There is a conflict of interest between the sorghum producers, for whom condensed tannins in sorghum have agronomic advantages, and sorghum users for whom condensed tannins in sorghum are perceived as nutritionally harmful and unpalatable. However, in recent years there has been growing interest in food phenolics due to their antioxidant potential. Thus, enhancing the content of phenolic compounds in plant foods through selective breeding and/or genetic improvement is now being viewed as a potent dietary option for disease prevention and control. However, the objectionable sensory attributes (bitterness and astringency) of phenolic compounds, especially condensed tannins, have resulted in low consumption of foods rich in these compounds. This study investigated the sensory attributes of products of sorghums varying in total phenol and condensed tannin content as well as their acceptance. A descriptive sensory panel described the sensory attributes including bitterness and astringency of two products, sorghum rice and bran infusions of six sorghum cultivars: three containing tannins and three with no detectable tannins. The products of all the sorghums (tannin and tannin-free) were perceived to different degrees as both bitter and astringent. The products of sorghums with the highest total phenol and tannin content were most bitter and astringent while those from tannin-free sorghums with the lowest total phenol content were least bitter and astringent. The products of NS 5511 (tannins - 1.8% catechin equivalents CE), were perceived similar in both bitterness and astringency to those of a tannin-free sorghum (PAN 8564). Using the Dual Attribute Time Intensity (DATI) sensory method the descriptive sensory panel determined the intensity and time course of bitterness and astringency of bran infusions of sorghums varying in total phenol and condensed tannin content. The infusion from the sorghum with the highest condensed tannin content (PAN 3860) was perceived as most bitter and most astringent and that from the tannin-free sorghum with the least total phenol content (Phofu) was least bitter and astringent. Bitterness of the sorghum infusions developed and reached maximum intensity significantly faster than astringency. The total duration of the astringency sensation lasted significantly longer than bitterness. The more bitter and more astringent the sorghum was, the longer the persistence of the bitter and astringent after-taste. The infusion of NS 5511 was again perceived similar to tannin-free sorghums in both bitterness and astringency. These findings seem to suggest that there is a condensed tannin threshold level at which the tannins are not ‘strongly’ perceived and thus are not objectionable. A consumer panel classified by 6-n-propylthiouracil (PROP) taster status assessed the colour, texture, flavour and overall liking of sorghum rice of two tannin-containing (tannin) sorghums and two tannin-free sorghums. The sorghum rice from PAN 3860, with the highest tannin content, received significantly lower acceptance ratings for all the sensory attributes than the other sorghums. With the exception of appearance, the acceptance of the sorghum rice from the tannin sorghum NS 5511 was not significantly different from that of the two tannin-free sorghums. The PROP tasters (medium and super) could distinguish differences among the sorghum cultivars varying in tannin content levels which presumably led to the significant difference in their acceptance ratings for the most bitter and astringent sorghum compared to others. On the other hand the non tasters preferred the cultivars equally, presumably because they could not detect taste differences (in bitterness and astringency) between the sorghum cultivars. The results of the consumer panel confirm the predictions made from the descriptive sensory panel results that not all the tannin sorghum products would be objectionable to consumers. It is proposed that the condensed tannin threshold level is 2.0% CE inclusive of the tannin content level of NS 5511 (1.8% CE). It is recommended that future breeding programmes investigate production of sorghums like NS 5511 with condensed tannin levels that fall within this threshold limit. The level of condensed tannins in these sorghums would provide the agronomic advantages for the farmer by reducing pre-harvest and post-harvest losses as well as provide the antioxidant benefits associated with them without negatively affecting the nutritional value of the food/feed. Since the negative sensory properties of these sorghums are not strongly perceived they would not be objectionable to consumers, thus making them a promising health option for millions of people. / Thesis (PhD)--University of Pretoria, 2009. / Food Science / unrestricted

京都大学 / 0048 / 新制・課程博士 / 博士(農学) / 甲第21310号 / 農博第2295号 / 新制||農||1063(附属図書館) / 学位論文||H30||N5144(農学部図書室) / 京都大学大学院農学研究科農学専攻 / (主査)教授 松村 康生, 教授 丸山 伸之, 教授 谷 史人 / 学位規則第4条第1項該当 / Doctor of Agricultural Science / Kyoto University / DGAM

A espécie Campomanesia phaea (O. Berg.) Landrum é popularmente conhecida como \"cambuci\". É uma das diversas espécies brasileiras de Myrtaceae com fruto comestível e ocorre nos estados de Minas Gerais e São Paulo, principalmente na Serra do Mar. Os frutos possuem intenso aroma agradável e são importantes fontes de compostos fenólicos. Apesar do excelente sabor e aroma do cambuci, a alta adstringência dos frutos, devido ao elevado conteúdo de taninos, reduz a sua aceitabilidade e aplicabilidade na indústria alimentícia. Uma maneira eficaz para remoção da adstringência é submeter o fruto a um processo de destanização, tal como atualmente utilizado para o caqui. O objetivo deste trabalho foi avaliar a variabilidade dos frutos provenientes de uma mesma região e de diferentes regiões, caracterizar frutos em diferentes estádios de maturação, avaliar a eficiência de tratamentos de destanização e determinar o efeito da destanização sobre o potencial funcional, através da determinação do teor e perfil de compostos fenólicos, capacidade antioxidante in vitro e inibição das enzimas do metabolismo de carboidratos. Os tratamentos testados foram: câmaras de etileno, câmara de etanol, ambiente