Determination of some individual phenolic compounds and antioxidant capacity of mead produced from different types of honey

The aim of this study was to promote mead (honey wine) production by testing the appropriateness of different honey varieties which were obtained from the flora of Turkey for the production of mead. Cotton‐Mezda (Gossypium spp.), pine (Pinus spp.) and flower honeys were used in the fermentation studies. Pure culture Saccharomyces cerevisiae yeasts were used in the mead studies. While determining the phenolic contents of meads via HPLC method, five phenolic acids and two flavonoids were used as standards with known antioxidant properties. In addition, total antioxidant activity was analysed in meads using trolox equivalent antioxidant capacity (TEAC). Among the phenolic acids, the most abundant one was protocatechuic acid (75.12–179.03 μg/L) and among flavonoids it was catechin (10.38–125.55 μg/L). It was found out that total phenolic content ranged from 103.56 GAE to 167.89 GAE mg/L. Copyright © 2017 The Institute of Brewing & Distilling     

Effect of Processing and Storage on Antioxidant Capacity of Honey

ABSTRACT: The impact of heat and filtration on the antioxidant capacity of clover and buckwheat honey during storage was analyzed. Processing clover honey did not significantly impact antioxidant capacity (determined by oxygen radical absorbance capacity [ORAC] assay); processing lowered the antioxidant capacity of buckwheat honey (33.4%). The antioxidant capacity of honeys was reduced after 6 mo of storage with no impact of storage temperature or container type detected at the end point of the storage period. Processed and raw clover honey antioxidant capacity decreased about 30%. Processed buckwheat honey decreased 24% in antioxidant capacity, whereas raw buckwheat honey decreased 49%. Antioxidant capacity of processed and raw honeys was similar after storage. Phenolic profiles, peroxide accumulation, 5-(hydroxymethyl)-2-furaldehyde (HMF), gluconic acid, and total phenolics were also analyzed. The impact of storage on antioxidant components of processed and raw honey was complex.     

Production and Antioxidative Activity of Mead Made From Honey and Black Rice (Oryza sativa var. Indica cv. Shiun)

In order to brew a red‐coloured alcoholic beverage having antioxidative activity, mead was made from honey and black rice grains. Alcoholic beverages made from honey and black rice grains contained around 10% (v/v) ethyl alcohol and a higher amount of phenolic compounds. Alcoholic beverages made from Chinese milk vetch honey and black rice grain contained anthocyanin and were red in colour similar to pink wine. The amount of total phenolic compounds present in the beverages made using Chinese milk vetch honey and buckwheat honey was 0.2 and 0.4 mg/mL, respectively. The DPPH radical scavenging activity of the mead made from the black rice grains was higher than that of beverages made from polished rice. The inhibitory activity of lipid peroxidation of the mead made from black rice grains was also higher.     

Impact of botanical source and processing conditions on physicochemical properties and antioxidant activity of honey in the northern part of Thailand

Phenolics, melissopalynological analysis, and selected physicochemical characteristics could differentiate floral honey origin. Botanical sources (longan, multifloral and Manuka) had more pronounced effect on honey properties than processing conditions. The conductivity was related to ash content and colour of honey. Total sugar, fructose and glucose content in all samples were not significantly different. Melissopalynological analysis was used to verify the botanical source of honey samples. Predominant pollen was identified. Results characterising antioxidant properties (DPPH radicals, hydroxyl radicals, and carbon-centred radicals scavenging activity) were confirmed via both Electron Spinning Resonance and oxygen radical absorbance capacity (ORAC). They showed that only hydroxyl radicals scavenging activity and ORAC were significantly different. Type and amount of phenolics in honey samples identified using HPLC could differentiate botanical source. Gallic acid and kaempferol were potential marker phenolics for longan honey. Multivariate statistical analysis allowed discrimination of honey from different botanical sources based on their phenolic profiles.     

