O objetivo deste trabalho foi produzir pigmentos em pó a partir dos subprodutos de vinificação da uva tinta, variedade Bordô (Vitis labrusca), através da secagem em spray dryer utilizando maltodextrina como agente carreador. Foram estudados os efeitos das condições de processo sobre algumas propriedades físico-químicas, além da estabilidade e da atividade biológica do material obtido. Extratos etanólicos das cascas e sementes da uva foram obtidos e concentrados até um terço do volume inicial. Este extrato foi então misturado com o agente carreador maltodextrina 10 DE nas concentrações de 10, 20 ou 30% e atomizado em spray dryer, com vazão de alimentação de 44 mL/min e temperaturas do ar de entrada de 130, 150 ou 170°C, num total de nove ensaios. Além disso, foi obtida uma amostra de extrato concentrado liofilizado, sem a presença do agente carreador, para efeito de comparação. Avaliou-se o rendimento do processo de atomização; e para as amostras obtidas determinou-se o teor de umidade, retenção de antocianinas, higroscopicidade e solubilidade em água, a fim de verificar a influência das condições de processo sobre essas características. Estas amostras também foram avaliadas quanto à morfologia, distribuição do tamanho de partículas e isotermas de sorção de umidade. Todas as amostras obtidas (atomizadas e liofilizada) foram avaliadas quanto à cor instrumental, espectroscopia de infravermelho, estabilidade durante a estocagem, presença de compostos bioativos (fenólicos, flavonóides, antocianinas e proantocianidinas), além de atividade antioxidante, antimicrobiana e de inibição da arginase de Leishmania. As condições de processo avaliadas (temperatura de secagem e concentração de agente carreador) tiveram forte influência nas características estudadas. O teor de umidade, a retenção de antocianinas, a morfologia e o tamanho das partículas, foram bastante influenciados pela temperatura de secagem e pela concentração de agente carreador, enquanto que a higroscopicidade sofreu maior influência da concentração de agente carreador. Esse parâmetro também apresentou grande influência nas isotermas de sorção de umidade das amostras. Não houve grande interferência do processo de secagem na composição química do material obtido, evidenciada pelos espectros de infravermelho. Quanto à avaliação da estabilidade durante a estocagem, foi observado que as amostras contendo maltodextrina conservaram mais as antocianinas e a cor, quando comparadas com as amostras sem carreador e os extratos líquidos, indicando, que o processo de secagem e a presença do carreador, promoveram um efeito protetor aos compostos e sua cor. Todas as amostras apresentaram altos teores de flavonóides totais, antocianinas, proantocianidinas e elevados valores de atividade antioxidante variando de 314,06 a 441,04 µmolesTE/g de extrato seco pelo método DPPH e de 993,32 a 1138,68 µmolesTE/g de extrato seco pelo método FRAP. Apresentaram atividade antimicrobiana principalmente contra Staphylococcus aureus e Listeria monocytogenes. Além disso, tiveram grande capacidade de inibir a enzima arginase de Leishmania com porcentagem de inibição variando de 54,60 a 83,43%. Os resultados encontrados sugeriram que o processo de secagem em spray dryer com maltodextrina, dos extratos obtidos dos subprodutos da uva Bordô, produziu pós com diversas características interessantes, como baixa higroscopicidade, alta solubilidade e estabilidade, além de grande potencial biológico. Tais resultados evidenciam que este subproduto da indústria vinícola pode ser aproveitado como fonte natural de ingredientes funcionais. / The aim of this work was to produce powder pigments from grape byproducts of Bordo variety (Vitis labrusca) by spray drying using maltodextrin as carrier agent. The effects of process conditions on some physicochemical properties, stability and biological activity of the product were studied. Ethanol extracts were obtained from grape pomace (skins and seeds) and concentrated to one-third the initial volume. This extract was then mixed with the carrier agent 10 DE maltodextrin at concentrations of 10, 20 or 30% and atomized in a spray dryer, with feed flow rate of 44 mL/min and inlet drying air temperatures of 130, 150 or 170°C a total of nine tests. In addition, a sample of freeze-dried concentrated extract without carrier agent was obtained for comparison. It was evaluated process yield and the samples obtained were initially evaluated for moisture content, anthocyanins retention, hygroscopicity and solubility in water, in order to verify the influence of process conditions on these characteristics. These samples were also evaluated for morphology, particle size distribution and moisture sorption isotherms. All samples (spray-dried powders and freeze-dried extract) were evaluated for instrumental color, infrared spectroscopy, stability during storage, presence of bioactive compounds (phenols, flavonoids, anthocyanins and proanthocyanidins) plus antioxidant activity, antimicrobial activity and inhibition of Leishmania arginase. Process conditions evaluated (inlet drying air temperature and carrier agent concentration) had a strong influence on the characteristics studied. The moisture content, anthocyanin retention, morphology and particle size of the samples were strongly influenced by drying temperature and carrier agent concentration while the hygroscopicity suffered greater influence of the carrier agent concentration. The concentration of carrier agent also had great influence on the moisture sorption isotherms of the samples. There was no significant interference of the drying process on the chemical composition of the material evidenced by infrared spectroscopy. Regarding the evaluation of stability during storage, it was observed that the samples containing maltodextrin, retained much more anthocyanins and original color when compared with the sample without a carrier or liquid extracts, indicating both, the drying process and the presence of carrier, promoted a protective effect to the compounds and its color. All samples showed high levels of flavonoids, anthocyanins, proanthocyanidins and high levels of antioxidant activity ranging from 314.06 to 441.04 µmolTE/g of extract (dry weight), by DPPH and 993.32 to 1138.68 µmolTE/g of extract (dry weight) by FRAP method. Most samples showed antimicrobial activity against Staphylococcus aureus and Listeria monocytogenes. Moreover, had great ability to inhibit the enzyme arginase of Leishmania with inhibition percentage ranging from 54.60 to 83.43%. The results suggest that the drying process of Bordo grape pomace extracts in a spray dryer with maltodextrin, produced powders with various interesting characteristics such as low hygroscopicity, high solubility and stability, and large biological potential. This shows that this byproduct of wine industry can be used as a natural source of functional ingredients.

