Fatty acids,tocopherols and proanthocyanidins in bramble seeds

Studies were conducted on the fatty acids, tocopherols and proanthocyanidins in the seeds of 10 bramble varieties from China. The oil yields from these seeds vary from 4.81% to 15.72%. The main fatty acids in bramble seed oils are C18:2 n-6 (51.0–66.1%), C18:3 n-3 (9.70–35.6%), C18:1 n-9 (9.85–16.3%), and C16:0 (2.01–5.73%). The major tocopherol in all seed oils of 10 varieties was γ-tocopherol. The composition (mg/100 g) was as follows: α-tocopherol 7.65–52.6, γ-tocopherol 46.9–106, δ-tocopherol 3.1–9.50, and the active vitamin E 15.9–61.5 among the varieties. The total proanthocyanidin content varies from 6.81 to 17.6 mg/g. The main oligomers in total proanthocyanidins are dimers, and the least are trimers. The contents and composite proportions of fatty acids, tocopherols and proanthocyanidins are different according the varieties, which should be taken into account when the bramble seeds are exploited.     

Organic acids,antioxidant capacity,phenolic content and lipid characterisation of Georgia-grown underutilized fruit crops

Four underutilized Georgia-grown fruit crops, namely loquat (Eriobotrya japonica), mayhaw (Crataegus sp.), fig (Ficus carica), and pawpaw (Asimina triloba), and their leaves were analysed for total polyphenols by Folin–Ciocalteau method, and antioxidant capacity by ferric-reducing antioxidant power (FRAP) and Trolox-equivalent antioxidant capacity (TEAC) assays. Organic acids and phenolic compounds were identified by RP-HPLC. For lipid profile, fruits were separated into two fractions – seed and fruit (i.e., without seed); lipid was extracted using the Folch method and analysed for fatty acids, phytosterols, tocopherols, and phospholipids. The major organic acid identified in all samples was malic acid (177–1918 mg/100 g FW). The predominant phenolic acids in all the fruits were gallic (1.5–6.4 mg/100 g FW) and ellagic (0.2–33.8 mg/100 g FW), and the most abundant flavonoid was catechin (12.2–37.8 mg/100 g FW). Total lipid content varied from 0.1% in mayhaw fruit to 21.5% in pawpaw seed. Linoleic acid was the predominant fatty acid in all of the samples (28.2–55.7%).     

Total phenolic content and antioxidant capacity of extracts obtained from six important fruit residues

The extracts from kinnow peel, kinnow seeds, litchi pericarp, litchi seeds, grape seeds, and banana peel were screened for total phenolic content (TPC), trolox equivalent antioxidant capacity (TEAC), 1,1 diphenyl-2-picryl hydrazyl (DPPH) radical scavenging activity, as well as reducing power. Kinnow peel extract exhibited the highest reducing power, TEAC, and DPPH free radical scavenging activity, whereas, the phenolic content of 37.4 mg GAE/g-dw was highest for grape seed extract. Banana peel extract with a low TPC showed the lowest reducing power, TEAC as well as DPPH free radical scavenging activity among the fruit residue extracts examined in the present study. Correlation analysis between the reducing power and DPPH radical scavenging ability; reducing power and ABTS radical scavenging activity; and ABTS and DPPH radical scavenging abilities showed a high degree of correlation (r² = 0.85-0.91). However, r² of 0.36, 0.66, and 0.49 between TPC and DPPH radical scavenging activity; TPC and reducing power; and TPC and ABTS radical scavenging ability, respectively, indicated that some non-phenolic compounds also contributed to the total antioxidant activity in fruit residue extracts examined in this study. To the best of our knowledge, this is the first paper presenting comprehensive data on TPC, reducing power, and antioxidant activity for the six fruit residues. This study demonstrated that kinnow peel, litchi pericarp, litchi seeds, and grape seeds, can serve as potential sources of antioxidants for use in food and pharmaceutical industry.     

