Difference In Ascorbic Acid Levels Research Articles

Microbial, nutritional, and organoleptic quality of pomegranate juice following high-pressure homogenization and low-temperature pasteurization.

This study investigated the effects of high-pressure homogenization (HPH) on microbial, nutritional, and organoleptic qualities of pomegranate juice. Juices subjected to HPH at 100 and 150MPa were compared to those subjected to thermal pasteurization at 55, 65, and 75 °C for 15 s, and to combined treatments. Physicochemical properties of pomegranate juices, such as color, pH, acidity, and total soluble solids, were marginally affected by either treatment. Significant microbial inactivation for the juices inoculated with Escherichia coli and yeast was achieved during 28 days of shelf life by HPH at 150MPa, followed by thermal treatment at 65 °C. There was no significant difference in ascorbic acid levels between the treated and fresh juice. Total polyphenol content and antioxidant activity were measured to be higher in case of both treatment methods. Analyzing treated HPH samples with electronic tongue and nose showed similar flavor profiles to the fresh juice. PRACTICAL APPLICATION: The work shows the benefits of using the advanced high-pressure homogenization (HPH) compared to common thermal treatment used today in fruit juice pasteurization. HPH is capable to provide sufficient reduction in microbial with better nutritional and organoleptic quality. In this manuscript, we showed the potential of HPH as alternative method for pasteurization on a highly healthy fruit like pomegranate. The work describes the advantages in HPH process through comprehensive analysis for nutritional, microbial, and sensorial quality.

The Effect of Ascorbic Acid (Vitamin C) on Transepithelial Corneal Cross-Linking in Rabbits.

To evaluate the effects of ascorbic acid (vitamin C), the main antioxidant agent in the cornea on transepithelial corneal cross-linking (CXL) where the main mechanism is oxidation. Twenty eyes of 20 rabbits were divided into 3 groups: Group 1 (7 eyes) had transepithelial corneal CXL after being fed with normal diet; Group 2 (7 eyes) had corneal CXL after once-daily subcutaneous injections of 200 mg of ascorbic acid in addition to normal diet; and the control group (6 eyes) was fed with normal diet but did not have corneal CXL performed. Ascorbic acid levels were measured in aqueous humor and plasma, and biomechanical measurements were applied to the cornea. There was a significant difference in ascorbic acid levels of plasma (P = 0.008) and aqueous humor (P = 0.006) between group 1 and 2. The Young's modulus values of group 1 and 2 were similar (P = 0.741) and were significantly higher than the control group (P = 0.02 and P = 0.01). The increase rate in Young's modulus values was 37.3% in group 1 and 43.9% in group 2 compared to control group. The ultimate strain values in group 1 and 2 were similar (P = 0.632) and were significantly higher than control group (P = 0.04, P = 0.03). The ultimate stress values in group 1 and 2 were similar (P = 0.836) and were significantly lower than control group (P = 0.001, P = 0.001). Systemic vitamin C does not appear to decrease effectiveness of transepithelial corneal CXL. Therefore, there is no reason to stop or reduce vitamin C supplementation before corneal CXL therapy.

Synergistic effects of ascorbic acid and thiazolidinedione on secretion of high molecular weight adiponectin from human adipocytes

To test the hypothesis that ascorbic acid (AA) and thiazolidinedione (TZD) would have additive effects on HMW adiponectin secretion by virtue of different modes of action. We determined the effects of supplementation of AA and/or TZD on expression and secretion of total and HMW adiponectin from human Simpson-Golabi-Behmel syndrome (SGBS) adipocytes in the absence or presence of the proinflammatory cytokine TNFα. AA supplementation significantly increased secretion of HMW adiponectin (1.7-fold) without altering adiponectin expression or total adiponectin secretion. TZD significantly increased expression (3-fold) and secretion of total (1.4-fold) but not HMW adiponectin. Combined supplementation resulted in a significant increase in expression (3-fold) and secretion of total (1.8-fold) and HMW (5-fold) adiponectin. Similar results were seen in cells co-treated with TNFα. These data show that AA and TZD have synergistic rather than simple additive effects on secretion of HMW adiponectin from human adipocytes and raise the possibility that differences in AA levels may contribute to the variability in adiponectin multimer profiles and efficacy of TZD in humans. Our results also provide a rationale for longitudinal clinical trials investigating the effects of AA supplementation with or without TZD on adiponectin and metabolic profiles.

