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Quantificação de vitamina C e capacidade antioxidante de variedades cítricas; Quantification of vitamin C and antioxidant capacity of citrus varieties

COUTO, Meylene Aparecida Luzia; CANNIATTI-BRAZACA, Solange Guidolin
Fonte: Sociedade Brasileira de Ciência e Tecnologia de Alimentos Publicador: Sociedade Brasileira de Ciência e Tecnologia de Alimentos
Tipo: Artigo de Revista Científica
POR
Relevância na Pesquisa
65.94%
A pesquisa teve por objetivo avaliar a variação do teor de vitamina C em diferentes variedades de laranjas e tangerinas de significado comercial no Brasil, como também medir a capacidade antioxidante destes citros. Foram realizadas análises para avaliação do índice de maturação no suco dos citros, como pH, sólidos solúveis totais e acidez total titulável, e foram determinados os teores de vitamina C e capacidade antioxidante, sendo os dados comparados para verificar as diferenças pelo teste de Tukey (p < 0,05). As tangerinas apresentaram teores de vitamina C e capacidade antioxidante menores que as laranjas. Os teores de vitamina C variaram entre 21,47 e 84,03 mg ácido ascórbico.100 mL-1 de suco, apresentados, respectivamente, pela tangerina-murcote e laranja-natal. A tangerina-murcote também apresentou a menor capacidade antioxidante (12,78%) e a maior capacidade antioxidante foi da laranja-lima (66,24%). Conclui-se que as diferentes variedades de laranjas e tangerinas possuem variação significativa nas variáveis analisadas, sendo que as laranjas apresentaram os maiores teores de vitamina C e capacidade antioxidante.; The objective of this research was to evaluate the variation of vitamin C in different commercial varieties of oranges and tangerines in Brazil and to measure the antioxidant capacity of these citrus. The analyses done for the evaluation of the maturity index of the citrus juices were pH...

Suplementação dietética de vitamina C, desenvolvimento e sanidade do pacu (Piaractus mesopotamicus Holmberg, 1887).; Dietary vitamin c supplementation, growth and health of pacu (Piaractus mesopotamicus Holmberg, 1887).

Almeida, Geraldo Silva de Campos
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 28/11/2003 PT
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O pacu, Piaractus mesopotamicus Holmberg, 1887 (Characiformes, Characidae), é uma das principais espécies da fauna aquática brasileira, com grande potencial para aqüicultura interior. Estudos sobre nutrição e determinação de exigências nutricionais são ferramentas para embasar a formulação de dietas completas e consolidar a piscicultura intensiva e viável da espécie. A suplementação dietética com vitamina C tem importância na eficiência alimentar, sanidade dos estoques e na economicidade das dietas e da criação. O objetivo deste projeto foi determinar as exigências nutricionais em vitamina C de alevinos de pacu. Os peixes (9,06 ± 1,40 g) foram alimentados com dietas contendo diferentes teores de vitamina C, ad libitum, duas vezes ao dia, durante 63 dias, e avaliados quanto ao desempenho, medido pelo ganho de peso (GDP), consumo de ração, conversão alimentar (CA), taxa de crescimento específico (TCE) e sanidade, considerando-se a incidência de sinais de deficiência em vitamina C e alterações hematológicas – contagem de eritrócitos (GV), hematócrito (HCT), hemoglobina (Hb), volume corpuscular médio (VCM) e leucócitos totais (GB). As rações semipurificadas foram suplementadas com dez níveis de inclusão: 0 (controle)...

