Influence of Solvent Polarity and Conditions on Extraction of Antioxidant,Flavonoids and Phenolic Content from A verrhoa bilimbi

This paper presents the influence of solvent polarity and extraction conditions on the extraction of total flavonoid, total phenolic and antioxidants from Averrhoa bilimbi. The experiment was performed using a different solvent at different extraction conditions, including extraction time （15-240 min）, temperature （30-70 ℃） and agitation speed （50-300 rpm）. Results showed that yields of extraction varies with solvent polarity. Extraction using 50% aqueous methanol gives the highest antioxidant activity and flavonoid content. The highest total flavonoid content （193.3 μg quercetin equivalent/g dry weight）, total phenolic content （717.8 μg gallic acid equivalent/g dry weight） and antioxidant activity （77%） was achieved using 50% methanol, at 70 ℃ and agitation speed of 300 rpm. This work may be useful for obtaining higher bioactive compounds during the extraction process of A. bilimbi.     

Chemical and Sensory Properties of Sauerkraut Produced with Leuconostoc mesenteroides Starter Cultures of Differing Malolactic Phenotypes

ABSTRACT: Research was conducted to determine whether Leuconostoc mesenteroides starter cultures with and without malolactic activity (MDC⁺ and MDC^-, respectively) influenced sensory and chemical properties of sauerkraut. No sensory differences were found between MDC⁺ and MDC− sauerkraut ( P ≥ 0.05). In addition, sulfur compound profiles of the resulting sauerkraut were nearly identical. Brining at lower NaCl (0.5%) with either inoculum changed both the microbiology and chemistry of the fermenting sauerkraut, leading to decreased sauerkraut sulfur flavor. Quantification of allyl isothiocyanate (AITC), dimethyl disulfide, dimethyl trisulfide (DMTS), methyl methanethiosulfinate, and methyl methanethiosulfonate (MMTSO₂) by gas chromatography-mass spectrometry showed that sauerkraut sulfur flavor correlated linearly with DMTS and MMTSO₂ ( P ≤ 0.01).     

Utilization of Yellowfin Tuna and Red Snapper Roe Protein Concentrate as Emulsifier in Mayonnaise

Roes of yellowfin tuna （Thunnus albacares） and red snapper （Lutjanus champecanus） are considered as abundant and underutilized by-product in Indonesia. The production of roe protein concentrate （RPC） is expected to increase the economic value and potency of their usage. Tuna and red snapper RPC was defatted using etano195% with one, two, three and four times of repetition. Both RPC made with four times repetition of defatting had the highest protein content （79.90% and 80.72%）, showed high emulsion activity （97.46% and 99.62%） and emulsion stability （97.10% and 99.48%）, and decreased the interfacial tension of 51% and 55.9%, respectively. Mayonnaise was made with 0, 25, 50, 75 and 100% substitution level of each RPC with four times repetition ofdefatting. The physical, chemical and organoleptic properties of mayonnaise were studied. The best mayonnaise formulation was obtained from 50% substitution level of tuna and red snapper RPC. Mayonnaise with tuna and red snapper RPC had good viscosity （5,920 cPs and 5,845 cPs）, high emulsion stability （90.5% and 91.73%） and small fat globule size （±2.5 lam and ± 2.25 lam）, respectively. These mayonnaises also showed high score of spreadability and low intense of fishy odor. However they still had quite strong of fishy flavor based on scoring test.     

Micro-oxygenation and oak chip treatments of red wines: Effects on colour-related phenolics,volatile composition and sensory characteristics. Part I: Petit Verdot wines

In this paper, the effects of micro-oxygenation before malolactic fermentation and oak chip treatments on Petit Verdot red wines have been evaluated. Our attention was focused on the colour characteristics, the phenolic compounds related to the colour of red wine, the volatile compounds, and the sensory characteristics of the wines. The micro-oxygenation treatment promoted the stabilisation of red wine colour by increasing the formation of colour-related phenolic compounds (higher concentrations of pyranoanthocyanins and anthocyanin-ethyl-flavan-3-ol adducts). Red wine aroma quality was improved with the addition of oak chips (eugenol and 4-vinyl-guaiacol concentration increased). Micro-oxygenation treatment resulted in higher scores for the plum/currant and spicy attributes, as well as the appearance of tobacco and nutty notes which were absent in the non-treated wines. Nevertheless, the typical oak chip aromas (vanilla and woody) were observed to a lesser extent in wines obtained by micro-oxygenation.     