Distribution of phenolic compounds in the graded flours milled from whole buckwheat grains and their antioxidant capacities

Whole buckwheat grains were milled into 16 flour fractions using the gradual milling system and the phenolic compounds and the antioxidant capacity of each flour fraction were investigated. The phenolic and flavonoid contents of both free and bound phenolic extracts of buckwheat flour fractions significantly increased in the order from the fraction number 1 (phenolics less rich fraction) to the fraction number 16 (phenolics rich fraction). The phenolic compounds in buckwheat existed primarily in free form, whereas the flavonoids existed in grain in insoluble bound forms, bound to cell wall materials. The amounts of ferulic acid and rutin increased from 2.5 and 2.5 μg/g flour of the phenolics less rich fraction to 609.5 and 389.9 μg/g flour of the phenolics rich fraction of grain, respectively. The higher phenolic contents in the phenolics rich fractions exhibited the stronger antioxidant capacity than the phenolics less rich fractions. As a result, the flour milled from the outer layers of buckwheat grains with large amount of phenolic compounds and antioxidant capacity are considered to have significant health benefits.     

Influence of pollen addition on mead elaboration: Physicochemical and sensory characteristics

Mead (honey-wine) results from the alcoholic fermentation of diluted honey using a wine yeast strain. However, mead elaboration can be hampered by several problems, including delayed or arrested fermentation, production of an unpleasant aroma, poor quality and inconsistency of the final product. These difficulties are due to honey’s low nutrient content, its natural antifungal components, and the inability of the yeast strain to adapt to these unfavourable growth conditions. In this study, we evaluated the results of adding pollen at concentrations ranging from 10 to 50 g/l as a fermentation activator to improve the fermentation kinetic and the quality of meads. The effect of pollen addition on the honey must, fermentation kinetics, physicochemical characteristics, aroma profiles and sensorial aspects of the obtained meads were evaluated. The results showed that pollen addition improved fermentation rates, alcohol yields, and the final characteristics of meads. An increase in the volatile contents of the meads and an improved sensory profile was observed with pollen addition; however, this improvement was not correlated with the concentration of pollen. The adequate dose of pollen was determined by the final characteristics and sensory profile of the meads.     

Improvement of mead fermentation by honey‐must supplementation

Through honey's fermentation, diverse beverages can be obtained, among which is mead, an alcoholic drink with 8 to 18% of ethanol (v/v). Since honey is a matrix with a low nutrient concentration and other unfavourable growth conditions, several problems are usually encountered, namely delayed or arrested fermentations, unsatisfactory quality parameters and lack of uniformity of the final product, as well as unpleasant sensory properties. In this context, the aim of this work was to optimize mead production through honey‐must supplementation with (a) salts, (b) vitamins or (c) salts + vitamins. The effects of the honey‐must formulation on the fermentation kinetics, growth profile and physicochemical characteristics of final meads were evaluated. The results showed minor differences in the fermentation profile and time between fermentations with the different formulations. The growth profile was influenced more by the yeast strain than by the supplements added to the honey‐must. In general, the honey‐must composition did not influence meads’ final characteristics, except regarding the SO₂ concentration of the meads produced using the strain QA23. In summary, the addition of salts and/or vitamins to honey‐must had no positive effects on the fermentation, growth profile or characteristics of the final products. Copyright © 2015 The Institute of Brewing & Distilling     

Antioxidant capacity and stilbene contents of wines produced in the Snake River Valley of Idaho