Bioactive compounds and antioxidant capacities in different edible tissues of citrus fruit of four species

Different edible tissues of citrus fruit, namely juice sacs (JS), segment membrane (SM), and segment (Seg), of four species, were examined for contents of bioactive compounds and total antioxidant capacities (TAC) by ferric reducing antioxidant power (FRAP) assay. Two flavanones (naringin and hesperidin) were identified by HPLC; hesperidin accounted for 18.5–38.5% of the total phenolics in the species Citrus unshiu, Citrus reticulata, and Citrus sinensis, while naringin was only found in Citrus changshanensis and it accounted for 53.7% of the total phenolics in SM of this species. In SM of all selected species, the contents of phenolic compounds and TAC were significantly higher than those in JS and Seg. Highest total phenolics, total flavonoids, naringin, and TAC were found in SM of C. changshanensis, while the highest carotenoid content was found in JS of C. reticulata. The contribution of vitamin C to TAC ranged from 26.9% to 45.9% in JS and Seg of all selected species. In SM, however, a high contribution from hesperidin was observed in C. unshiu (54.0%), C. sinensis (46.7%) and C. reticulata (30.0%). The results indicated that SM of citrus fruit were high in contents of bioactive compounds and TAC; it is thus recommended to consume citrus fruit with all edible tissues rather than juice or JS alone.     

A comparative study of tocopherols composition and antioxidant properties of in vivo and in vitro ectomycorrhizal fungi

In aerobic organisms, the free radicals are constantly being produced during the normal cellular metabolism. The antioxidant properties of many organisms and particularly of wild mushrooms with their content in antioxidant compounds such as tocopherols, can detoxify potentially damaging forms of activated oxygen. Herein, a comparative study of tocopherols composition and antioxidant properties of in vivo (fruiting bodies) and in vitro (mycelia) ectomycorrhizal fungi: Paxillus involutus and Pisolithus arhizus. Tocopherols were determined by high performance liquid chromatography (HPLC) coupled to a fluorescence detector. The antioxidant properties were studied in terms of DPPH radical-scavenging activity, reducing power and inhibition of β-carotene bleaching. Fruiting bodies revealed the highest antioxidant properties, including scavenging effects on free radicals (EC₅₀ = 0.61 and 0.56 mg/ml) and inhibition of lipid peroxidation capacity (EC₅₀ = 0.40 and 0.24 mg/ml for P. involutus and P. arhizus, respectively), than mycelia produced in vitro cultures. Nevertheless, mycelia revealed higher levels of total tocopherols than fruiting bodies, and particularly P. arhizus mycelium proved to be a powerful source of γ-tocopherol (154.39 μg/g dry weight).     

Polyphenol composition, vitamin C content and antioxidant capacity of Mauritian citrus fruit pulps

The pulp extracts of twenty-one varieties of citrus fruits (oranges, satsumah, clementine, mandarins, tangor, bergamot, lemon, tangelos, kumquat, calamondin and pamplemousses), commonly grown in Mauritius, were characterised in terms of their total soluble solids (TSS), titratable acidity (TA), polyphenol composition and vitamin C contents. Total phenolics ranged from 406.3 ± 14 to 1694 ± 19 ??g g^− 1 fresh weight (FW). Total flavonoids varied between 133 ± 6 and 965 ± 7 ??g g^− 1 FW and vitamin C contents were from 166 ± 19 ??g/mL to 677 ± 22 ??g/mL. The pulp of a pamplemousse variety had the highest TSS/TA ratio whereas lemon pulps had lowest TSS/TA ratios. The antioxidant activities of the pulp extracts were assessed and total phenolics correlated strongly with the trolox equivalent antioxidant capacity (TEAC), ferric reducing antioxidant capacity (FRAP) and hypochlorous acid (HOCl) scavenging activity assays. Based on their antioxidant activities, nine citrus fruits namely, one orange, tangor, kumquat, calamondin and pamplemousse variety and two mandarin and tangelo varieties were further characterised for their flavanone, flavonol and flavone levels by HPLC. Hesperidin (6.89 ± 0.06 to 26.98 ± 0.07 mg/g FW) and narirutin (0.27 ± 0.01 and 20.91 ± 0.10 mg/g FW) were present at high concentrations compared to the other flavonoid glycosides in the pulp extracts. Naringin was detected only in pulp extracts of pamplemousses. In the light of the data obtained, citrus fruit pulps represent an important source of phytochemicals with potent antioxidant capacity.     

