Changes In Antioxidant Properties Research Articles

Comparative Evaluation of Antioxidant Properties and Isoflavones of Tempeh Fermented in Two Different Wrapping Materials

Tempeh is an Indonesian traditional fermented soybean food that is well known for its nutritional value and health benefit. This study aimed to evaluate the effects of two commonly used packaging materials in tempeh production, namely banana leaf and polyethylene bag, on the antioxidant properties. Isoflavones, include daidzein and genistein, of tempeh fermented in banana leaf (TBL) and polyethylene bag (TP) were analysed with high-performance liquid chromatography. Total phenolic content and antioxidant activities were evaluated using Folin-Ciocalteu reagent, DPPH radical scavenging and β-carotene-linoleate bleaching assays, respectively. The changes of antioxidant properties of tempeh after different fermentation periods in both wrapping materials were observed, on day 0 (unfermented), day 1, day 2 and day 4. Total phenolic content, daidzein, genistein and the antioxidant activities were significantly (p < 0.05) increased in both TBL and TP as the fermentation progressed. A higher total phenolic content was found in TBL on day 1 and day 2 but TP exhibited the highest total phenolic content on day 4. Daidzein was the highest in TBL on day 2 but it was reduced on day 4 while genistein was the highest in TP on day 4. Antioxidant activities were positively (r = 0.272–0.969, p < 0.05) correlated to total phenolic content, daidzein and genistein. Although tempeh wrapped in banana leaf is a traditional way for tempeh packaging, it provided better antioxidant properties on day 1 and day 2, which is within the best period of tempeh consumption. Hence, the current findings provided useful information to manufacturer and consumer in selecting the suitable wrapping material for tempeh with optimal phytonutrients.

Antioxidant properties of minimally processed endives and escaroles vary as influenced by the cultivation site, cultivar and storage time

The influence of cultivar (CV), growth site (GS) and storage time (ST) on the quality of minimally processed endives was investigated by targeting curly and smooth-leafed cultivars, which were grown in two planting areas (Fiumicino and Fucino) and bagged in modified atmosphere at fixed conditions. The changes of antioxidant properties were examined at one and seven days post-packaging by measuring both contents of total flavonols (Fol), flavonoids (Fid), carotenes (Car) and chlorophylls (Chl) and the antioxidant capacity (AOC) through chemical (ORAC) and erythrocyte-based methods (CAA-RBC and hemolytic assays). Referring to one day of storage, curly types differed from smooth ones due to the total contents of Fid (341.0–891.7 vs 312.3–572.3 mg kg−1 CE), Fol (312.0–452.7 vs 194.3–520.3 mg kg−1 QE), Car (72.4–110.5 vs 7.3–38.8 mg kg−1) and Chl (342.7–824.6 vs 276.5–490.4 mg kg−1). CV and GS majorly affected the content variation, whilst ST did not exert any impact on the amounts of pigments (Chl and Car). As for the AOC at one day post packaging, curly and smooth endives respectively showed ORAC mean values of 5045± 2287 and 4822 ± 573 mmol kg−1 TE, CAA-RBC units of 27.5 ± 5.4 and 21.1 ± 2.6 μmol kg−1 QE, and hemolysis percentage of 62.5 ± 5.9 and 57.9 ± 10.9. The three factors acted on the AOC variation at the single level and CV x GS was the most affecting interaction. The ORAC values showed positive correlations with Fid, Fol and Chl contents as well as those of CAA-RBC vs Fid and pigment amounts, while only the Fol raise agreed with increased anti-hemolytic effects. Positive correlations among the AOC assays were significant just for ORAC vs CAA-RBC units. Finally, the principal component analysis clearly pointed at the curly types from Fiumicino as bearing the highest antioxidant quality.

Effect of UV irradiation on Echinaceae purpureae interactions with free radicals examined by an X-band (9.3GHz) EPR spectroscopy.