Desenvolvimento e validação de metodologia analitica, utilizando a CLAE, para determinação de vitamina C em frutas e seus principais produtos; Development and validation of analytical methodology, using the HPLC for determination of vitamin C in fruits and its main products

Mauro Luiz Aldrigue
Fonte: Biblioteca Digital da Unicamp Publicador: Biblioteca Digital da Unicamp
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 18/12/1998 PT
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75.93%
Atualmente, a vitamina C é a mais importante dentre as vitaminas comercializadas. Destaca-se por sua eficiente ação antioxidante, empregada em alimentos e seu largo uso como fármaco. Entre os compostos que apresentam esta atividade vitamínica, o ácido L-ascórbico (AA) é a forma mais difundida e comercializada, embora o produto de sua oxidação, o ácido desidroascórbico (DHAA) possua a mesma atividade vitamínica. Já, com cerca de 5% desta atividade, o ácido isoascórbico (IAA) é adicionado a vários alimentos, o, que leva a necessidade de métodos eficientes também para o seu controle. Para melhor avaliar o potencial vitamínico de fontes naturais de vitamina C, que são as frutas, os legumes e seus produtos, busca-se desenvolver métodos que determinem simultaneamente estas formas ativas, o que constitue em um dos grandes desafios metodológicos na atualidade. Assim, a metodologia para análise das formas ativas de vitamina C (AA, DHAA e lAA) foi estabelecida com a técnica de Cromatografia Líquida de Alta Eficiência (CLAE), utilizando coluna Spherisorb ODS-2, 5Jµm,150x4,6mm, fase móvel aquosa com 2,5mmol/L de cetrimida e 25mmol/L de acetato de amônia, pH 5,60 ajustado com ácido acético e vazão de 0,80mL/min...

Comparative study of six pear cultivars in terms of their phenolic and vitamin C contents and antioxidant capacity

Sánchez, Andrea C. Galvis; Gil-Izquierdo, Angel; Gil, Maria
Fonte: Wiley-Blackwell Publicador: Wiley-Blackwell
Tipo: Artigo de Revista Científica
Publicado em //2003 ENG
Relevância na Pesquisa
75.8%
The main phenolic compounds in six pear cultivars were identified and quantified using high-performance liquid chromatography/diode array detection (HPLC/DAD) and HPLC/electrospray ionisation mass spectrometry (HPLC/ESIMS). Major quantitative differences were found in the phenolic profiles. The peel contained higher concentrations of chlorogenic acid, flavonols and arbutin than the flesh, where only chlorogenic acid was detected. Total phenolics ranged from 1235 to 2005mgkg−1 in the peel and from 28 to 81mg k g−1 in the flesh. Ascorbic acid and dehydroascorbic acid were detected in the peel, whereas only dehydroascorbic acid was present in the flesh. The ranges of vitamin C content were from 116 to 228mg kg−1 in the peel and from 28 to 53mg kg−1 in the flesh. The antioxidant capacity was correlated with the content of chlorogenic acid (r = 0.46), while ascorbic acid made only a small contribution to the total antioxidant capacity of the fruit.

Changes in enzymes, phenolic compounds, tannins, and vitamin C in various stages of jambolan (Syzygium cumini Lamark) development

Brandão,Taís Silva de Oliveira; Sena,Amanda Reges de; Teshima,Elisa; David,Jorge Maurício; Assis,Sandra Aparecida
Fonte: Sociedade Brasileira de Ciência e Tecnologia de Alimentos Publicador: Sociedade Brasileira de Ciência e Tecnologia de Alimentos
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/12/2011 EN
Relevância na Pesquisa
65.79%
The physiological state of a fruit is closely related to ripening and climatic conditions during the growing period when the fruit undergo changes in color, texture, and flavor. The ripening of the fruit can involve a complex series of biochemical reactions with alteration in enzymes activities, phenols, tannins, and ascorbic acid. The activity of enzymes (carboximethylcellulase, polygalacturonase, and pectinlyase), the total concentration of phenolic compounds, condensed tannins, and vitamin C in five stages of maturation were studied. Significant changes were observed between the maturity stages. The phenolic compounds were higher at green stage (705.01 ± 7.41); tannins were higher at green/purple stage (699.45 ± 0.22). The results showed that the ascorbic acid levels of the pulp varied significantly from 50.81 ± 1.43 to 6.61 ± 1.04 mg.100 g-1 during maturation. The specific activity of pectin lyase was higher at green stage (1531.90 ± 5.83). The specific activity of polygalacturonase was higher at mature stage (1.83 ± 0.0018). The specific activity of carboximetilcelulose was higher at ripe mature stage (4.61 ± 0.0024). The low ascorbic acid content found in jambolan fruit indicates that this fruit is not a rich source of this nutrient; however...