Effects of genotype, location and baking on the phenolic content and some antioxidant properties of cereal species

In order to assess the effect of genotype, location and their interaction on total phenolic content (TPC) of chemical extracts, the whole grains of durum and soft wheat, oat, barley and triticale were evaluated. Data showed differences in phenolic content of chemical extracts among cereal species and the analysis of variance confirmed the key role of location. Besides TPC and trolox equivalent antioxidant capacity (TEAC) values assessed by chemical extraction were compared with those obtained with an in vitro digestive enzymatic extraction. Differences were found between methanolic and enzymatic extracts, and data confirmed that enzymatic technique enhanced extraction of antioxidants but pointed out lesser differences among cereal types. The breads obtained by flours enriched with different levels of bran were also evaluated. Chemical extracts highlighted the increasing levels of antioxidants according to bran enrichments, without pointing out changes caused by baking. The enzymatic extraction instead did not show differences regarding to bran enrichments, but documented a loss in antioxidant properties of breads in respect to corresponding flours. On the other hand the scarce differences between flours and corresponding breads did not allow asserting that baking modified the TPC and TEAC, independently of the extraction methods used. Indeed, during baking process, also the observed phenolic acids profile variations did not vary the antioxidant properties of breads.     

Localization of phenolic acids and antioxidant activity in sorghum kernels

White and red of sorghum grains were sequentially pearled into 11 pearling fines and the corresponding 11 pearled kernels to study the localization of phenolic acids within sorghum grains. All fractions were analyzed for phenolic acids content by HPLC and antioxidant capacity by FRAP assays. Four phenolic acids identified in all fractions were caffeic, p-coumaric, ferulic, and sinapic acids. Data showed that the distribution of phenolic acids and antioxidant capacity in two sorghum genotypes was heterogeneous. Around 60% of the phenolic acids and the antioxidant capacity were recovered in the initial three pearling fine fractions that constituted about 20% surface removal. The concentrations of the phenolic acids decreased significantly with sequential pearling. Significant correlation between total phenolic acids and antioxidant capacity was observed with all fractions except for the first pearling fines from the red sorghum.     

Effect of microwave treatment on phenolic content and antioxidant activity of citrus mandarin pomace

The effects of microwave treatment on the phenolic compounds and antioxidant capacity of citrus mandarin pomace were evaluated. After treatment, methanol extracts of citrus pomace were prepared and the contents of phenolic acids (free and bound) and flavanol, flavanone and flavonol compounds (FCs) were determined by HPLC. Antioxidant capacity of pomace extracts was measured using DPPH radical-scavenging assay, hydroxyl radical-scavenging assay and reducing power. After microwave treatment, the free fraction of phenolic acids increased, whereas the bound fractions decreased and antioxidant activity was increased. The content of total FCs increased with power but, at longer irradiation time, it declined which meant that some FCs might be degraded. The results indicated that appropriate microwave treatment could be an efficient process to liberate and activate the bound phenolic compounds and to enhance the antioxidant activity of citrus mandarin pomace.     

A comparative study of phenolic compounds and antioxidant and antiproliferative activities in frequently consumed raw vegetables

The aim of this study was to assess the antioxidant value and antiproliferative activity of some vegetables such as raw garlic (Allium sativum L), white and yellow, and red onions (Allium cepa L), red and green peppers (Capsicum annuum L.), and white cabbage (Brassica oleracea var. capitata f. alba), which were harvested in the same year and in the same geographical and climatic conditions. It was found that the highest content of some bioactive compounds (25.19 ± 2.2 mg GAE/g, 3.84 ± 0.3 mg CE/g, 4.88 ± 0.3 mg CE/g, 59.20 ± 0.8 μg CE/g, 1992 ± 99.8 μg AA/g, 452.7 ± 26.1 mg CGE/kg DW for polyphenols, flavonoids, tannins, flavanols, ascorbic acid, and anthocyanins, respectively) and the antioxidant activity (41.32 ± 3.9, 31.05 ± 2.7, 59.17 ± 5.2 and 58.94 ± 5.1 μM TE/g for DPPH, FRAP, CUPRAC and ABTS, respectively) was in red onion. Methanol extracts in concentration of 1,000 μg ml⁻¹ of garlic and red onion exhibited antiproliferative activity (83.1 ± 2.1 and 85.0 ± 3.2% of viability, respectively). In spite of relatively high antioxidant activity in methanol extracts of yellow onion, red and green pepper, no antiproliferative activity on both tumor cell lines was registered. In conclusion, among the studied vegetables raw red onion was the preferable. The interrelationship was in the following order: red onion > white onion = yellow onion > red pepper > garlic = green pepper > white cabbage. The antiproliferative activities of these vegetables were different: some samples reacted only on Calu-6 and the others—on SNU-601. Thus, vegetables from the same cultivation place were examined for their antioxidant and antiproliferative activities with four different methods. Based on obtained data a direct comparison between these vegetables was possible for the first time.     