Forty-two wines produced from grapes grown in Idaho were examined in this study. The samples examined were from four monovarietal wines (12 Cabernet Sauvignon, 9 Merlot, 7 Riesling, 14 Chardonnay). Wine samples represented twelve wineries that obtain their fruit from vineyards located within Idaho’s Snake River Valley. Titratable acidity, pH, specific gravity, colour measurements (lightness, chroma, and hue), % haze, total anthocyanins, total phenolics, total tannins, antioxidant capacity, and individual stilbene measurements were performed. The antioxidant capacities (ORAC values) of Idaho wines ranged from 3.1 (Merlot wine) to 87.0 (Cabernet Sauvignon wine) μmol of Trolox/ml (mean = 38.5 μmol of Trolox/ml). Mean ORAC values of Merlot wines (mean = 27.6 μmol of Trolox/ml) were lower than the other three styles (mean for Cabernet Sauvignon wines = 41.0 μmol of Trolox/ml, mean for Chardonnay wines = 42.8 μmol of Trolox/ml, and mean for Riesling wines = 39.4 μmol of Trolox/ml). Free stilbene levels (four different stilbenes) were examined by direct-HPLC/DAD/ESI-MS/MS method. Piceid and resveratrol (both trans- and cis-) were found in the samples. Stilbene levels ranged from 0.97 (Riesling wine) to 12.88 (Cabernet Sauvignon wine) mg (expressed as trans-resveratrol)/l. This is the first paper to report the current chemical composition of Idaho wines.     

Influence of Different Extraction Media on Phenolic Contents and Antioxidant Capacity of Defatted Dabai (<Emphasis Type="Italic">Canarium odontophyllum</Emphasis>) Fruit

Dabai (Canarium odontophyllum) is a potential “functional fruit”. Future commercialization of dabai fat as healthy oil may result in the accumulation of defatted dabai as a by-product. This study was carried out to determine the total phenolics and antioxidant capacity of defatted dabai parts as a new source of functional food and nutraceutical ingredient. In this study, defatted dabai parts were extracted using different extraction media (methanol, ethanol, ethyl acetate, acetone, and water) and analyzed for total phenolics, total flavonoids, total anthocyanins, and antioxidant capacity (ABTS⁺ radical scavenging and ferric-reducing antioxidant power assays) using spectrophotometric and high-performance liquid chromatography methods. Major phenolics in defatted dabai peel extracted using methanol were catechin and epigallocatechin while in water extract, major phenolic acid was ellagic acid. Defatted dabai peel also had higher anthocyanidin content than its pulp. The peel of a defatted dabai fruit extracted using methanol contained a high total phenolics and Trolox equivalent antioxidant capacity (TEAC). Ethyl acetate extract of defatted dabai parts had the least phenolics compared in ethanol and acetone extracts. Higher total phenolics and TEAC values were observed in water extract of a defatted dabai peel than ethanol, acetone, and ethyl acetate extracts. Hence, methanol extract of a defatted dabai peel could probably be used as a natural antioxidant.     

荞麦蜜酚酸含量的高效液相色谱测定及其抗氧化作用的研究

以中国产荞麦蜜为原料,采用高效液相色谱-电化学检测法(HPLC-ECD)测定其中的原儿茶酸、没食子酸、咖啡酸、丁香酸、p-香豆酸、绿原酸、阿魏酸和鞣花酸等8种酚酸的含量。结果表明,中国荞麦蜜中含有原儿茶酸、没食子酸、咖啡酸、p-香豆酸、阿魏酸等五种酚酸,其含量分别为没食子酸为461μg/100g蜂蜜,p-香豆酸为150μg/100g蜂蜜,咖啡酸为79μg/100g蜂蜜,原儿茶酸为30μg/100g蜂蜜,阿魏酸为39μg/100g蜂蜜。本文还对荞麦蜜酚酸提取物的抗氧化作用进行了研究,结果显示荞麦蜜酚酸提取物对超氧阴离子自由基、羟基自由基、DPPH自由基和脂质过氧化均有抑制作用。     

Iron decreases the antioxidant capacity of red wine under conditions of in vitro digestion

The hypothesis that iron and phenolics interact in the lumen during digestion and, consequently, decrease the antioxidant capacity of phenolics, was investigated in vitro. Mixtures of red wine, iron, and three dietary factors that may reduce or chelate iron in the lumen, namely ascorbic acid, meat and casein, were subjected to a simulated gastrointestinal digestion. The process involved incubation of samples for 4.5 h at 37 °C, at different pHs, in the presence of peptic enzymes and fractionation of digests through a dialysis membrane. Antioxidant capacity (FRAP assay), iron concentration (ferrozine assay) and total phenolic content (Folin-Ciocalteau assay) were measured in the in vitro digests. Iron decreased the antioxidant capacity and the total phenolic concentration of red wine. Ascorbic acid increased, while meat and casein decreased, the antioxidant capacity of red wine. Based on these results, it was concluded that protein and iron interact with red wine phenolics during the in vitro digestion and decrease their antioxidant capacity, supporting the initial hypothesis.     