Differential gene expression between wild-type and Gulo-deficient mice supplied with vitamin C

Jiao,Yan; Zhang,Jifei; Yan,Jian; Stuart,John; Gibson,Griffin; Lu,Lu; Willaims,Robert; Wang,Yong Jun; Gu,Weikuan
Fonte: Sociedade Brasileira de Genética Publicador: Sociedade Brasileira de Genética
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/01/2011 EN
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65.73%
The aim of this study was to test the hypothesis that hepatic vitamin C (VC) levels in VC deficient mice rescued with high doses of VC supplements still do not reach the optimal levels present in wild-type mice. For this, we used a mouse scurvy model (sfx) in which the L-gulonolactone oxidase gene (Gulo) is deleted. Six age- (6 weeks old) and gender- (female) matched wild-type (WT) and sfx mice (rescued by administering 500 mg of VC/L) were used as the control (WT) and treatment (MT) groups (n = 3 for each group), respectively. Total hepatic RNA was used in triplicate microarray assays for each group. EDGE software was used to identify differentially expressed genes and transcriptomic analysis was used to assess the potential genetic regulation of Gulo gene expression. Hepatic VC concentrations in MT mice were significantly lower than in WT mice, even though there were no morphological differences between the two groups. In MT mice, 269 differentially expressed transcripts were detected (> twice the difference between MT and WT mice), including 107 up-regulated and 162 down-regulated genes. These differentially expressed genes included stress-related and exclusively/predominantly hepatocyte genes. Transcriptomic analysis identified a major locus on chromosome 18 that regulates Gulo expression. Since three relevant oxidative genes are located within the critical region of this locus we suspect that they are involved in the down-regulation of oxidative activity in sfx mice.

Ascorbic acid and total vitamin C concentrations in plasma, gastric juice, and gastrointestinal mucosa: effects of gastritis and oral supplementation.

Waring, A J; Drake, I M; Schorah, C J; White, K L; Lynch, D A; Axon, A T; Dixon, M F
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /02/1996 EN
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75.83%
Epidemiological evidence suggests that high dietary ascorbic acid reduces gastric cancer risk. It may do this by either reducing N-nitroso compound formation in gastric juice, or by scavenging reactive oxygen species in gastric mucosa. The aim of this study was to discover if potential ascorbic acid protection might be increased by supplementation. Thirty two patients were supplemented with ascorbic acid, 500 mg twice daily for two weeks. Gastric juice, plasma, and upper gastrointestinal biopsy ascorbate concentrations were measured and compared with values in 48 unsupplemented patients. It was found that ascorbic acid and total vitamin C concentrations were considerably higher in biopsy specimens from oesophagus, body, antrum, duodenum, and rectum, compared with values in plasma or gastric juice. Plasma and mucosal concentrations were unaffected by the presence of chronic gastritis but gastric juice concentrations were substantially lower in patients with chronic gastritis than in patients with normal histological assessment (p < 0.01). Patients receiving ascorbic acid supplements had higher ascorbic acid concentrations in plasma (p < 0.001), gastric juice (p < 0.001), and at all biopsy sites in the upper gastrointestinal tract (p < 0.05). Gastric juice ascorbic acid and total vitamin C concentrations in gastritic patients...

High Vitamin C Intake Is Associated with Lower 4-Year Bone Loss in Elderly Men1,2