A comparative study on the antioxidant properties of Slovakian and Austrian wines

The antioxidant properties of 86 wine samples (35 white and 17 red from the Slovak, and 12 white and 22 red from the Burgenland, regions) were investigated by Electron Paramagnetic Resonance (EPR) spectroscopy using 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical and 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt cation radical (ABTS⁺) as oxidants. Generally, the red wines showed, on the average, more than 10 times higher antioxidant activity towards ABTS⁺ than the white wines. A similar ratio was found for the total phenolics content. A linear correlation was found between the antioxidant activities determined by DPPH and ABTS⁺ and the phenolics concentration. This trend is supported by the significant difference of the total integral value of the aromatic region in ¹H NMR (Nuclear Magnetic Resonance) spectra between the red and white wine samples. The content of the phenolic acid components of 16 selected wine samples determined by High Performance Liquid Chromatography (HPLC) correlates with the antioxidant activities. No significant differences were found between Slovakian and Austrian wines.     

A comparative study on phenolic profile,vitamin C content and antioxidant activity of Italian honeys of different botanical origin

The aim of our study was to identify and quantify the phenolic acids, flavonoids and vitamin C and to evaluate the antioxidant activity in ninety Italian honeys of different botanical origins (chestnut, sulla, eucalyptus, citrus and multifloral). The results showed that total phenolic and flavonoid contents varied from 11.08 to 14.26 mg GAE per 100 g honey and from 5.82 to 12.52 mg QE per 100 g honey, respectively. HPLC–UV analysis showed a similar but quantitatively different phenolic profile of the studied honeys. Vitamin C is present in all samples. Multifloral honey showed the highest amount of the detected total phenolic compounds and the highest vitamin C content. The DPPH value varied from 55.06 to 75.37%. Among the unifloral honeys, chestnut honey presented the highest levels of phenolic acids, flavonoids and vitamin C, which are closely associated with its high antioxidant activity. The results show that honey contains high amount of biologically active compounds, which play an important role in defining the nutraceutical quality of the product, and that the distribution of these compounds is influenced by the botanical origin.     

Effects of infrared heating on drying kinetics,antioxidant activity,phenolic content,and color of jujube fruit

This study investigated the effects of different infrared power (IP) levels (62, 88, and 125 W) and a pretreatment (soaking in a solution of 5 % potassium carbonate and 0.5 % olive oil) on the drying kinetics and some quality parameters of jujube fruit. The drying characteristics of jujube were greatly influenced by the pretreatment and IP level. The models of Lewis, Logarithmic, Page, and Aghbashlo et al. were fitted to the obtained experimental data using nonlinear regression analysis. The Page model showed a better fit to the experimental drying data when compared to the other models. The effective moisture diffusivity, calculated using Fick’s second law, ranged from 4.75 × 10^?10 to 4.17 × 10^?9 m²/s. Significantly, higher total phenolic content (TPC) and antioxidant capacity values were obtained for the pretreated samples subjected to higher IP levels. The total color change (ΔE) of the dried samples significantly increased with increasing IP level. Jujube fruits should be pretreated and then dried at 88 W IP to reduce phenolic degradation and undesired color changes and to increase the quality of the dried product.     

Determination of oil palm fruit phenolic compounds and their antioxidant activities using spectrophotometric methods

There is scarce information on the phenolics of oil palm fruits (Elaeis guineensis). In this study, phenolics were extracted from oil palm fruits and analysed using spectrophotometry for information on the different types of palm phenolics and their antioxidative activities. Analyses of the total phenolic content (TPC), total flavonoid content (TFC), o‐diphenols index, hydroxycinnamic acid index, flavonols index and phenol index showed ranges between 5.64 and 83.97 g L^?1 gallic acid equivalent (GAE), 0.31–7.53 g L^?1 catechin equivalent, 4.90–93.20 g L^?1 GAE, 23.74–77.46 g L^?1 ferulic acid equivalent, 3.62–95.33 g L^?1 rutin equivalent and 15.90–247.22 g L^?1 GAE, respectively. The antioxidant assay, 2,2‐diphenyl‐2‐picrylhydrazyl radical scavenging assay, showed antioxidative activities in all the extracts with results ranging from 4.41 to 61.98 g L^?1 trolox equivalent. The high antioxidant activities of the oil palm fruit phenolics were also found to increase with increasing TPC and TFC.     

