Antioxidant activity of Potentilla fulgens: An alpine plant of western Himalaya

Antioxidant activities of the methanol extract, fractions and isolated compounds from the roots of Potentilla fulgens Lodd. were evaluated by three in vitro experiments, namely, ABTS, DPPH, and FRAP assays. PF-2 was characterized as a new biflavanoid and designated as Potifulgene on the basis of NMR and mass spectrum, whereas PF-1 was identified as epicatechin. The activities of aqueous methanolic extract and fractions could be correlated with their respective total phenolic content and compared with standard natural antioxidants such as quercetin, vitamin C and pyrogallol. The root powder of the plant was extracted with methanol/water (80:20) by cold extraction and its extract was further partitioned with ethyl acetate, butanol and water fractions. Among the three fractions (ethyl acetate, butanol and water fraction) and the total aqueous methanolic extract, the butanol fraction exhibited good scavenging response measured in terms of TEAC (mM Trolox equivalent/mg extract). The butanol fraction was found to possess strong antioxidant activity (2.54 ± 0.69, 2.41 ± 0.53, 3.57 ± 0.05 mM Trolox equivalent/mg extract) with ABTS, DPPH and FRAP assays, respectively. The chemical composition of extracts, studied in terms of total polyphenol content (TPC), was found in the range of 20.61 ± 0.38 to 33.28 ± 0.11 mg/g gallic acid equivalent. A significant correlation was observed between total polyphenolics and antioxidant activity, indicating participation of phenolics in antioxidant activities of extract and fractions. The antioxidant activity of new biflavanoid (Potifulgene) was found to be higher, i.e. 6.85 ± 0.38, 4.24 ± 0.41, 5.35 ± 0.53 than that of epicatechin, 2.13 ± 0.05, 1.50 ± 0.02, 1.57 ± 0.03 with ABTS, DPPH and FRAP assays.     

Effect of extraction solvents on the phenolic compounds and antioxidant activities of bunga kantan (Etlingera elatior Jack.) inflorescence

In the present study, we investigated the effect of methanol, acetone (50%, 90% and 100%, v/v) and distilled water on the extractability of some of the antioxidant compounds (total phenols, tannins, flavonoids, anthocyanins) of bunga kantan inflorescence (Etlingera elatior Jack.). The antioxidant activity of each individual extract was also evaluated through DPPH (2,2-diphenyl-1-pic-rylhydrazyl) radical scavenging activity and ferric reducing antioxidant power (FRAP) assay. Of all the solvents employed, 50% acetone extract showed highest amount of total phenols (687.0 mg GAE/100 g) and total flavonoids (1431 mg QE/100 g), while 50% methanol extract showed maximum (5.9 mg c-3-gE/100 g) recovery for anthocyanins. Tannin extractability was found to be highest with 100% methanol (467.8 mg CE/100 g). The results obtained suggest the use of bunga kantan inflorescence as a potential source of natural antioxidants for food and nutraceutical applications.     

Characterization,bioactive compounds and antioxidant potential of three Brazilian fruits

With the objective of stimulating the cultivation and consumption of native Brazilian fruits, the physicochemical composition and antioxidant potential of three native species, namely the araticu-do-mato (Rollinia sylvatica A. St.-Hil.), pindo palm (Butia capitata (Mart.) Becc.) and mandacaru-de-três-quinas (Cereus hildmannianus K. Schum.) were determined in this study. The pindo palm fruit stood out because of its elevated carotenoid content (39.6 μg/g) and greater antioxidant capacity (26 μM trolox/g of fresh sample) by the ABTS (2,2-azino-bis-3-ethylbenzothiazoline-6-sulfonic) method, although by the DPPH (2,2-diphenyl-1-picrylhydrazyl) method, the pindo palm fruit (3847.5 g of fresh sample/g DPPH) and mandacaru-de-três-quinas fruit (3249.8 g of fresh sample/g DPPH) were considered to have the same antioxidant potential with no difference between them. The mandacaru-de-três-quinas fruit also showed the highest total phenolic compound content (1337.3 mg/100 g). Although the araticu-do-mato presented the highest vitamin C content (0.32 mg/g), it did not differ statistically from the mandacaru-de-três-quinas fruit (0.25 mg/g); on the other hand, it was considered to be equal to the pindo palm fruit (0.23 mg/g). The araticu-do-mato also showed the best result for the TSS/TTA (total soluble solids/total titratable acidity) ratio (41.92), thus it was adequate for in natura consumption and for processing as well.     