Sahni, Shivani; Hannan, Marian T.; Gagnon, David; Blumberg, Jeffrey; Cupples, L. Adrienne; Kiel, Douglas P.; Tucker, Katherine L.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /10/2008 EN
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56%
Vitamin C is essential for collagen formation and normal bone development. We evaluated associations of total, supplemental, and dietary vitamin C intake with bone mineral density (BMD) at the hip [femoral neck, trochanter], spine, and radial shaft and 4-y BMD change in elderly participants from the Framingham Osteoporosis Study. Energy-adjusted vitamin C intakes were estimated from the Willett FFQ in 1988–89. Mean BMD and 4-y BMD change was estimated, for men and women, by tertile/category of vitamin C intake, adjusting for covariates. We tested for interaction with smoking, calcium, and vitamin E intake. Among 334 men and 540 women, the mean age was 75 y and mean vitamin D intake was 8.25 µg/d (women) and 8.05 µg/d (men). We observed negative associations between total and supplemental vitamin C intake and trochanter-BMD among current male smokers (P-trend = 0.01). Among male nonsmokers, total vitamin C intake was positively associated with femoral neck BMD (P-trend = 0.04). Higher total vitamin C intake was associated with less femoral neck and trochanter-BMD loss in men with low calcium (all P-trend ≤ 0.03) or vitamin E intakes (all P-trend = 0.03). Higher dietary vitamin C intake tended to be associated with lower femoral neck-BMD loss (P-trend = 0.09). These associations were attenuated but retained borderline significance (P-trend < 0.1) after adjusting for potassium intake (a marker of fruit and vegetable intake)...

Sequential Analysis of Oxidative Stress Markers and Vitamin C Status in Acute Bacterial Osteomyelitis

Grbic, Rade; Miric, Dijana J; Kisic, Bojana; Popovic, Ljiljana; Nestorovic, Vojkan; Vasic, Aleksandar
Fonte: Hindawi Publishing Corporation Publicador: Hindawi Publishing Corporation
Tipo: Artigo de Revista Científica
EN
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In bacterial bone infections, excessively formed oxidants may result in local and systemic oxidative stress. Vitamin C is the major extracellular nonenzymatic antioxidant, also implicated in bone cells metabolism and viability. The physiological functions of vitamin C largely depend on its redox status. We sequentially assessed oxidative stress markers, hydroperoxides and malondialdehyde (MDA), total antioxidant activity (AOA), total vitamin C, ascorbic acid (Asc), and oxidized/reduced vitamin C ratio in 137 patients with acute osteomyelitis (OM). Compared to 52 healthy controls, in OM group baseline serum hydroperoxides, MDA and oxidized/reduced vitamin C ratio were higher whilst Asc and AOA were lower (P < 0.05, resp.). On the other side, total vitamin C levels in patients and controls were similar (P > 0.05), thereby suggesting a relative rather than absolute vitamin C deficiency in OM. During the follow-up, oxidative stress markers, AOA, and oxidizedreduced vitamin C ratio were gradually returned to normal, while there was no apparent change of total vitamin C concentrations. Persistently high values of oxidized/reduced vitamin C ratio and serum MDA were found in subacute OM. In conclusion, acute OM was associated with enhanced systemic oxidative stress and the shift of vitamin C redox status towards oxidized forms.

Dietary intake of vitamin C and vitamin E and the development of hypertensive disorders of pregnancy

Rumbold, A.; Maats, F.; Crowther, C.
Fonte: Elsevier Sci Ireland Ltd Publicador: Elsevier Sci Ireland Ltd
Tipo: Artigo de Revista Científica
Publicado em //2005 EN
Relevância na Pesquisa
75.87%
Objectives: To explore the relationship, if any, between dietary intake of the antioxidant vitamins C and E, and the development of pre-eclampsia and gestational hypertension. Study design: A prospective cohort study of pregnant women attending the antenatal clinic of the Women's and Children's Hospital in Adelaide, Australia, was carried out between April and July 2001. Women completed a semi-quantitative 116-item food frequency questionnaire (FFQ). Women's medical records were viewed after birth to collect data on pregnancy outcomes. Relationships were explored through cross-tabulations, chi-square analysis, and adjustments were made for potential confounders using binary logistic regression. Results: A total of 299 women completed the FFQ. Median intake of vitamin C was 188 mg and for vitamin E was 6.74 mg. There was no relationship between the intake of vitamin C and hypertensive disorders of pregnancy. For vitamin E, being in the lowest quartile of intake, was associated with an increased risk of hypertensive disorders (RR 1.75, 95% CI 1.11–2.75, P = 0.02). This relationship was confirmed after adjusting for the confounding factors of maternal age and parity. Conclusions: Little support was found for a relationship between dietary intake of vitamin C and the development of hypertensive disorders of pregnancy. Low vitamin E intake was associated with a significant increase in the risk of hypertensive disorders of pregnancy...

