葡萄酒酿造中苹果酸-乳酸发酵的应用

苹果酸-乳酸发酵(MLF)是葡萄酒酿造中非常重要的二次发酵过程,可有效降低葡萄酒中的苹果酸,突出果香,改善口感,是葡萄酒生物降酸的主要方法.本文介绍了苹果酸-乳酸发酵在葡萄酒酿造中的作用,以及苹果酸一乳酸发酵的诱导和抑制,对影响苹果酸-乳酸发酵的环境因素和现代发酵工程技术在苹果酸-乳酸发酵中新的应用与发展也作了阐述.     

苹果酸-乳酸发酵在葡萄酒酿造中的应用

苹果酸一乳酸发酵(MLF)是红葡萄酒酿造的必经步骤，是葡萄酒生物降酸的主要方法，MLF可有效降低葡萄酒中的苹果酸。苹果酸是一种具有强烈辛酸味的双羧基酸，常规的物理、化学降酸方法对苹果酸不起作用，而MLF可降解苹果酸，使之转化为单羧基的、口感酸味柔和的乳酸，使葡萄酒的有机酸含量降低，酒体协调性增加，并可提高其生物稳定性和风味复杂性。本文介绍了MLF的机理、引起MLF的微生物及其在葡萄酒酿造中的作用，对影响MLF环境因素和现代发酵工程技术(固定化技术和膜生物反应器)在MLF中的新的应用与发展也作了阐述。     

葡萄酒中MLF的研究及技术应用

MLF（苹果酸-乳酸发酵）是葡萄酒酿造的必经步骤,可有效降低葡萄酒中的苹果酸,突出了果香。改善了口感,是葡萄酒生物降酸的主要方法。本文介绍了MLF的机理、引起MLF的微生物及其在葡萄酒酿造中的作用．对影响MLF环境因素和现代发酵工程技术在MLF中的新的应用与发展也作了阐述。     

葡萄酒酿造中苹果酸-乳酸发酵的应用

苹果酸-乳酸发酵（MLF）是葡萄酒酿造中非常重要的二次发酵过程,可有效降低葡萄酒中的苹果酸,突出果香,改善口感,是葡萄酒生物降酸的主要方法。本文介绍了苹果酸-乳酸发酵在葡萄酒酿造中的作用,以及苹果酸-乳酸发酵的诱导和抑制,对影响苹果酸-乳酸发酵的环境因素和现代发酵工程技术在苹果酸-乳酸发酵中新的应用与发展也作了阐述。     

葡萄酒苹果酸-乳酸发酵代谢机理

苹果酸 -乳酸发酵 (MLF)是葡萄酒中乳酸菌 (LAB)进行的细菌降酸过程。伴随着MLF,还生成了双乙酰 ,乙偶姻等物质 ,从而影响着 MLF后酒的风味。通过对 MLF生化机理的研究 ,提出了 MLF是 LAB利用胞内苹果酸 -乳酸酶 (MLE)直接催化苹果酸转变成乳酸的过程。本文还对双乙酰及其衍生物的产生机理、MLF能量代谢和 MLE基因工程等方面进行了评述。     

两种乳酸菌在干红葡萄酒中MLF的比较

将两种乳酸菌MBR和VINIFLORA分别接种于赤霞珠干红葡萄酒中进行苹果酸-乳酸发酵(MLF).结果表明,在试验条件下,乳酸菌MBR的降酸幅度和降酸速率均高于乳酸菌VINIFLORA;MBR产生的挥发酸低于乳酸菌VINIFLORA;pH值变化在正常范围内;影响MLF的主要因素是SO2的含量和pH值的高低.说明在进行MLF时,乳酸菌MBR的发酵特性优于乳酸菌VINIFLORA.     

