Antioxidants and other chemical and physical characteristics of two strawberry cultivars at different ripeness stages

The present work evaluated the quality and antioxidant characteristics of ‘Osogrande’ and ‘Camino Real’ strawberries at different ripeness stages. Strawberries (Fragaria x ananassa Duch.) were harvested, selected, graded according to ripeness (green, pink or 3/4 ripe and ripe) and evaluated for pH, total soluble solids, total titratable acidity, sugar/acid ratio, vitamin C, total phenolic compounds, total ellagic acid, total and individual anthocyanins and antioxidant activity by 2,2-diphenyl-1-picrylhydrazyl (DPPH) and ferric reducing antioxidant power (FRAP). The highest total soluble solid content was found for pink (7.5° Brix) and ripe (7.9° Brix) ‘Osogrande’ strawberries. At pink stage, this cultivar showed higher amounts of total phenolics (2909.48 mg kg⁻¹ FW) and total ellagic acid (454.16 mg kg⁻¹ FW). Pink ‘Camino Real’ strawberries presented the highest content of vitamin C (528.55 mg kg⁻¹ FW). Antioxidant activity was higher for ‘Osogrande’ cultivar, at green stage, according to DPPH (11.91 μmol BHT g⁻¹ FW) and FRAP (36.75 μmol ferrous sulphate  g⁻¹ FW) assays and at ripe stage, only for DPPH assay (12.83 μmol BHT g⁻¹ FW). Anthocyanins increased along ripening, with more elevated concentrations in ripe ‘Camino Real’ strawberries (292.9 mg kg⁻¹ FW). Cyanindin-3-glucoside showed a higher concentration for the same treatment (17.23 mg kg⁻¹ FW), which might contribute to a more redish color. Although ripe berries have a better flavor and are more appreciated, higher antioxidant contents and activities were observed at pink stage in which higher amounts of total phenolics, total ellagic acid and vitamin C were noticed for both cultivars.     

Comparison of carotenoid and anthocyanin profiles of raw and boiled Solanum tuberosum and Solanum phureja tubers

Tubers of the closely related species Solanum tuberosum (potatoes) and Solanum phureja belong to the staff of life for humans. The coloration of the often very colorful tubers is caused by carotenoids (especially xanthophylls) and anthocyanins. The new S. phureja cultivars Mayan Gold and Mayan Twilight, the new S. tuberosum cultivar Red Laura and the traditional S. tuberosum variety Shetland Black were analyzed for their pigment content. The dominant anthocyanin in the red-skinned cultivars Red Laura and Mayan Twilight was characterized as pelargonidin-3-coumarylrutinoside-5-glucoside by LC-ESI-MS. The blue pigment of the Shetland Black cultivar was petunidin-3-coumaroylrutinoside-5-glucoside. Red Laura contained 10 mg anthocyanins g⁻¹ dry weight and Shetland Black 31 mg anthocyanins g⁻¹ dry weight. The main carotenoids in raw tubers are 9-cis-violaxanthin, lutein and one unidentified carotenoid in all S. tuberosum and S. phureja cultivars. Minor compounds were identified as neoxanthin and neochrome. Additionally, zeaxanthin and one further unidentified carotenoid could be found in Red Laura and Mayan Gold. No differences in the carotenoid composition between peel and parenchyma could be found. Total carotenoid content ranged from 2.57 ± 0.53 μg g⁻¹ dry weight in Shetland Black to 14.77 ± 2.22 μg g⁻¹ dry weight in Red Laura (calculated as β-carotene-equivalents). In heat processed tubers, high amounts of carotenoids either changed from all-trans to 9-cis and 13-cis-isomeric form or was degraded. The total pigment content was decreased by heat processing in all cultivars. 8.23 ± 2.98 μg g⁻¹ dry weight could be found in Mayan Twilight and 1.51 ± 0.31 μg carotenoids g⁻¹ dry weight in Shetland Black.     

