Loss Of Antioxidant Capacity Research Articles

Effects of age and lifetime flight behavior on senescence and reproduction in Drosophila (880.2)

The effects of aerobic activity on physiology and senescence may be profound in variably active species such as flying insects, which attain among the highest metabolic rates ever measured. Flight capacity in insects decreases with age, although limiting flight behavior extends lifespan, slows the age‐related loss of antioxidant capacity and accumulation of oxidative damage, and potentially allows for greater energy investment in non‐locomotor traits such as reproduction. We tested the effects of age and lifetime flight behavior on flight capacity, longevity and reproduction in Drosophila. Specifically, 5 day‐old adult flies were separated into three life‐long treatments: (A) those not allowed to fly (no flight or NF), (B) those allowed ‐ but not forced ‐ to fly (voluntary flight or VF), and (C) those mechanically stimulated to fly (induced flight or IF). Longevity was in the order NF>VF>IF, although the ability to fly and attain high metabolic rates persisted the longest in VF flies. Age‐specific fecundity did not vary among the groups, although NF flies had the greatest lifetime fecundity due to their longer lifespans. These results indicate that aerobic locomotor behavior can accelerate physiological senescence and trade‐off against other traits.Grant Funding Source: National Science Foundation IOS‐0725030

Influence of storage temperature and time on the physicochemical and bioactive properties of roselle-fruit juice blends in plastic bottle.

Roselle-fruit juice blends were made from roselle extract and mango, papaya, and guava juices at the ratio of 80:20, 60:40, 40:60, and 20:80, % roselle: fruit juice, respectively. The blends were pasteurized at 82.5°C for 20 min and stored in 100 mL plastic bottles at 28 and 4°C for 6 months. The effects of storage time and temperature on physicochemical and bioactive properties were evaluated. Total soluble solids, pH, and reducing sugars increased significantly (P < 0.05) in some blends while titratable acidity decrease with increasing storage time. Vitamin C, total monomeric anthocyanins (TMA), total phenols (TPC), and antioxidant activity (ferric reducing ability of plasma, FRAP) in all roselle-fruit blends (40% roselle) decreased significantly (P < 0.05) at 28 and 4°C as storage progressed. Vitamin C in all roselle-fruit blends (40% roselle) decreased from 58–55% to 43–42% when stored at 28 and 4°C, respectively. TMA losses were 86–65% at 28°C and 75–53% at 4°C while TPC losses were 66–58% at 28°C and 51–22% at 4°C. Loss of antioxidant capacity (FRAP) was 18–46% at 28°C and 17–35% at 4°C. A principal component analysis (PCA) differentiated roselle-juice fruit blends into two clusters with two principle components PC1 and PC2, which explained 97 and 3% (blends stored at ambient temperature) and 96 and 4% (blends stored at refrigerated temperature) of the variation, respectively. PC1 differentiated roselle-guava juice blends which were characterized by vitamin C, TPC, FRAP, and pH, while PC2 from another cluster of roselle-mango and roselle-papaya juice blends and was characterized by TSS, RS, and color parameters (L* a* b*). However, TMA was the main variable with the highest effect on all roselle-fruit juice blends regardless of the storage time and temperature.

Glutathione peroxidase contributes with heme oxygenase-1 to redox balance in mouse brain during the course of cerebral malaria

