游离二氧化硫与葡萄酒氧化褐变及氧化还原电位的相关性分析

为探讨游离SO_2对葡萄酒氧化褐变的影响及建立葡萄酒氧化褐变的快速预警策略,利用加速氧化的方法,通过分析2种葡萄酒氧化褐变过程中褐变程度、游离SO_2、氧化还原电位的变化,研究游离SO_2与葡萄酒氧化褐变及氧化还原电位的关系。试验结果表明:在加速氧化过程中,葡萄酒的游离SO_2快速下降,褐变程度和氧化还原电位加速上升;游离SO_2对葡萄酒氧化褐变具有抑制作用,当游离SO_2含量低于3. 92 mg/L时其抗氧化作用较弱。葡萄酒中游离SO_2与氧化还原电位呈显著的负相关关系,可以利用实时检测氧化还原电位的方法来监测游离SO_2的含量,并对葡萄酒的氧化褐变提供快速预警。     

活性氧处理对南方山葡萄酒品质的影响

以"桂葡1号"和刺葡萄2种南方山葡萄酒为对象,研究活性氧处理对葡萄酒总酯、游离花色苷、原花青素及色泽等品质的影响。结果表明,在活性氧处理参数为33.34 mg/min·L的情况下,2种葡萄酒的活性氧适宜处理时间均为5 min,其总酯含量均提高10%以上,与自然陈酿1年的葡萄酒总酯含量相当。活性氧处理使葡萄酒的游离花色苷和原花青素降低,但处理5 min后其仍高于自然陈酿1年的葡萄酒。活性氧处理能使葡萄酒的色度降低,色调升高,外观上接近长时间陈酿的葡萄酒的色度和色调。     

酸菜贮藏期间褐变机理的探讨

酸菜贮藏期间的褐变严重影响了感官品质。实验针对酸菜贮藏期间的褐变机理进行探讨。测定酸菜在褐变前后还原糖、氨基酸、还原性抗坏血酸、总酚、可溶性蛋白含量的变化情况。研究结果表明,酸菜在发生褐变后还原性抗坏血酸、总酚、还原糖的含量发生显著性下降,氨基酸含量变化差异不显著,可溶性蛋白含量显著性增高。实验证明,酸菜褐变包括抗坏血酸氧化、酚类化学氧化,不排除美拉德褐变的可能性。     

2种南方山葡萄酒体外抗胆固醇氧化能力

采用与健康人体类似条件的体外胆固醇氧化模型,研究2种葡萄酒对自由基引发的胆固醇氧化的抑制能力,并分析了葡萄酒中主要抗氧化物质的含量。实验结果表明,2种葡萄酒对胆固醇的氧化具有明显的抑制作用,桂葡萄1号葡萄酒的抑制能力高于刺葡萄酒;在葡萄酒与胆固醇氧化模型的体积比为1∶50,1∶100,1∶200时,反应24 h桂葡1号葡萄酒对胆固醇的抑制率分别为98.4%、97.2%、80.9%,刺葡萄酒的抑制率分别为96.6%、92.9%、72.8%;桂葡1号葡萄酒和刺葡萄酒中的游离花色苷、原花青素的含量分别达到759.9、403.1和712.6、465.0 mg/L,白黎芦醇的含量为5.62和4.25 mg/L;富含多酚类抗氧化物质是南方山葡萄酒抗胆固醇氧化的物质基础。     

温度对软包装葡萄酒总酚和氧化褐变的影响

在不同温度条件下对红葡萄酒进行储存实验,运用福林-酚比色法测定不同温度条件下葡萄酒中总酚含量,同时检测葡萄酒褐变度的变化规律,研究分析温度对红葡萄酒氧化褐变及其氧化褐变速率的影响。研究发现,温度越高,葡萄酒总酚减少越快,氧化褐变度也越大。研究将为红葡萄酒储存和包装研究提供理论基础。     

白汤酱油储藏期间褐变与美拉德反应的关系

白汤酱油在储藏期间会发生褐变并引起品质变化。以褐变指数为测定指标考察了温度、氧气和光照条件对白汤酱油色变的影响,并进一步分析了酱油褐变(褐变指数、色率、红色指数、色差等)与美拉德反应(氨基氮、总糖、还原糖和游离氨基酸等)的关系。结果表明:温度和氧气含量对白汤酱油的褐变反应影响较大,而光照影响不明显。褐变指数、色率和照度与储藏时间之间符合指数拟合方程。在储藏过程中,总氮基本不变,氨基氮、总糖和还原糖含量下降,p H、总酸升高;丙氨酸、甘氨酸、甲硫氨酸含量基本不变,酪氨酸含量增加,其他多数氨基酸含量呈下降趋势;葡萄糖含量降低,其他还原糖类变化缓慢。白汤酱油中含量最多的氨基化合物谷氨酸和羰基化合物葡萄糖间的美拉德反应对白汤酱油颜色影响最大。     