一株降解生物胺乳酸菌用于葡萄酒苹果酸乳酸发酵的特性研究

葡萄酒等发酵食品中微生物通过脱羧作用形成生物胺，高浓度的生物胺对人体有害。该研究以课题组前期分离得到的一株可降解生物胺的Lactobacillus plantarum NXU-Q12为试验菌株，将其应用于葡萄酒酿造。采用HPLC法测定该菌株的生物胺降解率；采用顶空固相微萃取-气相色谱-质谱联用(head space-solid phase microextraction-gas chromatography-mass spectrometer, HS-SPME-GC-MS)和电子鼻测定经该菌株苹果酸-乳酸发酵(malolactic fermentation, MLF)前后的葡萄酒中挥发性化合物，以此评价该菌株对葡萄酒品质的影响，为葡萄酒酿造过程中生物胺的控制提供解决途径。结果表明，L.plantarum NXU-Q12在发酵葡萄酒的过程中具有降解苹果酸而不降解酒石酸、柠檬酸和甘油的特点，且MLF后酒样(赤霞珠葡萄酒、马瑟兰葡萄酒)中的酒精度、总酸、还原糖、挥发酸、甘油含量以及pH值均符合葡萄酒国家标准。此外，赤霞珠、马瑟兰酒样中L-苹果酸含量在MLF 32 d后均降至0.1 g/L以下...     

葡萄酒苹果酸-乳酸发酵工艺控制研究进展

本文介绍了苹果酸-乳酸发酵(MLF)的机理、引发MLF的微生物及其在葡萄酒酿造中的作用,对影响MLF环境因素和现代发酵工程技术(固定化技术)在MLF中新的应用与发展也作了阐述.     

梅鹿辄干红葡萄酒苹果酸-乳酸发酵过程中酸的变化

红葡萄酒和某些白葡萄酒经MLF,苹果酸经脱羧转化为乳酸和CO2,改善葡萄酒品质.利用葡萄酒成分快速分析仪对昌黎产区2007年份梅鹿辄干红葡萄酒MLF过程成分变化进行了检测,分析酒体中苹果酸、乳酸、总酸、pH值及挥发酸成分的变化.结果表明,高pH值和低SO2更容易触发和启动MLF,80%的苹果酸在MLF后期被快速降解掉.苹果酸到乳酸的转化引起总酸的降低和pH值的升高,苹果酸脱羧引起的降酸占降酸总量的94%以上;pH值在MLF前后上升了0.09～0.14;挥发酸略有升高,为0.03～0.06g/L.     

葡萄酒苹果酸乳酸发酵研究进展

苹果酸乳酸发酵(Malolactic fermentation,MLF)指在乳酸菌作用下将L-苹果酸脱羧基形成L-乳酸的过程,是葡萄酒生产难以控制的二次发酵过程,主要由酒类酒球菌引起.MLF对大部分红葡萄酒、一些白葡萄酒和汽酒最终的质量有重要的影响.自发进行的MLF结果往往难以预测,甚至引起葡萄酒的腐败.主要阐述引起MLF的微生物、MLF对葡萄酒品质的影响、MLF的生物学、影响MLF的因素、MLF在葡萄酒酿造中的应用等方面的研究现状,以期探索更好的控制MLF的技术.     

Saccharomyces cerevisiae-Oenococcus oeni interactions in wine: current knowledge and perspectives

Winemaking can be summarized as the biotransformation of must into wine, which is performed principally by Saccharomyces cerevisiae strains during the primary or alcoholic fermentation. A secondary fermentation, the so-called malolactic fermentation (MLF) is a biodeacidification that is often encouraged, since it improves wine stability and quality. Malolactic fermentation usually occurs either spontaneously or after inoculation with selected bacteria after alcoholic fermentation. The main organism responsible for MLF, the lactic acid bacterium Oenococcus oeni, develops in physicochemically harsh conditions, which may lead to MLF failure. Furthermore, yeast that ferment must before or together with O. oeni can prevent or stimulate the progress of MLF. These phenomena are part of the interactions observed between yeast and bacteria. The mechanisms that govern yeast bacteria interaction are reviewed and the consequences for winemaking are discussed. In the light of recent advances, future prospects are also presented.     

