah, Malbec and Cabernet Sauvignon varietals presented the highest antioxidant activity and most favorable sensory features, and this result was independent of wine\'s vintage and origin. As a last step, the wines produced with V. vinifera grapes (n=73) were classified, using hierarchical cluster analysis, in relation to commercial value, sensory quality and antioxidant activity measured by ORAC and DPPH assays, and the groups were characterised in relation to the phenolic composition.The results showed that the antioxidant capacity correlated to the total contents of phenolic compounds, flavonoids, gallic acid, quercetin, catechin, ferulic acid, myricetin, kaempferol, and rutin, where only the contents of quercetin, gallic acid, and myricetin were different (p < 0.05) whithin clusters. None of the phenolic compounds analysed in this research was associated with sensory differences within clusters.

Thesis (MSc Food Sc)--Stellenbosch University, 2015. / ENGLISH ABSTRACT: The sensory profiles and the phenolic composition of C. genistoides, C. longifolia, C. maculata and C. subternata, used for commercial production of honeybush tea, were determined with the aim to develop quality control tools, such as sensory wheels and statistical models to predict the basic taste and mouthfeel modalities using compositional data. Optimum fermentation parameters for C. longifolia in terms of aroma and flavour development were determined by investigating eight temperature/time regimes (80°C and 90°C for 8, 16, 24 and 32 h), using descriptive sensory analysis (DSA). Fermentation at 80°C/24 h or 90°C/24 h significantly reduced the negative sensory attributes present and produced a tea of good sensory quality. Previously, 80°C/24 h and 90°/16 h were shown to deliver optimum quality for the other three Cyclopia species. A large sample set (N = 150) consisting of C. genistoides, C. maculata and C. subternata, harvested during three production years (2010, 2012 and 2013), as well as C. longifolia harvested in 2013, was used to develop sensory wheels. All the samples were produced by fermentation at the two optimum fermentation temperature/time regimes of each species. The plant material was sourced from different production regions and plantations to ensure inherent plant variation was accommodated. The “characteristic” and generic sensory profile of honeybush was defined as a “fynbos-floral”, “woody”, “fynbos-sweet” aroma and flavour, with a sweet taste and slightly astringent mouthfeel. Species-specific sensory profiles were also identified. Cyclopia genistoides had a strong “rose geranium” flavour and a perceptible bitter taste, whereas C. longifolia had a similar sensory profile to that of C. genistoides, however, C. longifolia’s “rose geranium” flavour was less prominent and its bitter taste not perceptible. Cyclopia maculata and C. subternata were both described as having “caramel” and other “sweet-associated” notes and a slightly astringent mouthfeel. These results were used to develop a generic sensory wheel for both aroma and flavour, as well as similar wheels for each of the four Cyclopia species. Each sensory wheel reflects the relative intensity of the sensory attributes, while prevalence of the major attributes were accommodated in accompanying bar graphs. Sorting was investigated as a rapid profiling technique to serve as an alternative to the standard profiling method, descriptive sensory analysis (DSA). Instructed sorting was identified as a possible rapid sensory profiling tool for the honeybush industry, especially when samples need to be classified according to a selected list of sensory attributes. Uninstructed sorting can be used when the aim is to categorise a group of samples freely according to similarities and thus determine the natural grouping of samples within a broader sample set. The phenolic content of the respective four Cyclopia species differed qualitatively and quantitatively. Of the compounds quantified only four compounds were present in all four species, i.e. hesperidin, vicenin-2, mangiferin and isomangiferin. A larger number of compounds were present in three out of four species. The predictive value of the phenolic compounds towards the intensity of the taste and mouthfeel attributes (sweet, sour, bitter and astringent) was