Is buttery aroma perception in wines predictable from the diacetyl concentration?

An important flavour compound associated with malolactic fermentation (MLF) is the volatile di-ketone, diacetyl (2,3-butanedione), which is considered as the major contributor to buttery flavour in wines. Commercial Chardonnay, Cabernet Sauvignon, Merlot and Shiraz wines from eight vintages (1992–1999), 20 viticultural regions and 28 wine producers were analysed for diacetyl and also the buttery aroma intensity was rated by a trained sensory panel. The wines examined were found to have a wide range of diacetyl concentration, i.e. 0.3 to 0.6 mg/L (mean value 0.4 mg/L) for the 24 Chardonnay wines, and 0.3 to 2.5 mg/L (mean value 1.1 mg/L) for the 43 red wines. The buttery aroma, while significantly correlated with diacetyl concentration in the Chardonnay wines ( P < 0.01), was not predicted very well by the regression equation, but the prediction was improved when the free sulfur dioxide concentration of the wines was taken into account (adjusted R²= 0.43, P < 0.01). There was a weak, although statistically significant, correlation between diacetyl concentration and the buttery rating for the red wine data set, when the sulfur dioxide concentration was taken into account (adjusted R²= 0.12, P < 0.05). This weak correlation may have been, in part, due to the generally low concentration of diacetyl in relation to the published aroma threshold in red wine. It was also noted that there was a substantial decrease in diacetyl concentration for a subset of red wines, but not for white wines, of various vintages cellared for three years at 15C.     

Colour stabilization of red wines by microoxygenation treatment before malolactic fermentation

Microoxygenation allows the addition of small, continuous and controlled amounts of oxygen, in order to improve wine quality. Then, the effect of this treatment on colour stabilization and phenolic composition was studied. Four single varietal red wines were elaborated during three consecutive vintages. One part of them was microoxygenated before malolactic fermentation, the other part being maintained in stainless steel tanks without microoxygenation.     

Determination of phenolic compounds in wines: Influence of bottle storage of young red wines on their evolution

Various analytical methods based on the HPLC-DAD technique were used to determine 38 phenolic compounds in red wines. While anthocyanins and hydroxycinnamic acids were determined by direct injection of wine samples, hydroxybenzoic acids, catechins, procyanidins and flavonols required an analytical pretreatment involving liquid–liquid partitioning with ethyl ether followed by solid-phase extraction on C₁₈ mini-columns. The proposed analytical methods were used to establish the phenol composition of Mencía and Brancellao, two varietal young red wines, and its influence on colour stability during storage in bottles for one year. At the end of malolactic fermentation, Mencía wine was found to contain much greater amounts of anthocyan pigments than was Brancellao wine. This resulted in a higher colour density but a weaker hue in Mencía wine than in Brancellao wine. Phenolic compounds evolved similarly in both wines during storage; changes in such compounds involved a decrease in the levels of monomeric anthocyanins, phenolic acids, epicatechin and flavonols, and an increase in those of procyanidins. The absence of a relationship between the changes in colour density and monomeric anthocyanins in both wines suggests that copigmentation and polymerization with other phenolic compounds (viz. phenolic acids, catechins and/or flavonols) prevail over degradation of the pigments.     