Influência da embalagem e estocagem no conteúdo de beta-caroteno e ácido ascórbico em suco de manga “Ubá” industrializado

This work investigated the content and stability of two natural antioxidants – β-carotene and ascorbic acid (AA) – in mango juice industrialized and stored during different storage times, correlating the recommendations of vitamins A and C with the content found in the juice. β-carotene and AA were analyzed in juice sold in tetra pak packaging, during five storage times (1 to 5 months) and in glass containers, during three storage times (after 3, 4 and 5 months of storage). The analysis was carried out using High Performance Liquid Chromatography (HPLC). No statically differences (α = 5 %) were found between the different times of storage for both compounds analyzed, both in tetra pak package and glass container. Furthermore, no significant differences were found between the β-carotene content of the juices sold in both containers. However, we found statistical differences in AA levels between the different packages, with glass containers showing greater content compared to tetra pak packaging. Thus, losses occasioned by package permeability to oxygen should be subject of concern in the food industry.

The ascorbic acid content of tomato fruits is associated with the expression of genes involved in pectin degradation

BackgroundHigh levels of ascorbic acid (AsA) in tomato fruits provide health benefits for humans and also play an important role in several aspects of plant life. Although AsA metabolism has been characterized in detail, the genetic mechanisms controlling AsA accumulation in tomatoes are poorly understood. The transcriptional control of AsA levels in fruits can be investigated by combining the advanced genetic and genomic resources currently available for tomato. A comparative transcriptomic analysis of fruit tissues was carried out on an introgression line containing a QTL promoting AsA accumulation in the fruit, using a parental cultivar with lower AsA levels as a reference.ResultsIntrogression line IL 12-4 (S. pennellii in a S. lycopersicum background) was selected for transcriptomic analysis because it maintained differences in AsA levels compared to the parental genotypes M82 and S. pennellii over three consecutive trials. Comparative microarray analysis of IL 12-4 and M82 fruits over a 2-year period allowed 253 differentially-expressed genes to be identified, suggesting that AsA accumulation in IL 12-4 may be caused by a combination of increased metabolic flux and reduced utilization of AsA. In particular, the upregulation of a pectinesterase and two polygalacturonases suggests that AsA accumulation in IL12-4 fruit is mainly achieved by increasing flux through the L-galactonic acid pathway, which is driven by pectin degradation and may be triggered by ethylene.ConclusionsBased on functional annotation, gene ontology classification and hierarchical clustering, a subset of the 253 differentially-expressed transcripts was used to develop a model to explain the higher AsA content in IL 12-4 fruits in terms of metabolic flux, precursor availability, demand for antioxidants, abundance of reactive oxygen species and ethylene signaling.

The stability of ascorbic acid in Artemia urmiana following enrichment and subsequent starvation

Summary The effects of vitamin enrichment on ascorbic acid (AA) levels in Artemia urmiana were studied by applying an emulsion containing ascorbyl palmitate (AP) as a vitamin C source. Nauplii were kept at 28� C in incubators containing the enrichment medium (cod liver oil, AP, sodium polysurbate, a-tocopherol and tap water) for 0, 12, 18 and 24 h and then starved at 5� C for 0, 12, 18 and 24 h. AA was determined using a reversed phase high performance liquid chromatography coupled to an electrochemical detector. The results showed that nauplii of A. urmiana had high levels of ascorbic acid in their body tissues (1534 ± 166 l gg )1 dry weight) and that the AA concentration increased following enrichment. The maximum enrichment level was reached by hour 18, declining by hour 24. There was a significant difference in AA levels between enriched and non-enriched artemia (P < 0.05). Although AA contents were enhanced in all groups during starvation in cold conditions, the increases were not considerable. However, a clear correlation could be observed between duration of starving and rise in AA levels in non-enriched and 12 and 18 h enriched groups.

Occupational social class, educational level and area deprivation independently predict plasma ascorbic acid concentration: a cross-sectional population based study in the Norfolk cohort of the European Prospective Investigation into Cancer (EPIC-Norfolk).

To investigate the independent association between three different measures of socioeconomic status and plasma ascorbic acid level. Cross-sectional population based study. 20 292 men and women aged 39-79 y who participated in the EPIC-Norfolk study. Individuals in manual social classes, who had no educational qualifications or those who lived in the most deprived areas had significantly lower levels of plasma ascorbic acid compared to those in nonmanual social classes, with at least O-level qualifications or who lived in less deprived areas. The magnitude of effect for each measure of socioeconomic status was greater in current smokers compared to current nonsmokers. Education and social class were stronger predictors of differences in ascorbic acid levels, an indicator of dietary health behaviour, than a deprivation index based on the Townsend score. This suggests that education could be particularly important in influencing large socioeconomic differentials in health related behaviours and potentially, health outcomes in the UK.