Antioxidant activity of methanolic extract of emblica fruit (Phyllanthus emblica L.) from six regions in China

The phenolic contents of methanolic extracts of emblica (Phyllanthus emblica L.) fruit from six regions in China were measured in this work. The antioxidant activities of these extracts were also evaluated. Total phenolic content was ranged from 81.5 to 120.9 mg gallic acid equivalents (GAE)/g and the flavonoid content was varied from 20.3 to 38.7 mg quecetin equivalents (QE)/g, while proanthocyanidin content was ranged from 3.7 to 18.7 mg catechin equivalents (CE)/g. Among all the methanolic extracts analyzed, the Huizhou sample exhibited a significantly higher phenolic content than other samples (P<0.05). The antioxidant activities were evaluated by in vitro experiments using scavenging assays of 1,1-diphenyl-2-picrylhydrazyl (DPPH) radicals, hydroxyl radicals, and superoxide anion radicals, chelating ability of ferrous ion, reducing power, and inhibition capability of Fe (II)-induced lipid peroxidation, respectively. The Huizhou sample was found to have the strongest antioxidant activities in scavenging DPPH radicals, superoxide anion radicals, and had the highest reducing power, while the Chuxiong sample showed the best performance in chelating iron and inhibiting lipid peroxidation. Furthermore, the Chuxiong sample exhibited a stronger inhibition activity of the hydroxyl radicals compared with other samples. The high correlation coefficient was existed between the phenolic content and superoxide anion radical scavenging activity, but no significant correlation was found between the former and hydroxyl radical scavenging activity. Methanolic extracts of emblica fruit from some selected regions exhibited stronger antioxidant activities compared to those of the commercial compounds (quercetin and BHA). It might be considered as a potential plant source of antioxidants.     

Identification and quantification of phenolic compounds responsible for the antioxidant activity of sweet potatoes with different flesh colours using high performance thin layer chromatography (HPTLC)

The objectives of the present study were to develop a simple high performance thin layer chromatography (HPTLC)-based protocol: (i) to allow high-throughput profiling of phenolic compounds of microwaved roots from 295 sweet potato varieties and breeding lines, (ii) to quantify the content of anthocyanins and caffeoylquinic acid (CQA) derivatives, and (iii) to determine their respective contributions to the antioxidant activity of sweet potato methanolic extracts using the DPPH test. Analysed accessions were separated into three groups: white-fleshed (n = 100), orange-fleshed (n = 64) and purple-fleshed (n = 131). Purple-fleshed accessions presented the highest mean CQA content. After DPPH treatment and transmittance scanning of the plate at 517 nm, the most active free radical scavengers were found to be the four CQAs (CGA, 3,4-, 4,5- and 3,5-diCQA) while the anthocyanins were found to be less active. The total antioxidant capacity of the sweet potato methanolic extracts was mostly linked to total CQAs content. This method can now be used for fast routine analysis and selection of sweet potato breeding clones.     