Analysis of protein amino acids,non-protein amino acids and metabolites,dietary protein,glucose, fructose,sucrose, phenolic,and flavonoid content and antioxidative properties of potato tubers,peels, and cortexes (pulps)

The composition and antioxidative activity of whole potato tubers from five Korean cultivars, three peels from one cultivar, and eight pulps (cortexes) after peeling from six different cultivars were evaluated. Whole tubers were sectioned into three parts followed by analysis of the peels and pulps of each part. The following characteristics were determined: the dimensions and water content of whole tubers; nutritional protein content consisting of protein and free amino acids by an automated Kjeldahl nitrogen assay; free non-protein amino acids, metabolites, and fructose, glucose, and sucrose content by HPLC; phenolic compounds by HPLC and LC/MS; total phenolics and flavonoids by colorimetry; and antioxidative properties by ABTS, DPPH, and FRAP assays. The results demonstrate differences and similarities in the content of nutritional and bioactive compounds and in their bioactivities from whole potatoes, peels, and pulps. The present study reports for the first time the analysis of multiple potato nutrients and bioactive components as well the antioxidative properties of whole potatoes, peels, and pulps derived from the same tubers. The described methods are expected to facilitate the analysis of commercial and newly-developed potato cultivars, peels, and pulps and relate their composition and antioxidative activities to their reported nutritional, health-promoting, and industrial properties.     

The effects of extraction method on the measured tocopherol level and antioxidant activity of L. nobilis vegetative organs

Tocopherol contents of Tunisian Laurus nobilis vegetative organs were screened for antioxidant activity. Tocopherol isomers extracted by probe sonication and micro-scale saponification were analysed by reversed-phase high performance liquid chromatography (RP-HPLC) with UV detection to determine the optimum extraction method. Total phenolic, flavonoid and proanthocyanidin contents were determined spectrophotometrically. Significant variations in the amounts of α-, γ- and δ-tocopherols were observed with the two different extraction methods as well as with different plant parts. Leaf extract contained the highest amount of α-tocopherol (139 mg/100 g fresh weight), but root extract contained the highest content of flavonoids (11.12 mg catechin equivalents (CE)/g dry weight or DW), total phenolics (55.45 ± 2.9 mg GAE/g DW) and condensed tannins (9.76 ± 0.1 mg CE/g DW). Acetonic extract of laurel leaf exhibited the highest antioxidant activity response to lipid peroxidation in the β-carotene-linoleic acid system, which may have been due to the high content of α-tocopherol. These findings suggest that laurel leaf may be a source of natural α-tocopherol and that it may be increasingly important for human consumption, as well as for the agro-food, cosmetic and pharmaceutical industries.     

Effect of solvents in extracting polyphenols and antioxidants of selected raw vegetables

Thirty-seven raw vegetables were extracted using four solvent systems: 70% acetone, 70% ethanol, 70% methanol, and distilled water. The extracts were tested for their total phenolic content, total flavonoid content and antioxidant activities (using diphenylpicryl-hydrazyl (DPPH) and ferric reducing antioxidant power (FRAP) assays). The results revealed the effect of different extracting solvents in altering the quantitative analyses of all vegetables and 70% acetone was identified as the most efficient solvent for extracting polyphenolic antioxidants from the vegetables. The highest total phenolic content and total flavonoid content were obtained from 70% acetone extract of Portulaca oleracea (138.2 ± 2.1 mg GAE/g dw basis) and 70% methanol extract of Cosmos caudatus (27.7 ± 1.0 mg QE/g dw basis), respectively. The 70% acetone extract of Etlingera elatior with moderate amount of total phenolic content exhibited the highest antioxidant activity in both assays. The correlation analyses within 37 different extracts of each solvent extraction demonstrated weak to moderate relationships between all the studied parameters. The highest r value of 0.7139 (p < 0.001) was determined between total phenolic contents and FRAP values of the 70% methanol extracts. Meanwhile, a wide range of correlation coefficients was derived from correlation analyses within four different extracts of each vegetable, with the highest relationship between total phenolic contents and FRAP values for the extracts of Coriandrum sativum (r = 0.9998, p < 0.001).     

Sigmoidal kinetics of anthocyanin accumulation during fruit ripening: A comparison between açai fruits (Euterpe oleracea) and other anthocyanin-rich fruits

Anthocyanins are natural colorants with increasing interest. Euterpe oleracea fruits (EOF) (açai) are an interesting phenolic compounds source. They are extremely rich in two anthocyanins: cyanidin-3-glucoside and cyanidin-3-rutinoside. In this study, the anthocyanin content was evaluated in EOF during their ripening, allowing to characterize very important parameters for the post-harvest industry: their maximum accumulation rate, per day, (Δy), their maximum concentration in fruits (CMAX) and the corresponding maturity class (S). Samples of 12 racemes from three plantations were collected twice a month during their ripening process. The maturity class of EOF was recorded at each harvesting and their anthocyanin content was determined by an HPLC method after solvent extraction. Anthocyanin accumulation was described (p < 0.05) by sigmoidal equations and Δy, CMAX and S values were determined. The Δy of EOF reached 35.63 mg kg⁻¹ fruits day⁻¹, whereas CMAX reached 1443 mg kg⁻¹ fruits. On average, in the beginning of maturation, both anthocyanins were present in similar proportions. However, in the last maturity stages, cyanidin-3-glucoside became less abundant than cyanidin-3-rutinoside. On the basis of the data available on strawberries, grapes, pomegranates and lychees, it was possible to verify that the sigmoidal mathematical model of anthocyanin accumulation is transposable.     

