Antioxidant capacity, total phenolics and sugar content of selected Thai health beverages

This study was to determine antioxidant capacity, total phenolics and sugar content of 12 pasteurized and sterilized Thai health beverages, products of The Royal Chitralada Projects. The antioxidant capacities were analyzed using 2,2-diphenyl-l-picrylhydrazyl radical scavenging and the photochemiluminescence (PCL) assay. Folin-Ciocalteu assay and Nelson's reducing sugar test were used to determine total phenolic compounds and sugar contents, respectively. Sacred lotus root drink showed the significantly highest antioxidant capacity in both equivalents to trolox and equivalents to ascorbic acid but not in the PCL test. In contrast, chrysanthemum drink and roselle drink showed the significantly highest values of both the total antioxidant capacity of water and lipid-soluble substances in the PCL assay. Bael fruit drink had the significantly highest total phenolic compounds. There were significant correlations between the total phenolic compounds and the antioxidant capacity values of both assays (r = 0.4-0.5).     

Antioxidant capacity,total phenolics and nutritional content in selected ethiopian staple food ingredients

Abstract

The total antioxidant capacity, total phenolics content (TPC) and nutritional content of five types of enset (Enset ventricosum) flour in comparison with four staples (teff [Eragrostis tef], wheat, corn and tapioca) were evaluated. Teff, corn and “amicho” (corm of enset) had the highest ferric reducing antioxidant power (FRAP). The FRAP and TPC of teff (1.8?mmol Trolox equivalence/100?g dry matter (DM) and 123.6?mg gallic acid equivalent/100?g DM, respectively) were over 4-fold larger than the lowest obtained from “bulla” (dehydrated juice of pseudostem of enset). Corn had the lowest IC₅₀ value of 1,1-diphenyl-2-picrylhydrazyl radical scavenging (10.27?mg DM mL^?1). Teff had the highest crude fat content (3.71%) and some mineral profile (P, Mg, Mn and Cu). Enset products had higher fiber, Ca, K, Mg and Mn content as compared to wheat and corn. Ethiopian staple teff has a potential for developing value-added food products with nutritional and health benefits.     

Antioxidant activity of selected foodstuffs

The growing interest in the substitution of synthetic food antioxidants by natural antioxidants and in the health implications of antioxidants as nutraceuticals has fostered research on vegetable sources and the screening of raw materials for identifying antioxidants. Plant and plant products have been used as a source of medicine for a long time. Among the more important constituents of edible plant products, low molecular weight antioxidants are the most important species. It is known that consumption of fruits and vegetables is essential for normal health of human beings. The aim of the present work was to evaluate the total antioxidant activity of selected natural food materials by an in vitro method involving the measurement of oxidation of linoleic acid by fluorimetry. Among the food materials chosen for the present study, pomegranate peel gave the maximum antioxidant activity due to the presence of its high polyphenolic content. At a concentration of 60 ppm, pomegranate peel powder reduced lipid peroxidation by 65% in an in vitro assay.     

Antioxidant activity of selected foodstuffs

The growing interest in the substitution of synthetic food antioxidants by natural antioxidants and in the health implications of antioxidants as nutraceuticals has fostered research on vegetable sources and the screening of raw materials for identifying antioxidants. Plant and plant products have been used as a source of medicine for a long time. Among the more important constituents of edible plant products, low molecular weight antioxidants are the most important species. It is known that consumption of fruits and vegetables is essential for normal health of human beings. The aim of the present work was to evaluate the total antioxidant activity of selected natural food materials by an in vitro method involving the measurement of oxidation of linoleic acid by fluorimetry. Among the food materials chosen for the present study, pomegranate peel gave the maximum antioxidant activity due to the presence of its high polyphenolic content. At a concentration of 60 ppm, pomegranate peel powder reduced lipid peroxidation by 65% in an in vitro assay.     

Antioxidant activity of selected commercial seaweeds

This study aims to evaluate the antioxidant activity (total antioxidant and free radical scavenging activities) of seaweeds commercially available in the Malaysian supermarket. Four types of seaweeds namely Nori (Porphyra sp.), Kumbu (Laminaria sp.), Wakame (Undaria sp.) and Hijiki (Hijikia sp.) were used in the study. The extracts were prepared with water and ethanol, respectively. The b-carotene bleaching and 1,1-diphenyl-2-picrylhydrazyl (DPPH) assays were used to determine antioxidant properties of seaweeds by measuring the decrease in absorbance at 470 and 517 nm. In water extract, Kumbu showed the highest total antioxidant activity of 63% compared with other samples. Kumbu, Nori and Hijiki exhibited higher radical scavenging activity than Wakame when extracted with water. Wakame exhibited the highest antioxidant and free radical scavenging activities in ethanolic extract with 58% and EC50 = 0.42 mg/ml respectively. The results of ANOVA analysis show significant differences (p<0.05) in the means of total antioxidant and free radical scavenging activities of the seaweeds. The results showed that processed commercial seaweeds exhibited varying degrees of antioxidant properties.     