investigated using Pearson‟s correlation analysis, partial least squares regression (PLS) and step-wise regression analysis. Potential “candidate predictors” for taste and mouthfeel attributes were identified such as the xanthones, mangiferin and isomangiferin, being responsible for bitter taste and astringency. / AFRIKAANSE OPSOMMING: Die sensoriese profiel en fenoliese samestelling van C. genistoides, C. longifolia, C. maculata en C. subternata, waarvan heuningbostee geproduseer word, is bepaal om gehaltebeheer hulpmiddels te ontwikkel soos sensoriese wiele en statistiese modelle wat die fenoliese samestelling kan gebruik om die basiese smaak en mondgevoel eienskappe van infusies te voorspel. Die optimum fermentasie parameters vir C. longifolia in terma van aroma- en geurontwikkeling is bepaal deur agt temperatuur/tyd kombinasies (80°C en 90°C vir 8, 16, 24 en 32 h) te ondersoek met behulp van beskrywende sensoriese analise (BSA). Fermentasie by 80°C/24 h of 90°C/24 h het „n beduidende afname in die negatiewe sensoriese eienskappe veroorsaak en tot die ontwikkeling van tee met ʼn goeie sensoriese kwaliteit gelei. Die fermentasie parameters, 80°C/24 h en 90°/16 h, is voorheen aangedui as die optimale kondisies vir die ontwikkeling van „n goeie kwaliteit tee vir die ander drie Cyclopia spesies. 'n Groot stel monsters (N = 150), bestaande uit C. genistoides, C. maculata en C. subternata en ge-oes gedurende drie produksiejare (2010, 2012 en 2013), sowel as C. longifolia ge-oes in 2013, is gebruik om die sensoriese wiele te ontwikkel. Die twee optimum fermentasie temperatuur/tyd kombinasies van elke spesie is gebruik om die monsters te produseer. Plantmateriaal afkomstig van verskillende produksiegebiede en plantasies is versamel ten einde te verseker dat die monsters „n betekenisvolle hoeveelheid inherente variasie dek. Die generiese en "karakteristieke" sensoriese profiel wat met heuningbos geassosieer word, is gedefinieer as 'n "fynbos-blomagtige", "houtagtige", "fynbos-soet" aroma en geur, met 'n soet smaak en effense vrank mondgevoel. Spesies-spesifieke sensoriese profiele is ook geïdentifiseer. Cyclopia genistoides het 'n sterk "roos malva" geur en „n merkbare bitter smaak. Die sensoriese profiel van C. longifolia is soortgelyk aan dié van C. genistoides, maar sy "roos malva" geur was minder prominent en 'n bitter smaak was nie sensories waarneembaar nie. Beide C. maculata en C. subternata het waarneembare "karamel" en ander "soet-verwante" eienskappe, asook 'n effense vrank mondgevoel getoon. Die volle stel data is uiteindelik gebruik om 'n generiese sensoriese wiel vir heuningbostee, asook spesies-spesifieke sensoriese wiele vir elk van die vier Cyclopia spesies saam te stel. Die onderskeie sensoriese wiele weerspieël die relatiewe intensiteit van elk van die sensoriese eienskappe, terwyl die voorkoms-frekwensie van die onderskeie sensoriese eienskappe in gepaardgaande kolomgrafieke geillustreer is. Sortering, 'n vinnige profileringsmetode, is as alternatief tot die standaard profileringsmetode, beskrywende sensoriese analise (BSA), ondersoek. Gestrukteerde sortering is geïdentifiseer as 'n moontlike hulpmiddel vir die heuningbosbedryf om die sensoriese profiel van heuningbos te bepaal, veral wanneer „n groot aantal monsters vinning geklassifiseer moet word volgens 'n lys geselekteerde sensoriese eienskappe. Ongestrukteerde sortering kan gebruik word wanneer die doel is om „n groot aantal monsters vrylik te kategoriseer volgens hul sensoriese ooreenkomste of verskille. Die fenoliese saamestelling van die vier Cyclopia spesies het kwalitatief en kwantitatief verskil. Slegs vier van die gekwantifiseerde verbindings was teenwoordig in al vier spesies, naamlik hesperidien, visenien-2, mangiferien en isomangiferien. Meer verbindings was egter teenwoordig in drie van die vier spesies. Die voorspellingswaarde van die fenoliese verbindings tot die intensiteit van die smaak en mondgevoel eienskappe (soet, suur, bitter en vrank) is ondersoek met behulp van Pearson se korrelasie, gedeeltelike kleinste-kwadrate regressie (PLS) en stapsgewyse regressie analises. Potensiële "kandidaat voorspellers" vir die smaak en mondgevoel eienskappe, soos die xantone, mangiferien en isomangiferien, verantwoordelik vir 'n bitter smaak en vrank mondgevoel, is geïdentifiseer.