Evaluating the Influence of Malolactic Fermentation Inoculation Practices and Ageing on Lees on Biogenic Amine Production in Wine

Biogenic amines are compounds, produced primarily by lactic acid bacteria (LAB) that negatively affect the wholesomeness of wine. Standard winemaking practices can greatly influence the levels of biogenic amines in wine. The aim of this study was to determine the relative contribution of different malolactic fermentation (MLF) practices and ageing of wines on fermentation lees to the final levels of biogenic amines. Wines were made on small scale over two harvest seasons with two red grape cultivars. Treatments included spontaneous MLF, co-inoculated MLF, MLF inoculated after alcoholic fermentation (conventional inoculation) and 4 months of ageing in the presence and absence of fermentation lees of all MLF treatments. Biogenic amine concentrations were measured by high-performance liquid chromatography at key winemaking stages and statistically analysed for the effects of MLF treatment and winemaking stage. Results indicate that the presence of indigenous LAB increased the risk of biogenic amine formation. Inoculation proved to reduce biogenic amine production over time compared to spontaneous MLF and co-inoculation even more than conventional inoculation. The presence of yeast lees during ageing generally led to higher final concentrations of biogenic amines in wines than the absence of lees. This study confirms other works that conclude that spontaneous MLF and uncontrolled ageing on yeast lees are generally unpredictable and pose a risk of biogenic amine contamination in finished wines.     

北五味子汁苹果酸-乳酸发酵工艺优化及其抗氧化性研究

探究北五味子汁苹果酸-乳酸发酵（MLF）工艺并研究发酵过程中抗氧化活性变化。利用新鲜北五味子作为原材料,通过单因素和响应面优化试验研究北五味子汁苹果酸-乳酸发酵工艺,并测定其体外抗氧化活性。结果表明最优工艺条件为：酒酒球菌接种量7%、发酵温度24 ℃、发酵时间8 d、初始pH 3.4。此优化条件下,北五味子汁经过MLF后,苹果酸降解率为59%。DPPH自由基清除率是发酵前的1.22倍,还原力是发酵前的1.44倍,铁离子还原能力（FRAP）是发酵前的1.03倍,ABTS自由基清除率是发酵前的1.10倍。结果表明北五味子汁通过苹果酸-乳酸发酵能提高抗氧化能力。     

苹果乳酸发酵生产葡萄酒

二次发酵-苹果乳酸发酵（MLF）在葡萄酒生产过程中起非常重要的作用.酿酒需要选择合适的酿酒酵母和细菌,乳酸菌接种方案以及工艺条件控制系统.本文介绍了MLF发酵过程的优缺点、效益和技术缺陷.讨论了启动和运行MLF的方法及葡萄酒生产过程中各种微生物之间的相互作用.微生物主要是指酵母菌属中的酿酒酵母和酒类酒球菌属中的酿酒细菌.     

Malolactic fermentation of Tempranillo wine: contribution of the lactic acid bacteria inoculation to sensory quality and chemical composition

Malolactic fermentation (MLF) of Tempranillo Rioja wines (Spain) inoculated with two lactic acid bacteria (LAB) strains were studied and compared with spontaneous MLF. Inoculation with selected Oenococcus oeni lyophila shortened MLF duration up to 19 days and lead to wines with more fresh and fruity characters, especially when implantation was 100%. We demonstrated modifications in the concentration of volatile and nitrogenous compounds and a good correlation between analytical and sensory attributes was also noted. In addition, the low initial amino acid concentration and the consumption of these compounds by the inoculated yeast strain during alcoholic fermentation resulted in wines with very low biogenic amines levels (under 3.75 mg L^?1) after MLF and 3 month storage period in all cases. The results showed the significance of choose the most suitable starter to elaborate quality wines and suggest the control of amino acid content in must and wine to prevent the formation of biogenic amines.     