Oxidative stress has been attributed both a key pathogenic and rescuing role in cerebral malaria (CM). In a Plasmodium berghei ANKA murine model of CM, host redox signaling and functioning were examined during the course of neurological damage. Host antioxidant defenses were early altered at the transcriptional level indicated by the gradually diminished expression of superoxide dismutase-1 (sod-1), sod-2, sod-3 and catalase genes. During severe disease, this led to the dysfunctional activity of superoxide dismutase and catalase enzymes in damaged brain regions. Vitagene associated markers (heat shock protein 70 and thioredoxin-1) also showed a decaying expression pattern that paralleled reduced expression of the transcription factors Parkinson disease 7, Forkhead box O 3 and X-box binding protein 1 with a role in preserving brain redox status. However, the oxidative stress markers reactive oxygen/nitrogen species were not accumulated in the brains of CM mice and redox proteomics and immunohistochemistry failed to detect quantitative or qualitative differences in protein carbonylation. Thus, the loss of antioxidant capacity was compensated for in all cerebral regions by progressive upregulation of heme oxygenase-1, and in specific regions by early glutathione peroxidase-1 induction. This study shows for the first time a scenario of cooperative glutathione peroxidase and heme oxygenase-1 upregulation to suppress superoxide dismutase, catalase, heat shock protein-70 and thioredoxin-1 downregulation effects in experimental CM, counteracting oxidative damage and maintaining redox equilibrium. Our findings reconcile the apparent inconsistency between the lack of oxidative metabolite build up and reported protective effect of antioxidant therapy against CM.

Effect of temperature on hot-air drying rate and on retention of antioxidant capacity in apple leathers

Fruit leathers are pectic gels, eaten as snack or dessert, obtained by dehydrating fruit purees. In this work, apple leathers were prepared by a hot-air drying process which allows the formation of a gel, following the “saccharide–acid–high methoxyl pectin” gelation mechanism. Leathers were produced at 50, 60 and 70°C, from two formulations: control and added with potassium metabisulphite (KM) as antioxidant. The drying process was studied applying a diffusive model, while antioxidant capacity (AC) losses were represented by a first-order model. Activation energy for drying (20.6kJ/mol) was lower than those estimated for AC losses in control (31.5kJ/mol) and KM-added (37.9kJ/mol) leathers. Therefore, the drying time reduction achieved by increasing air temperature is not sufficient to decrease AC losses in the range covered. AC retention decreased in both formulations at increasing air temperature. KM-added samples showed higher AC retention than the controls, except for those dried at 70°C. Kinetic constants were lower for KM-added samples, suggesting a protective effect of the additive, especially at moderate air temperatures. In the most favorable situation, AC retention was of only 16%. Therefore, the functional character of these products may not be preserved if dried with hot air and the research on economically viable, less-severe drying technologies should be intensified.

Effects of age and lifetime behavioral patterns on locomotion in Drosophila

The effects of behavior on physiology and senescence may be profound in variably active species such as flying insects, which attain among the highest metabolic rates ever measured. Previous studies have shown that limiting flight behavior in insects extends lifespan and slows the age‐related loss of antioxidant capacity and accumulation of oxidative damage in flight muscles. In this study, we manipulated the lifetime flight behavior of Drosophila melanogaster. Specifically, 5‐day old adult flies were separated into three life‐long treatments: (A) those not allowed to fly (no flight), (B) those allowed – but not induced – to fly (voluntary flight), and (C) those mechanically stimulated to perform over 100 flight bouts per day (induced flight). Consistent with the oxidative stress model of aging, Drosophila prevented from flying lived longer than those allowed or stimulated to fly. Flight capacity, measured as the ability to fly in a hypodense gas mixture (21% O2, 39.5% N2, 39.5% He; 0.81 g l−1), decreased with age in all treatment groups, but decreased earliest in flies from the no‐flight treatment. Extended longevity in flies from the no‐flight treatment suggests that oxidative damage accrued more slowly in this treatment group. However, early loss of flight capacity in the no‐flight group indicates that disuse effects were the primary determinant of the age‐dependent muscle impairment in this group. Additional experiments are ongoing to compare age‐dependent oxidative damage, flight muscle ultra‐structure, flight kinematics, immune function, reproduction and metabolic capacity among the treatment groups. Supported by NSF IOS‐0725030.

Characterization and storage stability of the extract of Thai mango (Mangifera indica Linn. Cultivar Chok-Anan) seed kernels.