Les pyranoanthocyanes sont des pigments présents dans les vins rouges qui évoluent considérablement pendant la vinification et l’élevage. Ils contribuent à la stabilité de la couleur au cours du vieillissement. Ce sont aussi de bons marqueurs de l’oxydation d’un vin rouge. Cependant, leur impact sensoriel est encore mal connu. L’objectif de cette thèse est de mettre en évidence un possible impact gustatif des pyranoanthocyanes. Pour répondre à cette problématique, une stratégie de caractérisation, de purification et de quantification a été élaborée. La chromatographie de partage centrifuge (CPC) a été utilisée comme technique chromatographique principale pour fractionner des échantillons de vin rouge micro-oxygénés. Huit fractions de composition différente ont été collectées. La première fraction est composée essentiellement de pigments coumaroylés, la seconde fraction principalement de flavanol-pyranoanthocyanes. Les pigments de ces deux fractions ont été purifiés par CLHP préparative puis semi-préparative. L’analyse de la structure par résonnance magnétique nucléaire a permis la caractérisation de quatre nouveaux pigments. La quantification des différentes familles de pigments dans des vins micro-oxygénés ou avec des modalités variables de dioxyde de soufre a été réalisée par UCLHP-DAD-ESI-QToF. Les résultats ont montré une évolution de la contribution des familles de pigments en corrélation avec l’oxygène. En particulier, la corrélation de la concentration en hydroxyphényl-pyranoanthocyanes avec l’oxygène et le SO2 a été pour la première fois mise en évidence. Les quatre nouveaux pigments ont été quantifiés dans tous les vins étudiés. Ils ont montré le même schéma d’évolution que leurs familles de pigments respectives. Ce sont donc de bons marqueurs de l’oxydation d’un vin rouge. Les pigments des deux premières fractions issues de la CPC ont été solubilisés dans une solution modèle de vin et utilisés pour l’analyse sensorielle. La fraction 1 ne nous a pas permis de conclure quant à un possible impact sensoriel. Un test triangulaire construit autour de six concentrations croissantes a été mis en place pour la caractérisation de la fraction 2. Les dégustateurs ont perçu un impact sensoriel en bouche et décrivent de l’amertume et une sensation de rondeur. C’est un premier résultat significatif en faveur de la compréhension et de l’amélioration de la connaissance de l’impact gustatif des pyranoanthocyanes dans les vins rouges. / Pyranoanthocyanins are pigments occurring in red wines. They considerably evolve during winemaking and aging. They contribute to wine color stability during aging. They are also great markers of oxidation. However, data about their sensory impact are still scarce. In order to answer this dilemma, characterization, purification and quantification strategies have been developed. Centrifugal partition chromatography (CPC) has been used as the main chromatographic technique for micro-oxygenated red wine fractionation. Eight fractions with variable composition have been collected. The first fraction is mainly composed of coumaroylated pigments, and the second fraction mainly composed of pyranoanthocyanins-flavanols. Pigments from these fractions have been purified using preparative and semi-preparative HPLC. Nuclear magnetic resonance for structural analysis allowed characterizing four new pigments. The concentration of several groups of pigments has been evaluated in micro-oxygenated red wines of red wines with variable modalities of Sulphur dioxide, using UPLC-DAD-ESI-QToF. The results showed a correlation between the contribution of pigments and oxygen. More specifically, the correlation between the concentration in hydroxyphenyl-pyranoanthocyanins and oxygen and Sulphur dioxide has been highlighted for the first time. The four new pigments have been quantified in all wine samples. They showed the same trend than their respective groups of pigments. They can therefore be considered as good markers of oxidation.Pigments from the two first CPC fractions have been solubilized in a wine-like medium and used for sensory analysis. Fraction 1 did not allow concluding a possible sensory impact. A triangle test has been built using six increasing concentrations to evaluate the impact of fraction 2. The wine-tasters have perceived in-mouth impact and described bitterness and roundness. This is a very first significant result in favor of understanding and improving knowledge about gustative impact of pyranoanthocyanins in red wines.