Mead production: effect of nitrogen supplementation on growth,fermentation profile and aroma formation by yeasts in mead fermentation

Mead is an alcoholic beverage, produced since ancient times, resulting from an alcoholic fermentation of diluted honey by yeasts. When it is produced in a traditional manner, mead producers can encounter several problems related to a lack of essential nutrients, such as available nitrogen. Thus, the aim of this study was to evaluate the effect of nitrogen addition to honey‐must on the fermentation performance of two Saccharomyces cerevisiae wine yeasts, QA23 and ICV D47, as well as on the mead composition and production of volatile aroma compounds. A portion of honey‐must was supplemented with diammonium phosphate (DAP) to achieve the nitrogen concentration required by yeast to complete alcoholic fermentation. The supplementation with DAP reduced the fermentation length to around 7 days, but not all sugars were fully consumed, suggesting that other factors could be interfering with yeast growth. For both yeasts the specific growth rate and final biomass were higher in musts supplemented with DAP. Mead final composition was similar under the two experimental conditions. Analysis of the volatile profile revealed that the concentrations of the volatile fatty acids and volatile phenols were higher in meads supplemented with DAP. The concentrations of ethyl hexanoate, ethyl octanoate and isoamyl acetate were above their perception threshold and were higher in meads supplemented with DAP, which could contribute to the enhancement of the fruity character. This study could be useful for the optimization of mead production and quality improvement. Copyright © 2015 The Institute of Brewing & Distilling     

苦荞红曲保健酒的抗氧化活性

为研究苦荞红曲保健酒的总黄酮和总酚的体外抗氧化活性,测定其对DPPH自由基、ABTS自由基的清除能力和铁离子还原/抗氧化能力（FRAP值）,并且与市售黄酒、VC、Trolox进行对比。结果表明,苦荞红曲保健酒有一定DPPH自由基清除率、ABTS自由基清除率和铁离子还原力。被测样品的抗氧化活性与总黄酮、总酚的含量有显著的相关性（P〈0.01）。     

Determination of the antioxidant capacity: influence of the sample concentration on the measured values

The aim of the present analysis was to study the influence of the sample concentration on the measured antioxidant capacity, since such investigations are scarce but necessary to ensure the reproducibility of the results. Pure substances (ascorbic acid, gallic acid, Trolox^®, uric acid) and food extracts (strawberry nectar, tomato extract, white tea) were analysed using seven common antioxidant capacity assays (three versions of Trolox equivalent antioxidant capacity, TEAC; ferric reducing antioxidant power, FRAP; photochemiluminescence, PCL; oxygen radical absorbance capacity, ORAC and total phenolics assay). For all applied pure substances and in most of the assays effects of the sample concentration on the measured antioxidant capacity were observed. Since it remains speculative how sample concentration does affect the measured antioxidant capacity exactly, it is strongly recommended to use at least three sample concentrations for analysis to detect and to discuss concentration-dependent effects.     

Effect of baking on dietary fibre and phenolics of muffins incorporated with apple skin powder

Apple fruit skin, a rich source of dietary fibre and phenolics, is a by-product of apple processing. The effect of baking on the dietary fibre, phenolics, and total antioxidant capacity was investigated using a model system of muffins incorporated with dried apple skin powder (ASP) as a value-added food ingredient. The blanched, dehydrated, and ground ASP contained approximately 41% total dietary fibre and oxygen radical absorption capacity (ORAC) of 52 mg Trolox equivalents g⁻¹ dry weight. The total dietary fibre content, total phenolic content, and total antioxidant capacity of muffins were positively correlated to the amount of ASP incorporated into muffins. The mean percent recovery of quercetin glycosides, catechins, chlorogenic acid, phloridzin, and cyanidin galactoside after baking were 61%, 57%, 53%, 44%, and 20%.     