Submitted by Celso Magalhaes (celsomagalhaes@ufrrj.br) on 2017-07-17T14:02:13Z No. of bitstreams: 1 2017 - Gabriela Nunes Mattos.pdf: 1178206 bytes, checksum: 6807a11fca850794a1c7f5b18bbed4c4 (MD5) / Made available in DSpace on 2017-07-17T14:02:13Z (GMT). No. of bitstreams: 1 2017 - Gabriela Nunes Mattos.pdf: 1178206 bytes, checksum: 6807a11fca850794a1c7f5b18bbed4c4 (MD5) Previous issue date: 2017-02-13 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior - CAPES / During vinification process a large volume of waste is generated, being the grape pomace, the main by-product. Due to its composition, rich in phenolic compounds and other nutrients, grape pomace can be considered as a low cost source of inputs, for example, in obtaining additives for the reduction of microbial contamination and lipid oxidation. The objective of this work was to evaluate the effect of using an extract of grape pomace from the vinification of Alicante bouschet grapes on the microbiological quality and the oxidative stability of tilapia sausages stored under refrigeration for 60 days. The powder of the extract of the grape pomace was obtained by hydroethanolic extraction and subsequent spray drying. The liquid and powder extracts were analyzed for the content of phenolic compounds, total anthocyanins and monomeric and antioxidant capacity by ABTS and ORAC methods. The sausage was produced using as raw material fillet and mechanically separated meat (CMS) of tilapia. Five sausage formulations were tested: Control (without antioxidant), Positive control (addition of synthetic antioxidant), T1% (addition of 1% of powdered extract), T0.5% (addition of 0.5% powdered extract) And T0.5% SC (addition of 0.5% powdered extract and curing salt). Tilapia sausages were analyzed for their centesimal composition, amino acid and fatty acids concentrations and lipid oxidation. The microbiological quality of the sausages was evaluated for 60 days. The bagasse extracts showed a high concentration of anthocyanins, phenolic compounds and antioxidant capacity, and after microencapsulation, the powders also showed adequate anthocyanin retention. Sausages formulated with powdered grape pomace extract presented the moisture content as recommended by Brazilian legislation, high ash and protein content, low lipid concentration, presence of essential amino acids, and it was rich in monounsaturated fatty acids. Sausages can be considered a nutritional food, as their ratio of saturated / polyunsaturated fatty acids was high. It was not verified the occurrence of lipid oxidation in all the samples along the storage, which was justified by the low concentration of the polyunsaturated fatty acids and lipid content. The grape pomace extract, the BHT and the curing salt promoted the maintenance of the microbiological quality of the sausages throughout the useful life. The acceptance test was carried out with 77 tasters and showed that the control, positive control, T1% and T0.5% SC sausages were accepted, unlike the T0.5% formulation. Considering the results obtained, the grape pomace extract showed to be a natural antioxidant potential to be used by the food industry as an additive. / No processo de vinifica??o ? gerado um grande volume de res?duo, sendo o baga?o de uva, o principal coproduto. Devido ? sua composi??o rica em compostos fen?licos e outros nutrientes, o baga?o de uva pode ser transformado em uma fonte de insumos de baixo custo, por exemplo, na obten??o de aditivos para a redu??o da contamina??o microbiana e oxida??o lip?dica. O objetivo do trabalho foi avaliar o efeito da aplica??o do extrato de baga?o de uva Alicante bouschet em p?, oriundo de vinifica??o de uvas tintas, na qualidade microbiol?gica e na estabilidade oxidativa de salsichas de til?pia armazenadas sob refrigera??o durante 60 dias. O extrato do baga?o de uva em p? foi obtido por extra??o hidroetan?lica e subsequente secagem por spray drying. Os extratos do baga?o de uva l?quido e em p? foram analisados quanto ao teor de compostos fen?licos, antocianinas totais e monom?ricas e capacidade antioxidante por ABTS e ORAC. A salsicha foi produzida usando como mat?ria-prima o fil? e a carne mecanicamente separada (CMS) de til?pia. Foram testadas cinco formula??es de salsicha: Controle (sem antioxidante), Controle positivo (adi??o de antioxidante sint?tico), T1% (adi??o de 1% de extrato em p?), T0,5% (adi??o de 0,5% de extrato em p?) e T0,5%SC (adi??o de 0,5% de extrato em p? e sal de cura). As salsichas de til?pia foram analisadas quanto ? sua composi??o centesimal, conte?do de amino?cidos, ?cidos graxos e oxida??o lip?dica. A qualidade microbiol?gica das salsichas foi avaliada por 60 dias. Os extratos do baga?o apresentaram elevada concentra??o de antocianinas, compostos fen?licos e capacidade antioxidante, e ap?s a microencapsula??o, os p?s tamb?m mostraram reten??o de antocianinas adequada. As salsichas formuladas com extrato de baga?o de uva em p? apresentaram teor de umidade conforme preconizado pela legisla??o brasileira, alta concentra??o de cinzas, baixo conte?do lip?dico e alto teor proteico, presen?a de amino?cidos essenciais, al?m de serem ricas em ?cidos graxos monoinsaturados. As salsichas podem ser consideradas de boa qualidade nutricional, uma vez que sua rela??o ?cidos graxos polinsaturados: saturados foi elevada, al?m do baixo teor de lip?dios encontrado. N?o foi verificada a ocorr?ncia de oxida??o lip?dica em todas as amostras ao longo do armazenamento, o que foi justificado pela baixa concentra??o dos ?cidos graxos polinsaturados e teor lip?dico. O extrato de baga?o de uva, o BHT e o sal de cura promoveram a manuten??o da qualidade microbiol?gica das salsichas ao longo da vida ?til. O teste de aceita??o, realizado com 77 provadores, mostrou que as salsichas controle, controle positivo, T1% e T0,5%SC foram aceitas, ao contr?rio da formula??o T0,5%. Considerando os resultados obtidos, o extrato de baga?o de uva mostrou-se um potencial antioxidante natural a ser utilizado pela ind?stria aliment?cia como aditivo.