anóxico, etanol no cálice e imersão em etanol. Os resultados mostram que frutos de uma mesma localidade apresentam variações no tamanho e na acidez. Frutos de diferentes regiões apresentaram variação significativa nos teores de fenólicos totais, minerais e na capacidade antioxidante. Com a maturação não foi observado grande variação no teor de sólidos solúveis totais e nem na acidez, porém o conteúdo de fenólicos decresce do estádio mais jovem para o mais maduro. Os processos de destanização com vapor e imersão em etanol foram os mais eficientes na redução do conteúdo de taninos, no entanto esses processos reduziram a capacidade antioxidante e a capacidade de inibição das enzimas α-amilase e α-glicosidase dos frutos. / The specie Campomanesia phaea (O. Berg.) Landrum is popularly known as \"cambuci\". It is one of several Brazilian species of Myrtaceae with edible fruit and occurs in the states of Minas Gerais and São Paulo, especially in the mountains of the sea. The fruits have an intense aroma and are important sources of phenolic compounds. Despite the excellent flavor and aroma of cambuci, high astringency of the fruit, due to the high tannin content, reduces its acceptability and applicability in the food industry. An effective way to astringency removal is to submit the fruit to a deastringency process, as currently used for the persimmon. The aim of this study was to evaluate the variability of the fruits from the same region and from different regions, characterize fruits in different maturation stages, evaluate the efficiency of treatments to astringency removal, and determine the effect of astringency removal about the functional potential, by determining the content and profile of phenolic compounds, antioxidant capacity, and in vitro inhibition of enzymes of carbohydrate metabolism. Treatments tested for removing the astringency were: ethylene chamber, ethanol chamber, anoxic environment, ethanol in the cup, and immersion in ethanol. The results showed that fruit in the same locality exhibit variations in size and acidity. Fruits from different regions showed significant variation in levels of total phenolics, minerals and antioxidant capacity. During maturation it was not observed a wide variation in the content of total soluble solids and acidity, but the phenolic content decreased from the younger stage to the more mature stage. The processes of detannization with ethanol steam and dipped in ethanol were the most effective in reducing the tannin content, however these processes led to reduced antioxidant capacity and capacity of inhibition of the enzymes α-amylase and α-glucosidase in fruits.

A espécie Campomanesia phaea (O. Berg.) Landrum é popularmente conhecida como \"cambuci\". É uma das diversas espécies brasileiras de Myrtaceae com fruto comestível e ocorre nos estados de Minas Gerais e São Paulo, principalmente na Serra do Mar. Os frutos possuem intenso aroma agradável e são importantes fontes de compostos fenólicos. Apesar do excelente sabor e aroma do cambuci, a alta adstringência dos frutos, devido ao elevado conteúdo de taninos, reduz a sua aceitabilidade e aplicabilidade na indústria alimentícia. Uma maneira eficaz para remoção da adstringência é submeter o fruto a um processo de destanização, tal como atualmente utilizado para o caqui. O objetivo deste trabalho foi avaliar a variabilidade dos frutos provenientes de uma mesma região e de diferentes regiões, caracterizar frutos em diferentes estádios de maturação, avaliar a eficiência de tratamentos de destanização e determinar o efeito da destanização sobre o potencial funcional, através da determinação do teor e perfil de compostos fenólicos, capacidade antioxidante in vitro e inibição das enzimas do metabolismo de carboidratos. Os tratamentos testados foram: câmaras de etileno, câmara de etanol, ambiente anóxico, etanol no cálice e imersão em etanol. Os resultados mostram que frutos de uma mesma localidade apresentam variações no tamanho e na acidez. Frutos de diferentes regiões apresentaram variação significativa nos teores de fenólicos totais, minerais e na capacidade antioxidante. Com a maturação não foi observado grande variação no teor de sólidos solúveis totais e nem na acidez, porém o conteúdo de fenólicos decresce do estádio mais jovem para o mais maduro. Os processos de destanização com vapor e imersão em etanol foram os mais eficientes na redução do conteúdo de taninos, no entanto esses processos reduziram a capacidade antioxidante e a capacidade de inibição das enzimas α-amilase e α-glicosidase dos frutos. / The specie Campomanesia phaea (O. Berg.) Landrum is popularly known as \"cambuci\". It is one of several Brazilian species of Myrtaceae with edible fruit and occurs in the states of Minas Gerais and São Paulo, especially in the mountains of the sea. The fruits have an intense aroma and are important sources of phenolic compounds. Despite the excellent flavor and aroma of cambuci, high astringency of the fruit, due to the high tannin content, reduces its acceptability and applicability in the food industry. An effective way to astringency removal is to submit the fruit to a deastringency process, as currently used for the persimmon. The aim of this study was to evaluate the variability of the fruits from the same region and from different regions, characterize fruits in different maturation stages, evaluate the efficiency of treatments to astringency removal, and determine the effect of astringency removal about the functional potential, by determining the content and profile of phenolic compounds, antioxidant capacity, and in vitro inhibition of enzymes of carbohydrate metabolism. Treatments tested for removing the astringency were: ethylene chamber, ethanol chamber, anoxic environment, ethanol in the cup, and immersion in ethanol. The results showed that fruit in the same locality exhibit variations in size and acidity. Fruits from different regions showed significant variation in levels of total phenolics, minerals and antioxidant capacity. During maturation it was not observed a wide variation in the content of total soluble solids and acidity, but the phenolic content decreased from the younger stage to the more mature stage. The processes of detannization with ethanol steam and dipped in ethanol were the most effective in reducing the tannin content, however these processes led to reduced antioxidant capacity and capacity of inhibition of the enzymes α-amylase and α-glucosidase in fruits.

