Ultrafiltration (UF), using Romicon pilot-scale hollow-fiber cartridges (Model HFXS-MK11) in the batch mode, was investigated as a possible procedure for clarifying, stabilizing and preserving White Riesling (WR) and Thompson Seedless (ThS) grape juice. The effect of UF processing of SO₂-treated or untreated juice, of process temperature and membrane molecular weight cut-off (MMWCO) on UF juice composition and quality, was determined. "Sparkling clear" pale light-colored UF permeates were obtained and subjected to storage stability trials at different temperatures. Juice parameters evaluated included proteins, phenolics, polyphenol oxidase (PPO), microorganisms, browning, haze and sensory properties. UF at elevated temperatures of up to 50°C, compared to lower temperatures, had the advantage of increased rate of filtration with decreases in browning or haze of clarified permeates and of markedly reduced microbial loads. UF of SO₂-treated juices (13- 20 ppm free) had several advantages including further reduction in browning, haze, and microbial load, and complete inhibition of PPO activity. More proteins (34% - 92%) than phenolics (2% - 27%) were retained by UF membranes. However, more proteins and less phenolics were retained in SO₂-treated than untreated juices. Increasing MMWCO from 10,000 to 100,000 had no effect on the retention of browning, haze, or microorganisms but decreased the retention of proteins from 58 percent to 34 percent in SO₂-treated WR juice. A MMWCO of 50,000 or less retained essentially all PPO. ThS juice browned more than WR during juice preparation and UF processing, yet its clarified permeates were lighter. It contained less phenolics, more proteins and more PPO activity, and higher percentages of its proteins and phenolics were retained by UF membranes. UF juices processed with or without low concentrations of SO₂ (13-20 ppm free) could be stored for at least one year at 1°C without fermentation spoilage. At 21°C only the treated juices could be stored for this long, untreated juices fermenting within one week. At 1°C, there was no increase in browning, but a gradual increase in haze upon storage, the latter being greater in untreated juices. At 21°C, browning increased gradually, resulting in pale golden juices but haze formation was markedly less than in juices stored at 1°C. Similar but accelerated changes occurred with storage at 38°C. The above changes correlated with the disappearance of free SO₂. Although juices were preserved for up to one year, "absolute juice sterility" was never obtained. Leakages around the cartridge gaskets, rather than failure of membranes, was believed to be responsible. Sensory analysis detected no significant differences (p = 0.05) in color, aroma and taste between juices processed with SO at 30°C and 50°C. Juices processed without SO₂ were not significantly different in color, but demonstrated small differences (p = 0.05) in aroma and taste. The SO₂-treated and untreated juices at both processing temperatures, as well as treated juices stored at 21°C and 1°C for twelve months, were significantly different (p = 0.01) in color, aroma and taste. Although these juices had different flavor "characters," only small or no significant differences (p = 0.05) in desirability were detected. It is concluded that good quality clarified grape juice but of different flavor "character" can be produced by UF, either in the presence or absence of SO₂. Both juice "styles" (± SO₂) may find preferred use, but juices processed with SO₂ have the advantage of ambient storage, retaining good quality after one year at 21°C. Recommended optimum processing conditions are 50°C, in the presence of minimal amounts of SO₂ (13-20 ppm free), using membrane molecular weight cut-off of 30-50,000. However, application of the process to "cold-sterilization" of grape juice requires further evaluation. / Graduation date: 1983

Thesis (M.S. in food science)--Washington State University, December 2008. / Title from PDF title page (viewed on July 10, 2009). "Department of Food Science." Includes bibliographical references (p. 84-94).

The feasibility of using hollow fiber ultrafi1tration for clarification, stabilization and preservation of white grape juice was evaluated. Flux and process parameters of a hollow fiber membrane ultrafi1tration unit (Romicon pilot scale, model FXS-MXII), were studied using white Riesling grape juice. Optimum processing conditions were determined for different nominal membrane molecular weight cut-off values. The effect of cut-off value changes on viscosity, pectin retention, pH, sugar content, titratable acidity, haze reduction and color were evaluated. Optimum conditions for processing were nominal membrane molecular weight cut-off = 50,000, temperature = 50°C, inlet pressure = 1.75 Kg/cm², outlet pressure = 1.40 Kg/cm², permeate flux = 72.57 L/M²-H. Concentration polarization and fouling of the membrane increased with feed juice viscosity and were limiting factors in permeation rate. A 93% retention of pectins was achieved and haze reduction was in the range of 91-93%. Sugar content, pH, titratable acidity, and color were not affected for any of the nominal membrane molecular weight cut-off values. / Graduation date: 1984

Promotionsarbeit--Eidgenössische Technische Hochschule, Zürich. / Vita. Bibliography: p. 73-79.