Comparison of composition and antioxidant capacity of some cereals and pseudocereals

Polyphenols, phenolic acids, fibres and antioxidant capacity were determined in water, acetone and methanol extracts of buckwheat, rice, soybean, quinoa and 3 amaranth cultivars. Their antioxidant activities were comparatively assessed by total radical‐trapping antioxidative potential (TRAP), ferric ion‐reducing antioxidant power (FRAP), cupric‐reducing antioxidant capacity (CUPRAC) and nitric oxide (NO^?) assays, which comprised of contributions from polyphenols and phenolic acids (especially from the most abundant ferulic acid). The correlation coefficients between polyphenols and antioxidant activities of cereal and pseudocereal methanol extracts with FRAP, NO^?, CUPRAC and TRAP were 0.99, 0.97, 0.96 and 0.77, respectively. The weakest correlation was with dietary fibres, an average one exhibited with tannins and marked correlation was shown with the phenolics. All the applied methods have shown that pseudocereals have higher antioxidant activity than some cereals (rice and buckwheat) and can be successfully replaced by cereals in case of allergy.     

Effects of maturity stage and storage on cactus berry (Myrtillocactus geometrizans) phenolics,vitamin C,betalains and their antioxidant properties

The CIE-LAB coordinates, total phenols, betalains and vitamin C were determined in berry cactus fruit at different maturity stages, before and after storage. The contribution of those antioxidant compounds to the Trolox equivalent antioxidant capacity (TEAC) and oxygen radical absorbance capacity (ORAC) were assessed as well. The simple phenolics profile was determined by high performance liquid chromatography with diode array detection (HPLC-DAD). After storage, the fruit develops similar colour compared to ripe and overripe fresh fruit. Total phenols and vitamin C were reduced by up to 82.4% and 68.5%, respectively, as fruit matures and after storage. On the contrary, beta-cyanins increase up to 51.8% as fruit matures and after storage. Betalains contribute with 58.4% to TEAC and up to 43.4 to ORAC values. Gallic acid and quercetin were the major simple phenolics present. Due to the contents of antioxidant compounds and the outstanding antioxidant activities, cactus berries could contribute to health.     

Phenolic Compounds and Antioxidant Capacities of 10 Common Edible Flowers from China

The free and bound phenolic compounds in 10 common Chinese edible flowers were investigated using reversed phase high‐performance liquid chromatography. Their antioxidant capacities were evaluated using 2,2‐diphenyl‐1‐picrylhydrazyl (DPPH) radical‐scavenging activity, 2,2'‐azino‐bis(3‐ethylbenzothiazoline‐6‐sulphonic acid) (ABTS) radical‐scavenging activity, oxygen radical absorption capacity (ORAC), ferric reducing antioxidant power (FRAP), and cellular antioxidant activity (CAA). Free factions were more prominent in phenolic content and antioxidant capacity than bound fractions. Paeonia suffruticosa and Flos lonicerae showed the highest total phenolic content (TPC) 235.5 mg chlorogenic acid equivalents/g of dry weight and total flavonoid content 89.38 mg rutin equivalents/g of dry weight. The major phenolic compounds identified were gallic acid, chlorogenic acid, and rutin. P. suffruticosa had the highest antioxidant capacity in the DPPH, ABTS, and ORAC assays, which were 1028, 2065, 990 μmol Trolox equivalents/g of dry weight, respectively, whereas Rosa chinensis had the highest FRAP value (2645 μmol Fe²⁺ equivalents /g of dry weight). The P. suffruticosa soluble phenolics had the highest CAA, with the median effective dose (EC₅₀) 26.7 and 153 μmol quercetin equivalents/100 g of dry weight in the phosphate buffered saline (PBS) and no PBS wash protocol, respectively. TPC was strongly correlated with antioxidant capacity (R = 0.8443 to 0.9978, P < 0.01), which indicated that phenolics were the major contributors to the antioxidant activity of the selected edible flowers.