According to the Centers for Disease Control, roughly 9.4% of the US population is diabetic, and at least 35% of the US population has metabolic syndrome. These diseases are associated with increased mortality risk, reduced quality of life, and altered taste perception of foods. With increased occurrence of these metabolic diseases, there is a greater need for research oriented towards using lifestyle modifications to combat illness. A relationship between flavanol consumption, health benefits, and taste perception has been well documented. Dietary flavanols are secondary plant metabolites that exist naturally in a wide array of polymerization states. The mechanisms behind the protective effects of flavanols are not entirely understood, particularly when considering how the mean degrees of polymerization (mDP), or average compound size, impacts the health benefits. Moreover, it is known that flavanol mDP influences the sensory attributes of flavanol-rich foods including bitterness and astringency. It is known that obesity and sensitivity to bitterness both influence perception of certain taste attributes such as sweetness and bitterness. The influence of these bitter and astringent sensations determined by flavanol mDP on consumer preferences for flavanol-rich products remains unknown. These influences on preference pose potential barriers to consumption, resulting in the loss of health benefits. The objectives of the research detailed here were i) to determine the effect of dietary consumption of small to medium-sized flavanols on markers of metabolic syndrome that were brought on by diet-induced obesity, ii) to determine how flavanol mDP influences the consumer perception and liking of flavanol-rich, wine-like products based on differences in consumer phenotype, and iii) to explore the potential to manipulate mDP of wine using traditional winemaking techniques. By way of an in vivo mouse model, it was observed that regardless of mDP, flavanols delivered at low dose, as part of a high-fat diet, reduced adipose-derived inflammatory cytokine production but did not prevent associated weight and fat gain. This suggests that small to medium sized flavanols may, at low dose, delay the onset of the pro-inflammatory state, which could ultimately protect against metabolic derangements associated with obesity and diabetes. Regarding the consumer acceptance of wine-like products made from flavanols of different mDP, and therefore different in bitterness and astringency intensity, it was observed in a consumer panel (n = 102) that when segmenting the panelists by body fat % and BMI classification, increased adiposity was associated with decreased ability to differentiate wine samples made with flavanols of different mDP. Moreover, differences in liking and ability to differentiate bitterness and astringency intensities were not as pronounced when segmenting the panelists based on bitterness sensitivity. This suggests that obesity may impact preference for flavanol-rich foods more so than sensitivity to flavor attributes associated with these products. Finally, in an exploratory effort to manipulate mDP of red and rosé wines using traditional winemaking techniques, no differences in mDP were observed in young wines, but significant differences in flavanol concentration were detected. It is hypothesized that aging of these wines could lead to greater differences in mDP, especially for those that had a high flavanol concentration at baseline. Future work will continue to build off these studies so that flavanol-rich products such as red wine can be optimized for health benefits and consumer acceptability of dietary polyphenols. / Ph. D. / According to the Centers for Disease Control, roughly 9.4% of the US population is diabetic, and at least 35% of the US population has metabolic syndrome. These diseases are associated with increased mortality risk, reduced quality of life, and altered taste perception for certain food types. With increased occurrence of these metabolic diseases, there is a greater need for research oriented towards using lifestyle modifications to combat illness. Dietary flavanols, which are potent antioxidants derived from plants, are being explored for their ability to mitigate chronic disease. They exist naturally in a wide variety of sizes and structures depending on plant of origin, growing conditions, and food processing conditions. It is believed that the size of these compounds impacts their health effects and influences their taste profile; smaller compounds are more bitter while larger compounds are more astringent. The purpose of this research was to determine the effect of flavanol supplementation on markers of the metabolic syndrome and how differences in taste due to differences in flavanol size influence consumer liking and perception of winelike products. It was determined in this study that dietary flavanols, delivered at low dose in the context of a high-fat diet can slightly improve fasting blood glucose levels and prevent inflammation. When examining consumer preferences for wines made from dietary flavanols that are distinctly different in terms of bitterness and astringency, it was determined that overall, consumers liked wines that were less intense in terms of bitterness and astringency. However, when examining consumers classified as having a high body fat percentage or high BMI, their ability to differentiate the wines was decreased compared to lean counterparts. These findings suggest that dietary flavanol supplementation at a physiologically relevant dose may improve symptoms of diabetes and metabolic syndrome. Future work confirming these observations in humans is warranted, as are studies devoted to better understanding of the taste preferences of the obese population. This will allow for optimization of flavanol-rich foods that maximize health benefit while also being palatable to consumers.