Qualitative analysis of hydrolysable extract from mango (Mangifera indica Linn. cultivar Chok-Anan) seed kernel was performed by means of reversed phase high-performance liquid chromatography coupled to diode array detection and electrospray ionization mass spectrometry (RPHPLC-DAD-ESI-MS). The main phenolic compound was identified as methyl gallate by comparing their retention time, UV-vis absorption spectra and mass spectra with a reference standard. Quantification of phenolic compounds was performed by HPLC-DAD, which revealed that the extract contained total phenolics at a concentration of 194.1mg GAE/g dry weight of mango seed kernel (MSK), of which 85.7% was identified as methyl gallate. In addition, the antioxidant activities of the extract and the main compound were assessed by the 2,2-diphenyl-1-picrylhydrazyl and 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) assays, by the ferric thiocyanate method and by an assay of metal chelating activity. Tyrosinase inhibition was also investigated. Furthermore, the antioxidant capacity and the total phenolic content of MSK extract stored in a plastic (polyethylene) PE bag decreased during storage at freezing (-20°C), refrigerated (7°C) and room (28-32°C) temperature for 182days. The loss of antioxidant capacity and total phenolic content increased at higher storage temperatures for more than 182days.

Impact of cooking and drying on the phenolic, carotenoid contents and in vitro antioxidant capacity of Andean Arracacha (Arracacia xanthorrhiza Bancr.) root

The influence of different cooking regimes such as boiling, oven, microwave and hot-air drying on the retention of total phenolics (TP), total carotenoids (TC) and in vitro antioxidant capacity (AC) for three colored arracacha roots was studied. Continuous losses of TP, TC and AC during the course of the different cooking processes were observed. Boiling at 99.5° C for 20 min turned to be the best method to cook this root due to a high retention of TP, TC and AC in comparison to oven cooking at 200° C for 45 min and microwave cooking at 800 W for 5 min. During boiling, chlorogenic and caffeic acids and derivatives remained relatively stable. The drying temperature was negatively correlated to the residual content of TP and AC for the yellow and cream arracacha roots, but for the cream/purple arracacha variety, blanching preserved the TP and AC. Significant losses in chlorogenic and caffeic acids and derivatives were mainly observed during hot-air drying. These results suggested that TP are responsible to a large extent of the AC displayed by arracacha root during the different evaluated cooking regimes.

Effect of refining processes on antioxidant capacity, total contents of phenolics and carotenoids in palm oils

Antioxidant capacity (AC), total phenolic content (TPC) and total carotenoid content (TCC) in palm oils at various stages of the refining process from two technological modes were determined. The obtained mean FRAP and DPPH values for the methanolic extracts of palm oils from mode 1 (19.5–102.8μmol TE/100g and 18.8–103.0μmol TE/100g) were lower than for oils from mode 2 (25.6–134.8μmol TE/100g and 25.4–135.4μmol TE/100g). The total phenolics (4.1–12.4mg GA/100g) and carotenoids (0.18–45.8mg/100g) in the studied oils were correlated with their antioxidant capacities determined by FRAP and DPPH methods (r=0.6623–0.9878). During the refining process, for both technological modes resulted in a loss of AC by 80%, TPC by 26–55% and TCC by 99%. The bleaching step caused the highest losses of AC as determined by FRAP 41% and 46%, DPPH by 43% and 48%, while TPC loss was 45% and 23% and loss of carotenoids was 49% and 56%, in mode 1 and mode 2, respectively.