Bioactivity and total phenolic content of 34 sour cherry cultivars

Thirty four sour cherry cultivars were investigated for their total phenolic content, total anthocyanin content, total antioxidant capacity and cancer cell proliferation inhibition activity. Birgitte × Böttermö and Fanal, which contained the highest total phenolics (754 ± 13.4 and 596 ± 5.7 mg gallic acid equivalent/100 g, respectively), displayed the strongest total antioxidant capacity (63 ± 7.5 and 52 ± 6.9 μmol trolox equivalent/g, respectively) and cancer cell proliferation inhibition activity (63 ± 1.7 and 70 ± 1.6%, respectively). Surefire and Favorit were the cultivars with lowest total phenolic content (111 ± 2.2 and 74 ± 2.5 mg gallic acid equivalent/100 g, respectively) and total anthocyanin content (40 ± 1.1 and 21 ± 0.5 malvin equivalent/g, respectively), total antioxidant capacity (12 ± 2.3 and 9 ± 3.1 μmol trolox equivalent/g, respectively) and cancer cell inhibition activity (7 ± 3.5 and 2 ± 0.2%, respectively). Multivariate data analysis on proton nuclear magnetic resonance (¹H-NMR) data showed discrimination of the cultivars according to their bioactivity. The present study suggests that combination of ¹H-NMR and multivariate statistical analysis can be used to predict and discriminate total phenolic content, total anthocyanin content, total antioxidant capacity and cancer cell proliferation inhibition activity of sour cherry cultivars.     

Antioxidants in digestive tracts and gonads of green urchin (Strongylocentrotus droebachiensis)

Digestive tracts and gonads of green urchin (Strongylocentrotus droebachiensis) were evaluated for their antioxidant potential and total phenol and flavonoid contents. Antioxidant potentials of freeze-dried samples were evaluated using lipophilic and hydrophilic oxygen radical absorbance capacity (ORAC) assays. Analyzed samples showed antioxidant activity with total ORAC values of 864 and 885 μmol of TE/g d.w. for digestive tracts and gonads, respectively. Acetonitrile-rich and ethyl acetate extracts from freeze-dried samples showed ORAC values (1500-2100 μmol of TE/g) higher than crude tissues (∼870 μmol of TE/g), while water-rich extracts were less active (260-370 μmol of TE/g). Eluates 1 and 2 obtained from C₁₈ solid-phase extraction of the water-rich fraction showed ORAC values (650-1600 μmol of TE/g) up to 6 times higher than their parent extracts. Total phenol and flavonoid contents of freeze-dried samples ranged from 53 to 123 mg of GAE/100 g d.w. and 1.4-1.8 mg of RE/100 g, respectively. ORAC values from digestive tracts samples showed significant correlations with total phenols (r² = 0.76, p = 0.049, n = 12) and flavonoids (r² = 0.80, p = 0.021, n = 12), while a very weak correlation was observed for samples from gonads. This is the first study to quantify antioxidant properties of green urchin tissues, and show that edible gonads might provide valuable antioxidants to consumers while digestive tracts might be valorized as an alternative source of antioxidants in food additive ingredients.     

Chemical composition and antioxidant properties of mature and baby artichokes (Cynara scolymus L.), raw and cooked

Artichoke is a traditionally consumed vegetable in many countries. In the past decade, the immature (baby) variety has been successfully introduced in the international food markets. The aim of this study is to compare the chemical composition and antioxidant properties of mature and baby artichokes, in raw state and after cooking. For this purpose, the proximate chemical analysis was estimated, and aqueous and hydroalcoholic extracts were obtained to determine the contents of total polyphenols, caffeic acid, chlorogenic acid, and cynarin. Proximate analysis revealed that cooking increased proteins and lipids in baby artichokes (p < 0.05). The total phenolics content was similar in mature and baby artichokes and increased after cooking (p < 0.05). Cooked baby artichokes exhibited the highest total phenolics, caffeic acid, chlorogenic acid, and cynarin contents, as well as free radical scavenging capacity, measured as DPPH. Our results show that baby artichokes exhibit higher scavenging capacity than mature artichokes, and thus they constitute a particularly interesting source of putative antioxidant polyphenols, a quality that is improved by the application of thermal treatment.     