L’astringence est une sensation de sécheresse ressentie en bouche lors de la dégustation des vins rouges, qui résulte de la complexation entre les polyphénols du vin et les protéines de la salive, provoquant une diminution de lubrification en bouche. Parmi les protéines salivaires, les protéines riches en prolines (PRP) sont connues pour leur capacité à se lier aux polyphénols et à précipiter avec eux. Une meilleure connaissance de ce phénomène au niveau moléculaire est nécessaire pour le comprendre et le maîtriser. Il a été montré qu’un peptide de quatorze acides aminés, IB714, dont la séquence est conservée au sein des protéines riches en proline, était un mime représentatif des PRP. Un travail préliminaire par spectrométrie de masse résolue en énergie a permis de caractériser les interactions entre des polyphénols et le peptide IB714. Une échelle d’affinité en phase gazeuse a ainsi été déterminée. Cependant, cette méthodologie d’analyse d’un système modèle ne permet pas de s’accommoder de la complexité du vin. C’est pourquoi nous avons conçu une nouvelle stratégie reposant sur l'utilisation de sondes moléculaires immobilisée sur des billes magnétiques. Dans un premier temps nous avons élaboré une sonde peptidique, en greffant le peptide IB714 sur des billes magnétiques portant des fonctions carboxylates. Cette sonde peptidique a ensuite été étudiée avec des polyphénols modèles. Après sédimentation des billes magnétiques, les polyphénols non captés par la sonde ont été dosés par spectrométrie de masse en utilisant un étalon interne. Une échelle d'affinité en phase liquide a été établie de cette manière. Les positions relatives des polyphénols modèles sur cette échelle sont similaires à celles qui ont été établies en phase gazeuse. Dans un second temps, nous avons construit sur le même principe une sonde polyphénolique. Pour cela, un polyphénol modifié chimiquement a été immobilisé sur des billes magnétiques portant des fonctions amines. Cette sonde polyphénolique a été utilisée pour étudier l'interaction avec le peptide IB714. Par ailleurs, pour préparer une étude des interactions entre polyphénols et protéines salivaires avec des mélanges plus complexes que les systèmes modèles, une étude de fractionnement des protéines salivaires a été entreprise, permettant notamment de d’éliminer l’amylase, protéine majoritaire de la salive humaine. De même, un fractionnement d’un vin rouge a été entrepris pour disposer de fractions de tannins caractérisées par spectrométrie de masse. La sonde peptidique est l’outil moléculaire qui offre le plus de perspectives de développement ultérieur. / Astringency is a pucker or dry mouth sensation, typically experimented with red wine tasting, that finds its origin in the complexation of polyphenols with salivary proteins, producing a reduced lubrication of the oral cavity. Among salivary proteins, proline rich proteins (PRPs) are well known for their capacity to bind and precipitate dietary polyphenols. A better knowledge of this phenomenon at the molecular level is required in order to master it. A 14 amino acid stretch from the PRP IB7 has been synthesized and shown to be a representative mimic of PRPs. Previous work by Energy Resolved Mass Spectrometry (ERMS) allowed characterizing the keys parameters of the interactions between these polyphenols and the IB714 probe. An affinity scale in the gas phase was determined in this way. However, the ERMS approach was hardly compatible with the complexity of wine polyphenols, and a validation of the affinity scale in condensed phase was required. Thus, we designed a new strategy relying on the use of molecular probes immobilized on magnetic beads. A peptidic probe was obtained by grafting the synthetic IB714 peptide on magnetic beads bearing carboxylate functions, and used to study its interaction with model polyphenols. After magnetic precipitation of the beads, unbound polyphenols left in the supernatant were quantified by mass spectrometry using an internal standard. An affinity scale in liquid phase was established in this way. Relative positions of model polyphenols on this latter scale were similar to those determined by ERMS. A polyphenolic probe was obtained by grafting a model polyphenol on beads bearing amine functions. This probe has been used to study the interaction with IB714. To prepare further work on more complex mixtures, attempts were made to fractionate human saliva; this allowed eliminating amylase, the major salivary protein. Wine tannins were also fractionated, in order to isolate condensed polyphenols that are characterized by mass spectrometry. The peptidic probe is the molecular tool that offers the best perspectives for future work.

