Antioxidant capacity, scavenger activity, and ellagitannins content from commercial oak pieces used in winemaking

In 2005, the European Union authorized the use of oak wood pieces in winemaking, and consequently, the addition of oak chips has been generalized. Thus, the antioxidant capacity, scavenger activity, and ellagitannins content from fourteen different commercial oak wood pieces (Quercus spp.) that can be found on the Portuguese market as alternatives to barrels for aging wines were studied. Commercial oak wood pieces samples from Quercus petraea had significantly higher antioxidant activity values than the pieces from Quercus alba species. In general, antioxidant capacity and scavenging activity decrease with the toasting level of the oak wood pieces samples analyzed. A similar effect was detected in the individual ellagitannin content studied. On the other hand, with the toasting process, the total phenolic content and the ellagic acid concentration increased. Finally, a correlation analysis revealed that ellagitannins contribute to the antioxidant capacity of oak wood pieces studied. From the data presented in this paper, antioxidant capacity and ellagitannin content of the oak wood pieces studied have been clearly related either to the oak wood species used, particle size, or to toasting levels.     

Phenolic compounds in Imburana (<Emphasis Type="Italic">Amburana cearensis)</Emphasis> powder extracts

In response to the increasing demand for aged distilled spirits, wood extracts have been investigated as accelerating agents in distilled spirits. The aim of this work was to obtain and to evaluate the potential use of Amburana cearensis powder extracts as an accelerating aging agent in sugar cane distilled spirits. Wood powder was submitted to different toasting treatments using conventional drying oven and microwave oven. Instead of using the traditional reflux extraction method, the phenolic compounds were extracted by means of ultrasonic treatment using a 50% ethanolic solution with pH adjusted to 4.5. The concentration of gallic acid, 5-hydroxymethylfurfural, furfural, vanillic acid, syringic acid, vanillin, coniferaldehyde, sinapaldehyde and coumarin, determined by high performance liquid chromatography (HPLC) were used as quality parameters of powder toasting treatment and ethanolic extraction. The use of toasted wood powder combined with ultrasonic extraction showed higher yields when compared to the traditional solvent extraction method when obtaining wood extracts. The extraction method presented in this work is also less time consuming.     

Presence of polycyclic aromatic hydrocarbons in woody chips used as adjuvant in wines, vinegars and distillates

Samples of 15 commercially available batches of wood chips, used in alcoholic beverage industry, were extracted and analyzed for their content in polycyclic aromatic hydrocarbons (PAHs). Total amounts of PAHs varying between 0.96 and 15.1 ng/g of wood were found, with medium to low MW compounds being mainly present. Carcinogenic benzo[a]pyrene was found in such a value, however, not alarming if maximum mandatory levels in food are considered.PAHs content in chips was unaffected by wood origin, size or toasting level while further investigations dealing with phenomena occurring during the wood seasoning could be necessary.     

Monosaccharide anhydrides,new markers of toasted oak wood used for ageing wines and distillates

In order to shed light on the thermal carbohydrate transformation chemistry, the non-volatile composition of natural and toasted oak wood samples of different origins were studied. GC–MS analysis revealed the presence of monosaccharide anhydrides (MAs) only in toasted oak wood samples. They were formed by the cellulose and hemicelluloses thermal degradation produced during the toasting process, and the content was dependent on the degree of toasting. The principal MAs formed in the oak wood toasting process were 1,6-anhydro-β-d-glucopyranose (levoglucosan), 1,6-anhydro-β-d-galactosane (galactosan) and 1,6-anhydro-β-d-mannopyranose (mannosan), with levoglucosan being the dominant MAs detected. Monosaccharide anhydrides can be considered specific products formed during the thermal treatment of wood; therefore they are proposed as markers of toasted wood and could be used to monitor and determine the intensity of toasting process.     