The effect of UVA (315–400 nm) irradiation on Echinaceae purpureae interactions with free radicals was examined by the use of electron paramagnetic resonance (EPR) spectroscopy. The changes of antioxidant properties of E. purpureae with time of UV irradiation from 10 to 110 min (10 min steps) were determined. DPPH as the paramagnetic reference was used in this study. Changes of EPR signals of the reference after interactions with nonirradiated and UV-irradiated E. purpureae were detected. Interactions of the tested E. purpureae samples caused decrease of the EPR signal of DPPH as the result of its antioxidant properties. The decrease of the amplitude of EPR line of DPPH was lower for interactions with UV-irradiated E. purpureae. EPR examination confirmed antioxidant properties of E. purpureae. The weaker antioxidant properties of E. purpureae after UV irradiation were pointed out. E. purpureae should be storage in the dark. The tests bring to light usefulness of electron paramagnetic resonance with microwave frequency of 9.3 GHz (an X-band) in examination of storage conditions of pharmacological herbs.

Changes of Major Antioxidant Compounds and Radical Scavenging Activity of Palm Oil and Rice Bran Oil during Deep-Frying.

Changes in antioxidant properties and degradation of bioactives in palm oil (PO) and rice bran oil (RBO) during deep-frying were investigated. The alpha (α)-tocopherol, gamma (γ)-tocotrienol and γ-oryzanol contents of the deep-fried oils were monitored using high performance liquid chromatography, and antioxidant activity was determined using 2-diphenyl-1-picryl hydrazyl (DPPH) radical scavenging activity. Results revealed that the antioxidant activity of PO decreased significantly (p < 0.05), while that of RBO was preserved after deep-frying of fries. As expected, the concentration of α-tocopherol in PO and γ-tocotrienol in both PO and RBO decreased significantly (p < 0.05) with increased frying. Results also showed that γ-tocotrienol was found to be more susceptible to degradation compared to that of α-tocopherol in both PO and RBO. Interestingly, no significant degradation of α-tocopherol was observed in RBO. It is suggested that the presence of γ-oryzanol and γ-tocotrienol in RBO may have a protective effect on α-tocopherol during deep-frying.

Release of free ferulic acid and changes in antioxidant properties during the wheat and rye bread making process

Changes in the free ferulic acid (FFA) contents and antioxidant properties during bread making processes were determined. Experimental breads were produced from whole meal and white wheat and rye flours, and fermented using either baker’s yeast or sourdough starter. Sourdough fermented bread contained the highest content of FFA. Release of occurred mainly during dough fermentation. A further increase in the ferulic acid content in the bread crumb and a decrease in the crust was observed. Total antioxidant properties of sourdough bread, defined as the sum of lipophilic and hydrophilic compound activities, were significantly (p<0.05) higher than for yeast bread. Sourdough bread contained more methanol soluble phenolic compounds, proteins, tocochromanols, and oxidized products of fatty acids than yeast bread. The equilibrium between the anti- and pro-oxidative compound contents resulted in similar antioxidant properties for bread using both types of fermentation, and to results observed for the flour used for baking.

Effects of Milling-process and pasta making on ABTS•+scavenging activity of hydrophilic and lipophilic extracts of durum wheat varieties

Epidemiological studies associated consumption of whole-durum wheat products with reduced incidence of chronic diseases, diabetes and cancer. These health benefits have been mainly attributed to antioxidant activity (AA) due to the unique phytochemical content of wheat. Milling, extrusion and drying process can influence the activity of these beneficial compounds. In order to have a deep insight into the changes of nutritional value from raw material to pasta, the aim of this study was: i) to compare the AA of hydrophilic and lipophilic extracts of five durum wheat genotypes along the pasta chain; ii) to evaluate the changes in antioxidant properties of whole meal after processing in semolina and pasta. To this aim TEAC (Trolox Equivalent Antioxidant Capacity) assay based on ABTS•+ [2,2′-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) scavenging activity was used due to its high reproducibility and simplicity.Low genotype variability was observed for both hydrophilic and lipophilic extracts. Milling proc...

