Using Dimethyldicarbonate to Minimize Sulfur Dioxide for Prevention of Fermentation from Excessive Yeast Contamination in Juice and Semi-Sweet Wine

ABSTRACT: Sulfur dioxide (SO₂) at 0, 10, 25, and 50 mg/L and/or dimethyldicarbonate (DMDC) at 0, 50, 100, and 200 mg/L at different pH levels (3.0, 3.2, 3.4, and 3.6) in juice and semi-sweet wine were evaluated by monitoring yeast growth and visible fermentation at 20 °C after excessive yeast contamination (500 to 700 colony forming units/mL), using Saccharomyces bayanus. The treatments with the least preservatives that prevented yeast growth and visible fermentation at all pH levels in juice were 50 mg/L SO₂+ 100 mg/L DMDC and in wine were 10 mg/L SO₂+ 50 mg/L DMDC. DMDC and minimal SO₂ levels prevented fermentation in juice and semi-sweet wine with excessive yeast contamination.     

葡萄全汁乳酸发酵菌株筛选及其风味分析

为葡萄全汁乳酸发酵饮料研制提供优良菌株资源.以“桂葡1号”葡萄果汁为原料,以耐酸性及风味评价为指标,筛选葡萄果汁乳酸发酵的优良菌株,研究优选菌的单菌及复配发酵对果汁风味物质的影响.植物乳杆菌R23及副干酪乳杆菌R37能耐受pH值3.0高酸,其发酵香与葡萄果香协调;两菌复配生长是共生型,其发酵风味比单菌更饱满丰富;乳酸发...     

Factors Influencing Ellagic Acid Precipitation in Muscadine Grape Juice During Storage

Ellagic acid sedimentation in white muscadine grape juice was monitored following different processing treatments and storage temperatures. High storage temperatures (40°C) greatly accelerated sediment formation, and pasteurization (100°C, 10 min) resulted in a faster sediment formation than sterile filtration. Sediment also increased substantially after juice was hydrolyzed (121°C and pH 2 for 10 min). Ultrafiltration of juice through a 10,000 or 30,000 dalton membrane resulted in significantly less sediment formation in the juice. Treatment of juice with polyvinylpolypyrrolidone (0.1– 0.2 g/L juice), egg albumen (6–10 mg/L juice) or gelatin (0.05 – 0.4 g/L juice) resulted in a significant reduction of juice phenolics and sediment formation. A commercial pectinase added to the grapes increased sediment formation and total phenolics in the juice. Levels of ellagic acid in juice were very low and did not correlate well with amount of sediment formed.     

直接碘量法测定葡萄酒中总二氧化硫含量的不确定度评定

根据《化学分析中不确定度的评估指南》,通过对直接碘量法测定葡萄酒中总二氧化硫含量的不确定度进行分析。结果表明,由重铬酸钾及二氧化硫摩尔质量引起的不确定度较小,对结果无显著影响;由重复性引起的不确定度最大;测定样品时,碘标准溶液体积的用量引入的不确定度也较大;测定分析得葡萄酒中总二氧化硫含量的最后结果为136 mg/L±1 mg/L;k=2。     

复合益生菌协同发酵葡萄汁菌种筛选与工艺优化

为增强葡萄汁的保健功能,以巨玫瑰葡萄为原料,选择21株益生菌对葡萄汁进行发酵,经过初筛和复筛,得到适宜葡萄汁发酵的植物乳杆菌21802和短乳杆菌6239,并将两株菌进行复配,以活菌数和感官评分为指标,对复合益生菌协同发酵葡萄汁工艺进行优化。结果表明,复合益生菌协同发酵葡萄汁最佳发酵工艺条件为:植物乳杆菌21802与短乳杆菌6239的菌种比例1:2,葡萄汁料水比2:1,接种量5%,发酵温度36 ℃,发酵时间60 h。此条件下发酵所得益生菌发酵葡萄汁的活菌数可达到8.98×10⁹ CFU/mL,感官评分为91.1分。     