High pressure processing of swede (Brassica napus): Impact on quality properties

Abstract The effects of combined pressure/temperature treatments (200, 400 and 600 MPa, at 20 and 40 °C) on the physical and nutritional properties of swede roots (Brassica napus var. napobrassica) were assessed. Changes induced by high pressure processing (HPP) on the original properties of swede samples were compared with those produced by thermal treatment (blanching). All studied treatments altered the physical properties of swede, resulting in a loss of hardness and water binding capacity. The strongest alteration of texture was observed after HPP at 400 MPa, while 600 MPa was the treatment that better preserved the texture properties of swede. Blanching caused less total colour changes (ΔE) than HPP. Antioxidant properties of swede were measured as total antioxidant capacity, ascorbic acid and total phenol content. All treatments caused a loss of antioxidant capacity, which was less pronounced after HPP at 600 MPa and 20 °C and blanching. Four glucosinolates were detected in swede roots, glucoraphanin, progoitrin, glucobrassicanapin and glucobrassicin. Glucobrassicanapin and glucobrassicin contents were reduced with all studied treatments. Progoitrin content was not affected by blanching and HPP at 200 MPa. HPP at higher pressure levels (400 and 600 MPa), though, induced an increase of progoitrin levels. The results indicated that blanching and HPP at 600 MPa and 20 °C were the treatments that better preserved the original quality properties of swede. Industrial relevance Development of mild processing technologies that minimally affect the sensory and texture of products is a challenge for the food industry. The present work has studied the effects of combined pressure–temperature treatments on the colour, texture, antioxidant activity and glucosinolate profile of fresh-cut swede (Brassica napus) as an alternative to traditional blanching techniques.

109 POSTER Promoter hypermethylation of the NORE1A occurs in endometrial cancer

Oxidative stress has been attributed both a key pathogenic and rescuing role in cerebral malaria (CM). In a Plasmodium berghei ANKA murine model of CM, host redox signaling and functioning were examined during the course of neurological damage. Host antioxidant defenses were early altered at the transcriptional level indicated by the gradually diminished expression of superoxide dismutase-1 (sod-1), sod-2, sod-3 and catalase genes. During severe disease, this led to the dysfunctional activity of superoxide dismutase and catalase enzymes in damaged brain regions. Vitagene associated markers (heat shock protein 70 and thioredoxin-1) also showed a decaying expression pattern that paralleled reduced expression of the transcription factors Parkinson disease 7, Forkhead box O 3 and X-box binding protein 1 with a role in preserving brain redox status. However, the oxidative stress markers reactive oxygen/nitrogen species were not accumulated in the brains of CM mice and redox proteomics and immunohistochemistry failed to detect quantitative or qualitative differences in protein carbonylation. Thus, the loss of antioxidant capacity was compensated for in all cerebral regions by progressive upregulation of heme oxygenase-1, and in specific regions by early glutathione peroxidase-1 induction. This study shows for the first time a scenario of cooperative glutathione peroxidase and heme oxygenase-1 upregulation to suppress superoxide dismutase, catalase, heat shock protein-70 and thioredoxin-1 downregulation effects in experimental CM, counteracting oxidative damage and maintaining redox equilibrium. Our findings reconcile the apparent inconsistency between the lack of oxidative metabolite build up and reported protective effect of antioxidant therapy against CM.

Phenolic composition and antioxidant capacity of different heat‐processed forms of sweetpotato cv. ‘Beauregard’

SummarySweetpotato [Ipomoea batatas (L.) Lam.] cv. ‘Beauregard’ roots were cooked using three different heat‐processing techniques (baked in a conventional oven, baked in a microwave oven, and boiled). Total phenolic content, individual phenolic acids, and antioxidant capacity were determined using Folin‐Denis assay, HPLC (high‐performance liquid chromatography), and DPPH (1,1‐diphenyl‐2‐picrylhydazyl) assay, respectively. The skin tissue (raw or processed) contained the highest concentration of total phenolics. All heat‐processing methods resulted in a significant loss in total phenolic content and antioxidant capacity of the skin tissue. However, compared with the other processing methods, conventional oven baking resulted in greater losses in antioxidant capacity of skin tissue. Total phenolic content ranged from a low of 1.58 mg chlorogenic acid equivalent g−1 dry tissue weight in boiled pith tissue to a high of 17.7 mg chlorogenic acid equivalent g−1 dry tissue weight in raw skin tissue. The antioxidant capacity was highest in raw skin tissue (22.9 mg Trolox equivalent g−1 dry tissue weight). Chlorogenic acid was the principal phenolic acid found in all sweetpotato tissues. Caffeic acid and three isomers of dicaffeoylquinic acid (diCQA) were also identified and quantified.