Total serum vitamin C concentration in pregnant women: implications for a healthy pregnancy

Hassan,Garba Ibrahim; Onu,Amodu Bala
Fonte: Instituto de Medicina Integral Prof. Fernando Figueira Publicador: Instituto de Medicina Integral Prof. Fernando Figueira
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/09/2006 EN
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76.01%
OBJECTIVES: total serum vitamin C (L-ascorbic acid) concentration was measured in 90 pregnant women, 30 in each trimester (age range 18-35 years) and a control group of age-matched non-pregnant women. METHODS: total serum vitamin C concentration was measured using the 2.4-dinitrophenylhydrazine method which involves the conversion of vitamin C to dehydroascorbic acid in the presence of copper (II) ions and subsequent measurement of the resulting bis-hydrazone at 540nm. RESULTS: the total vitamin C concentration in the first trimester was 2.55 ± 0.82 mg/dl and 2.32 ± 0.40 mg/dl and 0.77 ± 0.10 mg/dl in the second and third trimesters respectively. Relative to serum total vitamin C concentration in the controls (3.15 ± 0.13 mg/dl) these values are significantly lower (p < 0.05). CONCLUSIONS: low serum vitamin C in pregnancy may indicate utilization of this vitamin to mop up the excess reactive oxygen species and maintain its normal homeostasis. Therefore, Vitamin C supplementation during pregnancy is recommended in order to boost the body's low vitamin C level and prevent the predisposition to low birth weight babies, premature delivery and pre-eclamsia all of which are known to be associated with sub-optimal vitamin C levels during pregnancy.

Evaluation of the Antioxidant Capacity, Phenolic Compounds, and Vitamin C Content of Different Peach and Nectarine [Prunus persica (L.) Batsch] Breeding Progenies

Cantín Mardones, Celia M.; Moreno Sánchez, María Ángeles; Gogorcena Aoiz, Yolanda
Fonte: American Chemical Society Publicador: American Chemical Society
Tipo: Artículo Formato: 26120 bytes; application/pdf
ENG
Relevância na Pesquisa
65.88%
The version of the publisher is available at: http://pubs.acs.org/journal/jafcau; Antioxidant capacity and contents of total phenolics, anthocyanins, flavonoids, and vitamin C were evaluated in 218 genotypes from 15 peach and nectarine breeding progenies. Significant differences were found among progenies on the fruit antioxidant profile, corroborated by the high contribution showed by cross to the phenotypic variance of each phytochemical trait analyzed (16−45%). Phytochemical profile varied depending on peach/nectarine and yellow/white flesh color qualitative traits. On the other hand, no significant effect of year was found on the bioactive profile of peaches and nectarines. Antioxidant capacity was linearly correlated to total phenolic content, but correlation varied depending on the progeny. No correlation was found for vitamin C versus any other phytochemical trait. The results suggest the importance of genetic background on the antioxidant profile of peaches and nectarines and stress its relevance for the ultimate objective of this work: selecting new peach and nectarine genotypes rich in bioactive compounds to benefit consumer’s health.; This study was supported by Spanish MICINN (Ministry of Science and Innovation) Grants AGL-2005-05533 and AGL-2008-00283 and the regional government of Aragn (A44). C.M.C. was supported by a FPU fellowship from the Spanish MICINN.; Peer reviewed

Effect of climatic and sulphur fertilisation conditions, on phenolic compounds and vitamin C, in the inflorescences of eight broccoli cultivars