Les tannins sont des polymères de polyphénols présents en quantité significative dans le vin rouge, et responsables de l’astringence et de l’amertume. L’astringence est une sensation de sècheresse et de rugosité en bouche résultant d’une forte interaction entre les tannins et les protéines de la salive impliquées dans la lubrification de la cavité buccale. L’amertume, quant à elle, est un goût stricto sensu résultant de l’interaction spécifique des tannins avec les récepteurs du goût situés dans les papilles linguales. Des études récentes ont montré que les tannins sont susceptibles d’interagir avec les lipides. Or les lipides sont présents lors de la dégustation d’un vin comme composants des membranes buccales ou des aliments gras. Cependant, le rôle des lipides dans les perceptions sensorielles d’un vin n’est pas bien connu d’un point de vue œnologique. L’objectif de cette thèse était d’étudier au niveau moléculaire les interactions tannin-lipide, pour mieux comprendre leur rôle dans les propriétés gustatives du vin. Le présent travail décrit l’effet de deux entités représentatives des tannins du vin : un monomère, la catéchine, et un dimère, la procyanidine B1, sur deux modèles lipidiques. Le premier modèle est un modèle membranaire représenté par des vésicules multilamellaires composées de POPC/Cholestérol (70/30), qui mime la composition lipidique des membranes buccales. Le deuxième modèle est une émulsion huile dans l’eau (H/E) stabilisée par le DMPC, qui mime les gouttelettes lipidiques présentes dans les aliments gras. L’organisation et la dynamique des lipides composant ces deux modèles ont été étudiées par la spectroscopie RMN (1H, 2H, 13C) en présence et en absence des deux entités de tannins. Leur localisation dans les membranes lipidiques a également été explorée, de même que leur affinité pour les lipides avec la détermination des constantes d’association tannin-lipide. Les résultats ont mis en évidence un effet fluidifiant des tannins à la fois sur le modèle de membranes buccales et sur le modèle de gouttelettes lipidiques. On a démontré que cet effet de désordre est lié à la nature chimique des tannins, ainsi qu’à leur position dans la membrane. De plus, les résultats sur l’affinité tannin-lipide sont en faveur d’une compétition avec les protéines salivaires. En outre, les résultats de biophysique se sont avérés conformes avec ceux d’une analyse sensorielle menée en parallèle qui a révélé que les aliments gras sont susceptibles de diminuer l’astringence du vin. Ces travaux montrent l’impact des composés phénoliques sur l’ordre membranaire et soulignent pour la première fois un rôle potentiel des lipides sur le goût du vin. D’une part, les interactions tannin-lipide, en perturbant l’environnement lipidique des récepteurs du goût enchâssés dans les membranes buccales, pourraient affecter la fonctionnalité du récepteur et son interaction avec les tannins, et donc l’amertume. D’autre part, une éventuelle compétition entre les interactions tannin-lipide et tannin-protéine de la salive pourrait diminuer l’astringence durant la dégustation d’un vin. Dans le domaine de l’œnologie, cette thèse vient étayer le ressenti des dégustateurs à savoir la modification du goût du vin due aux aliments et ouvre de nouvelles perspectives dans le cadre de l’association mets-vins. / Tannins are polyphenol polymers present in significant amounts in red wine responsible for astringency and bitterness. The former is a tactile perception involving dryness and roughness in the mouth due to the interaction between tannins and saliva proteins and the latter is a primary taste due to the interaction between tannins and taste receptors in taste buds. Tannins are now known to also interact with lipids. Although not present in wine, lipids are yet present during tasting in the oral membranes of tasters and in fatty foods when wine is consumed during a meal. However, although the influence of lipids is well known to wine tasters through food pairing, there is no scientific evidence to support this hedonic feeling. The aim of the thesis is to study tannin-lipid interactions at molecular level in order to better understand their implication in wine gustative properties. The present work describes the effect of the main representative grape tannin subunits, the catechin monomer and the B1 dimer, both on a model of oral membranes and food fat globules. They are represented by a dispersion of POPC/cholesterol multilamellar vesicles and a olive oil in water emulsion stabilized by DMPC as emulsifier, respectively. The organization and dynamics of the lipids composing these two models were investigated by solid-state NMR spectroscopy (1H, 2H, and 13C) in the absence and the presence of the two tannin subunits. The affinity of tannins for lipids was also explored by the determination of the thermodynamic association constant. The results pointed out a fluidizing effect of tannins both on the membrane model, as previously shown on a simpler membrane model, and on the emulsion lipid droplets. The disorder caused by tannins was shown to be related to their location in the lipid structure depending on the tannin chemical nature. Moreover, the strength of the interaction between tannins and membrane lipids was revealed to be in the same order of magnitude of that between tannins and saliva proteins. In addition, the biophysical results were in accordance with those of a sensory analysis led in parallel that revealed that fatty foods are prone to decrease wine astringency. These pioneering works shows the impact of phenolic compound on membrane order and highlight for the first time the potential role of the tannin-lipid interactions on wine taste. On the one hand, by disrupting the lipid environment of taste receptors embedded in oral membranes, tannin-lipid interactions could affect the receptor functionnality and therefore the interaction with tannin molecules, so bitterness. On the other hand, the existence of a possible competition between lipids and saliva proteins for interacting with tannins during tasting could reduce astringency.