Processing and Storage Effects on Monomeric Anthocyanins, Percent Polymeric Color, and Antioxidant Capacity of Processed Blackberry Products

Blackberries are a rich source of polyphenolics, particularly anthocyanins, that may contribute to the reduced risk of chronic disease; however, as with most berries, the fresh fruit are only seasonally available. With most of the blackberries consumed as frozen or in thermally processed forms after long-term storage, the purpose of this study was to evaluate the effects of processing and 6 months of storage on the anthocyanins and antioxidant capacity of blackberries that were individually quick-frozen (IQF), canned-in-syrup, canned-in-water, pureed, and juiced (clarified and nonclarified). Monomeric anthocyanins, percent polymeric color, and antioxidant capacity by oxygen radical absorbance capacity (ORAC FL) and photochemiluminescence (PCL) were determined postprocessing (1 day) and after 1, 3, and 6 months of storage. Processing resulted in increases in polymeric color values (up to 7%) and losses in monomeric anthocyanins (up to 65%). For most products, processing also resulted in losses in antioxidant capacity (by ORAC FL and PCL). Storage at 25 degrees C of all processed products resulted in dramatic losses in monomeric anthocyanins with as much as 75% losses of anthocyanins throughout storage, which coincided with marked increases of percent polymeric color values of these products over 6 months of storage. There were no changes in ORAC FL or PCL for processed products throughout long-term storage. No significant changes in antioxidant capacity or anthocyanin content were observed in IQF fruit during long-term storage at -20 degrees C.

Cytokinin promotes catalase and ascorbate peroxidase activities and preserves the chloroplast integrity during dark-senescence

Increased oxidative stress displayed during dark-senescence of wheat leaves (Triticum aestivum L.) is caused not only by the increased levels of radicals but also by a loss of antioxidant capacity. Mature leaves were incubated in 6-benzylaminopurine (BAP 10(-4)M) or water (control) during 6d in the dark. The senescence-delaying effect of BAP was associated with the retention of the chloroplast structure, 60% of the initial content of chlorophyll (Chl) and 77% of the initial content of protein. BAP reduced the degradation of the light-harvesting chlorophyll a/b binding protein (LHCP-2), and the large (LSU) and small subunits (SSU) of Rubisco. Our results indicated that the presence of the NADPH:protochlorophyllide oxidoreductase (POR, EC.1.6.99.1) was not promoted by the cytokinin, leading to the conclusion that BAP maintains the level of Chl, preventing its degradation, rather than inducing Chl biosynthesis. The internal structure of chloroplasts was maintained in BAP-treated leaves for up to 6d, with well-organized grana thylakoids and small plastoglobuli; in contrast, chloroplasts of control leaves deteriorated rapidly from day 4 with disorganized internal membranes, and more and larger plastoglobuli. BAP increased the activities of catalase (CAT, EC 1.11.1.6) and ascorbate peroxidase (APX, EC 1.11.1.11) and reduced the level of H(2)O(2) in the delayed-senescence tissue. The present research indicates that BAP reduces levels of reactive oxygen species (ROS), and enhances the activity of antioxidant enzymes (CAT, APX). Our results suggest that BAP protects the cell membranes and the photosynthetic machinery from oxidative damage during delay of senescence in the dark.

Cardiovascular Disease, Estrogen Deficiency, and Inflammatory Cytokines

The incidence of hypertension increases in women after menopause, as does the susceptibility to myocardial infarction and other cardiovascular diseases.1 The mechanisms responsible for increased cardiovascular disease risk after menopause are unknown. However, postmenopausal women exhibit increases in inflammatory markers, such as C-reactive protein and inflammatory cytokines, which have been suggested to increase the risk of cardiovascular disease. Arenas et al2 report data in this issue of Hypertension that support this hypothesis. With menopause, the sex hormone levels decrease drastically. Estrogens have been shown to be antioxidative and to modulate both vasoconstrictor and vasodilator systems. For example, estradiol is known to increase NO synthase synthesis and activity3 and to reduce expression of the angiotensin (Ang) type 1 receptor (AT1R).4 Therefore, loss of estrogen production with menopause should be associated with increases in oxidative stress mediated by the renin–Ang system (RAS) because of increased expression of AT1Rs. This could occur even in the face of no change or lower levels of Ang II with aging. The consequences of increasing oxidative stress would lead to reductions in bioavailable NO because of the increased superoxide production but also the loss of antioxidant capacity. The combination of NO and superoxide produces peroxynitrite, a potent oxidant that is thought to reduce the levels of prostacyclin and increase the levels of thromboxane A2 because of peroxynitrite-mediated protein nitration.1 Both reactive …