Stamen from Paeonia ostii 'Fengdan Bai' and Paeonia rockii is rich in phenolic compounds and popularly used as tea materials with various pharmaceutical functions. In order to investigate whether stamen from other tree peony cultivars could be used as a natural antioxidant, the quality of stamen from thirty-five cultivars collected from the same garden was evaluated based on their phenolic composition and content by high-performance liquid chromatography analysis and in vitro antioxidant properties coupled with comprehensive chemometrics analysis. The results revealed that phenolic contents and antioxidant capacities of tree peony stamen were unique and cultivar dependent. Stamen from 'Zi Erqiao' exhibited the highest total phenolic and flavonol content, and strongest antioxidant activities, while that of 'Fengdan Bai' and P. rockii were at below-average levels among test samples. Further, thirty-seven cultivars of tree peony were divided into three major groups with a significant difference in total metabolites content and antioxidant properties, which were mainly contributed by six phytochemical compounds. Among these, naringin and benzoylpaeoniflorin were found to be critical chemical markers for the identification of tree peony stamen with high quality by chemometric analysis. Moreover, correlation analysis suggested that stamen from the earlier flowering cultivars with the hidden pistil, double petal, shorter thrum, more carpel and volume were possibly of higher quality. Together, cultivars with stamen enriched in phenolics and antioxidants properties, and their relevant critical phenotypic and phytochemical traits were screened out. This study would benefit the rapid identification of tree peony stamen with high quality and provide a valuable reference for its development and utilization as functional foods and pharmaceutical resources.

Thesis (MSc Food Sc)--University of Stellenbosch, 2011. / ENGLISH ABSTRACT: The sensory characteristics and chemical composition of rooibos infusions were analysed to establish the extent of variation in sensory attributes and compositional parameters, and investigate whether correlations exist between the sensory characteristics and the phenolic composition. To capture as much potential variation as possible, 69 rooibos samples were collected throughout the 2009 harvesting season from different production areas. The samples were also representative of the different quality grades (A, B, C or D) which are based on the appearance of the leaves, and the colour and flavour of the infusion. Quantitative descriptive analysis was used to develop sensory profiles for each of the rooibos infusions. Considerable variation in the sensory characteristics was observed, highlighting the need for standardised terminology that can be used to describe what is often referred to as “characteristic” rooibos flavour. Aroma, flavour, taste, and mouthfeel descriptors were generated and assembled into a rooibos sensory wheel. The most recurring attributes were selected to compile a rooibos sensory lexicon which provides a definition and a reference standard for clarification of each term. A combination of “honey”, “woody” and “fynbos-floral” notes with a slightly sweet taste and subtle astringency may be regarded as “characteristic” rooibos attributes indicative of good quality tea. Pleasant “caramel” and “fruity-sweet” notes were also observed in a number of infusions, whereas negative descriptors, associated with poor quality rooibos, included “green” and “hay” flavours. Large variation in the composition of rooibos infusions was revealed through the quantification of soluble solids (SS), total polyphenols (TP), tannins and 14 monomeric phenolic compounds, as well as spectrophotometric colour measurements. High quality rooibos was associated with higher levels of SS, TP, tannins and phenolic compounds than low quality rooibos. Correlations between the compositional parameters and sensory attributes of the infusions indicated that several non-volatile compounds, including enolphenylpyruvic