No description available.

Lors de l’élevage des vins avec le bois de chêne, plusieurs molécules d’intérêts organoleptiques comme les ellagitanins (vescalagine, castalagine, roburines A, B, C, D, E et grandinine), sont extraites. Leurs concentrations dans le bois et le vin sont très variables et leurs cinétiques d’extraction au cours de l’élevage ainsi que leurs propriétés organoleptiques dans les vins sont mal connues. Dans le but de classifier chaque douelle pour fabriquer des barriques avec des indices en polyphénols (IP) totaux significativement différents, un système proche infrarouge (NIRS), Oakscan®, a été mis en place par la tonnellerie Radoux. Notre objectif était d’étudier l’influence de ce mode de classifications des bois au niveau de la composition moléculaire et organoleptique des vins. Dans un premier temps, la classification NIRS des bois de chêne a été confirmée par quantification des concentrations en ellagitanins totaux et moléculaire par HPLC-UV-MS. Une forte variabilité des concentrations en ellagitanins des bois est observée entre 5,95 et 32,91 mg d’équivalent acide ellagique/g de bois. De plus, la classification NIRS des bois se corrèle avec les analyses chimiques (p < 0,02%). Cette nouvelle méthode permet donc de fabriquer des barriques avec un IP moyen différent (IP : 11 à 70). Dans un second temps, des vins de différentes origines et cépages sont élevés dans les barriques classifiées. La cinétique des teneurs en ellagitanins montre l’influence de la classification des bois de chêne (p < 5%). En effet, dès les premiers mois d’élevage, une augmentation en ellagitanins jusqu’à un maximum est obtenue. Plus les bois sont riches, plus le maximum de concentration en ellagitanins des vins est élevé et décalé dans le temps. Puis, une lente diminution des concentrations en ellagitanins est observée. Les influences du grain et de la chauffe des bois ont également été analysées. La solubilisation dans les vins des composés aromatiques des bois de chêne classifiés par Oakscan® montre dans plusieurs cas que les teneurs en aldéhydes furaniques et en syringol impliqués dans les perceptions du fumé/grillé sont corrélées avec la classification NIRS et également avec l’IP des bois. Ainsi, un vin élevé au contact de bois riches en polyphénols possède des concentrations en arômes fumé/grillé plus importantes. Néanmoins, l’intensité de la chauffe a un rôle prépondérant sur les concentrations de ces arômes boisés. Parallèlement, les propriétés organoleptiques des vins élevés avec du bois de chêne à 6, 12, 18 ou 24 mois et testées par un jury entrainé, montrent des différences significatives corrélées à l’IP des barriques. Les vins élevés au contact des IP les plus importants sont significativement décrits comme plus boisés, fumés/grillés et épicé au nez. En bouche, l’amertume et l’astringence sont significativement plus importantes pour les vins élevés dans les barriques possédant les plus fortes concentrations en ellagitanins. A contrario, le fruité des vins, au nez et en bouche, est généralement noté comme moins important pour les vins élevés avec des barriques à IP le plus haut.L’influence de la classification des bois, en fonction de leurs grains et de leurs IP, sur la consommation en oxygène des vins rouges a été suivie grâce à une méthode innovante et non invasive. Les résultats montrent que 96% de l’oxygène dans le vin à T0 est consommé huit jours après entonnage. Des différences significatives (p < 0,01%), entre les vitesses de consommation de l’oxygène et l’IP ou le grain des barriques, sont observées. La vitesse de consommation d’oxygène augmente en corrélation de l’IP des barriques ou de la taille du grain. Ces résultats permettent d’envisager l’utilisation de méthodes de sélection non empiriques et fiables des bois de chêne en fonction de leurs grains ou de leurs concentrations en ellagitanins ce qui permet de fabriquer des barriques classifiées à l’aide de nos résultats conférant, au vin, des propriétés organoleptiques maîtrisées. / During the wine aging with oak wood, some compounds with interesting organoleptic properties such as ellagitannins (i.e., vescalagin, castalagin, roburins A, B, C, D, E and grandinin) are extracted. The ellagitannins concentrations in oak wood and wine are highly variable and their extractions kinetic during the aging as well as their organoleptic impacts on wines are poorly known and still unclear. In order to classify each stave according to their polyphenolics index (IP) before making the barrels, an infrared system (NIRS), Oakscan®, was develop by the tonnellerie Radoux. Our aim was to study the influence of this wood classification on the wines molecular composition and organoleptic properties.In the first place, the NIRS oak staves classification has been confirmed by the determination