Immobilised yeast grape must deacidification in a recycle fixed bed reactor

Maloalcoholic fermentation (MAF) of grape must by Schizosaccharomyces pombe immobilised in calcium‐alginate double‐layer beads (ProMalic^®) was studied in Erlenmeyer flasks and in a total recycle fixed‐bed reactor operating in batch mode. The reaction is pseudo‐first order with respect to l ‐malic acid and under similar conditions deacidification is faster in the recycle reactor. This was attributed to mass transfer limitations which were confirmed in the recycle reactor by studying the influence of yeast load on the rate of MAF. Mass transfer limitations are also responsible for the lower activation energy of fermentation with the immobilised yeast (67 ± 9 kJ mol^?1) in comparison with the free cells (126 ± 19 kJ mol^?1). Alcoholic fermentation and MAF were performed simultaneously, both in the recycle reactor and in the industrial trials, confirming the efficacy of immobilised S. pombe to reduce grape must acidity without interfering with the main fermentation. Altogether, the present results are useful for the scale‐up of a recycle reactor to process large volumes of grape must.     

Influence of different pH values and inoculation time on the growth and malolactic activity of a strain of Oenococcus oeni

The present study was undertaken to evaluate the influence of medium pH and inoculation time on the growth and malolactic activity of an Oenococcus oeni culture. Samples of a commercial white grape juice adjusted to pH 3.2, 3.4 or 3.6, and inoculated with Saccharomyces cerevisiae strain CY3079, were inoculated with a malolactic culture ( Oenococcus oeni strain 31) at the beginning, middle, and end of alcoholic fermentation. The results obtained from this single case study show that it is possible to inoculate the bacterial culture at the three different times during alcoholic fermentation without slowing down or stopping alcoholic fermentation or causing failure of MLF. However, pH and timing of bacterial inoculation were critical to how rapidly MLF starts. At pH 3.2 a lowering of bacterial viability was observed, but a more important reduction was recorded at all tested pH levels when the bacteria were inoculated halfway through alcoholic fermentation. When inoculation was carried out at the end of alcoholic fermentation, the presence of yeast seemed to favour bacterial viability and activity and bacteria performed MLF even in difficult conditions such as pH values around 3. In all wines malolactic fermentation was accompanied by total degradation of malic and citric acids and production of L-lactic acid, D-lactic and acetic acids.     

发酵过程果酒成分对苹果酸乳酸发酵的影响

苹果酸-乳酸发酵（MLF）是果酒（葡萄酒、苹果酒）酿造中非常重要的二次发酵过程。本研究采用人工模拟果酒，研究果酒成分对MLF的影响。结果表明，葡萄糖抑制乳酸菌的MLF，果糖却有促进作用，而且果糖可解除葡萄糖对酿酒酒球菌MLF的抑制作用，果酒中葡萄糖和果糖的浓度及其比例是预测和控制MLF的重要参数；高浓度乙醇、低pH抑制乳酸菌的MLF，其抑制作用的大小与使用的菌种有关；酒中酚类物质（没食子酸和阿魏酸）对酿酒酒球菌的MLF几乎无任何显著影响；酒精发酵完成后果酒中营养的缺乏会抑制乳酸菌的MLF。     

葡萄酒中生物胺的产生与工艺控制

生物胺存在于多种发酵食品中，人体吸收过量的生物胺后会引起不良的生理反应。在葡萄酒苹果酸—乳酸发酵(MLF)过程中，有些乳酸菌能够对氨基波脱投产生生物胺。利用PCR与DNA探针技术能够快速检测葡萄酒中的组胺产生菌。工艺上采用接种法进行MLF，并在MLF完成后对乳酸菌进行有效清除、可以显著降低葡萄酒中生物胺的含量。