Improved sensitive techniques were developed for the determination of soluble proteins in grape, juice and wine. These techniques which permitted direct sample analysis without prior dialysis or concentration, were used for: 1) characterization of heat unstable proteins, 2) evaluating the effect of bentonite fining and ultrafiltration (UF) on the soluble proteins and heat unstable proteins in Gewurztraminer and Riesling juices and wines. Protein molecular weights (MW), isoelectric points (pI) and glycoproteins were determined by using LDS-polyacrylamide gel electrophoresis and 2-dimensional isoelectric focusing (IF)-LDS electrophoretic techniques with silver staining as well as protein blotting for glycoprotein detection. Relative concentrations of proteins in stained gels were determined by laser scanning densitometry. Bentonite fining tends to remove higher pi (5.8-8.0), intermediate MW (32,000-45,000) protein fractions first. In general, it is necessary to remove the lower pI (4.1-5.8), lower MW (12,600 and 20,000-30,000) fractions and glycoproteins to "protein stabilize" wines to heat testing. Unstable proteins precipitated by heat test were recovered and analyzed. These proteins were mainly of low MW (<30,000) and primarily glycoproteins. Protein fractions with MW of greater than 14,000 were more heat sensitive than lower MW fractions. Wines and juice were ultrafiltered with Romicon and Millipore systems operated with membranes of "nominal MW cut-off (MWCO)" of 10,000-100,000 daltons. A progressive increase in membrane retention of soluble protein was observed with decreasing MWCO, up to 99% of wine protein being retained with membranes of 10,000 dalton MWCO. However, certain high MW protein fractions also remained in permeates even with 10,000 MWCO membranes. In the order of 3-2 0 mg protein/L frequently remained in UF wine permeates, this correlated with the periodic detection of heat instability and of a low bentonite requirement for "protein stability" as determined by sensitive heat testing. "Protein stability" could be obtained with MWCO of 10,000 and 3 0,000; however, when not obtained, reductions in the order of 80-95% in "bentonite demand" were achieved. Protein stabilization of wines by UF is similar to that by bentonite fining in that it is necessary to remove the lower MW (12,600 and 20,000-30,000), lower pI (4.1-5.8) fractions, and glycoproteins to stabilize wines to heat testing. UF membranes were more effective at retaining wine proteins than juice proteins. UF juices were more susceptible to heat induced haze formation than UF wines. / Graduation date: 1986

Thesis (M. Ag. Sc.)--University of Adelaide, 1986. / Includes bibliographical references (leaves 79-83).

Thesis (M.Ag.Sc.)--University of Adelaide, April, 1986. / Bibliography: leaves 79-83.

The entire thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file; a non-technical public abstract appears in the public.pdf file. Title from PDF of title page (University of Missouri--Columbia, viewed on Sept. 21, 2009). Thesis advisor: Dr. Azlin Mustapha. Includes bibliographical references.