of the total ellagitannins concentration as well as the specific levels of each ellagitannins molecule by HPLC-UV-MS. A high variability of the ellagitannins level in wood between 5.95 ± 0.30 and 32.91 ± 0.98 mg ellagic acid equivalent/g of dry wood was observed. Furthermore, the wood infrared classification is correlated with chemical analyzes (p < 0.02%) and allow the production of barrels with different IP (IP: 11, 12, 16, 21, 26, 30, 35, 36, 39, 40, 41, 50, 51, 53, 62, 67 et 70).In a second place, some wines were aged in the classified barrels. The ellagitannins levels show the oak wood classification influences (p < 5%). Indeed, the first months of aging, the ellagitannins concentration increased until a maximum was obtain . Indeed, this maximum concentration in wine aged in barrel manufactured with the wood richer in ellagitannins was higher and latter (2.30 ± 0.05 after 4 months and 11.56 ± 0.31 mg ellagic acid equivalent/L of wine after 12 months respectively for the IP 21 and IP 70 barrels). After this maximum, a slow decrease of the ellagitannins level was observed. The influences of grain and toasting were also analyzed. The aromatics compounds solubilization of classified oak wood by Oakscan® show that the furanic aldehydes levels (furfural, alcool furfurylique et 5-méthylfurfural) and the syringol involved in the smocked/toasted aromas were correlated with the NIRS classification and the wood IP. So, a wine aged in contact with wood richer in polyphenols compounds was describe as more smocked/toasted. Nevertheless, the toasting intensity (which formed these compounds by thermo-degradation of hemicelluloses and lignins) plays a major role on their concentrations. Moreover, organoleptic properties of the wines aged with oak wood (barrels, staves) at 6, 12, 18 or 24 month and tested by trained judges were significantly impacted by the IP barrels. In fact, wine with the highest ellagitannins level was significantly described with a higher woody, smoked/burned and spicy in nose. In mouth, the bitterness and the astringency were significantly higher in wine containing the highest ellagitannins level. Whereas, the wine fruity aroma, in nose and mouth, was generally descript as lower in wine aged with the barrel with the IP higher.The influences of wood classification, in relation with the grain and the IP, on the red wine oxygen consumption after being put into barrels were analyzed with a new no invasive method. The results show that 96% of the oxygen in wine at T0 was consumed after 8 days. Significant differences (p < 0.01%) between the oxygen consumption speed and the barrel IP or the grain were observed. The oxygen consumption speed increase with correlation of barrel IP or the size of grain. These results allows the utilization of method not empirical and reliable method to select oak wood regarding their grain or their ellagitannins concentration in order to be able to produce oak barrels classified by means of our results to give organoleptic properties controlled to the wine.

Made available in DSpace on 2016-04-28T14:58:38Z (GMT). No. of bitstreams: 1 Augusto CesarVieira Neves Junior.pdf: 2971994 bytes, checksum: e609bbbaf217d220df7b14eb6fba68bf (MD5) Previous issue date: 2009-07-21 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / Minimally processed products are safe and ready to eat, in spite of adding value, has a short life. Edible coatings can be an important tool to ensure the quality and increase the shelf life of minimally processed products, including persimmon. The 'Mikado' variety Persimmon has astringency and need a specific astringency process to get a minimally processed product with quality. Therefore, the objective of this work was to develop and characterize the edible coatings for use in 'Mikado' minimally processed persimmon. It was necessary to determine the exposure time of the fruit to alcohol vapor until the decrease of astringency. It was performed the flowchart for the fresh-cut of persimmon evaluating the quality of the final product. Evaluations of thickness, gas permeability, mechanical properties of coatings applied were also performed. It was also verified the efficiency of use 70% alcohol (7.00 mL ?lcool.Kg-1 fruit) to reduce astringency. There were performed the following analysis: firmness, pH, total soluble solids (? Brix), total titratable acidity, total tannins and weight loss and sensory analysis during the process. These analyses were necessary to determine the time of exposure to the alcohol vapor to decrease the concentration of soluble tannic acids in fruit that it was not tasted by panelists and determine that concentration. It was evaluated persimmon storage with and without coatings. Three experiments were conducted during this work. In the first experiment, it was set up