Antioxidant components and antioxidant/antiradical activities of desert truffle (Tirmania nivea) from various Middle Eastern origins

Dried desert truffles from Bahraini, Iranian, Moroccan and Saudi origins were examined for their antioxidant and antiradical activities using four analytical methods: ferric reducing ability (FRAP), DPPH, deoxyribose, and nitric oxide (NO). Chemical constituents contributing towards these activities were also investigated. Generally, these truffles possessed varying concentration of antioxidant chemicals averaging 9.6 ± 0.15, 12.0 ± 8.34, 1860 ± 361, 1328 ± 167 and 293 ± 32 mg/100 g dw, for ascorbic, anthocyanins, total esterified phenolics, total free phenolics and total flavonoids, respectively; total carotenoids averaged 681 ± 245 g/100 g dw. Dried truffles also varied with regard to their antioxidant and antiradical activities. The FRAP value averaged 15.41 ± 3.51 mmol/100 g dw. Antiradical activity measured as percent inhibition of DPPH quenching averaged 30.6 ± 12.97% and EC₅₀ of 0.55 ± 0.38 mg. The average EC₅₀ of NO scavenging activity was 159.4 ± 69.3 μg, whereas the average percent inhibition of deoxyribose degradation was 55.9 ± 30.1%. The Iranian truffles yielded the highest in several variables, whereas the Moroccan truffles possessed the lowest values of many variables among the four tested samples. Significant correlation was established between total and free phenolics and FRAP values, and between flavonoids and percent radical inhibition using DPPH, NO and deoxyribose assays.     

Effet de la digestion gastro-intestinale in vitro sur les composés phénoliques et l’activité antioxydante du thé vert Camellia sinensis L. issu de l’agriculture biologique

ObjectivesThe aim of this work is to study the effect of in vitro digestion on the contents of total polyphenols and flavonoids and the antioxidant activity of green tea (Camellia sinensis L.) from organic farming.Material and methodsOptimization of the tea cooking conditions was carried out by a central composite design. The contents of total polyphenols and flavonoids of the undigested and digested plants were determined by spectrophotometric methods. Phenolic extracts of green tea and digested lyophilizes were analysed by Attenuated total reflection-Fourier transform infrared. Evaluation of the antioxidant activity was carried out by three methods: DPPH, ABTS, and CUPRAC.ResultsDigestion causes a decrease in the levels of total polyphenols and flavonoids. The spectra obtained during the ATR-FTIR analysis showed intense bands corresponding to the O-H bonds, and C = C, C-H, C-O, and C = C bonds confirmed the presence of the polyphenols. A gradual decrease in the intensity of the absorption bands was observed during the three phases of digestion. The study of the effect of in vitro digestion on antioxidant activity indicates decreased antioxidant activity during two digestive phases (salivary and intestinal) and a marked increase during the gastric phase compared to the extract of the undigested plant.ConclusionThis study shows that the three phases of digestion reduce the levels of total polyphenols and flavonoids. Two phases of digestion (salivary and intestinal) cause a decrease in antioxidant activity, while an increase in this activity was observed in the gastric phase.     

Effects of soaking conditions on the antioxidant potentials of oolong tea

The antioxidant properties of water extracts of oolong tea (Commercial name: Fenghuangdancong) prepared using different soaking temperatures and times were investigated. The yield of powdered extract ranged from 6.7% at 80 °C for 3 min soaking to 22.7% at 100 °C for 10-min soaking. Oolong tea extracts reduced peroxidation of peanut oil and delayed the time of POV20 (peroxide value). Among these soaking treatments, soaking for 10 min in 100 °C water produced extracts with the greatest ability to inhibit the peroxidation of peanut oil. As well, the SC50 (scavenging-percentage) of the α, α-diphenyl-β-picrylhydrazyl radical (DPPH radical) was 0.119 mL of oolong tea extract using 3-min soaking at 100 °C, which is closed to the SC50 of 0.109 mL (2 mg/mL) for vitamin C. The DPPH radical scavenging activity of oolong tea extracts increased with increasing temperature of the soaking water indicating greater extraction of antioxidant compounds. In addition, inhibition of oxidation of peanut oil and DPPH radical scavenging activity by water extract of oolong tea was associated with polyphenol concentrations. Sensory assessment, found that the water extract of oolong tea using 3-min soaking at 95 °C had the strongest aroma and sweetness attributes.     

