通过电导率的变化来判断葡萄酒的酒石稳定性

1、原理:酒石酸氢钾在葡萄酒中存在着溶解平衡: HOOC-CHOH-CHOH-COOK==HOOC-CHOH-CHOH-COO~- K~ 当外界条件发生变化时(例如降低温度),钾离子与酒石酸氢离子结合生成酒石酸氢钾沉淀,影响葡萄酒的稳定性。在葡萄酒的生产过程中通常采用冷     

电导率法检验葡萄酒的冷稳定性

通过对同一葡萄酒样品在添加过量的酒石酸氢钾前后"温度-电导率"曲线的比较,找出葡萄酒中酒石酸氢钾饱和时所对应的最高温度--"临界温度",这是确定葡萄酒冷稳定性的关键指标."临界温度"低于15℃的干红葡萄酒和低于12℃的干白葡萄酒在所要求的温度范围内是稳定的.     

葡萄酒冷稳定测试方法及研究进展

酒石酸氢钾饱和而析出形成沉淀,是导致葡萄酒不稳定的主要原因。生产需要进行冷稳定处理以保证酒石稳定性,即冷稳定性。而冷稳定必须通过稳定性测试才能判断,所以使用合理准确的测试方法非常重要。本文阐述了葡萄酒的冷冻-融化法、冷藏法、电导率/微接触法、饱和温度法、离子浓度积法等几种冷稳定测试方法,并比较了各方法的原理、操作方法以及特点,以期为葡萄酿酒生产提供有益借鉴。     

葡萄酒冷稳定性的评估方式

通过测量葡萄酒在加入酒石酸氢钾前后不同时间电导率的变化,从而找出电导率变化的差值与葡萄酒冷稳定性与否之间的关系,同时与其它测定葡萄酒冷稳定性的方法作了比较,证明了电导率法在评估葡萄酒冷稳定性方面的先进性和必要性。     

预测葡萄酒酒石酸氢钾稳定性的新方法

在葡萄酒中酒石酸氢钾（KHT）的多少是影响葡萄酒稳定性的重要因素之一，酒石酸氢钾经常处于超饱和状态。在葡萄酒中酒石酸氢钾的溶解度决定于温度、酒度、pH值。在新葡萄酒中酒石酸盐的沉积，也受胶体的影响。因此，其沉淀量不好预知。酒石沉淀可在新葡萄酒的贮存过程中很快地出现，也可在装瓶后的葡萄酒中缓慢地出现，因此，必须在装瓶前使葡萄酒稳定，使其装瓶后不出现酒石沉淀。1 饱和温度的概念饱和温度，广义地说是指溶质在溶液里达到饱和状态时的温度。在一定范围内，超过或低于此温度就会造成溶液由饱和变为不饱和或由不饱和变为…     

葡萄酒冷冻前的预处理—二次结晶吸附

葡萄酒在冷冻处理前通过酒石酸氢钾晶体的吸附作用可以除去影响结晶的杂质，进一步提高结晶效果和葡萄酒的冷稳定性。     

预测葡萄酒酒石酸氢钾稳定性的新方法

酒石酸氢钾(KHT)是影响葡萄酒稳定性的重要因素,其溶解度决定于温度、酒度、pH值。当温度低于饱和温度时酒石酸盐就不会析出,产生沉积物。白葡萄酒的TSAT<9℃;红葡萄酒的TSAT<16℃;桃红葡萄酒的TSAT<11℃。(孙悟)     

谈啤酒冷贮及冻罐现象

经发酵的酒液必须贮存一段时间,以使啤酒陈酿、老熟,啤酒冷贮对啤酒的保质期起到关键性的作用。冷贮包括两个方面:①冷贮时间。②冷贮温度。冷贮的作用:1、使啤酒口味协调,提高啤酒的胶体稳定性。2、溶解、饱和二氧化碳,赋予啤酒杀口力。3、酵母、冷凝固物等混浊颗粒的凝聚沉降,酒液的澄清。冷贮需要在较低的温度下进行,如时间太     

关于葡萄酒中钙稳定性的工艺探讨

有关葡萄酒稳定性,一般计论较注重其酒石酸氢钾的稳定性而对钙的稳定性涉及较少。实践证明,在工艺处理过程中,葡萄酒的酒石酸钙稳定性是一个更为复杂而又重要的过程。本文对此问题作一探讨。     