acid-2-glucoside, quercetin-3-glucoside, and iso-orientin, were associated with the characteristic sweet taste of rooibos, while bitterness was related to certain flavonoids such as luteolin, quercetin and aspalathin. The only compound significantly correlated to astringency was rutin, although it is likely that aspalathin and several other monomeric flavonoids also contribute to astringency. The tannin content was not associated with astringency possibly because of the limitations associated with the tannin quantification method. To determine whether compositional changes resulting from steam pasteurisation of rooibos leaves influence the sensory quality of rooibos infusions, differences in the phenolic composition and sensory attributes of infusions, prepared from unpasteurised and pasteurised rooibos, were analysed. Steam pasteurisation significantly reduced the SS, TP and aspalathin content of rooibos infusions, as well as the absorbance, especially at a wavelength of 450 nm. It also resulted in significant reductions in the intensities of most of the aroma and flavour attributes, especially the “green” notes associated with low quality rooibos. After steam pasteurisation the prominent “green” flavour of certain samples was frequently replaced by a “hay” flavour. The taste attributes, sweetness and bitterness, remained unchanged, whereas the astringency of rooibos infusions decreased significantly. / AFRIKAANSE OPSOMMING: Die sensoriese eienskappe en chemiese samestelling van rooibostee is geanaliseer ten einde die mate van variasie van die sensoriese sowel as die chemiese profiel te bepaal, asook om vas te stel of korrelasies bestaan tussen die sensoriese eienskappe en die fenoliese samestelling van rooibostee. Om soveel as moontlik potensiële variasie in te sluit, is 69 rooibos monsters tydens die 2009 oesseisoen van verskillende produksiegebiede versamel. Die monsters is ook verteenwoordigend van die verskillende kwaliteitgrade (A, B, C en D), wat op grond van die voorkoms van die teeblare, en die kleur en geur van die tee toegeken is. Kwantitatiewe beskrywende analise is gebruik om ‘n sensoriese profiel vir elke rooibostee op te stel. Aansienlike variasie in die sensoriese eienskappe is waargeneem. Dit het die behoefte aan gestandaardiseerde terminologie onderskryf, wat gebruik kan word om die term “karakteristieke” rooibos geur in meer detail te omskryf. Spesifieke terme vir aroma, geur, smaak en mondgevoel is geformuleer, en gebruik om ‘n sensoriese wiel vir rooibostee saam te stel. Terme wat die meeste voorgekom het, is gekies om in ‘n sensoriese leksikon vervat te word wat ‘n definisie en ‘n verwysingstandaard vir elke term voorstel. Die “karakteristieke” sensoriese eienskappe van goeie kwaliteit rooibostee kan soos volg gedefinieer word: ’n kombinasie van “heuning”, “houtagtige” en “fynbos-blom” geure met ‘n effense soet smaak en ‘n sagte vrankheid. Aangename “karamel” en “vrugtige-soet” geure is ook waargeneem, terwyl terme soos “groen” en “hooi” met swak kwaliteit rooibostee geassosieer is. Groot variasie in die samestelling van rooibostee is verkry deur kwantifisering van die inhoud van oplosbare vastestowwe (SS), totale polifenole (TP), tanniene, en 14 monomeriese fenoliese verbindings, asook spektrofotometriese kleurmetings. Hoë kwaliteit rooibostee is geassosieer met hoër vlakke van SS, TP, tanniene en fenoliese verbindings in vergelyking met lae kwaliteit rooibos. Korrelasies tussen laasgenoemde parameters en die sensoriese eienskappe het aangedui dat sekere nie-vlugtige verbindings, bv. fenielpirodruiwesuurglukosied, kwersetien-3-glukosied en iso-orientien, geassosieer is met die kenmerkende soet smaak van rooibos, terwyl ‘n bitter smaak geassosieer is met spesifieke flavonoïede soos luteolien, kwersetien and aspalatien. Die enigste verbinding wat betekenisvol gekorreleer het met vrankheid was rutien, maar dit is waarskynlik dat aspalatien en ander monomeriese flavonoïede ook bygedra het tot vrankheid. Die tannieninhoud het nie verband gehou met vrankheid nie, vermoedelik as gevolg van die beperkinge van die chemiese metode vir