Evaluation of antioxidant activities of phenolic compounds from two extra virgin olive oils

The aim of this work was to investigate the antioxidant properties of two varieties of olive oil (Chétoui and Chemlali), and to study the protective effect of phenolic extract (PE) from these varieties against low density lipoprotein (LDL) oxidation in vitro. Antioxidant activities were examined as well, using different radical scavenging assays: radical scavenging activity by DPPH, and total antioxidant status by ABTS. The antioxidant effect of the oils on human LDL was evaluated by measuring levels of conjugated dienes and polyunsaturated fatty acids. Chemlali oil was less rich in total phenols (158 mg/kg) than Chétoui oil (395 mg/kg) (p < 0.05). The highest antioxidant activity was attributed to Chétoui oil (78.56% vs. 37.23% of DPPH and 2.42 vs. 0.61 mmol Trolox/kg; p < 0.05). Chétoui PE had a significantly greater inhibitory effect on LDL oxidation than Chemlali PE (lag time = 116 ± 6.05 min vs. 64 ± 11.31 min at 0.3 mg/l of PE respectively; p < 0.05). The differences in quantity and quality of the studied oils influenced their biological activities and they could provide beneficial effects in cardiovascular disease by inhibiting LDL oxidation.     

Nutritional composition and antioxidant properties of Canarium odontophyllum Miq. (dabai) fruits

The present study sought to determine the nutritional composition and antioxidant properties of Canarium odontophyllum Miq. (dabai) fruits from different districts in Malaysia, namely Kanowit, Sarikei, Kapit and Song in Sarawak. Two varieties of the fruits were investigated. Lipid (21.16 ± 4.71 to 25.76 ± 3.03 g/100 g FW) was the major macronutrient in dabai fruits, while the predominant minerals were calcium, sodium and potassium. The fruit protein was rich in aspartic and glutamic acids which accounted for 45–49% of total amino acids. Purple dabai fruits from Kapit were found to contain the highest total phenolic levels, flavonoids and anthocyanin contents (p < 0.01) and to exhibit the most significant antioxidant activities (p < 0.01), using trolox equivalent antioxidant capacity (TEAC) and ferric reducing ability (FRAP) assays. Antioxidant activities were highly correlated with total phenolic and flavonoid contents of dabai fruits.     

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).     

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.     

Radical scavenging,antioxidant and metal chelating activities of Annona cherimola Mill. (cherimoya) peel and pulp in relation to their total phenolic and total flavonoid contents

This study aimed to evaluate the total phenolic and flavonoid content, radical scavenging activity (by DPPH and ABTS tests) and antioxidant capacity (by β-carotene bleaching test) of Annona cherimola (cherimoya) fruits cultivated in Italy for human consumption. The metal chelating activity and ferric reducing power were also determined. A. cherimola peel and pulp were characterized by a total phenolic content of 14.6 and 12.6 mg chlorogenic acid equivalents/100 g fresh weight, respectively. A similar trend was observed with flavonoid content. Both extracts exhibited high antioxidant activity through different mechanisms of action. In particular, peel extract demonstrated the strongest free radical scavenging activity with an IC₅₀ value of 57.7 μg/mL. The same extract was more effective in preventing β-carotene oxidation (IC₅₀ value of 63.5 μg/mL after 60 min) and showed higher chelating ability (IC₅₀ value of 79.6 μg/mL) than pulp extract. This work demonstrated the high quality of cherimoya fruits cultivated in Italy, and recommends the peel of this fruit product that may be of interest from a functional point of view as a major source of natural antioxidants.     

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.     

Survey of antioxidant capacity and nutritional quality of selected edible and medicinal fruit plants in Hong Kong

Twenty-two samples (including fruits, pulp, peel, or seeds) from 13 edible and medicinal fruit plant species selected in Hong Kong were investigated for their antioxidant capacity, nutritional quality and phenolic profiles. Significant variation existed among the tested samples in all the antioxidant and nutritional parameters. Proanthocyanidins, flavonoids and phenolic acids were identified as major categories of phenolic compounds in these samples. Whole fruits of Hong Kong gordonia exhibited the strongest antioxidant capacity (213.4 mmol trolox/100 g DW) and had the second highest content of carotenoids. Seeds of Annona squamosa possessed the highest contents of total protein, fat and amino acids (17.6, 37.2 and 14.4%, respectively). Most peel and some seeds contained high levels of phenolics, carotenoids and vitamin C, which contributed to their strong antioxidant activity. Some of the fruits, peel or seeds from these Hong Kong plants can be a potential resource of functional components and nutraceuticals.     