Les déchets issus de l’industrie vinicole française sont traditionnellement traités et valorisés en distilleries. Ce travail porte sur l’étude de la valorisation à échelle industrielle d’un des résidus ultimes des distilleries : le marc de raisin épuisé. Les marcs issus de différents bassins de productions français ont été caractérisés chimiquement, principalement par leur taux de tannins condensés et de sucres. Les conditions d’extraction des tannins condensés ont été optimisées en laboratoire puis le procédé a été transféré à l’échelle industrielle. Plusieurs extractions ont été menées dans trois distilleries partenaires et l’analyse chimique (en termes de polyphénols, de tannins condensés, de sucres et de matières inorganiques) des différentes fractions isolées a été réalisée. Des extraits industriels ont permis la fabrication du premier panneau de particules dont l’adhésif est constitué à 80 % de tannins de marcs de raisins et renforcé à l’aide d’une résine synthétique satisfaisant à la norme européenne de cohésion interne. Ces extraits industriels ont également partiellement substitué une résine phénol-formaldéhyde pour la production de panneaux de particules. Différents post-traitements ont été réalisés sur les extraits de marcs afin d’en augmenter la réactivité chimique vis-à-vis d’agents de réticulation. Une filtration à un seuil de coupure de 1 µm a entrainé une légère amélioration des performances adhésives, alors qu’une hydrolyse acide de l’extrait les a dégradées. Un procédé d’ultrafiltration des extraits à 5 kDa ou 1 kDa a permis d’obtenir des extraits beaucoup plus réactifs et ouvre des perspectives pour la production d’adhésifs biosourcés pour le bois / Wastes from the French wine industry are traditionally treated and upgraded in distilleries. This work deals with the study of an industrial-scale valorization of a final waste from distilleries: the spent grape pomace. Pomace from different French production areas were chemically characterized, in terms of condensed tannins and polysaccharides. An extraction process of condensed tannins has been optimized in laboratory and was then transferred to an industrial scale. Several extractions were carried out in three partner distilleries and chemical analysis (in terms of polyphenols, condensed tannins, sugars and inorganics) of the different isolated fractions were performed. Industrial extracts were used for the elaboration of the first particleboard whose adhesive constituted by 80% of grape pomace tannins and strengthened with a synthetic resin to satisfy the European standard for internal bond. These industrial extracts were also used to partially substitute a phenol-formaldehyde resin for the production of particleboards. Different post-treatments were performed on the pomace extracts in order to increase their chemical reactivity toward cross linking agents. Filtration with a cut-off of 1 µm led to a slight improvement in adhesive performances, whereas acid hydrolysis of the extract have degraded it. An ultrafiltration process of the extracts at 5 kDa or at 1 kDa enabled to get much more reactive extracts and opened up prospects for the production of bio-based adhesives for wood

Les marcs de raisin issus de la viniculture constituent un gisement de ressource naturelle abondant, sous valorisé et riche en polyphénols. Une méthode d?extraction de ces tannins condensés a été développée et optimisée en vue d'une application en adhésif pour les produits dérivés du bois. Les tannins ont été caractérisés par Résonance Magnétique Nucléaire, spectroscopie Infra Rouge (FTIR), spectrométrie de masse (MALDI TOF) et Analyse Thermomécanique (TMA). Des panneaux de particules ont été fabriqués à l'aide des colles élaborées en laboratoire et testés suivant les normes françaises en vigueur, plusieurs dépassent largement les valeurs seuils / The extraction of condensed tannins from grape pomace was examined using water medium in the presence of different bases as catalyst (NaOH, Na2CO3, NaHCO3 and Na2SO3). Two different extraction processes and the influence of 4 parameters (i.e., temperature, reaction time, chemical reagents and concentration of the chemical reagents) on the tannin extracts yields and properties were studied. The tannin fractions were characterized by Fourier transform-infrared spectroscopy, thermogravimetric analysis, carbon nuclear magnetic resonance spectroscopy and matrix assisted laser desorption ionization time of flight mass spectrometry ( MALDI-TOF ). It was demonstrated that it is possible to extract reactive tannins from grape pomace in basic medium. The tannin extracts obtained by precipitation in acidic conditions display a high phenolic content (Stiasny number higher 95%) but low water solubility and low reactivity toward formaldehyde because of the formation of catechinic acid phlobatannins during the acidification step. The tannins extracts obtained by lyophilization of the liquid, despite of their lower phenolic contents, displayed promising properties for adhesive applications. The optimum temperature of the extraction process was 100 °C, reaction time was 120 min; the best concentration of reagent was 10% (w/w). It was also shown that addition of sulphite ions during the extraction step improved the process :y the introduction of a sulfonic group through sulfitation increased both tannin solubility and reactivity as a result from the opening of the heterocyclic ring during extraction The structure of grape pomace sulfited tannin extracts did not present noticeable discrepancy exception of the ratio of the opening pyran ring which was different as a function of the catalyst used. The opening of pyran ring during the tannins extraction seem to be more important by using Na2CO3 and NaHCO3 than when using NaOH. The FT-IR bands assigned to aromatic ring vibration and carbonyl groups were stronger and no bands attributed to sulfited groups were tested detected in acidified tannins compared to lyophilized tannins. The TG2 results showed that the weight lost of these tannin extracts mainly composed of two steps. The first step starts from room temperature to 200 °C. It is attributed to the mass lost of water and some easy-degraded small low molecules. The secondly steps which is the mainly degradation step of tannin extract samples from 200 to 400 °C. The results from 13C-NMR showed that condensed tannin extracts from grape pomace were consistent with dominant procyanidin units with a minor amount of prodelphinidin units that are linked together by a C4-C8 bond. Relatively low carbonhydrate and high catechinc acid content was observed in acidified tannins compared to lyophilized tannins. It was shown by MADI-TOF experiments that grape pomace tannin extracts are mainly composed of flavoinoid oligomers up to 6 repeating units in lyophilized tannins and 10 repeating units in acidified tannins respectively, with dominant procyanidin units. A small proportion of substitution with glucose and gallic acid was detected in procyanidin units of polyflavonoid oligomers. The degree of polymerization of acidified tannins is higher than lyophilized tannins. Two different formulations (nonfortified tannin adhesive and fortified with addition of 20% of polymeric 4, 4'-diphenyl methane diisocyanate (p-MDI)) were used to press one layer wood particle board. It was shown that the nature of the extraction reagent (NaOH, Na2CO3 or NaHCO3) greatly impacts the properties of the resins and the mechanical properties of the panel internal bonding strengths. The particleboards bonded by the tannins extracted using Na2CO3 as catalyst give the best performance and were good enough to pass relevant international standard specifications for interior grade panels. Formaldehyde emission of these panels was below the European Norm requirements (<= 6.5 mg/ 100g panel)

Thesis (Masters of Environmental Health)--Cape Peninsula University of Technology, 2018. / In the Western Cape, South Africa and other regions globally, grape pomace (GP) is one of the abundant agro-waste from the winery industry. This study reports on the hyper-extraction of fermentable sugars from GP treated with white rot fungi (WRF) Phanerochaete chrysosporium BKMF 1767 to facilitate improved biovalorisation for total reducing sugars (TRS) extraction in conjunction with Nepenthes mirabilis digestive fluids. TRS were quantified using the 3,5-dinitrosalicylic acid (DNS) reagent method. The free readily dissolvable sugars from the GP recorded for the bio-treated (BT) samples was 206.39 ± 0.06 mg/L and for the untreated (UT) samples was 271.05 ± 0.02 mg/L. Overall, the TRS yield for the Bio-treated (BT) and untreated (UT) samples was recorded as 205.68 ± 0.09 and 380.93 ± 0.14 mg/L, respectively, using hot water pretreatment (HWP) with 2266.00 ± 0.73 (BT) and 2850.68 ± 0.31 mg/L (UT), respectively, for dilute acid pretreatment (DAP); with 2068.49 ± 6.02 (BT) and 2969.61 ± 8.054 mg/L (UT) respectively, using the cellulase pretreatment (CP) method. Using the HWP as a reference, the relative increases imparted by the biotreatment was higher (51%) for DAP and low (33%) for CP. The combination of conventional used pre-treatment methods (hot water pretreatment, dilute acid pre-treatment, and cellulase pre-treatment) in a single pot system was also done while monitoring the total residual phenolics (TRPCs) in the samples. Furthermore, powder X-ray diffraction (pXRD) were used to measure the crystallinity index (CrI) and functional groups of pre- and post-pretreated GP to ascertain the efficiency of the pre-treatment methods, with quantification of lignin, holocellulose, and ash. Overall, the TRS yield for N. mirabilis pre-treated agro-waste was 951 mg/L ± 4.666 mg/L, with biomass having a lower CrI of 33%, and 62% residual lignin content. Furthermore, reduced TRPCs were observed in hydrolysate, suggesting limited inhibitory by-product formation during N. mirabilis pre-treatment

Ce travail a porté sur l'extraction de substances naturelles de sous-produits de la vigne en mettant en œuvre des procédés "verts" tels que l'extraction par eau sous-critique et la purification par filtration membranaire. Ces procédés représentent une alternative à l'extraction par solvant, traditionnellement utilisée dans la production de substances bio-sourcées. La majeure partie de cette étude a été menée sur des marcs de raisin de cépages variés, l'extraction a été optimisée et comparée sur la base du rendement, de la composition chimique et de l'activité antioxydante des extraits obtenus. De tous les cépages testés, les extraits de Dunkelfelder ont présenté l'activité antioxydante la plus élevée et la concentration en familles de molécules polyphénoliques la plus importante. En outre, ce marc de raisin de Dunkelfelder a été utilisé comme modèle afin d'optimiser les différents paramètres du procédé tels que la température, la pression et le temps de séjour hydraulique. Après la phase d'extraction par eau sous-critique, les extraits obtenus se sont révélés riches en de nombreuses familles de molécules. Ainsi, une étape de purification des composés cibles avant usage industriel s'est révélée indispensable. Le couplage de l'extraction par eau sous-critique avec des procédés membranaires représente une solution innovante pour la purification de ces extraits. Des essais de filtration tangentielle de l'extrait ont été menés avec onze membranes d'ultrafiltration (100 kDa à 2 kDa) et neuf membranes de nanofiltration (1000 Da à 150 Da). Le suivi du procédé s’est appuyé sur une détermination des paramètres opératoires optimisés et sur la détermination des coefficients de rétention des différentes familles des macro et micromolécules. Les résultats obtenus ont démontré que l'utilisation des technologies membranaires pourrait dans le futur, constituer une innovation technologique pour la purification des composés bio-actifs / This work has dealt with extraction of natural substances from winery by-products using "green" processes such as extraction by subcritical water and purification by membrane processes. These processes are an alternative to solvent extraction traditionally used in the natural products industry. Main part of the work was done on different grape pomace, extraction was optimized and compared in terms of yield, chemical composition, and antioxidant activity of extracts. Dunkelfelder extracts exhibited the strongest antioxidant activity and comparison of chemical compositions of the different extracts indicated. Furthermore this Dunkelfelder grape pomace was used as model in order to optimize the different process parameters such as temperature, pressure and hydraulic retention time. After the subcritical water extraction, extracts produced were found to be rich in several families of molecules. An essential purification step of target compounds prior to industrial use was indispensable. Coupling the subcritical water with membrane processes offers an innovative solution for the purification of these extracts. Thereby, the extract was assayed in a cross-flow apparatus against eleven membranes of ultrafiltration (100 to 2 kDa) and nine membranes of nanofiltration (1000 to 150 Da). The monitoring of the process was carried out by determining performance parameters and retention coefficients of different families of macro and micromolecules. The results obtained have demonstrated that the use of membrane technologies could bring innovative changes in the recovery of bioactive compounds for future industries.