Embora os efeitos benéficos da ingestão moderada do vinho sejam bem conhecidos, a capacidade antioxidante de sucos de uva é ainda pouco estudada. O suco de uva é um alimento composto por uma importante quantidade de polifenóis e pode ser incluído entre os alimentos com potencial antioxidante. Seu estudo é muito relevante pelo amplo consumo desta bebida e a importância econômica que apresenta em nossa região. Atualmente contamos com diferentes sucos de uva no mercado, brancos, tintos e roses, orgânicos ou convencionais. O suco de uva possui vários nutrientes e compostos bioativos com atividades antioxidante, antimutagênica, anticarcinogênica e antiaterogênica, entre outras. Os polifenóis são nutrientes de grande importância no suco de uva, visto que a presença destes pode contribuir para coloração, acidez e outras características importantes do suco. Aos polifenóis, já são atribuídas várias atividades benéficas a saúde do homem. Entretanto, pouco se sabia sobre a atividade do suco, o qual é uma substância complexa. Neste sentido, este estudo buscou avaliar: 1) atividade antioxidante e antimutagênica de diferentes sucos de uva e a influência de metais presentes nestes sucos; 2) atividade antioxidante do suco de uva rose; 3) atividade neuroprotetora e hepatoprotera do suco de uva em ratos Wistar jovens; 4) atividade antioxidante sérica do suco de uva em ratos Wistar jovens; 5) atividade neuroprotetora, hepatoprotetora, antigenotóxica em ratos Wistar envelhecidos; e 6) proteção do resveratrol e da catequina frente a diferentes agentes estressores em diferentes linhagens da levedura S. cerevisiae. Alguns metais apresentaram correlações positivas com estas atividades, como o Manganês, e negativas como, por exemplo, o Enxofre. O conteúdo de minerais variou entre sucos brancos e tintos. Entretanto, entre os mais prevalentes, está o potássio. Sendo assim, as correlações apresentadas também diferenciam entre os sucos brancos e tintos. Modelos in vivo contaram com grupos de ratos Wistar (machos) que foram tratados por gavagem duas vezes ao dia durante 30 dias, tendo no total um volume de suco de uva corresponde ao seu peso. Os ratos foram divididos em três grupos: controle (recebeu salina), suco de uva convencional e suco de uva orgânico. No 30º dia os animais recebiam uma dose equivalente ao seu peso de um agente estressor (CCl4) e após cinco horas foram sacrificados. Foi possível observar que os sucos de uva estudados possuem atividade antioxidante e antimutagênica importante no modelo da levedura S. cerevisiae. No modelo in vivo (ratos Wistar) observou-se uma ação neuroprotetora, hepatoprotetora e antioxidante sérica em ratos jovens. Nos ratos mais velhos observou-se também ação antigenotóxica importante. Nestes trabalhos, observou-se importantes correlações entre as atividades benéficas e o conteúdo polifenólico, principalmente referente ao conteúdo de resveratrol e catequina, nãoflavonóide e flavonóide, respectivamente. Observando-se que o suco de uva é uma mistura complexa, foram realizados estudos envolvendo estes polifenóis a fim de analisar a influência dos mesmos isoladamente no modelo da levedura S. cerevisiae. Foi possível observar pelos resultados que ambos os polifenóis, quando em quantidades semelhantes, são antioxidantes em potencial, sem diferença estatística. Entretanto, utilizando-se linhagens proficientes e deficientes nos sistemas de defesa antioxidante, foi possível observar que os danos causados pelos agentes estressores são revertidos por ambos polifenóis pela ação principalmente da enzima catalase. Estudos adicionais com modelos específicos para determinadas doenças ou até mesmo com humanos fazem-se necessários, entretanto pode-se concluir que o suco de uva é um alimento rico em polifenóis, vitamina C, minerais e que possui uma importante atividade antioxidante tanto in vitro como in vivo. / Submitted by Ana Guimarães Pereira (agpereir@ucs.br) on 2015-03-09T18:17:17Z