山西老陈醋生产过程中挥发性提取物的抗氧化活性分析

本文研究了山西陈醋在酒精发酵,醋酸发酵和熏醅开始和结束时的挥发性成分,并采用DPPH自由基清除率法,醛/酸法(ACA法)和HepG2细胞氧化损伤模型来评价其抗氧化活性。DPPH法结果表明,陈醋挥发性提取物具有清除DPPH自由基能力,并且呈明显的剂量依存关系。醋酸发酵开始时的提取物达到最高的清除率(93.02%),其次为熏醅结束时(86.52%)。ACA法结果表明,挥发性提取物具有抑制己醛氧化的能力。熏醅结束时提取物抑制己醛氧化的能力最强,其次为醋酸发酵开始和结束时的提取物。除熏醅开始样品外,其他老陈醋挥发性提取物对HepG2细胞氧化损伤无保护作用,甚至成为促氧化物。结果表明,山西老陈醋挥发性提取物有较强的体外抗氧化活性,但是对HepG2细胞氧化损伤的保护作用微弱。     

Determination of polycyclic aromatic hydrocarbons in alcoholic drinks and the identification of their potential sources.

Some polycyclic aromatic hydrocarbons (PAHs), particularly those with a high molecular mass, have been classified as probably being carcinogenic to humans by the International Agency for Research on Cancer (IARC). The significance of the determination of PAHs is reflected by the special attention the European Union is paying to regulating their maximum allowed levels in various types of foodstuffs. Like tobacco and smoked meats, alcoholic drinks can also contain these carcinogenic chemicals, as the latter have been detected in the charred insides of barrels, some ingredients such as caramel or the smoke released during the drying of germinated barley in beer or whisky. This paper determined the contents of seven PAHs in alcoholic beverages of variable alcoholic strength that had been aged in charred barrels for different times (months, years). The aim was to elucidate the dependence of the formation of seven PAHs on the type of charring (traditional or convective) used and the charring intensity (light, medium or heavy). Based on the results, the way the tree raw material is toasted strongly influences PAH levels in alcoholic drinks; thus, traditional charring produces increased amounts of PAHs from the wood relative to convective toasting. The sum of the analysed PAH concentrations in the aged alcoholic beverages studied ranged from zero for a white wine to 172 ng l(-1) for a 'brandy de jerez solera'. The carcinogenic indicator benzo[a]pyrene was found at concentrations below 10 ng l(-1). These PAH concentrations in alcoholic beverages are very low relative to those in smoked and char-broiled foodstuffs. Any health hazards, however, can be minimized by using convective toasting to manufacture the barrels where the drinks are to be aged.     

Development of Active Films From Pectin and Fruit Extracts: Light Protection,Antioxidant Capacity,and Compounds Stability

Pectin films containing fruit extracts were developed and tested in relation to ultraviolet light transmission, phytochemical contents, and antioxidant capacity during 90 d shelf life storage. Aqueous and alcoholic extracts from 5 different fruits (acerola, cashew apple, papaya, pequi, and strawberry) were obtained. Because the alcoholic extracts from acerola, cashew apple, and strawberry presented the highest phytochemical content and antioxidant capacity, they were incorporated into pectin films individually or as a mixture. Incorporation of these extracts into pectin films provided antioxidant capacity while retaining the physical properties. The pectin films containing fruit extract acted as adequate light barrier and prevented photooxidation. Among the prepared films, the pectin film containing acerola extract afforded the highest antioxidant capacity, with a half‐life of 99 d. Overall, the results revealed that incorporation of fruit extracts into pectin films potentially produces antioxidant films and coatings for different food applications.     