Antioxidant activity and phenolic composition of organic and conventional grapes and wines

The phenolic compounds and antioxidant activity from Monastrell variety grapes obtained by organic and conventional agriculture during the last month of ripening and the wines obtained from them were studied. Samples of grapes were collected from the last month of ripening to full maturity in each plot, and winemaking was carried out on the day of the final collection of grape samples, coinciding with the maturity of the grapes. The antioxidant activity a month before harvesting was higher in the organic grapes (5.7 ± 0.03 mM Trolox/g) than in the conventional ones (4.40 ± 0.05 mM Trolox/g), although these differences disappear in the moment of harvesting. Similarly the total amount of phenolic compounds a month before harvesting was higher in the organic grapes (974.2 ± 54.4 mg/kg) than in the conventional grapes (447.7 ± 27.8 mg/kg), although these differences disappear at the moment of harvesting. In wine, phenolic compounds and the antioxidant activity were slightly higher in organic wine than in conventional wine, although the differences were not significant.     

Antioxidant capacity and phenolic content of selected commercially available cruciferous vegetables

Antioxidant activity, free radical scavenging activity and phenolic content of red cabbage (Brassica oleracea var. capitata rubra), Chinese cabbage (Brassica rapa pekinensis var cylindrica), green cabbage (Brassica oleracea var capitata), mustard cabbage (Brassica juncea var rugosa) and Chinese white cabbage (Brassica rapa var chinensis), grown in Malaysia, were evaluated. Red cabbage had the highest antioxidant activity and phenolic content compared to the other cruciferous vegetables studied (p < 0.05). The contributions of all cruciferous vegetables to the antioxidant activity was >79%. The radical scavenging activity was in the order of Chinese white cabbage > red cabbage > mustard cabbage > Chinese cabbage > green cabbage. There was a significant difference (p < 0.05) in the means of scavenging activity observed between cabbage, Chinese cabbage and Chinese mustard. Phenolic content was significantly different (p < 0.05) among all the cruciferous vegetables studied, and was in the order of red cabbage > Chinese white cabbage > green cabbage > Chinese cabbage >mustard cabbage. The study indicated that red cabbage possessed the highest antioxidant capacity and phenolic compounds concentration among all the cruciferous vegetables studied.     

Investigation on possible relationships between the content of sulfate and selected metals in Chianti wines

The content of sulfate in water was measured through a back-titration involving addition excess barium chloride, centrifugation and barium quantification in the supernatant via atomic absorption spectroscopy. The results were within 2.0% those found via gravimetric methods (GM). Model hydro-alcoholic solutions (ethanol 13%, v/v) with known amounts of Na₂SO₄ were analyzed, showing very good recovering factors (relative error <2.0%). The sulfate determination in wines was carried out on mineralized samples. Nine randomly selected wine samples were used to set up the method. Very good agreements were found with values obtained via GM and turbidimetric method (TM). Relative estimated standard deviations for this method average 2.0% of the concentrations, and relative discrepancies from values from GM and TM average 1.0%. The effective execution times were reduced by a factor of four with respect to GM. Eleven more red Chianti bottled wines were analyzed for the content of sulfate, copper and other metals. The sulfate content ranged from 399(12) to 902(17) mg (K₂SO₄)/L. Sulfate and copper positively correlated when sulfate content was higher than ca. 200 mg (K₂SO₄)/L and samples were from a certain winery, suggesting that vine or wine treatments with copper sulfate were significant. The linear regression factor was R² = 0.959 and significance factor P = 0.0001.     

Antioxidant and anti-atherogenic activities of olive oil phenolics

The aim of the current study was to investigate the antioxidant and cellular activity of the olive oil phenolics oleuropein, tyrosol, hydroxytyrosol, and homovanillic alcohol (which is also a major metabolite of hydroxytyrosol). Well-characterized chemical and biochemical assays were used to assess the antioxidant potential of the compounds. Further experiments investigated their influence in cell culture on cytotoxic effects of hydrogen peroxide and oxidized low-density lipoprotein (LDL), nitric oxide production by activated macrophages, and secretion of chemoattractant and cell adhesion molecules by the endothelium. Inhibitory influences on in vitro platelet aggregation were also measured. The antioxidant assays indicated that homovanillic alcohol was a significantly more potent antioxidant than the other phenolics, both in chemical assays and in prolonging the lag phase of LDL oxidation. Cell culture experiments suggested that the olive oil phenolics induce a significant reduction in the secretion of intercellular adhesion molecule-1 and vascular cell adhesion molecule-1 (and a trend towards a reduced secretion of monocyte chemoattractant protein-1), and protect against cytotoxic effects of hydrogen peroxide and oxidized LDL. However, no influence on nitric oxide production or platelet aggregation was evident. The data show that olive oil phenolics have biochemical and cellular actions, which, if also apparent in vivo, could exert cardioprotective effects.     