BIOCHEMICAL CHANGES ASSOCIATED WITH CHILLING IN PINEAPPLE FRUIT

Pineapple (Ananas comosus [L.] Merr.) fruit of variable cultivar ('Smooth Cayenne' and PRI hybrid '73-50') and maturity were stored at chilling temperatures to investigate the mechanism for blackheart inducement and development. When chilled for three weeks at 13degreesC followed by 7 days storage at 25degreesC, fruit of both cultivars developed significantly increased polyphenol oxidase (PPO) activities concurrently with blackheart symptoms. Fruit stored continuously at 25degreesC developed no blackheart. There was no correlation between peroxidase activity (POD) and blackheart development for either cultivar. The influence of fruit maturity on blackheart development was also investigated, by storing 'Smooth Cayenne' fruit of six maturity ranges for 3 weeks at 10degreesC, or for 3 weeks at 10degreesC followed by 7 days at 25degreesC. Immature fruit developed negligible blackheart, while fruit of mid-range maturity were susceptible, the latter also developed increased PPO activity after 4 weeks. Over mature fruit developed a translucent breakdown of the pulp, rather than blackheart. Differences in subsequent fruit susceptibility to blackheart were not consistent with PPO activities at harvest. Total phenol concentration increased with fruit maturity, but high phenol concentration was not consistent with increased blackheart incidence. There was no significant difference in ascorbic acid levels at harvest between the maturity ranges. The suggestion in the literature that ascorbic acid level at harvest indicates susceptibility to blackheart is not support by our data.

Aqueous humor uric acid and ascorbic acid concentrations and outcome of trabeculectomy.

To determine if there is an association between the surgical outcome of trabeculectomy and uric acid and ascorbic acid concentrations in the aqueous humor at the time of the procedure. Aqueous humor samples were collected from the eyes of 169 of 249 adult patients who underwent trabeculectomy alone for any type of glaucoma between April 1989 and July 1995. Postoperatively, all medical records were reviewed and outcomes were classified as successful, unsuccessful, or indeterminate. The ascorbic acid and uric acid concentrations were determined in masked fashion by high-pressure liquid chromatography. Factors associated with surgical outcome were determined. Uric acid concentration was higher in unsuccessful eyes (mean+/-SD, 0.21+/-0.08 mmol/L, n=26) than in successful eyes (0.15+/-0.09 mmol/L, n=91, 95% confidence interval for difference, 0.02-0.10 mmol/L). Ascorbic acid levels were not significantly different in the eyes with unsuccessful (1129.9+/-601.9 micromol/L) and successful (1334.3+/-511.0 micromol/L) surgery (95% confidence interval for difference, -475.2 to 66.4 micromol/L, P=.13) surgery. Other factors associated with failure were previous surgery and surgery performed at the inferior limbus. A multiple polytomous logistic regression analysis was performed, after excluding the small number of operations performed at the inferior limbus. The odds ratio for failure increased by a factor of 1.68 for every 1-mmol/L increase in uric acid (95% confidence interval, 1.16-2.43, P=.006). Uric acid levels were higher at the time of surgery in eyes that had unsuccessful outcomes than in those with successful outcomes. No significant difference in ascorbic acid levels was detectable. A higher uric acid level in the aqueous humor is a risk factor for trabeculectomy failure and might be tested as a prognostic indicator [corrected].

BRAIN ASCORBIC ACID LEVELS: MICE AND RATS SELECTED FOR DIFERENCES IN ACUTE REACTTONS TO ETHANOL

There are variations of ascorbic acid levels in different brain areas of mice and rats. However, there are no differences in ascorbic acid levels between lines of mice selectively bred for differences in ethanol sensitivity for 25 generations. Thus, it is unlikely that brain ascorbic acid plays a significant role in the acute sedative effects of ethanol in these mice. Studies with inbred strains of mice known to differ in ethanol preference, acute sensitivity and withdrawal sensitivity also failed to reveal any differences in brain ascorbic acid levels. There were differences in ascorbic acid content between selectively bred lines of rats in various brain areas at generation five of selection.

Response of Plants to Air Pollutants. III. A Relation between Ascorbic Acid Levels and Ozone Susceptibility of Light-Preconditioned Tobacco Plants

The effects of prefumigation light regimes on plants indicate that light modifies the response of plants to ozone. Taylor et al. (11) reported that ozone injury to Pinto bean was reduced when plants were grown at the higher level of 2 light intensities. Menser et al. (7) found that ozone damage to tobacco plants was diminished by an extended 22-hour photoperiod immediately before fumigation. Ascorbic acid is known to protect plants from ozone and other oxidizing agents. Freebairn (3) increased the tolerance of Pinto bean plants to ozone either by supplying ascorbic acid to the roots or by foliar applications. Freebairn and Taylor (4) made tissue analysis of smog-sensitive plants sprayed with ascorbic acid. They found that concentrations of ascorbic acid in the leaves increased and resulted in partial to complete protection from air-pollution injury. This paper presents results of a study to determine the effects of light preconditioning on ascorbic acid levels in tobacco plants; and the relation of ascorbic acid levels to ozone injury of 2 tobacco varieties, one resistant and the other sensitive to ozone. Ascorbic acid concentrations reported represent the excess formed in synthesis over that utilized in metabolism. The results show that light preconditioning caused notable differences in ascorbic acid levels. These differences were associated with changes in the degree of ozone injury.