葡萄酒中酒石酸氢钾稳定性

葡萄酒中含有中性酒石酸钙（CaT2）和酸性酒石酸氢钾（KHT）两种酒石酸盐，其溶解度较小，经常在酒中形成沉淀物，沉于容器底部，结晶如石，称为酒石。酒石酸氢钾的溶解度随着温度的降低和酒度的增加而减少，但酒石酸钙的沉淀不受温度的影响，其沉淀作用慢，时间长，故常见的酒石沉淀主要是酒石酸氢钾沉淀。1 葡萄酒中酒石酸氢钾沉淀的性质在葡萄酒中，酒石酸以3种形态存在：未离解态的酒石酸（H2T）、酒石酸氢根离子（HT-）、酒石酸根离子（T2-）。当溶液pH值为3.7时，HT-所占比例最大，产生KHT沉淀。葡萄酒中能否产生酒石酸氢钾沉…     

防止葡萄汁(酒)中酒石沉淀的方法

本文综述了影响葡萄汁中酒石沉淀的几个因素，如葡萄汁的温度、钾离子含量、酒石酸含量、ｐＨ值和高分子物质的种类及含量；介绍了几种防止葡萄汁中酒石沉淀的方法，如冷冻法、冷冻加晶种、离子交换法、电渗析法及钙盐中和法     

速冻米面食品膨松剂的研究

研究一种不含明矾、磷酸盐、酒石酸氢钾、硫酸钙等成分的新型米面食品膨松剂,采用:内酯、柠檬酸、酒石酸、碳酸氢钠等成分,开发出一种可适用于所有食品(包括速冻米面食品)的膨松剂,效果优于传统配方膨松剂.     

羧甲基纤维素(CMC)稳定葡萄酒酒石机理的研究

酒石稳定性一直是影响葡萄酒外观质量的主要因素之一。目前生产上用的酒石稳定方法主要是将酒石酸盐直接除去。这些方法会不同程度地影响葡萄酒的质量,而且效果不理想。近年来,有关报道指出,用食品添加剂——羧甲基纤维素(CMC)稳定酒石取得了较为满意的效果。本文对试样添加CMC前后的电导率进行测定并观察酒石晶体的形态,结果表明:CMC在葡萄酒中参与一部分反应,与酒石形成复合物;与酒石酸氢钾形成的复合物能稳定存在于葡萄酒中,但与酒石酸钙形成的复合物多数会沉淀下来。CMC稳定葡萄酒中酒石的主要原因是其能使葡萄酒的理化平衡不受外界环境的影响,故能保持长时间的稳定。     

Short- and long-term efficiency of carboxymethylcellulose (CMC) to prevent crystal formation in South African wine

Crystal formation in bottled wine occurs due to the over-saturation of wine with potassium bitartrate (KHT) salt when exposed to low temperatures. In this study, special focus was given to the efficiency of a crystallisation-inhibiting additive, carboxymethylcellulose (CMC), which is widely used in the food industry. In 2008, CMC was authorised by the International Organisation of Vine and Wine (OIV) for use in white and sparkling wines, but is not yet officially permitted in all wine-producing countries. The use of CMC could be of economical importance to the wine industry because energy costs due to cooling can be reduced. Unlike traditional cooling methods, the use of CMC theoretically prevents the loss of acidity. In this study, the short- and long-term efficiencies of CMC were investigated in South African white, rosé and red wines. Efficiency was determined primarily by measuring changes in potassium (K(+)) and tartaric acid (H(2)T) concentrations and visual crystal formation. As part of this study CMC's efficiency was compared with several other crystal inhibition treatments, and was also evaluated for its temperature stability over a year. CMC's effect on colour and total phenols was also assessed. The results reveal a high efficiency in preventing losses in K(+) and H(2)T concentrations in white wines, even with an ageing period of up to 12 months. The addition of CMC to rosé wines also delivered certain positive results, but less so for red wine. Three different commercial CMCs were also compared with mannoproteins to prevent changes in K(+) and H(2)T concentrations in three different wines. Furthermore, sensory evaluation was performed to determine certain organoleptic changes as a result of CMC treatments.     

Short- and long-term efficiency of carboxymethylcellulose (CMC) to prevent crystal formation in South African wine

Crystal formation in bottled wine occurs due to the over-saturation of wine with potassium bitartrate (KHT) salt when exposed to low temperatures. In this study, special focus was given to the efficiency of a crystallisation-inhibiting additive, carboxymethylcellulose (CMC), which is widely used in the food industry. In 2008, CMC was authorised by the International Organisation of Vine and Wine (OIV) for use in white and sparkling wines, but is not yet officially permitted in all wine-producing countries. The use of CMC could be of economical importance to the wine industry because energy costs due to cooling can be reduced. Unlike traditional cooling methods, the use of CMC theoretically prevents the loss of acidity. In this study, the short- and long-term efficiencies of CMC were investigated in South African white, rosé and red wines. Efficiency was determined primarily by measuring changes in potassium (K⁺) and tartaric acid (H₂T) concentrations and visual crystal formation. As part of this study CMC's efficiency was compared with several other crystal inhibition treatments, and was also evaluated for its temperature stability over a year. CMC's effect on colour and total phenols was also assessed. The results reveal a high efficiency in preventing losses in K⁺ and H₂T concentrations in white wines, even with an ageing period of up to 12 months. The addition of CMC to rosé wines also delivered certain positive results, but less so for red wine. Three different commercial CMCs were also compared with mannoproteins to prevent changes in K⁺ and H₂T concentrations in three different wines. Furthermore, sensory evaluation was performed to determine certain organoleptic changes as a result of CMC treatments.     