Antifatigue Effects of Panax ginseng C.A. Meyer: A Randomised, Double-Blind, Placebo-Controlled Trial

The present study investigated the antifatigue effects of Panax ginseng C.A. Meyer in 90 subjects (21 men and 69 women) with idiopathic chronic fatigue (ICF) in a randomised, double-blind, placebo-controlled and parallel designed trial. A bespoke 20% ethanol extract of P. ginseng (1 g or 2 g day–1) or a placebo was administered to each group for 4 weeks, and then fatigue severity was monitored using a self-rating numeric scale (NRS) and a visual analogue scale (VAS) as a primary endpoint. Serum levels of reactive oxygen species (ROS), malondialdehyde (MDA), total glutathione (GSH) contents and glutathione reductase (GSH-Rd) activity were determined. After 4-week, P. ginseng administration decreased the total NRS score, but they were not statistically significant compared with placebo (P>0.05). Mental NRS score was significantly improved by P. ginseng administrations as 20.4±5.0 to 15.1±6.5 [95% CI 2.3∼8.2] for 1 g and 20.7±6.3 to 13.8±6.2 [95% CI −0.1∼4.2] for 2 g compared with placebo 20.9±4.5 to 18.8±2.9 [95% CI 4.1∼9.9, P<0.01]. Only 2 g P. ginseng significantly reduced the VAS score from 7.3±1.3 to 4.4±1.8 [95% CI 0.7∼1.8] compared with the placebo 7.1±1.0 to 5.8±1.3 [95% CI 2.2 ∼3.7, P<0.01]. ROS and MDA levels were lowered by P. ginseng compared to placebo. P. ginseng 1 g increased GSH concentration and GSH-Rd activity. Our results provide the first evidence of the antifatigue effects of P. ginseng in patients with ICF, and we submit that these changes in antioxidant properties contribute in part to its mechanism.Trial RegistrationClinical Research Information Service (CRIS) KCT0000048

Antioxidant Property Enhancement of Sweet Potato Flour under Simulated Gastrointestinal pH

Sweet potato is known to be rich in healthful antioxidants, but the stability of its antioxidant properties under gastrointestinal pH is very much unknown. Hence, this study aimed to evaluate the changes in antioxidant properties (total contents of phenolics and flavonoids as well as antioxidant activity) of sweet potato flour (SPF) under simulated gastrointestinal pH conditions. It was found that the yield of SPF crude phenolic extract increased from 0.29 to 3.22 g/100 g SPF upon subjection to gastrointestinal pH conditions (p < 0.05). Also elevated significantly were the total phenolic content (TPC), total flavonoid content (TFC) and antioxidant activity of SPF (p < 0.05). In summary, the antioxidant properties of SPF were enhanced under gastrointestinal pH conditions, suggesting that SPF might possess a considerable amount of bound phenolic and other antioxidative compounds. The antioxidant properties of SPF are largely influenced by pH and thus might be enhanced during the in vivo digestive process.

Stability and antioxidant potential of purified olive mill wastewater extracts

A purified olive extract (POE) rich in phenolic and oleosidic compounds was prepared from olive mill wastewaters by adsorption onto an amphoteric polymer resin with the yield of 2.2% (w/v). In addition to complex and simple phenolic compounds found in the POE, the highly hydrophilic elenolic acid and DEDA (dialdehydic form of decarboxymethyl elenolic acid, a non-phenolic secoiridoids) were also present in high concentration (45%, w/w). Among the phenolic constituents, the major compounds are hydroxytyrosol and its glucoside, DEDA linked to hydroxytyrosol (Hy-DEDA), p-coumaric acid and caffeic acid, verbascoside and some flavonoids. The high content (23%, w/w in gallic acid equivalent) and structural diversity of these phenolic compounds confer superior antioxidant potential of POE with an IC50 less than 8.5μg/ml determined by DPPH assay. The stability of bioactive components during storage of the extract and changes in antioxidant properties were studied under different conditions. Determination of kinetics of degradation revealed that air/oxygen is the determinant factor which influences the stability of POE under low temperature storage conditions, while exposure to sunlight did not have significant effect on their stability. Whilst an increase in storage temperature decreased the total content of phenolic compounds (20–24% reduction) and non-phenolic secoiridoid aglycons, a high antioxidant capacity was still observed particularly in the nitrogen-protected POE samples (93–95% of the initial value). This was believed to be due to the transformation of hydroxytyrosol-containing complex phenols, especially the secoiridoid ester Hy-DEDA, into free phenolic monomer. This contributed significantly to the maintenance of a high antioxidant potency of the whole extract during storage. The high antioxidant, radical scavenging activity and stability of the extract suggest potential applications in the food and pharmaceutical industries.