Aging marker profile in cachaça is influenced by toasted oak chips

Cachaça is the most important distilled spirit in Brazil and the fourth most consumed in the world. Aging is not mandatory for cachaça. When aging is carried out, casks generally do not undergo the final wood toasting. However the level of thermal degradation of wood influences the formation of new chemical compounds, which are released during the aging process and improve the quality of the spirit. The objective of this study was to verify the influence of origin of wood and toasting intensity of oak chips on the profile of aging markers in cachaça. Staves of oak wood from the forests of Allier, Vosges and Nièvre (France) were milled and screened at 9 mesh. The chips underwent light, medium and heavy toasting. The toasted chips were added to cachaça (1 g/L) and kept in a closed system at room temperature, without agitation, for 15 days. The aging congeners (gallic acid, 5‐hydroxymethylfurfural, furfural, vanillin, vanillic acid, syringaldehyde, sinapaldehyde, syringic acid and coniferaldehyde) were analysed using HPLC. The increase in toasting intensity enhanced the content of the aging markers in cachaça, especially syringic acid, vanillin, syringaldehyde, coniferaldehyde and sinapaldehyde. The generation of aging marker compounds was influenced only by the toasting intensity and not by the origin of the oak wood. Copyright © 2015 The Institute of Brewing & Distilling     

Antioxidant potential and content of phenolic compounds in extracts of twelve selected Malaysian commercial wood species

This study was performed to investigate the antioxidant values of twelve selected Malaysian wood species. Bark and heartwood were extracted with toluene: industrial methylated spirit (Tol: IMS) and evaluated for antioxidant activity. Folin–Ciocalteu reagent was used to determine the total antioxidant activity and total phenols of plant extracts. Free radical scavenging activity was evaluated using 2,2-dipheny-2-picrylhydrazyl (DPPH). Extractive yields, antioxidant activity and total phenolic content varied among wood species. N. heimii had the highest extractive yields (23.50 and 9.16 %), antioxidant (93.60 and 83.78 %) and total phenolic content (29.11 and 24.11 mgGAE/g) for bark and heartwood, respectively. The results provided promising evidence that those tropical timbers may be useful as potential sources of natural antioxidants and could be used as drug formulations.     

Changes in contents of phenolic compounds during maturing of barrique red wines

Concentrations of derivatives of benzoic and cinnamic acids and furaldehyde were studied during maturing of a red wine (a mixture of Cabernet Sauvignon and Merlot) in barrique barrels (Quercus robur). Samples were taken at three-week intervals over 6 months. The influence of degree of toasting of the wood on the amount of phenolic compounds in barrique wine was also investigated. The samples were pre-separated using a solid-phase extraction on an RP 105 polymeric sorbent and analysed by high-performance liquid chromatography with UV-DAD detection. Gallic, protocatechuic, p-hydroxybenzoic, vanillic, caffeic, syringic, p-coumaric, ferulic, benzoic and ellagic acids and p-hydroxybenzaldehyde, vanillin, 2-furaldehyde, 5-methoxy-2-furaldehyde and 5-methyl-2-furaldehyde were identified in the extracts of natural and toasted wood chips and in the extracts of the wine. Syringaldehyde was identified only in the extracts of the toasted wood chips. Ellagic acid can be regarded as a characteristic compound of barrique wine ageing and its constant level during some periods could become a marker of maturity of barrique wines. Due to the absence of furaldehydes in natural wines, these compounds can be considered as typical components of barrique wines and so they can serve as a marker of authenticity of barrique wines.     

A study of the antioxidant capacity of oak wood used in wine ageing and the correlation with polyphenol composition

The antioxidant capacity of oak wood used in the ageing of wine was studied by four different methods: measurement of scavenging capacity against a given radical (ABTS, DPPH), oxygen radical absorbance capacity (ORAC) and the ferric reducing antioxidant power (FRAP). Although the four methods tested gave comparable results for the antioxidant capacity measured in oak wood extracts, the ORAC method gave results with some differences compared to the other methods. Non-toasted oak wood samples displayed more antioxidant power than toasted ones due to differences in the polyphenol composition. A correlation analysis revealed that ellagitannins were the compounds mainly responsible for the antioxidant capacity of oak wood. Some phenolic acids, mainly gallic acid, also showed a significant correlation with antioxidant capacity.     