添加洋葱汁和二氧化硫的赤霞珠红葡萄酒发酵的比较

SO2是葡萄酒酿造广泛使用的抑菌剂和抗氧化剂,由于对人体健康的负面影响,近年来有很多替代品的研究.该研究在赤霞珠红葡萄酒自然发酵和接种发酵中添加洋葱汁(50 g/L)和SO2(60 mg/L),通过测定发酵过程中微生物种群量、主要酿造特性、色度和氧化还原电位的动态变化,比较了洋葱汁和SO2的应用效果.结果表明,接种酵母...     

南果梨果汁非酶促褐变反应机制研究

通过监测南果梨果汁在不同温度贮藏过程中非酶促褐变反应的褐变指数（browning index,BI）及5-羟甲基糠醛（5-hydroxymethylfurfural,5-HMF）、总酚、抗坏血酸、游离氨基酸、还原糖的含量,探究其非酶促褐变反应的主要反应机制和影响因素。通过动力学方程表达各反应进行的情况和主次关系,结果表明,南果梨果汁非酶促褐变的主要反应机制是美拉德反应和抗坏血酸氧化分解反应,多元酚氧化缩合反应和焦糖化反应在南果梨果汁非酶促褐变反应体系中影响较小。在不同的贮藏温度下,5-HMF和抗坏血酸的含量变化规律均符合零级反应动力学模型,随着贮藏温度的升高,南果梨果汁的非酶促褐变反应速度加快。     

无釉陶罐陈酿对贺兰山东麓‘赤霞珠’干红葡萄酒的影响

以贺兰山东麓‘赤霞珠’干红葡萄酒为原料,研究了陈酿9个月期间无釉陶罐、旧橡木桶和微氧罐3种不同材料容器对葡萄酒基本电化学参数、理化指标和香气感官的影响。结果表明,3种容器陈酿过程中葡萄酒的溶解氧和氧化还原电位有相似的变化规律,无釉陶罐的溶解氧含量和氧化还原电位较低,且变化平稳,表现出更加稳定的微氧特性。3种容器陈酿葡萄酒的总酸、pH、酒精度等无显著性差异,无釉陶罐的挥发酸含量显著低于旧橡木桶;随着陈酿进行,3种容器陈酿的葡萄酒总酚、单宁含量,整体呈现下降趋势;花色苷含量逐渐降低、色调逐渐升高,但色度呈现了“V”型变化,无釉陶罐表现出相对较好的颜色稳定性。3种容器陈酿的葡萄酒总体上香气演化相近,但无釉陶罐陈酿的葡萄酒表现出更多的果香味。综上,无釉陶罐具有良好的微氧特性,对葡萄酒品质调控更加稳定,可作为红葡萄酒陈酿容器应用于生产。     

常用护色剂对水煮藕片品质的影响

为了探讨常用护色剂双氧水( H2O2)、亚硫酸钠(Na2SO3)和次氯酸钠(NaClO)对水煮藕片褐变及生理品质的影响,以新鲜莲藕为试验材料,用护色剂H2O2、Na2 SO3和NaClO对水煮藕片进行了处理,并对其在储藏过程中总酚含量、还原糖含量、游离氨基酸含量、维生素C含量和5 -羟甲基糠醛(5- HMF)等生理指标以及明度L、总色度差△E、褐变度BI等色度指标的变化进行了测量.结果表明:H2O2、Na2SO3和NaClO都可以不同程度的抑制水煮藕片的褐变.H2O2和NaClO可以通过减轻美拉德反应的程度来抑制藕片的褐变;Na2SO3一方面可以降低维生素C的氧化分解速率,另一方面还可以减轻美拉德反应的程度,从而延缓水煮藕片的褐变.     

The effect of ascorbic acid on oxidative browning of white wines and model wines

The effects of ascorbic acid addition to white wines and model wines were either anti-oxidative or pro-oxidative, and depended, inter alia , on the duration of storage. Soon after its addition, ascorbic acid decreased the redox potential and brown colour of model wines and white wines. However, with time, these effects were reversed, and redox potential, SO₂ consumption and browning were greater in samples with added ascorbic acid. The point at which the net effect of ascorbic acid addition was to increase browning occurred earlier at higher SO₂ levels. Under a variety of accelerated (45®), or prolonged (ranging from three months to five years) storage conditions, the browning of model wines and white wines was invariably enhanced by ascorbic acid addition, and this enhancement took place whether or not SO₂ was present. The addition of SO₂ alone, rather than ascorbic acid alone or SO₂ plus ascorbic acid, appears to be the most effective and least expensive way of protecting white wine from browning during bottle conservation.     