Antioxidant activity and phenolic content in three lupin species

Total phenolic compounds, phenolic acids and flavonoid contents and antioxidant activities were measured in extracts from seeds of Lupinus albus, Lupinus luteus and Lupinus angustifolius cultivars. The total phenolic compound contents varied from 491.51 to 731.14 mg/100 g d.m. for cvs. Butan (L. albus) and Parys (L. luteus), respectively. Protocatechuic acid was the most abundant in seeds of yellow lupin (up to 73.60 mg/kg d.m.), whereas p-hydroxybenzoic acid in narrow-leaf lupin (about 43 mg/kg d.m.). The HPLC (high performance liquid chromatography) analysis revealed two dominant flavonoid compounds, which were identified by HPLC/MSⁿ to be apigenin-6,8-di-C-β-glucopyranoside and apigenin 7-O-β-apiofuranosyl-6,8-di-C-β-glucopyranoside. The highest content of the apigenin glycosides was recorded in yellow lupin while the lowest in white lupin. A positive correlation between the content of the analyzed compounds and the antioxidant activity measured by 2,2′-diphenyl-1-picrylhydrazyl (DPPH) method was established, but no such relation was found using the radical-trapping antioxidant parameter (TRAP) method. Modification of the peroxyl radical-trapping potential of lupin extracts by formation of phenoxyl radicals is suggested.     

Antioxidant activity and phenolic content of Portuguese wine aged brandies

The antioxidant activity and the phenolic composition (total polyphenols, phenolic acids and hydrolyzable tannins) of Portuguese brandies were analyzed with regard to the kind of wood (chestnut and Limousin oak), the barrels toasting level (light, medium and heavy), and the ageing time (first 4 years of ageing). In the experimental conditions, the botanical species affects significantly the antioxidant activity of the brandies. Those aged in chestnut wood present higher antioxidant activity than those aged in Limousin oak, which confirms the remarkable quality of the former. The antioxidant activity of the aged brandies is not significantly influenced by the wood toasting level, owing to the strong variability induced by this cooperage operation. During the ageing period, the antioxidant activity of the brandies undergoes a highly significant increase. The most significant correlations between antioxidant activity and phenolic composition of brandies were found for phenolic acids, mainly for gallic acid and ellagic acid.     

Antioxidant and vasodilatory effects of blackberry and grape wines

In contrast to the well-described various biological effects of grape wines, the potential effects of commonly consumed blackberry wine have not been studied. We examined in vitro antioxidant and vasodilatory effects of four blackberry wines and compared them with the effects of two red and two white grape wines. Although some blackberry wines had lower total phenolic content relative to the red grape wines, their antioxidant capacity was stronger, which may be related to a higher content of non-flavonoid compounds (most notably gallic acid) in blackberry wines. Although maximal vasodilation induced by blackberry wines was generally similar to that of red wines, blackberry wines were less potent vasodilators. Vasodilatory activity of all wines, in addition to their flavonoid and total phenolic content, was most significantly associated with their content of anthocyanins. No association of vasodilation with any individual polyphenolic compound was found. Our results indicate the biological potential of blackberry wines, which deserves deeper scientific attention.     

Antioxidant activity and polyphenol content in edible wild fruits from Nepal

Abstract

Fifteen fruits commonly used by the ethnic population in Nepal were studied for the antioxidant activity and total polyphenol content (TPC). Among them, Terminalia bellirica, Terminalia chebula, Phyllanthus emblica and Spondias pinnata were the most potent antioxidants as compared with vitamin C based on the 1,1-diphenyl-2-picryl hydrazyl radical assay. These fruits also contained high TPCs. Spondias pinnata, Pyrularia edulis, Melastoma malabathricum, Cipadema bacifera and Choerospondias axillaries fruits were evaluated for the first time. Moreover, Spondias pinnata was found to be more potent (16% radical scavenging activity at 5 μg/ml) than vitamin C (5% radical scavenging activity at 5 μg/ml). Antioxidant activity showed correlation to TPC with the correlation coefficients (R²) as 0.7189 and 0.7246 for the methanol and water extracts, respectively. This study suggests that a number of these fruits may have the potential to confer beneficial health effects due to their antioxidant activity and TPC.     