Interactions between metabolism of trace metals and xenobiotic agonists of the aryl hydrocarbon receptor in the antarctic fish Trematomus bernacchii: Environmental perspectives

Although Antarctica is a pristine environment, organisms are challenged with contaminants either released locally or transported from industrialized regions through atmospheric circulation and marine food webs. Organisms from Terra Nova Bay also are exposed to a natural enrichment of cadmium, but to our knowledge, whether such environmental conditions influence biological responses to anthropogenic pollutants has never been considered. In the present study, the Antarctic rock cod (Trematomus bernacchii) was exposed to model chemicals, including polycyclic aromatic hydrocarbons (benzo[a]pyrene), persistent organic pollutants (2,3,7,8-tetrachlorodibenzo-p-dioxin [TCDD]), cadmium, and a combination of cadmium and TCDD. Analyzed parameters included chemical bioaccumulation, activity, and levels of biotransformation enzymes (cytochrome P4501A); metallothioneins and the efficiency of the antioxidant system measured as individual defenses (catalase, glutathione, glutathione reductase, glutathione S-transferases, and glutathione peroxidases); and total scavenging capacity toward peroxyl and hydroxyl radicals. Reciprocal interactions between metabolism of inorganic and organic pollutants were demonstrated. Dioxin enhanced the accumulation of cadmium, probably stored within proliferating endoplasmic reticulum, and cadmium suppressed the inducibility of cytochrome P4501A, allowing us to hypothesize a posttranscriptional mechanism as the depletion of heme group availability. Clear evidence of oxidative perturbation was provided by the inhibition of antioxidants and enhanced sensitivity to oxyradical toxicity in fish exposed to organic chemicals. Exposure to cadmium revealed counteracting responses of glutathione metabolism; however, these responses did not prevent a certain loss of antioxidant capacity toward peroxyl radicals. The pattern of antioxidant responses exhibited by fish coexposed to cadmium and TCDD was more similar to that observed for cadmium than to that observed for TCDD. The overall results suggest that elevated natural levels of cadmium in Antarctic organisms from Terra Nova Bay can limit biotransformation capability of polycyclic (halogenated) hydrocarbons, thus influencing the bioaccumulation and biological effects of these chemicals in key sentinel species.

Evaluation of the Antioxidant Properties of Propofol and its Nitrosoderivative. Comparison with Homologue Substituted Phenols

Propofol (2,6-diisopropylphenol), some substituted phenols (2,6-dimethylphenol and 2,6-ditertbutylphenol) and their 4-nitrosoderivatives have been compared for their scavenging ability towards 1,1-diphenyl-2-picrylhydrazyl and for their inhibitory action on lipid peroxidation. These products were also compared to the classical antioxidants butylated hydroxytoluene and butylated hydroxyanisole. When measuring the reactivity of the various phenolic derivatives with 1,1-diphenyl-2-picrylhydrazyl the following order of effectiveness was observed: butylated hydroxyanisole>propofol>2,6-dimethylphenol>2,6-di-tertbutylphenol > butylated hydroxytoluene. In cumene hydroperoxide-dependent microsomal lipid peroxidation, propofol acts as the most effective antioxidant, while butylated hydroxyanisole, 2,6-di-tertbutylphenol and butylated hydroxytoluene exhibit a rather similar effect, although lower than propofol. In the iron/ascorbate-dependent lipid peroxidation propofol, at concentrations higher than 10 μM, exhibits antioxidant properties comparable to those of butylated hydroxytoluene and butylated hydroxyanisole. 2,6-Dimethylphenol is scarcely effective in both lipoperoxidative systems. The antioxidant properties of the various molecules depend on their hydrophobic characteristics and on the steric and electronic effects of their substituents. However, the introduction of the nitroso group in the 4-position almost completely removes the antioxidant properties of the examined compounds. The nitrosation of the aromatic ring of antioxidant molecules and the consequent loss of antioxidant capacity can be considered a condition potentially occurring in vivo since nitric oxide and its derivatives are continuously formed in biological systems.