Ce travail porte sur l’amélioration quantitative et qualitative du procédé de fabrication d’extraits de marc de raisin riches en composés phénoliques. Les effets de technologies alternatives de traitement de la biomasse végétale sur l’amélioration des rendements d’extraction ont été étudiés à l’échelle laboratoire. Leurs impacts sur la qualité biochimique des extraits obtenus ont été évalués via la caractérisation analytique des composés phénoliques.Une étude comparative de différentes technologies alternatives de pré-traitement en milieux aqueux (décharges électriques haute tension (DEHT), champs électriques pulsés (CEP) et ultrasons (US)), d’un marc de raisin issu d’un procédé de vinification en rouge, en amont de la diffusion, a permis d’approfondir la compréhension des phénomènes induits et de leurs effets sur l’amélioration de l’extractabilité des composés. Nous avons montré que le choix du procédé à mettre en oeuvre était relatif au type de composés phénoliques ciblés : la localisation tissulaire de ces composés est apparue comme un facteur-clé pour optimiser leur extraction. La technologie de pré-traitement par CEP, induisant un endommagement localisé des structures végétales, s’est avérée particulièrement intéressante pour extraire sélectivement les anthocyanes situés au niveau des couches de cellules supérieures de l’hypoderme de la pellicule de raisin. Nous avons, par la suite, montré que le pré-traitement par CEP, en milieu sec (sans ajout de solvant) et à intensité de champ électrique modérée, était plus efficace pour la récupération sélective des anthocyanes et moins énergivore qu’un traitement CEP de forte intensité d’une suspension aqueuse de marc. Pour ce faire, nous avons mis en place une nouvelle configuration de cellule qui nous a permis d’étudier la faisabilité d’un pré-traitement en milieu sec, sans ajout de liquide conducteur, et d’optimiser les paramètres opératoires (masse volumique, intensité du champ électrique, énergie spécifique) influençant la récupération subséquente, lors de la diffusion, des composés phénoliques. Afin d’intégrer notre démarche expérimentale dans une approche systémique de type « bioraffinerie », l’accent a été mis sur le traitement du marc réhydraté à posteriori de la diffusion. L’intensification du pressage de ce marc par chauffage ohmique (CO) permet d’améliorer les rendements globaux d’extraction tout en assurant un premier niveau de déshydratation de cette biomasse.Un bilan technico-économique montre que l’application successive des électro-technologies (pré-traitement par CEP en milieu sec et pressage assisté par CO à posteriori de la diffusion) permet une amélioration des rendements massiques d’extraction de l’ordre de 30 % comparativement au procédé classique. Ce gain matière compense l’augmentation du coût de production (+ 2.7 % comparativement au procédé classique) et résulte une diminution du coût de production de l’extrait (7.3 €/kg vs 9.4 €/kg pour le procédé classique). / This work aims at studying the effect of alternative technologies for the processing of winery byproducts on the improvement of extraction yields at laboratory scale. Their impacts on the biochemical quality of the extracts obtained from grape pomace were evaluated by the characterization of the extracted compounds. A comparative study on the effects of different alternative pre-treatment (pulsed electric field (PEF), high voltage electric discharges (HVED) and ultrasounds (US)) of aqueous suspensions of red grape pomace, prior to the extraction step, was realized with the specific objective of understanding the induced phenomena. The electroporation induced by PEF may allow the specific recovery of anthocyanins that are located in the upper cell layers of the hypodermis by facilitating the solvent penetration to particular skin tissues of grape. The location of targeted compounds with respect to tissue structures seems to be a key issue to optimize their extraction. As a consequence, we subsequently examined the feasibility of a PEF pre-treatment of relatively low humidity grape pomace for the enhancement of bioactive compounds extraction. We demonstrated that a relatively dry pomace (RH ≈ 55 %) can be effectively treated by PEF after optimal densification using a suitable configuration of the PEF cell. The PEF pre-treatment of a densified fermented grape pomace, at moderate electric field strengths, requires less output current and lower specific energy and is also more efficient for the selective recovery of anthocyanins than Hi-PEF pre-treatment of an aqueous suspension of grape pomace. We finally focused on the treatment of rehydrated grape pomace following the diffusion step. The enhancement of pressing of the grape pomace by ohmic heating allowed the recovery of two fractions: a solid fibrous residue partly dehydrated which could be further valorized as an agro-material or in feeding, and an extract, particularly rich in bioactive components.The technical-economic assessment shows that the successive application of electro-technologies (pre-treatment of grape pomace in dry environment by PEF followed by a pressing step assisted by ohmic heating) lead to an improvement of extraction yields of about 30 % compared to the conventional method. This mass improvement offset the increased production costs (+ 2.7 % compared to the conventional process) by reducing the total production costs of the extract (7.3 €/kg vs 9.4 €/kg for the conventional process).