A review of potassium nutrition in grapevines with special emphasis on berry accumulation

Potassium (K) is essential for vine growth and yield. Grape berries are a strong sink for K, particularly during ripening. Excess K levels in grape berries may have a negative impact on wine quality, mainly because it decreases free tartaric acid resulting in an increase in the pH of grape juice, must and wine. In Australia, high K status is common in most vineyards, which reflects the high K and high pH values of most Australian grape juice. This necessitates pH adjustment during the vinification process, and tartaric acid addition is a common practice in most Australian wineries. High K concentration may also lead to excessive loss of the additional tartaric acid by precipitation as potassium bitartrate and, as a consequence, pH adjustment becomes more difficult and expensive. Ensuring naturally low K levels in the berry will help reduce costs of input and waste management at the winery. Potential vineyard management options to manipulate berry K accumulation include selective use of rootstock/scion combination, canopy management and irrigation strategies. However, the impact of these practices on determining the optimum K concentration requires careful calibration of production parameters and the desirable grape juice and wine quality in relation to tissue K concentration. This paper reviews and discusses the possible functions of K in grape berries, translocation of K into the berry, and genetic and cultural factors that may affect the accumulation of K in the berry. This will help to identify the key research and management strategies needed for controlling K concentrations in grape berries.     

施钾水平对烤烟高钾新品系钾含量及生理特性的影响

为探明不同施钾量对烤烟高钾新品系钾含量和生理特性的影响,以K326为对照,高钾新品系GK8为供试材料,分析比较了烟株在不同供钾水平下钾含量及生理特性的差异。研究结果表明:烤烟高钾新品系各部位烟叶和茎中钾含量随着施钾量的增加而增加,而根中的钾含量却降低;施钾可促进烤烟高钾新品系生长前期合成叶绿素的能力,提高硝酸还原酶的活性,并对过氧化物酶活性有一定的调节作用。     

Effect of different carboxymethyl cellulose structure parameters on tartrates stability of red wine: viscosity and degree of substitution

ABSTRACT

The aim of this study was to investigate the effects of carboxymethyl celluloses (CMC) with different structures (viscosity and degree of substitution) on the stability of tartrates as well as the growth mechanism of potassium bitartrate (KHT) crystals. Six CMC samples with different viscosity and degree of substitution were investigated by GPC, XRD and SEM to establish their molecular weight, crystal structure, particle size and molecular morphology. As oenological additives, they were studied in model solution and in Cabernet Sauvignon wine. The tartaric stability and inhibitory efficiency were evaluated by conductivity via mini-contact test and compared with metatartaric acid and mannoproteins commercial additives. The results suggest that under the same degree of substitution (DS), with an increase of viscosity, CMC molecular chains agglomerate and fold, the solubility in the wine decreases, thus the effect of stabilising tartrate deteriorates. Whilst at the same viscosity, with an increase of DS, the charge density of CMC molecules increases and the binding ability of ions increases and thus the stabilising tartrate has an obvious effect. The negative charge on the ?COO? groups extended from CMC polymer tends to repulse the HT^? group in solution while attracting K⁺ ions to produce a concentration gradient at the crystal surface. In addition, CMC complexes with K⁺ ions in solution, reducing the number of K⁺ ions able to diffuse to the adsorption layer. Generally, CMC-6 with a higher the degree of substitution and lower viscosity had best application effect on tartrate stabilisation, and from the price and application performance, CMC was found to be superior to commercial additives like metatartaric acid and mannoproteins.     

我国硫酸钾生产综述及其展望

简单介绍了我国硫酸钾生产的几种工艺技术方法、特点以及主要工艺技术研究进展情况。特别介绍了原化工部长沙设计研究院开发成功的利用新疆罗布泊硫酸镁亚型盐湖卤水制取硫酸钾的新工艺。并结合我国钾盐资源的特点 ,对我国硫酸钾工业未来的发展趋势作出了预测     

无氯钾肥生产现状

我国目前生产的无氯钾肥主要有硫酸钾、硝酸钾和磷酸二氢钾等.文章简要介绍了生产各种无氯钾肥工艺方法及特点,特别介绍了用天然沸石作为离子交换剂,海水提钾制备无氯钾肥新工艺.