tannienbepaling. Om te bepaal of stoompasteurisasie van rooibos die sensoriese kwaliteit en chemiese samestelling van rooibostee beïnvloed, is die verskille in fenoliese samestelling en sensoriese eienskappe van die tee, berei van ongepasteuriseerde en gepasteuriseerde rooibos, ondersoek. Stoompasteurisasie het ‘n betekenisvolle verlaging teweegebring van die SS, TP en aspalatien inhoud, sowel as van die absorbansie van die tee, veral by ‘n golflengte van 450 nm. Dit het ook gelei tot ‘n statisties betekenisvolle vermindering van die intensiteit van die meeste aroma en geur eienskappe, veral die sogenaamde “groen” eienskap wat met swak kwaliteit rooibos verbind word. As gevolg van stoompasteurisasie is die opmerklike “groen” geur van sekere ongepasteuriseerde monsters herhaaldelik vervang deur ‘n “hooi” geur. Die smaakeienskappe, soet en bitter, was onveranderd, terwyl vrankheid statisties betekenisvol afgeneem het as gevolg van pasteurisasie.

La consommation de fruits est encouragée pour leur apport de composés bioactifs naturels. Ce travail a pour objectif de caractériser dix fruits indignes de la région amazonienne. La caractérisation a été effectuée initialement par des analyses bromatologiques, suivies de la détermination des minéraux Ca, Cu, Fe, Li, Mg, Mn, Na et Zn par spectrométrie d'émission optique ˆ plasma couplé par induction (ICP OES). Ensuite, la capacité antioxydante des fruits a été évalué à l'aide de différentes méthodes colorimétriques (DPPH, ABTS et NBT), ainsi que l'activité antiproliférative contre la lignée cellulaire du cancer du colon humain (caco-2). La composition phénolique a été déterminée par chromatographie en phase liquide à ultra haute performance (UHPLC) couplée à la spectrométrie de masse à haute résolution. Considérant les inconvénients des méthodes conventionnelles de détermination de la capacité antioxydante, un biocapteur enzymatique ampérométrique a été mis au point en utilisant comme transducteur un systéme de trois électrodes sérigraphiées sur PVC, contenant du bleu de Prusse (PB) comme médiateur électrochimique. Une capacité antioxydante lipophile élevée a été observée dans les pulpes de biriba et de bacuri, alors les fruits abiu, inaja et monguba présentaient une capacité antioxydante hydrophile importante. L'activité antiproliférative des fruits de biriba, inaja, monguba et pajura a entrainé une inhibition significative de la croissance cellulaire de caco-2. L'analyse chromatographique des extraits de biriba, inaja et monguba, a permis de quantifier respectivement 11, 25 et 21 composés phénoliques dotés d'activités biologiques importantes. / Fruit consumption is encouraged for their contribution of natural bioactive compounds. This work aims to characterize ten indigenous fruits of the Amazonian region. Characterization was performed initially by bromatological analyzes, followed by the determination of Ca, Cu, Fe, Li, Mg, Mn, Na and Zn minerals by Inductively Coupled Plasma Optical Emission Spectrometry (ICP OES). Then, the antioxidant capacity of the fruits was evaluated using different colorimetric methods (DPPH, ABTS and NBT), as well as the ant proliferative activity against the human colon cancer cell line (caco-2). The phenolic composition was determined by ultra high performance liquid chromatography (UHPLC) coupled with high-resolution mass spectrometry. Considering the disadvantages of conventional methods of determining antioxidant capacity, an amperometric enzyme biosensor has been developed using as a transducer a system of three screen-printed electrodes on PVC, containing Prussian blue (PB) as electrochemical mediator. A high lipophilic antioxidant capacity was observed in biriba and bacuri pulps, so abiu, inaja and monguba fruit had significant hydrophilic antioxidant capacity. The antiproliferative activity of the fruits of biriba, inaja, monguba and pajura resulted in significant inhibition of caco-2 cell growth. Chromatographic analysis of birib‡, inaj‡ and monguba extracts quantified respectively 11, 25 and 21 phenolic compounds with important biological activities.