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.     

Antioxidant activity and phenolic content of fresh and dry nuts with or without the seed coat

Total antioxidant activities based on ABTS free radical scavenging activity and phenolic content of fresh or dry hazelnuts, walnuts and pistachios assayed with their seed coats changed between 3063 and 11,076 μmol trolox equivalents/100 g d.w. and 256 and 755 mg gallic acid equivalents/100 g d.w., respectively. The walnuts used in this study showed the highest antioxidant activity, followed by pistachios and hazelnuts. The removal of seed coat reduced the total antioxidant activity of hazelnuts, walnuts and pistachios almost 36, 90 and 55%, respectively. The total antioxidant activities of investigated fresh and dry nuts are not considerably different. However, phenolic content and antioxidant activity in hydrophilic and ethanolic fractions obtained by successive extraction of nuts showed some variation. The antioxidant activity in 1-serving portion of fresh or dry walnuts is equivalent to that in almost 2-serving portions of black tea, and 1.2–1.7-serving portions of green and Earl Grey tea. One-serving portions of dry hazelnuts and fresh or dry pistachios contained antioxidant activity equivalent to that in 0.7–1-serving portions of black tea. The antioxidant activity measurements correlated with phenolic content (r² = 0.70). This study showed the potential of using fresh or dry nuts to develop functional foods with high antioxidant activity.     

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.     

Reaction time and DPPH concentration influence antioxidant activity and kinetic parameters of bioactive molecules and plant extracts in the reaction with the DPPH radical

The antioxidant activity of lemon and pomegranate juice, infusion of Java green tea, rosemary oil and pure chemicals was studied by the DPPH method. The chemical composition of the samples was determined by liquid chromatography–mass spectrometry (LC–MS). The kinetics of the reaction is different among extracts. The reaction of DPPH with lemon juice is complete in 3 min; 87 and 98 min are necessary for green tea infusion and pomegranate juice, respectively; 283 min are needed for rosemary essential oil. In samples with an intermediate and slow kinetic behavior, the antioxidant activity measured after 2 h of reaction is significantly higher than that measured after 30 min. These differences are 18% for Java green tea infusion, 21% for rosemary essential oil, 23% for pomegranate juice. The results demonstrate that the percentage of remaining DPPH decreases with increasing initial DPPH concentrations (between 25 and 200 μM), while keeping constant antioxidant/DPPH ratio. Moreover the time necessary to reach the steady state is dependent, while keeping the same antioxidant/DPPH ratio, on the initial DPPH concentration, showing that longer time intervals are required when using lower DPPH concentrations (25 μM). These results confirm the necessity of standardizing the method to be able to compare results from different laboratories.     

Polish wines: Characteristics of cool-climate wines

The aim of this work was to characterize the physical, chemical and antioxidant properties of selected Polish wines, produced from grapevines cultivated in the cool climate of Podkarpacie. Most of the analysed wines were characterized by a small amount of total extract (less than 4%), by ethanol concentration ranging from 9.9 to 11.0% and by titratable acidity from 4.0 to 8.7 g of malic acid/L. The total polyphenol content was closely correlated with antioxidant activity (R² = 0.96). Red wines were distinguished from white wines by 4–5 times higher antioxidant activity (671–746 mg of Trolox/100 mL) and by increased total amount of polyphenols (127–135 mg of catechin/100 mL). The prevailing volatile compounds of wines were amyl alcohols and isobutanol. Especially high concentrations of the above compounds were present in liqueur wines (>220 and 180 mg/L, respectively). Polish wines contained also high levels of ethyl acetate (11–161 mg/L).