Free radical scavenging and antibacterial activities of southern Serbian red wines

Free radical scavenging and antibacterial activities were determined for several red wines from different grape varieties from the southern Serbia wine region. The amount of polyphenols and anthocyanins in selected wines was investigated and the potential antibacterial activity of the wines against pathogenic strains of Staphylococcus aureus and Escherichia coli was also determined. The free radical scavenging and antibacterial activity of the wines was correlated with polyphenolic and anthocyanin content. The significant differences in the antioxidant and antibacterial activities between the wines from grape cultivars (Cabernet Sauvingon and Pinot Noir) and the indigenous varieties (Vranac and Prokupac) were not confirmed. The hypothesis of a protective effect of red wine is supported by our results that show that the red wines with higher amounts of polyphenols and anthocyanins had higher antioxidant and antibacterial properties.     

酿酒酵母F15和CC17共接种发酵对赤霞珠葡萄酒品质及感官特性的影响

为解决使用单一商业酵母菌株发酵引起的葡萄酒“同质化”问题,本研究以河北昌黎产赤霞珠葡萄为原料,以商业酿酒酵母（Saccharomyces cerevisiae）F15和本土优良酿酒酵母CC17为发酵剂进行单菌株和双菌株共接种（F15:CC17=1:1）发酵,同时监测酒精发酵过程中比重、温度、残糖、乙醇、总酸、pH、花青素、单宁、总酚、色度和色调的变化。发酵结束（192 h）后,分别对酒的香气成分和感官特性进行了测评。结果表明:与F15单菌株发酵相比,双菌株共接种发酵能够提高赤霞珠葡萄酒中花青素、单宁和总酚含量,增加酒的色度并使色调更趋向于红色;与CC17单发酵相比,共发酵组残糖、总酸含量较低;共发酵调谐主要香气成分,并增加饱和脂肪酸乙酯的含量。此外,感官评价结果表明共发酵葡萄酒色、香、味均优于F15单独发酵。因此,在酒精发酵过程中采用商业酵母与本土菌株共发酵是改善葡萄酒品质和感官特性有效方法。     

红葡萄酒中花色苷衍生物结构研究进展

颜色是影响红葡萄酒感官质量的重要指标之一,红葡萄酒颜色的深浅不仅决定着葡萄酒的感官品质,而且 对葡萄酒内在品质也有较大影响。花色苷是红葡萄酒中一种重要的水溶性天然色素,具有多种重要的生理功能和生 物活性。近年来发现的一些花色苷衍生物作为花色苷家族重要的补充,其种类、状态和含量对红葡萄酒的色泽特征 和陈酿潜能起到重要的作用。本文系统介绍了在红葡萄酒中发现的主要花色苷以及不同类型花色苷衍生物的结构特 征、形成途径和理化性质,以期为葡萄酒中花色苷衍生物的结构研究提供有益参考。     

发酵容器对赤霞珠干红葡萄酒中花色苷的影响

利用高效液相色谱-质谱(HPLC-MS)联用检测技术分析了法国旋转橡木桶和不锈钢发酵罐酿造的赤霞珠干红葡萄酒陈酿180d和360d后花色苷的种类、数量,并与CIELAB法测定的葡萄酒色泽比较,结果发现二甲花翠素类花色苷是赤霞珠干红葡萄酒的主体花色苷类型,其中二甲花翠素单葡萄糖苷和二甲花翠素乙酰化单葡萄糖苷作为特征峰,分别占其花色苷总量的50%和20%以上;发酵容器影响葡萄酒中花色苷的种类和含量;陈酿过程中酰化的花色苷均较其相应的糖苷下降幅度大;陈酿180d的葡萄酒红色色调的深浅主要由花色苷的含量高低决定,陈酿360d的葡萄酒红色色调深浅和花色苷的含量高低无关;橡木桶用于赤霞珠干红葡萄酒发酵能获得较不锈钢罐更浓的红色和黄色色调以及更深的总色度。为葡萄酒酿造工艺优化和产品质量监控提供了理论依据与快速准确的化学鉴定手段。     

Effect of ripening stage of grapes on the low molecular weight phenolic compounds of red wines

Different red wines were elaborated to study the effect of the date of the grape harvest on the levels of individual low molecular weight phenolic compounds, which are chiefly responsible for the wine color. Two red grape varieties and two consecutive years were studied at three different harvesting stages of grapes, and the changes during the 18 months of wine aging (12 months in oak barrels and 6 months in the bottle) were also followed. The results showed that the wines made from grapes harvested 1 week later than the usual date generally had higher contents of some simple phenols, which can act as cofactors that can maintain the color intensity and violet tonalities in aged wines. Besides, these wines had lower levels of caftaric and coutaric acids, which are two of the main substrates for oxidation and browning processes.     