Thesis (PhD (Chemical Engineering))--Cape Peninsula University of Technology, 2019 / The agro-processing industry is currently facing losses due to microbial spoilage of agricultural produce and associated value-added products such as beverages. Decay and undesired fermentation of fruit and beverages by fungal, yeast and bacterial spoilage organisms are among the major contributors of product losses in the food industry. When looking at the different level of food spoilage, it is common to find different spoilage organisms occurring in the same food item; which usually requires food producers to utilise a mixture of synthetic preservatives for spoilage organism control. Some of the synthetic chemical compounds with growth inhibition properties that have been used in food preservation are sulphur dioxide, benzoic, lactic, sorbic and acetic acid. These compounds act against a variety of spoilage microorganisms. In post-harvest control of fungi, triazoles, hydroanilide fenhexamid, dicarboximides and succinate dehydrogenase are also being used. Some spoilage organisms have been found to be resistant to the use of synthetic chemical preservatives which usually favour the use of higher dosage of preservatives in food. The use of synthetic chemicals as preservative and as postharvest control agents has been found to present serious health risks such as cardiovascular diseases, muscles and stomach pains, eyesight and skin damages and impairment of brain functions. The problem posed by the current use of synthetic chemicals in food put pressure on food producers and exporters to seek alternatives that will allow for the eradication of the use of synthetic chemicals as preservative in beverages and as postharvest control agents on fruits. Yeasts have been found to have the ability to grow at a faster rate on cheap media and to colonise dried surfaces rapidly. It has also been found that yeasts produce extracellular compounds of proteinaceous and volatile organic nature with growth inhibition properties against spoilage organisms. The current findings lack some engineering concept that could assist in the design of a production system for high scale production of biopreservation compounds from yeasts. The availability of a cost effective production media, the growth and production kinetics data using a cheaply available nutrient sources as well as the biological thermodynamic data are some of the gaps in biopreservation bioprospecting. Although several yeasts have already been studied to have great inhibition properties against fruit fungal pathogens, it was still unclear what was the minimum inoculum dose to be able to have a fungistatic and fungicidal effect on the growth of fruit spoilage organisms. The concept of combination of biopreservatives and the interaction effect of their biopreservation activity against consortia of spoilage organisms has also been lacking. As an attempt to seek alternatives to the use of synthetic chemicals as preservatives or postharvest control agents, Candida pyralidae Y1117, Pichia kluyveri Y1125 and Pichia kluyveri Y1164 strains were assessed for antimicrobial activity against spoilage yeasts (Dekkera bruxellensis, Dekkera anomala, Zygosaccharomyces bailii) and spoilage fungi (Botrytis cinerea, Colletotrichum acutatum and Rhizopus stolonifer). As alternative to refined media, a cost effective approach was explored whereby the use of agro-waste, i.e. grape pomace extracts (GPE), as production medium for biopreservation compounds, was studied. Production kinetics using modified existing models, subsequent to optimization using response surface methodology (RSM) for biopreservation compounds production was studied for the three biocontrol yeasts using GPE broth as the fermentation medium. The evaluation of the interaction study between mixtures of crude biopreservatives against consortia of common spoilage organisms present in beverages was also conducted by producing the crude biopreservation compounds separately from yeasts and then formulating growth inhibition combinations (GICs); GIC 1 (Candida pyralidae Y1117 and Pichia kluyveri Y1125); GIC 2 (C. pyralidae Y1117 and P. kluyveri Y1164), GIC 3 (P. kluyveri Y1125 and Pichia kluyveri Y1164); GIC 4 (C. pyralidae, P. kluyveri Y1125 and P. kluyveri Y1164). The spoilage organism consortia combinations, i.e. SC1, D. anomala and D. bruxellensis; SC2 (D. anomala and Z. bailii); SC3 (D. bruxellensis and Z. bailii) and SC4 (D. anomala, D. bruxellensis and Z. bailii) were also prepared. This study also investigated the effect of varying inoculum dose (ID) of Candida pyralidae strain Y1117, Pichia kluyveri Y1125 and Pichia kluyveri Y1164 on the biocontrol of Botrytis cinerea by contaminating the headspace of the growth medium with a fungal plug subsequent to biotreatment with different initial inoculum dose of the respective biocontrol yeasts. Finally, grape pomace extracts was used as fermentation medium to study the biological thermodynamics of biopreservation compound production from the three biocontrol yeasts. The results obtained demonstrated some interesting results. The antagonistic properties of C. pyralidae and P. kluyveri were observed on cheap solidified medium (grape pomace extracts) as well as on fruits (grapes and apples). These yeasts produced extracellular volatile organic compounds (VOCs) that could be responsible for yeast and fungal growth inhibition. Twenty-five VOCs in the category of alcohols, organic acids and esters were identified by GC-MS. The results of the kinetic study showed that the highest volumetric zone of inhibition (VZI) was 1.24 L contaminated solidified media (CSM) per mL biopreservation compounds used (BCU) when Candida pyralidae Y1117 