Formation of biogenic amines throughout the industrial manufacture of red wine

Changes in biogenic amines (histamine, methylamine, ethylamine, tyramine, phenylethylamine, putrescine, and cadaverine) were monitored during the industrial manufacture of 55 batches of red wine. The origin of these amines in relation to must, alcoholic fermentation, malolactic fermentation, sulfur dioxide addition, and wine aging and the interactions between amines and their corresponding amino acids and pH were statistically evaluated in samples from the same batches throughout the elaboration process. Some amines can be produced in the grape or the musts (e.g., putrescine, cadaverine, and phenylethylamine) or can be formed by yeast during alcoholic fermentation (e.g., ethylamine and phenylethylamine), although quantitatively only very low concentrations are reached in these stages (less than 3 mg/liter). Malolactic fermentation was the main mechanism of biogenic amine formation, especially of histamine, tyramine, and putrescine. During this stage, the increase in these amines was accompanied by a significant decline in their amino acid precursors. Significant correlations between biogenic amine formation and the disappearance of their corresponding amino acids were observed, which clearly supports the hypothesis that malolactic bacteria are responsible for accumulation of these amines in wines. No increase in the concentration of biogenic amines was observed after SO2 addition and during wine aging, indicating that sulfur dioxide prevents amine formation in subsequent stages.     

蔬菜抗氧化能力及与酚酸和总黄酮相关性研究

分析常见蔬菜总抗氧化活性,探讨蔬菜抗氧化能力与酚酸、总黄酮的相关性。采用ABTS、DPPH与FRAP法测定10种常见蔬菜的抗氧化能力,采用Folin-Ciocalteu法测总酚酸,硝酸铝-亚硝酸钠-氢氧化钠法测总黄酮,采用matlab软件进行拟合抗氧化与酚酸、总黄酮的函数方程。结果表明:抗氧化活性与主要抗氧化物质(酚酸和黄酮)的函数关系为Z=-137.743 2-0.918 2 X2+0.211 2Y2-0.422 9 XY+52.843 5 X+2.229 9Y。当总黄酮在6～26mg/100g时,总黄酮、酚酸的量对总抗氧化活性有促进作用;而在27～54mg/100g范围内,总黄酮和酚酸的含量对总抗氧化能力具有一定的抑制作用。     

The chemical and sensorial effects of lysozyme addition to red and white wines over six months' cellar storage

Lysozyme is an enzyme with muramidase activity which can lyse Gram-positive bacteria, including wine lactic acid bacteria. This enzyme provides a practical method for delaying or preventing the growth of Oenococcus oeni and consequently the onset of malolactic fermentation during the vinification of red and white wines. This paper reports the impact of lysozyme on the chemical and sensorial properties of commercially vinified red (Cabernet Sauvignon and Shiraz) and white (Riesling) wines. The addition of lysozyme to these wines had little or no effect on the content of alcohol, free and total sulfur dioxide and titratable acidity, and pH value. The lysozyme retained 75–80% activity in the Riesling wine after six months, however no detectable activity remained in the Cabernet Sauvignon and Shiraz wines after two days. Upon addition of lysozyme to both of the red wines, a rapid initial decrease (up to 17%) in red wine colour density and phenolic content occurred in association with the formation of a light precipitate. The reduction in red wine colour was also noted by the sensory panel. When added to the Riesling wine, lysozyme did not cause an increase in browning over the six month storage time, but did induce heat instability (haze), suggesting that white wines may require protein stabilisation following treatment with lysozyme. Sensory assessment by triangle difference testing revealed that, during the six month storage period, treatment with lysozyme did not cause important changes to either the aroma or palate of the red and white wines tested.     

Improvement of winemaking process using pulsed electric fields at pilot-plant scale. Evolution of chromatic parameters and phenolic content of Cabernet Sauvignon red wines

The influence of the application of a continuous pulsed electric fields treatment (PEF treatment) to grape pomace on the evolution of colour and phenolic content of Cabernet Sauvignon red wines has been investigated. Wine from grape treated by PEF presented at the end of alcoholic fermentation higher colour intensity (CI), total polyphenol index (TPI) and total anthocyanic content (TAC) than control wine. This effect was observed even although maceration time for PEF wine was 48 h shorter than for control. Differences remained during malolactic fermentation and maturation. After 4 months of aging in bottle, CI, TPI and TAC of PEF wine were 38%, 22% and 11% higher respectively than the control. HPLC phenolic profiles of wines were qualitatively similar, without detecting a selective effect on any phenol. No significant differences in sensory attributes between wines were detected. Results indicate that PEF is a promising technology in red winemaking for reducing the maceration time and increasing colour and phenolic extraction.     