游离SO2、溶解氧浓度对葡萄酒颜色及花色苷含量的影响

目的：探索不同浓度溶解氧与游离SO₂对赤霞珠干红葡萄酒在陈酿中的颜色及相关参数的影响。方法：以新疆吐鲁番鄯善县新葡王酒庄赤霞珠干红葡萄酒为酿制试材,在葡萄酒陈酿过程中通过添加不同浓度的游离SO₂与溶解氧,观察其对葡萄酒色度、色调和花色苷含量等指标的影响。结果：溶解氧与游离SO₂浓度较低时葡萄酒呈鲜艳的酒红色,充氧量为2 mg/(L·30 d)时可促进葡萄酒中花色素苷、单宁适度聚合,改善葡萄酒品质;游离SO₂质量浓度为15~30 mg/L时对葡萄酒的色调值影响不大,但对色度影响较为明显,超过30 mg/L时会使葡萄的酒颜色逐渐显橙色。结论：赤霞珠干红葡萄酒陈酿的适宜游离SO₂质量浓度为25 mg/L,充氧量为2 mg/(L·30 d)。     

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.     

The role of corks in oxidative spoilage of white wines

The permeability of corks to oxygen was examined by comparing the level of browning and the concentration of the antioxidants, free and total sulfur dioxide and ascorbic and erythorbic acids in wines bottled and sealed with two cork types and stored in an atmosphere of either nitrogen, oxygen or air. Three different batches of corks that had been treated with peroxide during processing, representing one cork type, and a batch of corks that had been treated with chlorine during processing representing the second cork type, were taken for the study. In bottled wines stoppered with one of the peroxide-treated corks (Cork A), there was a higher level of browning and a greater loss of the antioxidants in those wines in bottles stored under oxygen and air than that in the wines in bottles stored under nitrogen, indicating that corks of this batch were permeable to oxygen. There was no significant difference in the loss of ascorbic and erythorbic acid or the level of browning from bottled wines stored under the three gases and sealed with the chlorine-treated corks (Cork C). For the other two peroxide-treated corks (Corks B and D), there was no significant difference in the level of browning or loss of the antioxidants from bottled wines stored under the three gases and sealed with Cork B, nor was there a significant difference in the level of browning or loss of free or total sulfur dioxide from bottled wines stored under the three gases and sealed with Cork D. From comparative data, it was evident that oxidation of the wines sealed with Corks B and D was due to compounds in the corks rather than oxygen permeation through the corks, or oxygen ingress at bottling. Because the bottles of wine selected for this study were from batches that had already exhibited sporadic oxidation, the results found are indicative, but not necessarily representative, of the properties of all peroxide- and chlorine-treated cork types used in the wine industry.     

Aging of red wines made from hybrid grape cv. BRS Violeta: Effects of accelerated aging conditions on phenolic composition,color and antioxidant activity

Aging is an enological technique usually employed with Vitis vinifera wines for improving and stabilizing wine sensory attributes like red wine color. However, red wines made from non-vinifera grape cultivars are considered not suitable for classic wine aging because they are prone to color loss during processing and storage, mainly due to the major occurrence of non-acylated anthocyanidin 3,5-diglucosides. The recently developed hybrid grape cv. BRS Violeta gives rise to deep red-purplish colored wines characterized by an important contribution of p-coumaroylated anthocyanidin 3,5-diglucosides. In this work, Violeta red wines were subjected to control (storage at 15 °C) and accelerated (storage at 25, 35 and 50 °C) aging for 120 days. Total phenolic content was only significantly decreased by 23% in accelerated aged wines at 50 °C, whereas antioxidant capacity was mainly reduced in the first 20 days of aging (around 35% for all the wines, except for 45% for wine aged at 50 °C) and then remained almost stable. In contrast, total anthocyanin content decreased following expected first-order kinetics and the variation of rate constants with regard to temperature fitted well with an Arrhenius-type equation. The calculated activation energy for disappearance of anthocyanins (47 kJ/mol) was close to the lower limit of the range of values reported for thermal degradation of anthocyanidin 3-glucosides. In addition, half-life values for p-coumaroylated anthocyanidin 3,5-glucosides of Violeta wine aged at 50 °C almost doubled those of their corresponding non-acylated derivatives. The latter result is suggested to be the main reason behind the relatively high resistance of Violeta wine towards the disappearance of anthocyanin under accelerated aging conditions. Finally, chromatic characteristics of Violeta wines did not significantly change their C* values during aging but L* and h* values increased as expected, the latter mainly due to higher increases of the yellow color component (b*) over lower decreases of the red color component (a*). These color changes were more drastic in the accelerated aged wines and the wine aged at 25 °C still maintained interesting color characteristics close to those of the control aged wine that did not change very much.