The use of near infrared reflectance spectroscopy to identify the origin of oak shavings used in wine aging

Near infrared (NIR) reflectance spectroscopy combined with chemometrics was used to classify toasted and untoasted oak wood shavings sourced from two countries (France and USA). Oak wood shaving samples (n = 96) were scanned in the NIR region (680–2,500 nm) using a monochromator instrument operating in reflectance mode. Principal component analysis, partial least squares discriminant analysis (PLS-DA) and linear discriminant analysis (LDA) were used to classify the samples according to their country of origin and level of toasting. Full cross validation (leave-one-out) was used as the validation method when classification models were developed. Correct classification rates of 83, 87 and 100 % for samples sourced from USA, France and toasted treatment were obtained using PLS-DA. For LDA, correct classification rates of 80.4, 85 and 100 % were achieved for samples sourced from USA, France and toasted treatment, respectively. These results demonstrated the ability of NIR spectroscopy to discriminate between oak wood shavings sourced from two different countries and two levels of toasting.     

Effects of toasting on the carbohydrate profile and antioxidant properties of chickpea (Cicer arietinum L.) flour added to durum wheat pasta

The effects of the toasting process on the carbohydrate profile and antioxidant properties of chickpea flour were studied, along with the cooking behaviour, and antioxidant and nutritional properties of pasta enriched with the chickpea flour. The toasting process increased the resistant starch, insoluble dietary fibre and antioxidant properties of the flour. Addition of chickpea flour (raw and toasted) to durum wheat semolina changed the carbohydrate profile in the uncooked and cooked enriched pasta, especially with the toasted chickpea, and worsened the overall quality of the pasta. The increase in total phenolic content and total free phenolic acid content in the uncooked pasta was due to positive effects of addition of the chickpea flours, while the increase in the bound phenolics fraction in the cooked pasta was from the durum wheat, which was crucial for its high concentrations of ferulic acid. The increase in the free fraction of the Trolox equivalent antioxidant capacity in cooked pasta was consistent with the addition of chickpea.     

Antioxidant and antifungal activities of extracts from 15 selected hardwood species of Malaysian timber

The antioxidant activities, total phenols and antifungal activities of 35 extracts samples from 15 species of Malaysian timber were investigated. The methanol extracts from Mangifera indica heartwood were found to have superior antioxidant activity with an EC₅₀ value of 4.71±0.89 μg/ml. Antioxidant activities correlated with total phenols contents. The methanol extracts from Neobalanocarpus heimii bark and Cinnamomum porrectum heartwood showed moderate antifungal activity against a brown-rot fungus, Gloeophyllum trabeum. The methanol extracts from Neobalanocarpus heimii bark and Endospermum malaccense inner wood showed the highest antifungal activity against a white-rot fungus, Pycnoporus sanguineus, at a minimum effective amount of 100 μg. The activities of these extracts were equal to the activity of the positive control, glycyrrhizic acid dipotassium salt, suggesting that they have great potential as a source of fungistats.     

Antioxidant activities and related polyphenolic constituents of the methanol extract fractions from Broussonetia papyrifera stem bark and wood

Broussonetia papyrifera radix, fruits, leaves, and stems exhibit antioxidant, antinociceptive, antityrosinase, anti-inflammatory, and antiplatelet activities. However, study of the antioxidant activity of stem bark has been limited. In this work the antioxidant activity of stem bark and wood extracts were compared using different methods, and their phenolic constituents were analyzed. The bark ethyl acetate fraction exhibited the highest 2,2-diphenyl-2-picrylhydrazyl hydrate (DPPH) radical, hydroxyl radical scavenging activity, and the highest total phenolic and flavonoid contents. Both bark and wood n-butanol fractions showed stronger superoxide anion radical scavenging activity and reducing potential than other fractions. The bark and wood hexane fraction provided the highest level of ion chelating power. The high performance liquid chromatography (HPLC) analysis reveals there are more phenolic compounds in bark than in wood. These findings suggest that bark exhibits a higher antioxidant capacity than wood and that ethyl acetate and n-butanol fractions of B. papyrifera bark are potential natural resources for pharmacology of functional foods.     