was inoculated in a pH 3-diluted GPE broth (150 g L−1) incubated at 25 °C for 24 h. Similar conditions were applied for Pichia kluyveri Y1125 and P. kluyveri Y1164, albeit under slightly elongated fermentation periods (up to 28 h), prior to the attainment of a maximum VZI of only 0.72 and 0.76 L CSM mL−1 ACU, respectively. The potential biopreservation compounds produced were identified to be isoamyl acetate, isoamyl alcohol, 2-phenyl ethylacetate and 2-phenyl ethanol. The growth inhibition interaction study showed a variation in growth inhibition proficiency depending on the spoilage organisms or the consortia of spoilage organisms being deactivated. It was then suggested that, a food environment contaminated with a consortium of spoilage organisms can be controlled by employing either the crude biopreservation compounds from individual yeast or those of the following yeast combinations, GIC1-4, which showed a better growth inhibition proficiency against SC1-3. The fungistatic and fungicidal effects on the fungal pathogen were dose dependent. The fungistatic characteristics against Botrytis cinerea were displayed after 7 days when 102-105 cells mL-1 of Candida pyralidae Y1117, Pichia kluyveri Y1125 and Pichia kluyveri Y1164 were independently used in-vitro and in-vivo. However, 106-108 cells mL-1 inoculum doses displayed fungicidal characteristics. Additionally, the fungicidal property of yeasts studied was also confirmed on table grape (in vivo studies) using closed jar method. The biological thermodynamic study showed that, dried biomass molecular weight of 28.9 g/C-mol, 29.163 g/C-mol, and 27.176 g/C-mol were obtained for Candida pyralidae strain Y1117, Pichia kluyveri Y1125 and Pichia kluyveri Y1164 respectively. The results obtained successfully established useful biological thermodynamic data applicable to the design of adequate biopreservatives production system from yeasts using cheaply available nutrients source.

CoordenaÃÃo de AperfeÃoamento de Pessoal de NÃvel Superior / FundaÃÃo de Amparo a Pesquisa do Estado do Piauà / Objetivo: Investigar o potencial biotecnolÃgico do bagaÃo de uva, variedade Benitaka, cultivada no municÃpio de SÃo JoÃo do PiauÃ, PiauÃ, por meio de metodologias analÃticas cientificamente reconhecidas, buscando reconhecer os principais grupos de metabÃlitos responsÃveis por atividade antioxidante. Metodologia: As uvas (Vitis vinifera L.), variedade Benitaka, foram resultantes da safra 2011/2012 e coletadas no Polo de Viticultura do Assentamento Marrecas, no MunicÃpio de SÃo JoÃo do PiauÃ/PI e posteriormente higienizadas, prensadas em despolpadeira para separaÃÃo do bagaÃo, o qual foi submetido à desidrataÃÃo, trituraÃÃo, peneiramento e formaÃÃo do bagaÃo de uva em pÃ. A partir do bagaÃo de uva em pà foram realizadas anÃlises da composiÃÃo centesimal, conteÃdo de minerais, fibra dietÃtica total, solÃvel e insolÃvel, determinaÃÃo de Vitamina C, conteÃdo de antocianinas, perfil de Ãcidos graxos e investigaÃÃo de sua qualidade microbiolÃgica. Foram tambÃm elaborados extratos a partir de diferentes solventes, os quais foram analisados quanto à toxicidade frente à Artemia salina sp., conteÃdo de fenÃlicos totais, flavonÃides totais e taninos totais; atividade antioxidante in vitro pelos mÃtodos de DPPHâ e autooxidaÃÃo do sistema &#946;-caroteno/Ãcido linoleico; estabilidade oxidativa em Ãleo de soja e identificaÃÃo e quantificaÃÃo de polifenÃis por HPLC-UV. Os resultados foram expressos como mÃdia e desvio padrÃo (n=3) e utilizou-se o programa estatÃstico SAS para AnÃlise de VariÃncia e Teste de Tukey. Adotou-se o nÃvel de significÃncia de 5% (p<0,05). Resultados: Os resultados mostraram que no bagaÃo de uva em pà a quantidade de fibra dietÃtica total (46,17g/100g) se destacou quantitativamente em relaÃÃo aos carboidratos (29,2g/100g), proteÃnas (8,49g/100g) e lipÃdeos (8,16g/100g). O valor energÃtico total encontrado foi de 224Kcal/100g. A fraÃÃo fibra insolÃvel (79%) foi superior à fraÃÃo solÃvel (21%). O conteÃdo de Vitamina C foi de 26,25mg de Ãcido ascÃrbico/100g e de antocianinas, 131mg/100g. Os minerais ferro (18,08mg/100g), potÃssio (1,40mg/100g), zinco (0,98mg/100g), manganÃs (0,82mg/100g) e cÃlcio (0,44mg/100g) estavam presentes em maiores concentraÃÃes. A fraÃÃo lipÃdica foi composta principalmente por Ãcido linoleico (89,61%) e o teor de PUFA (89,61%) >MUFA (21,37%) >SFA (18,46%). O rendimento dos extratos variou de 6,85% a 45,5%, dependendo do solvente de extraÃÃo, sendo que o menor rendimento foi observado no extrato acetÃnico e o maior no extrato metanÃlico. O conteÃdo de fenÃlicos totais, flavonoides totais e taninos totais variaram em funÃÃo do solvente de extraÃÃo. Os extratos etanÃlico e acetÃnico conseguiram estabilizar o radical DPPHâ de forma eficiente, com valores de EC50 de 0,31 Âg/mL e 0,39 Âg/mL, os quais nÃo diferiram estatisticamente dos padrÃes quercetina (0,22 Âg/mL) e BHT (0,11 Âg/mL). Em relaÃÃo à avaliaÃÃo da atividade antioxidante pelo mÃtodo de autooxidaÃÃo do sistema &#946;-caroteno/Ãcido linolÃico, os extratos agiram de forma similar ao antioxidante sintÃtico BHT, com mÃdias de EC50 de 0.34 Âg/mL a 0.36 Âg/mL. O extrato etanÃlico aumentou a vida de prateleira do Ãleo de soja de forma similar ao BHT. O composto fenÃlico presente em maior concentraÃÃo foi isoquercitrina (12,94 mg/100g), seguido de rutina (7,54 mg/100g), quercetina (5,4 mg/100g) e resveratrol (2,5 mg/100g). ConclusÃo: Os resultados mostraram que o bagaÃo de uva representa uma fonte potencialmente importante de nutrientes e compostos fenÃlicos; alÃm de elevado potencial antioxidante, o que contribui para o seu elevado valor como um subproduto de frutos, com possibilidades de comercializaÃÃo como antioxidante natural.