No. of bitstreams: 1 Tese Caroline Dani.pdf: 26781741 bytes, checksum: 95432174adcbf84790c1b9c5d98a97fc (MD5) / Made available in DSpace on 2015-03-09T18:17:17Z (GMT). No. of bitstreams: 1 Tese Caroline Dani.pdf: 26781741 bytes, checksum: 95432174adcbf84790c1b9c5d98a97fc (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior, CAPES. / Although the beneficial effects of the moderate intake of wine are well known, the antioxidant capacity of grape juices is still little reported. Grape juice is a food which has important amount of polyphenols, thus, it can be included among the foods with high antioxidant potential. Studies with grape juice are very relevant since this beverage is widely consumed and presents economical importance in our region. Nowadays there are several types of grape juices in the market; white, purple and rose, organic or conventional. Grape juice has many nutrients and bioactive compounds with antioxidant, antimutagenic, anticarcinogenic and antiteratogenic activities. Polyphenols are components which play important roles in grape juice, since their presence contributes to the coloring, acidity and other characteristics of the juice. Several beneficial activities to human health are attributed to polyphenols. However, studies related to juice beneficial activity, a complex substance, were scarce. This study aimed to assess: 1) antioxidant and antimutagenic activities of different grape juices and the metals influence in these activities; 2) antioxidant activity of rose grape juice; 3) neuroprotective and hepatoprotective activities of grape juice in young Wistar rats; 4) serum antioxidant activity of grape juice in young Wistar rats; 5) neuroprotective, hepatoprotective and antigenotoxic activities in old Wistar rats; and 6) protective activity of resveratrol and catechin against distinct stressor agents in different strains of S. cerevisiae yeast. Some metals like Manganese and Sulfur showed positive and negative correlations with these activities, respectively. Moreover, mineral content varied between white and purple juices. However, Potassium was the most prevalent mineral (in both juices). Thus, the correlations reported could also distinguish white from purple juices. Wistar rats (male) were used as in vivo models. They were treated by gavage twice a day, for 30 days, receiving in total a volume of grape juice corresponding to their weight. Rats were divided into three groups: control (saline), organic and conventional grape juice. On the 30th day, half of each group received a single dose of the stressor agent CCl4 equivalent to their weight. After six hours, the animals were sacrificed. Experiments with the moldel yeast S. cerevisiae demonstrated that the grape juices studied present important antioxidant and antimutagenic activities. The in vivo model (Wistar rats) showed neuroprotective, hepatoprotective and seric antioxidant actions of grape juices in young rats. In oldest rats, antigenotoxic activity was found. These studies demonstrated important correlations between beneficial activities and polyphenolic content, mainly related to resveratrol and catechin, nonflavonoid and flavonoid compounds, respectively. Since grape juice is a complex mixture of compounds, involving these polyphenols were carried out in order to analyze their isolated influence on S. cerevisiae yeast model. Our results suggest that both polyphenols when applied in similar amountm have the same antioxidant potential. However, when studying strains proficient and deficient in antioxidant defense systems, the damages from stressor agents are reverted by both polyphenols, mainly under the action of catalase enzyme. Further studies with specific models of certain diseases or even with humans are needed. Our findings demonstrated that grape juice is a food rich in polyphenols, vitamin C and minerals which plays important in vitro and in vivo antioxidant activities.

