Selenium species in buckwheat cultivated with foliar addition of Se(VI) and various levels of UV-B radiation

Common (Fagopyrum esculentum Moench) and tartary (Fagopyrum tataricum Gaertn.) buckwheat was treated by spraying the leaves with a water solution containing 15 mg Se per litre in the form of sodium selenate in the flowering period. The selenium content in all parts of plant was found to be less than 200 ng g⁻¹ in non-treated and in the range 2700–4650 ng g⁻¹ in selenium treated buckwheat. Exposure to UV-B radiation lead to higher Se accumulation in flowers of both Se enriched cultivars. For speciation analysis enzymatic hydrolysis was carried out, separation and detection of selenium species was performed by high performance liquid chromatography–ultraviolet treatment–hydride generation atomic fluorescence spectrometry (HPLC–UV–HG-AFS). In flowers and leaves, on average 11% of the Se content was soluble and in the form of Se(VI), representing between 0.6% (flowers) and 3% (leaves) of the Se content. The remaining soluble non-amino acid organic Se was not detected by HPLC–UV–HG-AFS. In seeds 93% of the selenium content was found in the extracts and the main selenium species was SeMet with 93 ± 5% relative to the selenium content.     

Selenium biotransformation by Saccharomyces cerevisiae and Saccharomyces bayanus during white wine manufacture: Laboratory-scale experiments

The main purpose of this laboratory-scale study was to evaluate the transformation of inorganic selenium, as sodium selenite, when added to white grape juice as part of the fermentation process of white wine. The participation of yeast, added in the fermentation of the must, is necessary to convert inorganic selenium into organoseleno species. Two different yeasts, Saccharomyces cerevisiae and Saccharomyces bayanus were used for fermentation. The effects of different Se concentrations on cells and their viability during fermentation were evaluated. The alcoholic fermentation that produced wine was not affected by the presence of selenium, regardless of the type of Saccharomyces used. After 21 days of fermentation, the white wine and residual yeast were separated and analysed by ICP-MS and LC–ICP-MS for determination of total selenium and speciation. Selenomethionine was found to be the main Se-species in the selenised white wine. The results obtained are preliminary but they could be considered for future studies using both pilot and full-scale vinification processes.     

Qualitative and quantitative analysis of curcuminoids in herbal medicines derived from Curcuma species

A validated and sensitive HPLC–UV–MS method was developed for qualitative and quantitative analysis of curcuminoids in eight herbal medicines derived from four Curcuma species. The samples were separated on a YMC ODS-A C₁₈ column with a gradient elution of acetonitrile and 0.1% formic acid. Curcumin, demethoxycurcumin and bisdemethoxycurcumin showed good linearity (r > 0.9998) in the concentration ranges of 4.88–625, 4.29–550 and 3.98–510 μg/mL, respectively. The results suggested that the contents of three major curcuminoids in different herbal medicines varied significantly. Curcuminoids were only detected in Jianghuang, HuangsiYujin, and PengEzhu. Amongst them, Jianghuang contained the highest amounts of curcuminoids (40.36 mg/g), which were almost 20 times higher than HuangsiYujin (1.94 mg/g) and 400 times higher than PengEzhu (0.098 mg/g). Furthermore, amongst the Jianghuang samples collected from different areas, samples from Sichuan Province contained remarkably higher amounts of curcuminoids (22.21–40.36 mg/g) than other cultivation regions.     

Treating lamb’s lettuce with a cold plasma – Influence of atmospheric pressure Ar plasma immanent species on the phenolic profile of Valerianella locusta

The antimicrobial effectiveness of non-thermal plasma is scientifically accepted. Applications can be found in medicinal sterilisation processes. However, the effects of plasma treatments on plant food with regard to nutritional value are not yet sufficiently investigated. To study the interactions of plasma immanent reactive species with secondary plant metabolites, lamb’s lettuce (Valerianella locusta) was exposed to an atmospheric pressure plasma jet. Changes in the phenolic profile were compared to experiments with pure substances to determine the influence of the food matrix. Whereas pure flavonoids showed a strong time-dependent decrease, not originating from photo- or thermodesorption processes, the content of diosmetin in lamb’s lettuce significantly increased. Regarding phenolic acids, plasma exposure led to a strong reduction in lamb’s lettuce, while the concentration of pure monophenols changed little within the same period of time. Treatments with plasma-similar temperatures and UV radiation suggest that due to plasma-reactive species concomitant disintegration of cell membranes and oxidation of released cellular compounds are taking place. Time-dependent changes of the leaf surface morphology due to plasma-induced erosion have been observed by scanning electron microscopy.     