Thesis (MscAgric (Viticulture and Oenology))--University of Stellenbosch, 2009. / ENGLISH ABSTRACT: Tannins and colour components in red wine are important quality parameters. These factors can be manipulated in the vineyard by grape growing techniques or in the cellar by different winemaking practices. Grape seeds make a significant contribution to tannin concentration in wine when compared to those from the skins and pulp. Tannins contribute to the ageing potential, organoleptic properties and stabilisation of red wine colour. The colour of a red wine is also influenced by malolactic fermentation, the biological process that transforms malic acid into lactic acid which normally leads to an increase in pH. The subsequent change in pH alters the anthocyanin equilibrium, the primary colour components in red wine. Oxygen contributes to the polymerisation of anthocyanins over time to form more stable pigments that are less sensitive to pH fluctuations and sulphur dioxide bleaching. Limited research has been done on the use of oxygen after alcoholic fermentation and the impact it has on the phenolic composition of red wines. Similarly, only a few studies have examined the impact of either the addition or removal of seeds to the phenolic composition of a red wine in combination with oxygen addition. Additionally, little published data seems to exist on the effect of different pHs on red wine’s phenolic and colour development after oxygen addition. In our results we have shown that it is possible to stabilise wine colour by adding supplementary seeds before alcoholic fermentation. This led to an increase in colour intensity in certain cases. Some red wines produced without seeds had significantly lower colour intensities. This clearly suggests that catechins and proanthocyanidins are extracted from seeds and contribute to wine colour as they combine with other pigments to stabilise wine colour. Spectrophotometric and HPLC analyses have shown that the total phenolic content increased with seed concentration. However, we have observed that a wine may possibly become saturated with phenols when supplementary seeds are added. Anthocyanin concentrations often decreased when oxygen was added, while polymeric phenols and polymeric pigments sometimes increased. When applying different oxygen dosages to a red wine on commercial scale with microoxygenation, it was found that monomeric anthocyanins decreased as more oxygen was added and this decrease in anthocyanins led to the formation of stable polymeric pigments. This was reflected in the significant increase in colour intensity for the wines receiving oxygen. Small differences were detected in the total phenol and tannin concentration for the control and oxygenated wines. However, some of these phenolic and colour differences disappeared during subsequent ageing of the wine. When making wines of different initial pHs, we observed that the colour density decreased as the pH increased. The application of oxygen reduced the decrease in colour during MLF, especially at a lower pH. The addition of oxygen did not result in significantly different polymeric pigment concentrations in the various pH treatments, although the results could have been different if the wines were aged. However, pH differences in the range between 3.4 and 4.0 did not significantly influence the phenol composition of the wines under our conditions. This study led to a better understanding on the effect of oxygen additions under different conditions on red wine's phenolic and colour composition. / AFRIKAANSE OPSOMMING: Tanniene en kleur komponente teenwoordig in rooiwyn is belangrike kwaliteit parameters. Hierdie faktore wat wynkwaliteit