Profile of polyphenols and phenolic acids in bracts and receptacles of globe artichoke (Cynara cardunculus var. scolymus) germplasm

The aim of this work was to assess and quantify polyphenols and hydroxycinnamic acids in different parts of the heads of 6 globe artichoke cultivars by HPLC-DAD-MS/MS. Globe artichoke (Cynara cardunculus var. scolymus) has been used in folk medicine since Roman times, possibly because of high hydroxycinnamic acid and flavone levels. However, to our knowledge, little is known about how these compounds are distributed in different parts of the artichoke head (outer bracts, inner bracts and receptacle). The phenolic profile was significantly different between cultivars and in different parts of the head, suggesting that individual compounds are accumulated preferentially in specific head parts and cultivars. In particular, the phenolic profile of the outer bracts exhibits very low (443 mg kg⁻¹ dry matter) or zero hydroxycinnamic acid content, and these compounds are present mainly in the receptacle (the edible part; mean value, 1473 mg kg⁻¹ dry matter). This study presents data that indicate the different levels of phenolics in different parts of artichoke, and shows the potential of various artichoke parts as a source of different levels of dietary phenolics.     

Antioxidant activity and anti-inflammatory activity of ethanol extract and fractions of Doenjang in LPS-stimulated RAW 264.7 macrophages

BACKGROUND/OBJECTIVESFermentation can increase functional compounds in fermented soybean products, thereby improving antioxidant and/or anti-inflammatory activities. We investigated the changes in the contents of phenolics and isoflavones, antioxidant activity and anti-inflammatory activity of Doenjang during fermentation and aging.MATERIALS/METHODSDoenjang was made by inoculating Aspergillus oryzae and Bacillus licheniformis in soybeans, fermenting and aging for 1, 3, 6, 8, and 12 months (D1, D3, D6, D8, and D12). Doenjang was extracted using ethanol, and sequentially fractioned by hexane, dichloromethane (DM), ethylacetate (EA), n-butanol, and water. The contents of total phenolics, flavonoids and isoflavones, 2,2-diphenyl-1 picryl hydrazyl (DPPH) radical scavenging activity, and ferric reducing antioxidant power (FRAP) were measured. Anti-inflammatory effects in terms of nitric oxide (NO), prostaglandin (PG) E2 and pro-inflammatory cytokine production and inducible nitric oxide synthase (iNOS) and cyclooxygenase (COX)-2 expressions were also measured using LPS-treated RAW 264.7 macrophages.RESULTSTotal phenolic and flavonoid contents showed a gradual increase during fermentation and 6 months of aging and were sustained thereafter. DPPH radical scavenging activity and FRAP were increased by fermentation. FRAP was further increased by aging, but DPPH radical scavenging activity was not. Total isoflavone and glycoside contents decreased during fermentation and the aging process, while aglycone content and its proportion increased up to 3 or 6 months of aging and then showed a slow decrease. DM and EA fractions of Doenjang showed much higher total phenolic and flavonoid contents, and DPPH radical scavenging activity than the others. At 100 µg/mL, DM and EA fractions of D12 showed strongly suppressed NO production to 55.6% and 52.5% of control, respectively, and PGE2 production to 25.0% and 28.3% of control with inhibition of iNOS or COX-2 protein expression in macrophages.CONCLUSIONSTwelve month-aged Doenjang has potent antioxidant and anti-inflammatory activities with high levels of phenolics and isoflavone aglycones, and can be used as a beneficial food for human health.     