土壤和叶面施硒对烤烟硒积累的影响

通过盆栽试验,研究了不同来源硒对烤烟各器官硒含量和烟叶硒积累动态的影响。结果表明,不同施硒处理,烟叶硒积累速率均为单峰曲线,峰值在移栽后65 d左右,叶面喷硒处理峰值更高但下降也更迅速。烤烟各器官硒含量均随施硒量增加而增加。不同施硒方法对烟叶各叶位硒含量影响不同,土壤施硒处理不同叶位硒含量大小为上部叶>中部叶>下部叶,而叶面喷硒处理则为下部叶>中部叶>上部叶。     

Surface morphology and chemical composition of lamb’s lettuce (Valerianella locusta) after exposure to a low-pressure oxygen plasma

The influence of a low-pressure oxygen glow discharge plasma on secondary metabolites of lamb’s lettuce was examined. After extraction and hydrolysis the compounds were analysed by means of RP-HPLC. Whereas pure compounds showed a time-dependent degradation (flavonoids) or remained unchanged (phenolic acids), the exposure of lamb’s lettuce to the oxygen plasma led to a significant increase of protocatechuic acid, luteolin, and disometin after 120 s treatment time, independent of the applied plasma driving voltage. Contact angle (CA) measurements show an increased wettability of adaxial leaf surfaces after plasma exposure. A successive degradation of epicuticular waxes and cutin of the plant’s epidermis has been indicated by means of FTIR (ATR) and scanning electron microscopy (SEM). These findings suggest that reactive species in the plasma play a crucial role for the observed changes upon exposure to non-thermal plasma.     

Identification and antioxidative properties of transglycosylated puerarins synthesised by an archaeal maltogenic amylase

Puerarin is helpful for the prevention and treatment of various cardiovascular diseases. However, its insolubility often limits its uses. Transglycosylation reaction between 1% puerarin and 10% β-CD was catalysed by maltogenic amylase from archaeon Thermofilum pendens (TfMA) at 0.2 U/mg β-CD, 90 °C and pH 5.5, for 1 h in order to obtain puerarin glucosides of high water solubility. Seven puerarin derivatives with different number of additional α-glucosyl in the reaction solution were identified by HPLC–UV–MS analysis. Although less than puerarin, the transglycosylated puerarins still fully maintained their antioxidant activities, assessed by a radical scavenging test and a reducing power assay. Therefore, the transglycosylated puerarins exhibit a greater potential to be developed into new medicines and foods. This is the first report on the flavonoids glycosylation using the transglycosylation activity of archaeal maltogenic amylase.     

Phenolic compounds and antioxidant activity are differentially affected by drying processes in celery,coriander and parsley leaves

Convective drying (CO) is the most common technique for drying herbs, although it may diminish phenolic compounds content. Microwave drying (MW) has been suggested as an alternative, although its effects on phenolic compounds remain to be explored. The aim of this study is to compare the effects of different convective temperatures (40, 80 and 120 °C) and microwave powers (100, 500 and 1000 W) on drying time, polyphenols classes (HPLC-DAD) and antioxidant capacity in celery, coriander and parsley leaves. Microwave procedure reduced drying time (MW: 3 h–7 min; CO: 25–1.5 h) resulting more effective than CO. Increasing temperatures led to an initial decrease in total phenolic content (TPC) and antioxidant activity followed by an increase, potentially by the release of bound phenolic acids. Regarding MW, the highest polyphenol content was generally observed at 500 W, probably due to the hydroxycinnamic acid's rise. Antioxidant capacity was similar at 500 and 1000 W. There was a good agreement between TPC and antioxidant capacity. Consequently, MW seems a good alternative to reduce drying time. However, the maintenance or improvement of phenolic activity depends on the food matrix. Indeed, the best drying system and conditions to preserve phenolic compounds were variable depending on the herb type: celery (CO at 40 °C), coriander (both CO at 40 °C and MW at 500 W) and parsley (MW at 100 W).     

Determination of phenolic and other polar compounds in flaxseed oil using liquid chromatography coupled with time-of-flight mass spectrometry

A new method based on high-performance liquid chromatography coupled with electrospray ionisation time-of-flight-mass spectrometry (HPLC–ESI–TOF (MS)) has been used to analyse phenolic compounds in flaxseed oil. Some phenolic compounds such as secoisolariciresnol, ferulic acid and its methyl ester, coumaric acid methyl ester, diphyllin, pinoresinol, matairesinol, p-hydroxybenzoic acid, vanillin and vanillic acid have been detected from flaxseed oil. The quantification of these compounds in three varieties of flaxseed oils was carried out using their commercial standards. The efficiency, rapidity and high resolution of HPLC coupled to the sensitivity, selectivity, mass accuracy and true isotopic pattern from TOF (MS) have revealed an enormous separation potential allowing the determination of a broad series of phenolic and other polar compounds present in flaxseed oil for the first time.     