Influence of drought on some physiological parameters symptomatic for oxidative stress in leaves of chives ( Allium schoenoprasum)

Drought, created by withholding water, led to significant reductions in the absolute (−3.6%) and relative (−24.8%) water content of chives ( Allium schoenoprasum) leaves, a significant rise in the osmolarity of the leaf sap (+18.9%) and a loss of leaf transpiration (leaf diffusion resistance >20 s cm −1). Nevertheless, the leaves did not show signs of oxidative damage, as the concentration of chlorophylls and soluble proteins and the extent of lipid peroxidation did not change compared with well-watered plants. The concentration of carotenoids and UV radiation absorbing substances remained stable indicating no loss of antioxidant capacity. While it did not affect specific guaiacol peroxidase activity, drought increased the specific activity of ascorbate peroxidase significantly by almost 29% and reduced the specific lipoxygenase activity significantly by 60%. Both changes can be considered as beneficial under drought conditions as they potentially reduce the formation of reactive oxygen species. Chives proved to be tolerant to the imposed drought stress, the plants totally recovered within one week after rewatering.

Does the antioxidant potential of high pressure treated apple juice change during storage?

Benefits of application of high hydrostatic pressure for liquid foods processing are relevant as it preserves several food qualities. In this study, effects of high pressure treatment on the antioxidant capacity of apple juice and apple puree have been examined. For this purpose, two tests have been performed, with a linoleic acid emulsion and β-carotene as marker, and with 2,2'-azino-bis-(ethylbenzothiazoline-6-sulfonic acid) di-ammonium salt radicals. When freshly squeezed apple juice was tested, high pressure treatments were more deleterious than high temperatures, although more than 75% of the total capacity was preserved after extreme conditions (600 MPa, 60°C, 30 min). After 1 month storage at 4°C, antioxidant potential of apple juice remained comparable to the one of fresh apple juice stored for 1 month at 4°C. Anaerobic conditions reduced extremely initial losses in antioxidant capacity of apple puree. High pressure treatments were not able to completely stop complex enzymatic reactions in the matrix, but also have not caused any larger losses in antioxidant potential.

Antioxidants, von Willebrand factor and endothelial cell injury in hypercholesterolaemia and vascular disease

The relationship between antioxidants and endothelial cell injury was examined in 119 patients with ( n = 48) or without ( n = 71) vascular disease who were attending a hyperlipidaemia clinic. Serum levels of total antioxidant capacity, glutathione peroxidase (a protein antioxidant), von Willebrand factor (vWf, a specific endothelial cell product and marker of injury) and routine lipids were measured in the patients and from 58 healthy controls. Compared to controls, total antioxidant capacity ( P < 0.01) and glutathione peroxidase ( P < 0.0001) were lower whilst vWf was higher ( P < 0.0001) amongst the patients. Comparing patients with and without vascular disease, glutathione peroxidase was lower ( P < 0.03) and vWf was higher ( P < 0.05) in the presence of vascular disease but there was no difference in levels of serum lipids or total antioxidant capacity. vWf and glutathione peroxidase were inversely correlated ( r = −0.26, P < 0.005). We conclude that patients with hypercholesterolaemia have reduced antioxidant capacity and this is most severe in patients with clinically apparent vascular disease. This, linked to the finding of increased vWf in hypercholesterolaemia with highest levels in those patients with vascular disease, suggests that loss of antioxidant capacity may expose the vascular endothelium to excess oxidative damage. These results suggest a link between hypercholesterolaemia, impaired ability to resist free radical attack, and the development of atherosclerosis.