Polyphenols,methylxanthines, and antioxidant capacity of chocolates produced in Serbia

Different kinds of chocolates produced in Serbia were analyzed regarding total polyphenol, flavonoid and proanthocyanidin content using spectrophotometric methods. Flavan-3ols and methylxanthines in all samples were determined with RP-HPLC. DPPH, FRAP, ABTS and ORAC assays were applied for measuring antioxidant capacity. The average of all four antioxidant tests for each cocoa product was used for calculating antioxidant potency composite index (ACI). Obtained results for all four assays have shown that antioxidant capacity of analyzed chocolate/cocoa extracts followed cocoa, polyphenol, flavonoid, and proanthocyanidin contents. Although the addition of raspberries to dark chocolates had no significant influence on their total polyphenol, flavonoid and proanthocyanidin contents, statistical analysis showed that there was significant increase in the antioxidant capacity of dark chocolates with raspberry compared to plain dark chocolates (p = 0.007). Overall range for theobromine content varied from 5.5 to 22.3 mg/g depending on the product type, while the content of caffeine was 13–30 times lower in all analyzed cocoa products. In addition, correlation between antioxidant potency composite index and declared percentage of cocoa was high (R² = 0.798, p < 0.05) and indicated that declared cocoa content was a reliable indication for antioxidant capacity of chocolates produced in Serbia.     

Bioactive compounds extracted from Indian wild legume seeds: antioxidant and type II diabetes–related enzyme inhibition properties

Seven different wild legume seeds (Acacia leucophloea, Bauhinia variegata, Canavalia gladiata, Entada scandens, Mucuna pruriens, Sesbania bispinosa and Tamarindus indica) from various parts of India were analyzed for total free phenolics, l-Dopa (l-3,4 dihydroxyphenylalanine), phytic acid and their antioxidant capacity (ferric-reducing antioxidant power [FRAP] and 2,2-diphenyl-1-picrylhydrazyl [DPPH] assay) and type II diabetes–related enzyme inhibition activitiy (α-amylase). S. bispinosa had the highest content in both total free phenolics and l-Dopa, and relatively low phytic acid when compared with other seeds. Phytic acid content, being highest in E. scandens, M. pruriens and T. indica, was highly predictive for FRAP (r = 0.47, p < 0.05) and DPPH (r = 0.66, p < 0.001) assays. The phenolic extract from T. indica and l-Dopa extract from E. scandens showed significantly higher FRAP values among others. All seed extracts demonstrated a remarkable reducing power (7–145 mM FeSO4 per mg extract), DPPH radical scavenging activity (16–95%) and α-amylase enzyme inhibition activity (28–40%).     

Antioxidant and free radical scavenging capacity of the underutilized legume, Vigna vexillata (L.) A. Rich

The raw and processed seeds of the underutilized legume, Vigna vexillata (L.) A. Rich were extracted with 70% acetone and used for the evaluation of its antioxidant potential. The different heat treatments included dry heating, soaking followed by autoclaving with 0.1% sodium bicarbonate, soaking followed by autoclaving and autoclaving without soaking. The raw seed extract contained higher levels of total phenolics (11.7 g/100 g) and tannins (5.9 g/100 g) than the processed seed extracts. The extracts were further evaluated for their antioxidant activities using FRAP, Fe²⁺ chelation, phosphomolybdenum reduction, DPPH and ABTS⁺ radical scavenging, antihemolytic and β-carotene/linoleic acid emulsion systems. In general, the raw seed extracts were the most potent antioxidant suppliers and free radical scavengers. Interestingly, among the various processing methods, acetone extract of dry heated seed sample registered higher antihemolytic activity (86.2%) at the concentration of 500 μg/ml, whereas, in β-carotene/linoleic acid emulsion system, the extracts of raw seeds and the presoaked seeds followed by autoclaving with 0.1% sodium bicarbonate exhibited higher and comparable activity than other processed seed extracts.     

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 capacity of underutilized Malaysian Canarium odontophyllum (dabai) Miq. fruit

This study aimed to evaluate the antioxidant capacities of various parts of the dabai (Canarium odontophyllum Miq.) fruit. The antioxidant capacities of C. odontophyllum were evaluated using a β-carotene bleaching assay, ferric reducing antioxidant power (FRAP) and 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging assays. Total phenolic content of the dabai fruit was estimated using the Folin–Ciocalteu method. The antioxidant capacities ranked in the following order: skin > flesh + skin > flesh > kernel. Our findings show that a high correlation exists between total phenolic content and total antioxidant activity. This indicates that phenolic compounds could be the major contributors to the antioxidant capacity of C. odontophyllum fruit. Therefore, dabai fruit, especially the skin, can be recommended as a major source of natural antioxidants.     