Changes in antioxidant properties and their relationship to paclobutrazol‐ induced flooding tolerance in Welsh onion

AbstractBACKGROUND: Flooding is an important factor affecting Welsh onion production, because under such stress the production and quenching of reactive oxygen species (ROS) in plants will fail to be kept in a balanced state. The purpose of this study was to examine the effect of paclobutrazol (PBZ) on the growth and development of Welsh onion plants (Allium fistulosum L.), particularly to evaluate changes in antioxidant properties.RESULTS: Welsh onion plants were treated with 0 and 2 ppm per plant of PBZ, subsequently subjected to non‐flooding and flooding‐stress conditions for 0, 1, 5, 9 and 13 days, followed by a 4‐day drainage period. Flooding stress was judged by any decrease in biomass production and chlorophyll content. The results indicated that PBZ applied to plants was able to protect Welsh onion from flooding stress. The increased levels of antioxidant activity in different systems, including α,α‐diphenyl‐β‐picrylhydrazyl (DPPH)‐radical scavenging activity, superoxide anion radical scavenging, metal chelating activities and reducing power observed on flooding, afforded the Welsh onion improved flooding tolerance. Under non‐flooding conditions, the antioxidative activity of Welsh onion was regulated and elevated by PBZ pretreatment.CONCLUSION: It seems that the PBZ‐induced flooding tolerance of Welsh onion is mediated through increased activities of various antioxidative systems. Thus, pre‐applying 2 ppm per plant of PBZ 24 h prior to flooding could mitigate flooding stress. Copyright © 2008 Society of Chemical Industry

EFFECTS OF ACIDIFICATION ON PE ACTIVITY, COLOR AND ANTIOXIDANT PROPERTIES OF COLD BREAK TOMATO JUICE

ABSTRACT Turbidity maintenance, high antioxidant activity and attractive red color are important attributes of good tomato juice. Acidification was found effective in pectin esterase (PE) inactivation and turbidity maintenance. However, no information related to the changes of antioxidant properties after enzyme inactivation by acidification has been reported. In this article, acidification of cold break tomato juice to pH 2 or 3 was conducted after extraction. The changes of antioxidant properties (content and activity) and their correlation with PE activity and color in the juice were studied. Results indicated that acidification enhanced the viscosity of tomato juice by decreasing its PE activity. Significant increases of the main antioxidant contents (lycopene, polyphenols and vitamin C) and antioxidant activities (1,1‐diphenyl‐2‐picrylhydrazyl scavenging, ferrous ion chelating ability [FICA] and reducing power), as well as red color, were also found. In addition, the acidified cold break tomato juice exhibited better FICA and reducing power than butylated hydroxyanisole andα‐tocopherol. This finding reveals the possibility of producing tomato juice with high antioxidant capacities by acidification.PRACTICAL APPLICATIONSThe consumers' demand for healthy products with high quality toward fresh and health has increased remarkably these years. Tomato is one of the most popular vegetable juices, and its important quality aspects are color, stability and antioxidant capacity. Pectin esterase is the principal agent responsible for tomato juice stability. In addition, the goal of tomato juice processors is to optimize processing conditions by prevention of heat and oxidative damages on antioxidant components. Our results indicated that acidification may stabilize tomato juice and improve its color characteristics and main nutritional factors. Therefore, the acidification treatment could be used as a tool for providing the attractive color and enhancing the nutritional value and health‐promoting properties of cold break tomato juice.

Změny antioxidačních vlastností chmele při sušení, mletí, granulaci a skladování.

Posklizňovým sušením zeleného chmele se část antioxidační aktivity ztrácí. Ztráta zpravidla nepřekračuje 5 % původní hodnoty RADPPH. Sušení se projevilo i úbytkem obsahu polyfenolových látek. Mezi sušením v komorové a pásové sušárně nebyl z hlediska zachování antioxidačních vlastností chmele zjištěn podstatný rozdíl.Výsledky stanovení antioxidační aktivity v horkovodním výluhu hlávkových a mletých chmelů jsou srovnatelné a rozdíly statisticky neprůkazné. Rovněž granulací mletého chmele se jeho redukční aktivita prokazatelným způsobem nemění. V průběhu dlouhodobého skladování chmele dochází k poklesu antioxidačních aktivit s různou rychlostí v závislosti na teplotě skladování a formě chmele. Skladovací teplota nemá prokazatelný vliv na antioxidační aktivitu granulovaných chmelů, zabalených do vícevrstvé fólie bez přístupu vzduchu.