Wine grape pomace (WGP), the byproduct from winemaking, is a good source of polyphenols and dietary fibers, and may be utilized as antioxidant dietary fibers (ADF) for food applications. The objectives of this thesis research were to first determine the phenolic compounds, antioxidant and antimicrobial activities in red WGP under different drying processes for long-term storage, and to further evaluate the feasibility of using WGP as a functional food ingredient in yogurt and salad dressing for enhancing the nutritional value and improving storability of the products. Two types of WGP samples, pomace containing seeds and skins (P) and pomace with skins only (S) from Pinot Noir (PN) and Merlot (M) were studied. Samples were subjected to four different drying conditions: 40 °C conventional and vacuum oven, 25 °C ambient air and freeze dry. Total phenolic content (TPC, by Folin-Ciocalteu assay), anthocyanins (ACY, by pH differential method) and flavanols content (TFC, by vanillin assay) of the samples along with their antioxidant activity (DPPH radical scavenge method, RSA) and antibacterial activity (minimum inhibition concentration, MIC) were determined during 16 weeks of storage under vacuum condition at 15±2 °C. Meanwhile, dietary fiber profile was evaluated by using gravimetric-enzyme method. Results showed that dietary fiber contents of PN-P, PN-S, M-P and M-S were 57-63% d.m. with the majority of insoluble fraction. Freeze dried WGP retained the highest bioactive compounds with TPC 21.19-67.74 mg GAE/g d.m., ACY of 0.35-0.76 mg Mal-3-glu/g d.m., TFC of 30.16-106.61 mg CE/g d.m. and RSA of 22.01-37.46 mg AAE/g d.m., followed with ambient air dried samples. Overall, TPC, TFC and RSA were higher in PN than in M, and higher in pomace than in skins, while reverse results were observed in ACY. All samples lost significant amount of bioactive compounds during storage, in which ambient air and freeze dried samples had TPC reduction of 32-56% and 35-58%, respectively at the end of 16 weeks of storage. RSA in PN-P and M-P remained more than 50 mg TE/g d.m., meaning WGP still met the criteria of ADF definition after 16 weeks of storage. WGP extracts showed higher antibacterial efficiency against L. innocua than that of E. coli with MIC of 2, 7, 3 and 8% against L. innocua, and 3, 6, 4 and 9% against E. coli for PN-P, PN-S, M-P and M-S samples, respectively. This study demonstrated that Pinot Noir and Merlot pomace are good sources of ADF even after 16 weeks of storage at 15 °C and vacuum condition. Due to the highest antioxidant activity (RSA 37.46 mg AAE/g) and dietary fiber content (61%), PN-P was selected as ADF to be fortified in yogurt and salad dressing. Three types of WGP: whole powder (WP), liquid extract (LE) and freeze dried extract (FDE) with different concentrations were incorporated into yogurt (Y), Italian (I) and Thousand Island (T) salad dressings. TPC, RSA and dietary fiber content, major quality attributes including pH and peroxide value (PV) during the shelf life and consumer acceptance of fortified products were evaluated. The highest ADF were obtained in 3% WP-Y, 1% WP-I and 2% WP-T samples with the dietary fiber contents of 1.98%, 2.12% and 1.83% and RSA of 935.78, 585.60 and 706.67 mg AAE/kg, respectively. WP fortified products had more dietary fiber content than that of LE and FDE fortified ones because of the insoluble fractions. The pH dropped from 4.52 to 4.32 for 3% WP-Y during three weeks of storage at 4 °C, but remained stable in WGP-I and WGP-T samples after four weeks of storage at 4 °C. Adding WGP resulted in 35-65% reduction of PV in all samples compared to the control. In WGP-Y, the viscosity increased, but syneresis and lactic acid percentage were stable during storage. The 1%WP-Y, 0.5%WP-I and 1%WP-T samples were mostly liked by consumers. Study demonstrated that WGP can be used as a functional food ingredient for enhancing nutraceutical content and extending shelf-life of the food products. This study provided important information about the economically feasible drying methods for retaining the bioactive compounds in WGP during processing and storage and also suggested that WGP can be utilized as antioxidant dietary fiber to be fortified in consumer products to promote nutritional benefit and extend product shelf-life. / Graduation date: 2013