Phenolic and antioxidant composition of cider

Forty-four Asturian ciders were analysed for total phenolic content, phenolic profiles, and antioxidant capacity by the FRAP and the DPPH radical assays. The Folin index of ciders ranged between 446 and 1180 mg gallic acid/L. The phenolic profile of Asturian cider is mainly constituted by phenolic acids, flavan-3-ols, volatile phenols and dihydrochalcones. The methods to determine the antioxidant activity of ciders were optimised in terms of suitable reaction times, within-day and between-day repeatability. Thus, time courses of ciders in the DPPH and the FRAP assays were performed. Mean values for antioxidant activity of cider, expressed in ascorbic acid equivalents were 2.9 mM (as determined by the DPPH assay). When the FRAP assay was used, the antioxidant capacity of cider increased with the reaction time from 3.8 mM (4 min) to 5.4 mM (40 min). Multivariate approaches based on phenolic composition can be useful to predict the antioxidant capacity of cider. Folin index and flavanols and hydrocaffeic acid contents were the best predictors for antioxidant activity.     

Phenolic compounds and antioxidant activity of Spanish commercial grape juices

Evaluation of the antioxidant activity of components of the diet is important in order to establish healthy consumption patterns. Data are reported here on the antioxidant activity (FRAP and ABTS), of 20 commercial grape juices and 10 typical Spanish wines and on their content of total phenolic compounds, anthocyanins, flavonoids and 10 individual phenolic compounds (flavanols, benzoic acids and cinnamic acids, measured by HPLC-UV). Red grape juices had a significantly higher (p < 0.05) concentration of total phenols (1177 vs. 744 mg gallic acid/L), flavonoids (98 vs. 63 mg catechin/L) and a higher antioxidant activity (9.16 vs. 2.83 meq Trolox/L) in comparison to white grape juices. In comparison to the white wines, white grape juices contained more total phenols (744 vs. 286 mg gallic acid/L) and flavonoids (63 vs. 29 mg catechin/L) and evidenced higher antioxidant activity (p < 0.05). In comparison to the red wines, a lower content of total phenols (286 vs. 2358 mg gallic acid/L) and flavonoids (228 vs. 29 mg catechin/L) and an absence of anthocyanins were observed in the white wines, which are therefore less antioxidant. Although a two-fold higher concentration of antioxidant compounds was found in red wines than in red grape juices, the latter may be a good option for all age groups because of the absence of alcohol and the potentially beneficial health effects of their phenolic composition and elevated antioxidant activity.     

Total phenolic compounds and antioxidant potential of Hedychium spicatum Buch. Ham. ex D. Don in west Himalaya,India

Total phenolic compounds and antioxidant potential of Hedychium spicatum were analyzed for 16 different natural populations located in Uttarakhand (west Himalaya) for promotion as health or medicinal food. Total phenolic compounds varied among populations from 4.70 mg gallic acid equivalent (GAE) to 2.84 mg GAE/g dry weight. Three in vitro antioxidant assays, i.e. azinobisethylbenzothiazoline-6-sulphonic acid radical scavenging (ABTS) assay, diphenyl-2-picrylhydrazyl (DPPH) assay and ferric reducing antioxidant power (FRAP) assay, showed significant (p < 0.05) differences across populations. ABTS assay showed highest values of antioxidant potential ranging from 2.581 mM ascorbic acid equivalent (AAE) per 100 g to 1.91 mM AAE per 100 g dry weight, followed by FRAP assay (1.921–0.6635 mM AAE per 100 g). Lowest values were observed for DPPH assay, which varied from 0.549 to 1.059 mM AAE per 100 g dry weight. All assays (ABTS, DPPH and FRAP) showed significant (p < 0.05) correlation with total phenolic compounds. Total phenolic compounds showed a significant relationship (p < 0.05) to altitude.     

Influence of storage and in vitro gastrointestinal digestion on total antioxidant capacity of fruit beverages

Eight fruit beverages containing grape, orange and apricot, with/without iron and/or zinc and with/without milk added were analyzed for total antioxidant capacity (ORAC and TEAC methods), ascorbic acid content, and total polyphenols. The influence of cold storage (2-4 °C) during the product shelf-life (135 days) and antioxidant capacity after an in vitro gastrointestinal digestion were evaluated. Antioxidant capacity for all beverages together increased significantly (p < 0.05) at the end of storage (16.4% and 12.8% for ORAC and TEAC, respectively), whereas ascorbic acid remained stable. Regarding in vitro digestion, antioxidant values of bioaccessible fractions of fruit beverages increased (p < 0.05) 59% and 20% for ORAC and TEAC, respectively, while ascorbic acid and polyphenol content fell 36% and 16%, respectively (p < 0.05). Supplementation of fruit beverages with milk and/or Fe/Zn did not modify total antioxidant capacity of samples during either cold storage or during in vitro digestion.