Effect of roasting process on phenolic,antioxidant and browning properties of carob powder

Roasted carob powder was obtained using different time–temperature combinations and some quality characteristics such as total phenolic content (TPC), total antioxidant activity (TAA), browning index (BI) at 420 nm, UV absorbance (UV-A) at 294 nm, and pH has been investigated. Both the roasting temperature and time significantly (P < 0.01) affected the quality characteristics of the product. However, the roasting time was found to be a critical factor in determining the overall quality of the product. While the TPC, TAA, BI and UV-A values of the samples increased with the increasing roasting temperature and time, the pH of the samples decreased gradually. The quality characteristics of the carob powders changed markedly in between 20 and 60 min of roasting which indicates that the heat-induced reactions accelerate particularly in that period of roasting. The correlations between all these chemical properties of carob powder were found to be significant (P < 0.0001) during roasting.     

Antioxidant and protective properties of six Tanacetum species against hydrogen peroxide-induced oxidative stress in K562 cell line: A comparative study

The antioxidant activities of ethanolic extract of six species of Tanacetum (T. budjnurdense, T. hololeucum, T. chiliophyllum, T. sonboli, T. tabrisianum, T. kotschyi) from Iran were examined by employing various established in vitro assay systems. The results showed that all Tanacetum extracts displayed antioxidant activities, with IC₅₀ values ranging from 59.55 to 157.24 μg/ml, using 1,1-diphenyl-2-picrylhydrazyl (DPPH) assay. The extract of T. hololeucum, with an IC₅₀ value of 59.55 μg/ml was nearly two or three times more active than the other used Tanacetum extracts. The amounts of total phenolics and total flavonoids were also determined by spectrophotometer. A similar order of the amounts of phenolics and flavonoids in all plant extracts were found. The results showed that the extent of antioxidant activities is in accordance with the amounts of phenolics and flavonoids existing in all plant extracts. Regarding high performance liquid chromatography (HPLC) data, caffeic acid, ferulic acid, luteolin, apigenin and rutin were detected as major phenolic compounds in all the species investigated. Pretreatment of K562 cells with various concentrations of Tanacetum extracts (10–100 μg/ml) for 16 h prevent cell damage and enhanced activity of antioxidant enzymes induced by a treatment with H₂O₂. Moreover, lower level of glutathione caused by hydrogen peroxide in K562 cells were partly recovered by a pretreatment of cells with various Tanacetum species extract. These results may show the significant protection effect of Tanacetum sp. against oxidation of the cells.     

Fluctuations in the phenolic content and antioxidant capacity of dark fruit juices in refrigerated storage

The changes in total phenol content and antioxidant capacity were monitored in six industrial dark fruit juices during 29-day refrigerated storage. The initial total phenol values ranged from 1302.1 mg/L GAE (strawberry) to 1919.8 mg/L GAE (black currant) with a mean of 1573.3 mg/L GAE. All juices exhibited fluctuations in TP values with a marked increase after 48 hours in refrigerated storage, and a greater overall TP content in 5/6 studied juices after 29 days. Antioxidant capacity was evaluated using the DPPH radical scavenging assay and cyclic voltammetry (CV) and expressed as Trolox equivalent antioxidant capacity (TEAC). Black currant juice exhibited the highest TEAC values according to both CV (2.42 mM Trolox) and the DPPH assay (5.68 mM Trolox), while cranberry juice antioxidants exhibited the greatest storage stability and the smallest antioxidant capacity decrease on day 29, 20% (CV) and 15% (DPPH assay). At the end of 29-day storage 5/6 juices exhibited a significant loss in antiradical activity and all 6 juices exhibited a significant loss in TEAC derived from CV measurements. Significant linear correlation was observed between the results of CV measurements and the DPPH antiradical activity (r² = 0.62).