Vallejo, Fernando; Tomás Barberán, Francisco; García-Viguera, Cristina
Fonte: Springer Publicador: Springer
Tipo: Artículo Formato: 259768 bytes; application/pdf
ENG
Relevância na Pesquisa
65.89%
7 pages, 8 tables, 1 figure.; Flavonoids, hydroxycinnamoyl derivatives (sinapic and ferulic acid derivatives+caffeoyl-quinic acid derivatives) and vitamin C were quantified by HPLC-MS in five commercial and three experimental cultivars from freshly harvested broccoli inflorescences ( Brassica oleracea L. var. italica). In order to identify differences due to genetic and agronomic factors, the broccoli cultivars were grown under different climatic and agronomic conditions, i.e. early (winter) and late (spring) seasons with poor (15 kg/ha) and rich (150 kg/ha) sulphur fertilisation. The predominant sinapic and ferulic acid derivatives in all broccoli cultivars were 1,2-diferuloylgentiobiose, 1,2,2'-trisinapoylgentiobiose and 1,2'-disinapoyl-2-feruloylgentiobiose. In addition, the compounds 1,2-diferuloylgentiobiose, 1-sinapoyl-2,2'-diferuloylgentiobiose and 1,2,2'-triferuloylgentiobiose were identified in broccoli inflorescences for the first time. Extreme agronomic and environmental conditions (late season and rich sulphur fertilisation which could induce different stress situations on the plant) enhanced the phenolic content. Thus, total flavonoids showed the highest content, followed by total sinapic and feruloyl acid derivatives and total caffeoyl-quinic acid derivatives. In general...

Comparative study of six pear cultivars in terms of their phenolic and vitamin C contents and antioxidant capacity

Galvis-Sánchez, Andrea C.; Gil-Izquierdo, Ángel; Gil Muñoz, M.ª Isabel
Fonte: John Wiley & Sons Publicador: John Wiley & Sons
Tipo: Artículo Formato: 259768 bytes; application/pdf
ENG
Relevância na Pesquisa
75.8%
9 pages, 8 tables, 1 figure.; The main phenolic compounds in six pear cultivars were identified and quantified using high-performance liquid chromatography/diode array detection (HPLC/DAD) and HPLC/electrospray ionisation mass spectrometry (HPLC/ESIMS). Major quantitative differences were found in the phenolic profiles. The peel contained higher concentrations of chlorogenic acid, flavonols and arbutin than the flesh, where only chlorogenic acid was detected. Total phenolics ranged from 1235 to 2005 mg kg-1 in the peel and from 28 to 81 mg k g-1 in the flesh. Ascorbic acid and dehydroascorbic acid were detected in the peel, whereas only dehydroascorbic acid was present in the flesh. The ranges of vitamin C content were from 116 to 228 mg kg-1 in the peel and from 28 to 53 mg kg-1 in the flesh. The antioxidant capacity was correlated with the content of chlorogenic acid (r = 0.46), while ascorbic acid made only a small contribution to the total antioxidant capacity of the fruit.; ACGS acknowledges the Fundaçäao para a Ciência e Tecnologia (FCT), Portugal for a grant (PRAXIS XXI BD/18392/98). AGI is grateful to the Spanish MEC for a predoctoral grant.; Peer reviewed

Glucosinolates and vitamin C content in edible parts of broccoli florets after domestic

Vallejo, Fernando; Tomás Barberán, Francisco; García-Viguera, Cristina
Fonte: Springer Publicador: Springer
Tipo: Artículo Formato: 259768 bytes; application/pdf
ENG
Relevância na Pesquisa
65.93%
7 pages, 4 figuras, 4 tablas.; Total aliphatic and indole/aromatic glucosinolates and vitamin C content (ascorbic+dehydroascorbic acid) were evaluated in the edible portions of fresh harvested broccoli (Brassica oleracea L. var. italica) florets (Marathon cv.) before and after cooking and in the cooking water. High pressure boiling, steam cooking, microwaving and low pressure boiling (conventional) were the four domestic cooking processes used in this work. Results showed great differences among the four cooking processes and their influence on the content of glucosinolates and vitamin C. Thus, clear disadvantages were detected when cooking in a microwave due to the high loss of vitamin C (40%) and total glucosinolates (74%) in comparison with the rest of treatments. High pressure and conventional boiling had a significant loss rate of total glucosinolates (33% and 55% respectively) regarding fresh raw broccoli, due to the leaching into the cooking water. On the other hand, steaming had minimal effects on glucosinolates and vitamin C. Therefore, we can conclude that a large quantity of glucosinolates and vitamin C will be consumed in steamed broccoli when compared to the other cooking processes.; The authors are grateful to the Fundación Seneca and Consejería de Agricultura...