beïnvloed kan gemanipuleer word in die wingerd deur verskeie verbouingstegnieke toe te pas en in die kelder deur die toepassing van verskillende wynbereidingsmetodes. Die bydrae van sade tot die finale tannienkonsentrasie in rooiwyn is groot in vergelyking met dié van die pulp en doppe. Tanniene dra by tot die verouderingspotensiaal, organoleptiese eienskappe en die stabilisasie van die wynkleur. Die kleur van ‘n rooi wyn word ook beïnvloed deur appelmelksuurgisting (AMG), die biologiese proses wat appelsuur omskakel na melksuur en ‘n gevolglike toename in die pH van die wyn veroorsaak. Hierdie verandering in die pH van die wyn beïnvloed die antosianien ewewig, die primêre kleur komponente teenwoordig in rooiwyn. Suurstof dra by tot die polimerisasie van antosianiene oor tyd om meer stabiele kleur pigmente te vorm met ‘n hoër kleurintensiteit wat minder sensitief is teenoor pH veranderinge en die bleikingseffek van swaweldioksied. Beperkte navorsing is gedoen op die gebruik van suurstof na alkoholiese gisting en die impak daarvan op die fenoliese samestelling van ‘n rooiwyn. Slegs ‘n paar studies het die invloed van die verwydering of byvoeging van sade in kombinasie met suurstoftoediening op ‘n rooiwyn se fenoliese samestelling ondersoek. Dit wil voorkom of beperkte gepubliseerde data beskikbaar is oor die effek wat verskillende pH’s het op rooi wyn se fenoliese en kleurontwikkeling na suurstof byvoeging. Ons resultate het aangedui dat dit wel moontlik is om in sekere gevalle die kleur van ‘n rooiwyn te stabiliseer deur addisionele sade by te voeg voor alkoholiese fermentasie. Hierdie byvoeging het ‘n toename in kleurintensiteit tot gevolg gehad. Sekere wyne wat gemaak is sonder sade het ‘n kenmerkend laer kleur intensiteit gehad. Hierdie bevinding is ‘n duidelike bewys dat katesjiene en prosianidiene geëkstraheer word vanuit die sade en bydra tot wynkleur deurdat hulle met ander pigmente verbind om die kleur sodoende te stabiliseer. Spektrofotometriese en hoë druk vloeistof chromatografie (HDVC) analises het gewys dat die totale fenoliese konsentrasie neem toe met ‘n toename in saad konsentrasie. Daar is egter waargeneem dat ‘n wyn moontlik versadig kan raak met fenole wanneer addisionele sade bygevoeg word. Antosianien konsentrasies het meestal afgeneem wanneer suurstof bygevoeg is, maar polimeriese fenole en polimeriese pigmente het partykeer toegeneem. Met die toediening van verskillende suurstof dosisse tot ‘n rooiwyn op kommersiële skaal het ons bevind dat monomeriese antosianiene afneem wanneer meer suurstof bygevoeg word. Hierdie afname in antosianiene het egter gelei tot die vorming van stabiele polimeriese pigmente. Dié bevinding was gereflekteer in die toename in kleurintensiteit van wyne wat met suurstof behandel is. Klein verskille was waargeneem vir die totale fenol en tannien konsentrasies tussen die kontrole en wyne behandel met suurstof. Sekere van hierdie fenoliese kleur verskille het egter afgeneem tydens die daaropvolgende veroudering van die wyne. Wyne wat gemaak is met verskillende aanvanklike pH’s se kleurintensiteit neem af soos die pH toeneem. Die toediening van suurstof het die kleurverlies tydens AMG verminder, veral by ‘n laer pH. Die toediening van suurstof het nie verskillende polimeriese pigment konsentrasies by verskillende pH’s veroorsaak nie, maar ‘n verskil kon moontlik waargeneem word indien die wyne verouder was. pH verskille tussen 3.4 en 4.0 het egter nie die fenoliese samestelling van die wyne onder ons omstandighede beduidend beïnvloed nie. Hierdie studie het gelei tot meer kennis oor die effek van suurstoftoedienings onder verskillende kondisies op rooiwyn se fenoliese en kleursamestelling.