Phenolic composition of Merlot and Cabernet-Sauvignon grapes from Bordeaux vineyard for the 2009-vintage: Comparison to 2006, 2007 and 2008 vintages

Cabernet-Sauvignon and Merlot skin and seed extracts from Bordeaux grapes were investigated to determine both grape variety and vintage effect on phenolic composition. The total content of polyphenols and tannins in Merlot seeds was higher than that of Cabernet-Sauvignon allowing to discriminate the varieties. HPLC analyses underlined significant differences in the absolute concentration of proanthocyanidins amongst the two varieties and in their composition: mean degree of polymerisation (mDP) and percentage of galloylation of seed extracts were good indicators of grape variety. The vintage effect on the phenolic composition was confirmed for 2009 in comparison to previous vintages. Low values of mDP and concentrations of proanthocyanidins and anthocyanins were found in 2009 seeds and skins. The climatic conditions of 2009 (high rainfall before flowering followed by a strong hydric stress during berries development until ripening) let us hypothesise a lower activation of flavonoid pathway.     

Determination of vitamin K1 content in olive oil,chard and human plasma by RP-HPLC method with UV–Vis detection

The contents of phylloquinone (Vitamin K₁) were investigated in olive oil, chard and human plasma based on a reversed phase high performance liquid chromatographic method with acetonitrile/dichloromethane/methanol (60:20:20, v/v/v) as eluent in a C₁₈ μ-Bondapak column (10 μm, 300 × 3.9 mm) at 20 °C. Detection was by UV–Vis detector at 248 nm. In olive oil, the mean content of phylloquinone ranged from 12.7 to 18.9 μg/100 g, in chard ranged from 65.5 to 77.5 μg/100 g. In human plasma, phylloquinone content varied between 0.22 and 0.56 ng/ml.     

Selenium content in selected Slovenian foodstuffs and estimated daily intakes of selenium

Food is the primary source of selenium for man and, since selenium is an essential trace element, the nutritional selenium status is of importance. Data on this topic are currently lacking in Slovenia. In the present study, selenium contents of some selected foods purchased on the Slovenian market were determined and estimation of the daily dietary intake by analysing 20 diet samples collected in four Slovenian Army barracks was made. In determination of the selenium content in selected food, the highest values were found, as expected, in protein-rich food such as fish, meat and eggs (33–686 ng g⁻¹), but lower values in milk and dairy products (12–30 ng g⁻¹) and vegetables and fruits (0.3–77 ng g⁻¹). Analysis of 20 military total daily diet samples, gave an average selenium daily intake of 87 μg.     

氢化物发生-原子荧光光谱法测定富硒杂粮中的有机硒和无机硒

采用氢化物-原子荧光光谱法与无水乙醇提取相结合的方法测定了富硒杂粮中总硒、无机硒和有机硒的含量,并对仪器的试验参数进行优化。结果表明,富硒杂粮样品中硒主要以有机硒的形态存在,占硒总量的63.02%～95.10%,其中黄玉米有机硒含量最高,达到95.10%。该方法检出限为0.01 μg/L,总硒回收率为97.31%～103.53%,无机硒回收率96.10%～105.45%。本方法操作简单、灵敏度高、回收率好,适合富硒杂粮有机硒和无机硒的测定。     

Identification and kinetics of oxidized compounds from phosphatidylcholine molecular species

Heat-induced oxidative modifications of two phosphatidylcholine molecular species as potential functional food components were evaluated. 1-stearoyl-2-oleoyl-sn-glycero-3-phosphocholine (SOPC) and 1-stearoyl-2-linoleoyl-sn-glycero-3-phosphocholine (SLPC) were chosen as models. The optimal temperature for hydroperoxide formation was determined by MS for each standard: 125 °C for SLPC and 150 °C for SOPC. Oxidation was performed at these temperatures and degradation products were identified using LC–ESI-MS combined to an acid treatment. Kinetics of formation of oxidation products from SOPC and SLPC were monitored over 120 min and curves were drawn for each identified structure. Results showed that native phospholipids rapidly decreased with heat and that oxidation products showed functions, such as hydroxyl, oxo or epoxy groups. Kinetics pointed out that some of these quite stable oxidation products are likely to be found in sizable amounts in processed foods containing phospholipids.     