Phenolic compound profiles in selected Queensland red wines at all stages of the wine-making process

The phenolic profiles of Queensland red wines (two Cabernet Sauvignons and one Shiraz) from different stages of wine-making were studied. Samples were taken at crush, after the primary and malolactic fermentations, post-oaking, and post-bottling, and then extracted and separated into aqueous and organic fractions using liquid–liquid extraction and solid-phase extraction, and analysed by HPLC-DAD-MS. About 75% of the phenolic compounds were extracted into the aqueous fraction, with malvidin-3-glucoside and derivatives as the main components. The major non-anthocyanin phenolic compounds (∼25%) included gallic acid, syringic acid, ethyl gallate, caftaric acid, coutaric acid, caffeic acid, coumaric acid, catechin, and quercetin. The polymerisation of anthocyanins was shown to occur progressively throughout the wine-making process. Most of the 25 identified phenolic compounds had highest concentrations during the fermentation stage, and stabilised or slowly decreased thereafter. There were weak and insignificant correlations (P > 0.05) between individual phenolic compounds and the total antioxidant activities (ORAC). Four groups of phenolic compounds (anthocyanins, hydroxybenzoic acids, flavanols and hydroxycinnamic acids) each showed some correlation with the total antioxidant activity, as did the total polyphenol content, suggesting that the antioxidant properties of red wine are due to a complex mixture of phenolic compounds that vary in composition throughout the wine-making process.     

Effects of SO2 on lactic acid bacteria physiology when used as a preservative compound in malolactic fermentation

SO₂ is a preservative compound widely used at an industrial scale to control the cider‐making processes. However, little is known about the effect that sulfur dioxide exerts on the cell physiology of lactic acid bacteria (LAB) during malolactic fermentation, taking into account the cellular heterogeneity of the microbial populations. Analysis of flow cytometry results has shown how increasing SO₂ concentrations were not related to a significant rise in the dead cell subpopulation. SO₂ affected malolactic activity and cell viability, giving rise to different levels of LAB tolerance to the fermentation conditions. Malate consumption in the bioreactor and the enzymatic potential of whole cells were monitored during the bioconversion process under the different assayed conditions. After SO₂ exposure, specific malolactic activity of whole cells measured by enzymatic assays in which SO₂ or other inhibitory compounds were absent showed higher values than the malolactic activity determined in the bioreactor, suggesting that inhibition was not irreversible, at least not at the concentrations tested. A correlation between total malolactic activity and viable and viable but nonculturable cell concentrations was established. Increasing amounts of SO₂ in the fermentation media also affected the malic acid/lactic acid ratio. Changes observed on LAB physiology at different sulfiting levels could be useful for practical cider‐making applications. Copyright © 2012 The Institute of Brewing & Distilling     

壳聚糖-活性红4缔合体系的荧光猝灭与共振瑞利散射光谱分析及其在壳聚糖定量分析中的应用

在弱酸性Britton-Robinson缓冲体系中,壳聚糖对活性红4存在荧光猝灭作用,在激发波长（λEx）/发射波长（λEm）=285 nm/341 nm处,在0.050～2.00 μg/mL质量浓度范围内,其荧光猝灭程度与壳聚糖质量浓度呈良好的线性关系。线性方程为ΔF=68.78c＋2.648（c,μg/mL）,R2=0.999 2,检出限为0.039 μg/mL。在相同的介质环境中,壳聚糖-活性红4离子缔合体系于波长342 nm处产生强烈的共振瑞利散射特征峰,共振瑞利散射强度与壳聚糖质量浓度c呈良好线性关系,在0.050～6.00 μg/mL质量浓度范围内,线性方程为：ΔI=681.31c＋114.95（c,μg/mL）,R2=0.999 1,检测限为0.033 μg/mL。据此,建立以活性红4为探针定量分析壳聚糖的2 种新方法：荧光猝灭法和共振瑞利散射法。同时,将2 种方法就壳聚糖分子质量对测定结果准确性的影响进行研究。将2 种新方法应用于实际样品的定量检测,测定结果基本一致,且回收率结果令人满意。     