Embora os efeitos benéficos da ingestão moderada do vinho sejam bem conhecidos, a capacidade antioxidante de sucos de uva é ainda pouco estudada. O suco de uva é um alimento composto por uma importante quantidade de polifenóis e pode ser incluído entre os alimentos com potencial antioxidante. Seu estudo é muito relevante pelo amplo consumo desta bebida e a importância econômica que apresenta em nossa região. Atualmente contamos com diferentes sucos de uva no mercado, brancos, tintos e roses, orgânicos ou convencionais. O suco de uva possui vários nutrientes e compostos bioativos com atividades antioxidante, antimutagênica, anticarcinogênica e antiaterogênica, entre outras. Os polifenóis são nutrientes de grande importância no suco de uva, visto que a presença destes pode contribuir para coloração, acidez e outras características importantes do suco. Aos polifenóis, já são atribuídas várias atividades benéficas a saúde do homem. Entretanto, pouco se sabia sobre a atividade do suco, o qual é uma substância complexa. Neste sentido, este estudo buscou avaliar: 1) atividade antioxidante e antimutagênica de diferentes sucos de uva e a influência de metais presentes nestes sucos; 2) atividade antioxidante do suco de uva rose; 3) atividade neuroprotetora e hepatoprotera do suco de uva em ratos Wistar jovens; 4) atividade antioxidante sérica do suco de uva em ratos Wistar jovens; 5) atividade neuroprotetora, hepatoprotetora, antigenotóxica em ratos Wistar envelhecidos; e 6) proteção do resveratrol e da catequina frente a diferentes agentes estressores em diferentes linhagens da levedura S. cerevisiae. Alguns metais apresentaram correlações positivas com estas atividades, como o Manganês, e negativas como, por exemplo, o Enxofre. O conteúdo de minerais variou entre sucos brancos e tintos. Entretanto, entre os mais prevalentes, está o potássio. Sendo assim, as correlações apresentadas também diferenciam entre os sucos brancos e tintos. Modelos in vivo contaram com grupos de ratos Wistar (machos) que foram tratados por gavagem duas vezes ao dia durante 30 dias, tendo no total um volume de suco de uva corresponde ao seu peso. Os ratos foram divididos em três grupos: controle (recebeu salina), suco de uva convencional e suco de uva orgânico. No 30º dia os animais recebiam uma dose equivalente ao seu peso de um agente estressor (CCl4) e após cinco horas foram sacrificados. Foi possível observar que os sucos de uva estudados possuem atividade antioxidante e antimutagênica importante no modelo da levedura S. cerevisiae. No modelo in vivo (ratos Wistar) observou-se uma ação neuroprotetora, hepatoprotetora e antioxidante sérica em ratos jovens. Nos ratos mais velhos observou-se também ação antigenotóxica importante. Nestes trabalhos, observou-se importantes correlações entre as atividades benéficas e o conteúdo polifenólico, principalmente referente ao conteúdo de resveratrol e catequina, nãoflavonóide e flavonóide, respectivamente. Observando-se que o suco de uva é uma mistura complexa, foram realizados estudos envolvendo estes polifenóis a fim de analisar a influência dos mesmos isoladamente no modelo da levedura S. cerevisiae. Foi possível observar pelos resultados que ambos os polifenóis, quando em quantidades semelhantes, são antioxidantes em potencial, sem diferença estatística. Entretanto, utilizando-se linhagens proficientes e deficientes nos sistemas de defesa antioxidante, foi possível observar que os danos causados pelos agentes estressores são revertidos por ambos polifenóis pela ação principalmente da enzima catalase. Estudos adicionais com modelos específicos para determinadas doenças ou até mesmo com humanos fazem-se necessários, entretanto pode-se concluir que o suco de uva é um alimento rico em polifenóis, vitamina C, minerais e que possui uma importante atividade antioxidante tanto in vitro como in vivo. / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior, CAPES. / Although the beneficial effects of the moderate intake of wine are well known, the antioxidant capacity of grape juices is still little reported. Grape juice is a food which has important amount of polyphenols, thus, it can be included among the foods with high antioxidant potential. Studies with grape juice are very relevant since this beverage is widely consumed and presents economical importance in our region. Nowadays there are several types of grape juices in the market; white, purple and rose, organic or conventional. Grape juice has many nutrients and bioactive compounds with antioxidant, antimutagenic, anticarcinogenic and antiteratogenic activities. Polyphenols are components which play important roles in grape juice, since their presence contributes to the coloring, acidity and other characteristics of the juice. Several beneficial activities to human health are attributed to polyphenols. However, studies related to juice beneficial activity, a complex substance, were scarce. This study aimed to assess: 1) antioxidant and antimutagenic activities of different grape juices and the metals influence in these activities; 2) antioxidant activity of rose grape juice; 3) neuroprotective and hepatoprotective activities of grape juice in young Wistar rats; 4) serum antioxidant activity of grape juice in young Wistar rats; 5) neuroprotective, hepatoprotective and antigenotoxic activities in old Wistar rats; and 6) protective activity of resveratrol and catechin against distinct stressor agents in different strains of S. cerevisiae yeast. Some metals like Manganese and Sulfur showed positive and negative correlations with these activities, respectively. Moreover, mineral content varied between white and purple juices. However, Potassium was the most prevalent mineral (in both juices). Thus, the correlations reported could also distinguish white from purple juices. Wistar rats (male) were used as in vivo models. They were treated by gavage twice a day, for 30 days, receiving in total a volume of grape juice corresponding to their weight. Rats were divided into three groups: control (saline), organic and conventional grape juice. On the 30th day, half of each group received a single dose of the stressor agent CCl4 equivalent to their weight. After six hours, the animals were sacrificed. Experiments with the moldel yeast S. cerevisiae demonstrated that the grape juices studied present important antioxidant and antimutagenic activities. The in vivo model (Wistar rats) showed neuroprotective, hepatoprotective and seric antioxidant actions of grape juices in young rats. In oldest rats, antigenotoxic activity was found. These studies demonstrated important correlations between beneficial activities and polyphenolic content, mainly related to resveratrol and catechin, nonflavonoid and flavonoid compounds, respectively. Since grape juice is a complex mixture of compounds, involving these polyphenols were carried out in order to analyze their isolated influence on S. cerevisiae yeast model. Our results suggest that both polyphenols when applied in similar amountm have the same antioxidant potential. However, when studying strains proficient and deficient in antioxidant defense systems, the damages from stressor agents are reverted by both polyphenols, mainly under the action of catalase enzyme. Further studies with specific models of certain diseases or even with humans are needed. Our findings demonstrated that grape juice is a food rich in polyphenols, vitamin C and minerals which plays important in vitro and in vivo antioxidant activities.