Effect of Maturity at Harvest in Relation to Changes in Antioxidant Properties and Ethylene in ‘Chandler’ Strawberry Fruit

Abstract The relationship between fruit maturation and accumulation of hydrogen peroxide (H202), lipid peroxidation, ethylene (C2H4) production, antioxidant activity (hydrophilic, lipophilic and total) and the antioxidant enzyme ascorbate peroxidase (APX, EC 1.11.1.11) in fruit pericarp tissue of ‘Chandler’ (Fragaria xananassa Duch.) strawberry were measured. ‘Chandler’ fruit pericarp maturation and ripening were accompanied by a decline in H202 content early in fruit development followed by a rapid accumulation. An increase in membrane lipid peroxidation (thiobarbituric acid reactive substances, TBARS) coincided with accumulation of H202, which preceded a rise in C2H4 production. In general, antioxidant activity declined as fruit matured and ripened. APX enzyme activity increased by 2-fold and peaked at the pink stage of development and then gradually declined with ripening. H202 may serve as a signal molecule to initiate the cascade of oxidative processes during maturation and ripening. APX enzyme activity during maturation and ripening was not substantial and thus, may not have a role in alleviating accumulation of H202 and subsequent events related to oxidative senescence in fruit pericarp. To our knowledge, this is the first study to present fractionated antioxidant activities (HAA, LAA and TAA) from strawberry pericarp as assessed by the ABTS*+ radical cation assay. A fundamental understanding of the mechanisms involved in the senescent related-oxidative changes during strawberry fruit ontogeny in relation to quality and nutrition is discussed.

Changes in antioxidative properties of lactoferrin from women's milk during deamidation.

Spontaneous deamidation of lactoferrin preparations from women's milk was found during incubation for 28 days under simulated physiological conditions (0.85% NaCl, pH 7.0, 37 degrees C). After 28 days of incubation, this deamidation was associated with a 12% decrease in the total amide content in the protein. Addition of deamidated preparation to a suspension of lipoproteins from egg yolk in the presence of Rhodamine 6G decreased the total intensity of rapid and slow emission and also the intensity of the slow emission of Fe2+-induced chemiluminescence by 37, 48, and 53%, respectively, suggesting an increase in the antioxidative activity of lactoferrin during deamidation. Deamidation obviously stimulated the nonspecific interaction of lactoferrin with iron ions and, consequently, increased the antioxidant effect of the protein in this way. This was supported by the finding of decreased antioxidative effectiveness of lactoferrin during its complete saturation with iron under the incubation conditions.

Photochemiluminescent detection of antiradical activity. VI. Antioxidant characteristics of human blood plasma, low density lipoprotein, serum albumin and amino acids during in vitro oxidation.

During investigation of the mechanism of therapeutic efficacy of UV (254 nm)-irradiated autologous blood, the antioxidant capacity (AC) of plasma, serum albumin, 20 amino acids, uric acid, ascorbic acid and alpha-tocopherol was measured after irradiation in vitro. AC of plasma demonstrated a biphasic time course (decrease to in a minimum (greater zero) followed by an increase). AC of uric acid, ascorbic acid and alpha-tocopherol diminished under irradiation to zero. In contrast, albumin and seven amino acids developed AC following irradiation. During the Cu(+2)-induced oxidation of low-density lipoprotein (LDL), the AC measured in a system for water-soluble substances appeared, after a lag-phase, to be comparable to that of the conjugated diene formation; AC of LDL measured in a system for lipid-soluble substances demonstrated a biphasic course. Our results suggest that: (a) the oxidized products of some amino acids and proteins acquire antiradical properties at the same time that they are being produced; (b) the biphasic character of changes of antioxidant properties of blood plasma during UV irradiation represents the overlapping of two processes: disappearing of antioxidants and acquisition of AC by (lipo)proteins; and (c) the measurement of AC of blood plasma (lipo)proteins can possibly serve to detect the existence and extent of oxidative stress in human organism.