In Vitro Gastrointestinal Digestion Study of Pomegranate Juice Phenolic Compounds, Anthocyanins, and Vitamin C

Pérez-Vicente, Antonio; Gil-Izquierdo, Ángel; García-Viguera, Cristina
Fonte: American Chemical Society Publicador: American Chemical Society
Tipo: Artículo Formato: 259768 bytes; application/pdf
ENG
Relevância na Pesquisa
65.77%
5 pages, 5 figures.; Pomegranate is an important source of bioactive compounds, such as anthocyanins, other phenolic compounds, and ascorbic acid. In the present work an in vitro availability method has been used to assay the influence of the physiological conditions in the stomach and small intestine. This method enables the study of the release of anthocyanins, vitamin C, and total phenols from the pomegranate juice and their transformations during gastrointestinal digestion. Results have shown that pomegranate phenolic compounds are available during the digestion in a quite high amount (29%). Nevertheless, due to pH, anthocyanins are largely transformed into non-red forms and/or degraded (97%), and similar results are obtained for vitamin C (>95% degradation).; We thank FEDERCICYT (IFD1997-1337-C02-01), Hero S.A., and Juver for financial support. A.P.-V. thanks FEDER-CICYT (IFD1997-1337-C02-01) for a contract. Also, A.G.-I. is grateful to Spanish MEC for a grant.; Peer reviewed

The effect of storage temperatures on vitamin C and phenolics content of artichoke (Cynara scolymus L.) heads

Gil-Izquierdo, Ángel; Conesa, María Angeles; Ferreres, Federico; Gil Muñoz, M.ª Isabel
Fonte: Elsevier Publicador: Elsevier
Tipo: Artículo Formato: 259768 bytes; application/pdf
ENG
Relevância na Pesquisa
65.79%
4 pages, 3 figures.; The effect of temperatures (0, 2, 5, 7 and 10°C) for 14 days of storage on antioxidant constituents such as vitamin C and phenolic compounds of artichoke c.v. ‘Blanca de Tudela’ was studied. Three groups of phenolics were identified and quantified as: chlorogenic acid; 1,5-dicaffeoylquinic acid (1,5 di-CQA)+3,5-dicaffeoylquinic acid (3,5 di-CQA); and 1,4-dicaffeoylquinic acid (1,4-di-CQA)+4,5-dicaffeoylquinic acid (4,5 di-CQA). The content of vitamin C was higher in the internal bracts compared with the external ones (144 and 193 mg kg−1 fresh wt., respectively) and decreased after 14 days of storage under the assayed temperatures. Each individual group of phenolics was 10-fold higher in the internal bracts than in the external ones. At harvest, total phenolics (618 mg kg−1), chlorogenic acid (143 mg kg−1) and 1,4 di-CQA+4,5 di-CQA (207 mg kg−1), increased in internal bracts after storage, particularly at 2, 5 and 7°C. On the other hand, 1,5-di-CQA+3,5-di-CQA decreased from 260 to 150 mg kg−1 after storage. Consumption of the edible artichoke fraction could be an important source of natural antioxidants and provide significant nutritional value to the diet.; The authors are grateful to the Spanish CICYT for their financial support of this work ŽALI98-0843...