闪蒸工艺对干红葡萄酒中多酚含量和感官特性的影响

利用HPLC法和Folin酚比色法分别对经闪蒸工艺和传统工艺进行酒精发酵和苹果酸-乳酸发酵酿造的赤霞珠干红葡萄酒中进行了研究。结果表明,通过闪蒸工艺酿造的赤霞珠干红葡萄酒多数单体酚类物质和总酚要高于传统工艺。与传统工艺酿造的赤霞珠干红葡萄酒相比,其中闪蒸工艺酿造的赤霞珠干红葡萄酒咖啡酸、丁香酸、阿魏酸大幅度提高,没食子酸含量基本未发生变化。感官品评结果也显示,闪蒸处理的葡萄酒的综合感官质量显著高于传统方法处理的葡萄酒。与传统工艺相比,闪蒸工艺酿造的葡萄酒更适合多酚物质的转化,进一步改善酒的风味,实现口感的平衡。     

干红葡萄酒酿造过程中白藜芦醇的变化

采用赤霞珠、玫瑰香为原料,单品种发酵酿造干红葡萄酒,发酵期间葡萄酒中的白藜芦醇的变化情况直接采用HPLC直接进样方法检测。主发酵温度控制在26℃左右,主发酵前添加60mg／L的二氧化硫,在后发酵时补充加入10mg／L的SO2,能有效降低白藜芦醇的损失。两个单品种酿造的干红葡萄酒经过苹果酸一乳酸发酵后白藜芦醇总量都略微提高,分别达到4．92mg／L和3．87mg／L。     

Hydrogen sulfide oxidation by a microbial consortium in a recirculation reactor system: sulfur formation under oxygen limitation and removal of phenols

Wastewater from petroleum refining may contain a number of undesirable contaminants including sulfides, phenolic compounds, and ammonia. The concentrations of these compounds must be reduced to acceptable levels before discharge. Sulfur formation and the effect of selected phenolic compounds on the sulfide oxidation were studied in autotrophic aerobic cultures. A recirculation reactor system was implemented to improve the elemental sulfur recovery. The relation between oxygen and sulfide was determined calculating the O2/S2- loading rates (Q(O2)/Q(S)2- = Rmt), which adequately defined the operation conditions to control the sulfide oxidation. Sulfur-producing steady states were achieved at Rmt ranging from 0.5 to 1.5. The maximum sulfur formation occurred at Rmt of 0.5 where 85% of the total sulfur added to the reactor as sulfide was transformed to elemental sulfur and 90% of it was recovered from the bottom of the reactor. Sulfide was completely oxidized to sulfate (Rmt of 2) in a stirred tank reactor, even when a mixture of phenolic compounds was present in the medium. Microcosm experiments showed that carbon dioxide production increased in the presence of the phenols, suggesting that these compounds were oxidized and that they may have been used as carbon and energy source by heterotrophic microorganisms present in the consortium.     

Effects of Inhibitory Environmental Factors on Growth of Oenococcus oeni CCSYU2068 for Malolactic Fermentation of Cider Production

The effects of several inhibitory factors (sulfur dioxide, pH and ethanol) on the growth of lactic acid bacteria and the subsequent malolactic fermentation (MLF) were studied by inoculation of different culture strains of Oenococcus oeni, the major lactic acid bacteria (LAB) in cider production. After comparing their organoleptic properties, three strains of Oenococcus oeni were selected from indigenous and commercial sources and their inhibitory effects on cell growth and MLF examined. The malolactic bacteria expressed variations in tolerance to the environmental conditions of pH, sulfur and ethanol concentration. Isolated from an indigenous cider production facility, O. oeni L4 had a better capacity with constant growth even when the concentration of SO₂ was 50 ppm, ethanol 10% (v/v) and pH 3.0. O. oeni L4 showed better properties for metabolizing the major acids: malic, lactic and acetic acid. The decomposition mean rate of malic acid was as high as 228.52 mg/L per day with a low acetic acid concentration of 101.78 mg/L under the stress conditions of cider production.