Buckwheat honeys: Screening of composition and properties

The quality of 10 buckwheat honeys, collected from Italian and est European beekeepers declaring to produce monofloral honey, were evaluated by means of their pollen, physicochemical, phenolic and volatile composition data. The results of the traditional analyses and in particular electrical conductivity, optical rotation, pH and sugar composition revealed some poorly pure samples that could not fit in the buckwheat tipology. Honey volatiles, analysed by solid phase microextraction (SPME) and gas chromatography–mass-spectrometry (GC/MS), showed more than 100 volatile compounds, most of them present in all honey samples but with quantitative variation. Besides many furfural derivates, 3-methylbutanoic acid was the main volatile compound found in most of honeys. Also the presence of 2- and 3-methylbutanal and pheynalcetaldehyde confirmed the typical buckwheat aroma of some studied samples, corroborating physicochemical data. The HPLC phenolic profile was similar across the samples and p-hydroxybenzoic and p-coumaric acids proved to be the main components.     

Comparative study of phenolic compounds in Cabernet Sauvignon wines made in traditional and Ganimede fermenters

Chemical profiles of anthocyanin and non-anthocyanin phenolics of Cabernet Sauvignon wine made by two different winemaking techniques (traditional vinification and Ganimede method) were determined by high performance liquid chromatography–mass spectrometry (HPLC–MS). Particularly, effect of extraction on and subsequent stability of the phenolic compounds from the end of fermentation to bottling were investigated. The results showed that the total anthocyanin content was higher in the young wines produced in the Ganimede fermenter. The anthocyanin contents in these wines subsequently decreased significantly after two years of ageing. By contrast, the traditional vinification was slightly better than the Ganimede to yield the non-anthocyanin phenolics. This indicates that the Ganimede fermenter might be suitable for the production of brightly coloured red wines for early consumption, which could save time and labour cost for industrial production of highquality wines.     

叶面施硒对猕猴桃含硒量、镉铅积累及品质的影响

以“贵长”猕猴桃为供试材料,通过叶面喷施、叶面喷施＋土壤穴施、土壤穴施方法喷施不同质量浓度的亚硒酸钠,测定分析猕猴桃果实中硒、镉、铅含量及果实品质。结果表明,适宜质量浓度的硒肥能促进猕猴桃果实硒含量的增加、减少猕猴桃对镉和铅的吸收、提高猕猴桃品质。且硒肥能增加猕猴桃含硒量0.002 9～0.050 5 mg/kg;降低6.98%～28.49%的镉和23.46%～51.03%的铅蓄积;较好地改善猕猴桃果实的风味与营养品质,促进果实生长;施硒的综合效果顺序为叶面喷施＋土壤穴施＞叶面喷施＞土壤穴施。在猕猴桃生产中,建议使用5.00～10.00 mg/L的亚硒酸钠溶液进行叶面喷施或结合土壤穴施的处理方式。     

黄精含硒多糖的分离提取及含硒量分析技术研究

本文以富含硒元素恩施药材—黄精为原料,对黄精含硒多糖的分离提取技术进行了初步研究。实验采用水浸提、乙醇醇析提取、sevage脱蛋白、沉淀、真空冷冻干燥等方法研究黄精含硒多糖的提取工艺,并用蒽酮比色法和原子吸收法对多糖含量、硒含量进行了测验。结果表明:黄精水溶性含硒多糖最佳提取参数为:温度90℃、提取时间4h、料液比1:50、提取次数为2次,水溶性多糖含量为3.12%,硒的含量为0.5973μg/g。     

Identification of hydroxycinnamic acid–tartaric acid esters in wine by HPLC–tandem mass spectrometry

In this work hydroxycinnamic acid esters of tartaric acid (mono-p-coumaroyl tartaric acid, monocaffeoyl tartaric acid, monoferuloyl tartaric acid esters) were separated, identified and quantified in several red wines by high performance liquid chromatography coupled with tandem mass spectrometry. The method features direct analysis of wines with no preparation and analysis of grape juice with minimum sample manipulation. For the identification was used both a triple quadrupole and a quadrupole–Tof, while for the quantification a triple quadrupole.     

Bioactive compounds and in vitro antioxidant activities of peel,flesh and seed powder of kiwi fruit

The aim of this work was to assess the bioactive compounds and antioxidant potential of powder obtained by the lyophilisation of the peel, flesh and seeds of kiwi fruit. Eight typical varieties of kiwi fruit in Shaanxi, China, were selected, and the pH value, content of Vc, total polyphenols, and flavonoids of different parts of the kiwi fruit were analysed. The content of phenols was determined by HPLC. The results revealed that phenolic compounds, such as protocatechuic acid, chlorogenic acid, caffeic acid, rutin, p‐hydroxybenzoic acid and quercetin, were rich in different parts of kiwi fruit and highest in the peel. The Vc content was highest in the flesh. The antioxidant activities show the same trend as the total polyphenol content. The kiwi fruit peel and seed can be used to reduce agro‐industrial waste and are promising ingredients for use in the enrichment of products providing dietary fibre, bioactive compounds and antioxidant action.