Antioxidant activity,quality parameters and mineral content of Portuguese monofloral honeys

Physicochemical properties (pH, free, lactonic and total acidity, electrical conductivity and moisture), main mineral content (potassium, sodium, calcium, magnesium and iron) and antioxidant activity (total phenolics, 1,1diphenyl-2-picrylhydrazyl radical scavenging and ferric reduction antioxidant power) were determined for 39 Portuguese monofloral honeys (rosemary, orange, thyme, arbutus, locust podshrub and heather) with different geographical origins. Portuguese honeys showed good chemical and nutritional qualities fulfilling the criteria described in Directive 2001/110/CE. Potassium was the main mineral component representing 85% of total minerals. The mineral composition of sodium (4.63–200.60 mg/kg), calcium (0.43–72.30 mg/kg), magnesium (3.05–82.20 mg/kg) and iron (below 7.06 mg/kg) were higher for heather, eucalypt and arbutus honeys. Monofloral honeys of arbutus (Arbutus unedo), locust podshrub (Ceratonia siliqua L.) and heather (Erica umbellata) showed higher antioxidant activity with phenolic contents higher than 600 mg gallic acid equivalents (GAE)/kg, a DPPH scavenging activity higher than 50% and a ferric reduction antioxidant power above 600 μM Fe²⁺. Furthermore, the chemometric analysis revealed that total phenolic content was a crucial variable explaining the antioxidant activity of arbutus and locust podshrub honeys characteristic of the south of Portugal.     

Antioxidant activities of some Greek wines and wine phenolic extracts

Antioxidant activities and phenolic composition of eight Greek wines were determined. Red wines scavenged 1,1′-diphenyl-2-picryl-hydrazyl radical (DPPH) to a much greater degree than whites, in proportion to their phenolic contents. Red wines inhibited β-carotene bleaching, while white wines were almost inactive. Red wines were more active than quercetin in DPPH and less active in β-carotene assay. Xinomavro-red must exhibited significant activities in both assays. Roditis-white must scavenged DPPH, and exhibited some activity in β-carotene assay. Young Xinomavro and Roditis wines and their extracts were more active in scavenging DPPH than the respective aged wine and extracts. However, young Xinomavro wine and its extracts were less active than those of aged wine in β-carotene assay. Roditis wine extracts exhibited only limited activity in β-carotene assay. Xinomavro young and aged wine extracts rich in anthocyanins and flavanols were more active than the others in both assays used.     

Antioxidant activity and polyphenol content of green tea flavan-3-ols and oligomeric proanthocyanidins

The antioxidant activity and total phenolics content (TPC) of freshly prepared green tea extract (GTE) as affected by time, temperature and stirring were determined using the ferric reducing antioxidant power (FRAP) and Folin–Ciocalteu assays, respectively. Acetone–water fractions of GTE containing flavan-3-ols and oligomeric proanthocyanidins were evaluated at concentrations between 25 and 500 µg/ml. Increasing the extraction time from 3 min to 10 min resulted in a significant increase in both the FRAP values and TPC. Increasing the extraction time from 10 min to 30 min was without any significant effects on both FRAP and TPC values. Moreover, the FRAP values were correlated with the TPC. GTE fractions had widely different FRAP values that were well correlated with the TPC of the fraction. It was concluded that brewing conditions such as extraction temperature, period of extraction, ratio of tea leaves to extracting water, and stirring are important factors for determining the FRAP values and TPC in GTE. These factors should be taken into consideration during preparation for nutritional benefits during usual consumption of this beverage. Elevated FRAP and TPC values corresponded to those GTE fractions with a higher amount of phenolic compounds, which have stronger antioxidant activities.     

Antioxidant activity and polyphenol content of green tea flavan-3-ols and oligomeric proanthocyanidins

The antioxidant activity and total phenolics content (TPC) of freshly prepared green tea extract (GTE) as affected by time, temperature and stirring were determined using the ferric reducing antioxidant power (FRAP) and Folin-Ciocalteu assays, respectively. Acetone-water fractions of GTE containing flavan-3-ols and oligomeric proanthocyanidins were evaluated at concentrations between 25 and 500 μg/ml. Increasing the extraction time from 3 min to 10 min resulted in a significant increase in both the FRAP values and TPC. Increasing the extraction time from 10 min to 30 min was without any significant effects on both FRAP and TPC values. Moreover, the FRAP values were correlated with the TPC. GTE fractions had widely different FRAP values that were well correlated with the TPC of the fraction. It was concluded that brewing conditions such as extraction temperature, period of extraction, ratio of tea leaves to extracting water, and stirring are important factors for determining the FRAP values and TPC in GTE. These factors should be taken into consideration during preparation for nutritional benefits during usual consumption of this beverage. Elevated FRAP and TPC values corresponded to those GTE fractions with a higher amount of phenolic compounds, which have stronger antioxidant activities.