Effects of toasting procedures on the levels of polycyclic aromatic hydrocarbons in toasted bread

Some polycyclic aromatic hydrocarbons (PAHs), particularly those with a high molecular weight, have been classified as probably carcinogens to humans by the International Agency for Research on Cancer (IARC). The significance of the determination of PAHs is reflected by the special attention of the European Union, which is paying to regulate the maximum allowed levels of PAHs in foodstuffs such as smoked foods. Like other thermally processed foodstuffs, toasted bread can contain these carcinogenic chemicals, not only due to a contamination at source but also during toasting. In order to check PAHs generated from toasting in sandwich bread, several treatment conditions were evaluated: direct toasting (flame-toasting, coal-grilling or gas oven-toasting) or indirect toasting (electric oven-toasting). PAHs were extracted by solid–liquid extraction (SLE) and determined by liquid chromatography with fluorescence detection (LC-FD). Based on the results, the used toasted technique would strongly affect in PAH levels in the final product. No samples obtained by electric oven and toaster were polluted; otherwise the samples toasted by charcoal and flame grilling presented very important levels. Up to 350 μg/kg of total PAHs were detected in toasted samples by wood flame. Differences between different ways of toasting could be ascribed to deposition of PAHs from smoke. Finally, several commercial toasted samples of bread were tested to determine PAHs. Overall, the PAH levels were very low. Benzo[a]pyrene ranged from no detectable to 0.23 μg/kg.     

Use of species other than oak to flavor wine: an exploratory survey

The concept of geographical exclusivity prompted an exploratory survey with toasted woods other than oak to flavor wine. A total of 11 woods and oak (Quercus alba) were cut into chips 20 × 10 × 2.5 mm and toasted at 200 °C for 2 h (light toast) or 210 °C for 3 h (dark). Weight losses and changes in CIE color space were monitored. The toasted chips were infused in unoaked chardonnay (5 g L(-1)) for 2 wk. Parallel infusions were done with model wine (water, ethanol, tartaric acid) adjusted to pH 3.5. Ultraviolet absorbances due to infusion were recorded on the basis that that lignin compounds and their potential pyrolysates are based on phenolic structures that absorb in the ultraviolet range. Weight losses on light and dark toasting were highly variable between species as were color changes, suggesting potential for different flavor outcomes from chemical changes. Ultraviolet absorbance curves were also highly variable showing that different species yielded different quantities of potentially flavor-active phenolic compounds in real and model wine. More absorbing matter was extracted from the light toast treatments, and light toast oak, which demonstrated the greatest weight loss on light toasting, yielded the widest range of ultraviolet-absorbing matter. In an informal sensory trial with the 24 species/toast combinations infused in chardonnay all but one wood, Cupressus macrocarpa, resulted in flavors reminiscent of oaked wines. A hedonic consumer trial with 4 species and oak compared with uninfused chardonnay showed that each of the 4 had potential as a flavorant. Thus, woods unsuited to barrel construction could provide unrealized flavor opportunities in the wine industry, and could extend to flavoring spirits.     

Reevaluation of antimicrobial and antioxidant activity of Thymus spp. extracts before and after encapsulation in liposomes

The antioxidant and antimicrobial activity of four Thymus species (boissieri, longicaulis, leucospermus, and ocheus) extracts were determined. Two methods (Rancimat and malondialdehyde by high-performance liquid chromatography) were used to measure the antioxidant action in comparison with common commercial antioxidants, including butylated hydroxytoluene and alpha-tocopherol. The extracts that presented high antioxidant activity were encapsulated in liposomes and their antioxidant action was again estimated. Thermal-oxidative decomposition of the samples (pure liposomes and encapsulating extracts) was studied using the differential scanning calorimetry method. The modification of the main transition temperature for the lipid mixture and the splitting of the calorimetric peak in the presence of the antioxidants were also demonstrated by differential scanning calorimetry. All extracts showed antioxidant and antimicrobial activities. Some extracts showed superior or equal antioxidant activity to alpha-tocopherol. When the extracts were encapsulated in liposomes, their antioxidant as well as antimicrobial activities proved to be superior from the same extracts in pure form.