An improved and fast UHPLC-PDA methodology for determination of L-ascorbic and dehydroascorbic acids in fruits and vegetables: evaluation of degradation rate during storage

Spínola, Vítor; Mendes, Berta; Câmara, José S.; Castilho, Paula C.
Fonte: Springer-Verlag Publicador: Springer-Verlag
Tipo: Artigo de Revista Científica
Publicado em /01/2012 ENG
Relevância na Pesquisa
75.95%
This study provides a versatile validated method to determine the total vitamin C content, as the sum of the contents of L-ascorbic acid (L-AA) and dehydroascorbic acid (DHAA), in several fruits and vegetables and its degradability with storage time. Seven horticultural crops from two different origins were analyzed using an ultrahigh-performance liquid chromatographic–photodiode array (UHPLC-PDA) system, equipped with a new trifunctional high strength silica (100% silica particle) analytical column (100 mm×2.1 mm, 1.7 μm particle size) using 0.1% (v/v) formic acid as mobile phase, in isocratic mode. This new stationary phase, specially designed for polar compounds, overcomes the problems normally encountered in HPLC and is suitable for the analysis of large batches of samples without L-AA degradation. In addition, it proves to be an excellent alternative to conventional C18 columns for the determination of L-AA in fruits and vegetables. The method was fully validated in terms of linearity, detection (LOD) and quantification (LOQ) limits, accuracy, and inter/intraday precision. Validation experiments revealed very good recovery rate of 96.6±4.4% for L-AA and 103.1±4.8 % for total vitamin C, good linearity with r2-values >0.999 within the established concentration range...

Antioxidant responses of damiana (Turnera diffusa Willd) to exposure to artificial ultraviolet (UV) radiation in an in vitro model: part I; UV-C radiation

Soriano-Melgar,Lluvia de Abril Alexandra; Alcaraz-Meléndez,Lilia; Méndez-Rodríguez,Lía C.; Puente,María Esther; Rivera-Cabrera,Fernando; Zenteno-Savín,Tania
Fonte: Nutrición Hospitalaria Publicador: Nutrición Hospitalaria
Tipo: info:eu-repo/semantics/article; journal article; info:eu-repo/semantics/publishedVersion Formato: text/html; application/pdf
Publicado em 01/05/2014 ENG
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Introduction: Ultraviolet type C (UV-C) radiation has higher energy than the UV-B radiation and has been less studied because it is completely absorbed by the ozone layer. However, artificial UV-C radiation can generate diverse modifications in the plants. Given that exposure to UV-C for short periods of time increases the antioxidant content, improving the appearance and shelf-life of products, its potential application in postharvest treatments to modify the antioxidant content of medicinal plants, such as damiana (Turnera diffusa), is novel and relevant. Objective: To determine the effects of UV-C radiation on enzymatic and non-enzymatic antioxidant defenses, as well as oxidative damage levels, in damiana (Turnera diffusa) plants in vitro. Results: UV-C radiation decreased superoxide dismutase (SOD, EC 1.15.1.1) and total peroxidases (POX, EC 1.11.1) activities, the concentration of chlorophylls (a and b), carotenes, vitamin C, and total antioxidant capacity. UV-C radiation increased the phenolic compound levels in damiana. Loss of antioxidant defenses was higher in damiana plants exposed to higher UV-C doses and/or for longer periods. This study suggests that UV-C radiation induces oxidative stress, evidenced as increased protein carbonyls and phenolic compound content...

Effects of cultural practices on total phenolics and vitamin C content of organic table grapes

Isci,B.; Gokbayrak,Z.; Keskin,N.
Fonte: South African Journal of Enology and Viticulture Publicador: South African Journal of Enology and Viticulture
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/01/2015 EN
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The total phenolic and vitamin C contents of organic table grapes were determined by spectrophotometry and HPLC, respectively, after several quality-increasing treatments were applied at véraison for two growing seasons. Cane girdling and cluster-berry thinning resulted in different responses in the cultivars. 'Red Globe' generally was found to produce the lowest quantity of total phenolics in the berries, while 'Trakya Ilkeren' was the cultivar that accumulated the highest phenolics. Vitamin C accumulation in the berries was also affected by the treatments. The effect of the treatments was inconclusive in 'Buca Razakisi'. The application of both girdling and thinning caused more accumulation of vitamin C in the 'Alphonse L.' and 'Trakya Ilkeren' berries.