two coatings which were used in the second trial of minimally processed. It was evaluated four different types of coatings: cassava starch, sodium alginate, carboxymethyl cellulose (CMC) and bovine gelatin. In the first experiment (edible coating), it was set up two coatings which were used in the experiment of minimally processed. Four different types of coatings were evaluated: cassava starch, sodium alginate, carboxymethyl cellulose (CMC) and bovine gelatin. In the second experiment (astringency reduction) it was defined the time required to keep the fruits in alcohol atmosphere to reduce total soluble tannins tasted by panelists. The times tested were: 10 hours, 36 hours, 55 hours, 83 hours, 107 hours, 130 hours and 155 hours. It was defined a flowchart for persimmon minimally processed. The best coatings applied in minimally processed persimmon were the cassava starch and CMC. The firmness of the fruit remained until to 55 hours of exposure to alcohol vapor. Fruits were exposure to 83 hours or up caused loss firmness below that it is commercially tolerated. The astringency was not tasted by panelists from 55 hours exposure of alcohol vapor. The threshold detection of total soluble tannin in the pulp of fruit was 0.8161 ?g.100g-1. The tannins content decrease with the increasing exposure of fruit to alcohol vapor. The reduction of astringency with 70% alcohol vapor may not be the most indicated method due to high losses in this step (21.76%). The minimally processed fruits treated with CMC coating showed less dark spots in the pulp than the other treatments and all treatments were microbiological adequates. / Produtos minimamente processados s?o produtos seguros e de pronto consumo, que apesar de agregar valor, possui uma vida ?til mais reduzida. Os revestimentos comest?veis podem se constituir em importante ferramenta para garantir a qualidade e estender a vida ?til de produtos minimamente processados, entre eles, o caqui. O caqui Mikado por ser adstringente necessita de um processo adequado de destaniza??o para gerar um produto minimamente processado de qualidade. Diante disto, este trabalho teve como objetivos o desenvolvimento e caracteriza??o de revestimentos comest?veis para a utiliza??o em caqui Mikado minimamente processado, determina??o do tempo necess?rio de exposi??o ao vapor de ?lcool para que o fruto n?o apresente adstring?ncia e elabora??o de um fluxograma para o processamento m?nimo de caqui com avalia??o da qualidade do produto final. Para o desenvolvimento e caracteriza??o dos revestimentos foram realizadas avalia??es de espessura, permeabilidade gasosa, propriedades mec?nica e pr?via sensorial do caqui Mikado minimamente processado tratados com os revestimentos comest?veis. Definiram-se dois revestimentos [amido de mandioca e carboximetilcelulose (CMC)], a partir de quatro revestimentos (amido de mandioca, alginato de s?dio, CMC e gelatina bovina) para serem testados em caqui minimamente processado. Foi tamb?m avaliado o tempo de exposi??o ao vapor de ?lcool a 70% (7mL de ?lcool.Kg-1 de fruto), por meio de an?lises f?sicas, qu?micas e sensoriais. Tais analises foram necess?rias para determinar o tempo de exposi??o ao vapor de ?lcool que diminuiria a concentra??o de ?cido t?nico sol?vel nos frutos at? que este n?o fosse mais sensorialmente percept?vel, determinando esta concentra??o e verificando-se se o fruto tinha firmeza adequada ao minimamente processado. Desta forma, foi poss?vel determinar o limiar de detec??o dos taninos sol?veis (0,8161?g.100g-1) e o tempo de exposi??o ao vapor de ?lcool mais adequado para o processamento m?nimo, que provavelmente estava entre 55 e 83 horas, sendo que os tempos testados foram de: 10 horas; 36 horas; 55 horas; 83 horas; 107 horas; 130 horas; e 155 horas. A firmeza dos frutos se manteve adequada at? as 55 horas de exposi??o ao ?lcool, sendo que um tempo igual ou superior a 83 horas de exposi??o causou perda de firmeza a um n?vel abaixo do tolerado comercialmente. Por fim foi obtido um fluxograma da produ??o de caqui Mikado minimamente processado e avaliado o armazenamento com e sem revestimentos, sendo realizado para isto analises f?sicas, qu?micas, microbiol?gicas e sensoriais ao longo do per?odo de armazenamento de 10 dias. Para a realiza??o deste experimento (processamento m?nimo de caqui) utilizou-se revestimentos de amido de mandioca e de CMC, e o tempo de destaniza??o foi de 70 horas. Verificou-se que a destaniza??o neste tempo pode n?o ser a mais adequada devido ?s altas perdas verificadas nesta etapa (21,76% dos frutos n?o se mostraram adequados ao processamento m?nimo). Os frutos minimamente processados tratados com revestimento de CMC apresentaram-se com menos manchas na polpa que os demais tratamentos e todos os tratamentos mostraram-se adequados microbiologicamente.