葡萄汁过量氧化研究进展

葡萄汁过量氧化是白葡萄酒酿造中的一项新技术，并逐渐引起了酿酒师的广泛重视。探讨了葡萄酒中类黄酮及其褐变机理；论述了过量氧化在实际应用中所涉及的工艺措施，如氧气供给数量、供给方式、分析控制以及SO2的添加等；讨论了过量氧化对葡萄酒微生物及其品质，如风味、色度及其香气等方面的影响；同时阐述了过量氧化存在的一些问题及其应用前景。     

葡萄胡萝卜复合果蔬汁饮料的研制

选用葡萄、胡萝卜为主要原料,研制复合果蔬汁饮料,进行了配方工艺优化研究。通过正交试验确定了葡萄胡萝卜复合果蔬汁的最佳配方为：砂糖10％,葡萄胡萝卜混合汁20％,柠檬酸0．1％。使用混合稳定剂,参数为黄原胶0．4g／L、羧甲基纤维素0．6g／L、海藻酸钠0．8g／L,稳定效果较好。     

桑葚葡萄复合果汁饮料的研制

研究了以桑葚、葡萄为主要原料加工复合果汁饮料的工艺。最佳配方为:桑葚汁10%、葡萄汁30%,糖10%,柠檬酸0.2%,CMC 0.2%。该饮料口感清爽、风味纯正、酸甜适口,是一种具有开发潜力的新型功能饮料。     

浓缩红葡萄汁的粘度与酒石析出

采用浓缩与低温处理相结合的方法可更好地去除葡萄汁中的酒石。它是利用酒石的溶解度随温度的降低而减小的原理 ,通过降低葡萄汁贮存温度使葡萄汁中的酒石酸氢钾和酒石酸钙(统称酒石 )结晶沉淀于容器底部 ,分离后达到除酒石的目的。实验中发现 ,70°Bx的葡萄汁在 2 5℃贮存时反而比在 4℃更容易使酒石结晶析出。经分析 ,导致这种现象的关键因素在于低温下高浓度葡萄汁的粘度抑制了酒石结晶的生成。试验中测定了不同糖度的葡萄汁在不同温度下的粘度变化 ,并找出了浓缩葡萄汁的粘度与酒石析出的关系。     

Use of Rectified Grape Juice in Yogurt Edulcoration

ABSTRACT: Plain yogurt was prepared by adding 5 or 10% rectified grape juice (RGJ) or 3% sucrose to concentrated milk. Influence of the sweeteners addition on fermentation, and on syneresis, rheological, and sensorial properties after 14 d of storage was analyzed. Addition of a 10% RGJ increased the fermentation and reduced the lactic acid production; however after 14 d of storage the pH and L-lactic production were similar to the control. Syneresis was not affected by sweeteners addition. The storage modulus (G') andloss modulus (G") were slightly different from the control in samples added to a 5 or 10% RGJ. The panelists found that yogurt added to a 10% RGJ was significantly ( P < 0.001) sweeter than the control and also significantly ( P < 0.001) sweeter than those added to a 3% of sucrose.     

Production and Evaluation of Yogurt with Concentrated Grape Juice

Fruit yogurt was prepared by adding concentrated grape juice (pekmez) CGJ, to milk. Optimum CGJ concentration and its influence on quality and fermentation process of yogurt were evaluated. The pH, titratable acidity, protein content, viscosity, whey syneresis, starter bacteria, mold and yeast counts were determined weekly at 4°C for 1 month. Addition of 10% CGJ provided desired sweetness. After 4h incubation of 5–10–15% CGJ-added yogurts the pH was 4.44, 4.98 and 5.90, respectively, and the control was pH 4.26. CGJ addition increased fermentation time and decreased viscosity. During storage, acidity of 10% CGJ-added yogurt remained lower (P<0.05) than controls. CGJ did not affect (P>0.05) protein content and molds or yeasts were not detected.     

优选非酿酒酵母与酿酒酵母在模拟葡萄汁发酵中生长动力学及酯酶活性分析

目的:探究非酿酒酵母与酿酒酵母混合发酵过程中酵母的生长状况及酯酶活性的变化规律。方法:通过测定川南白酒窖池中分离的非酿酒酵母在液体发酵培养基中的酯酶活性,从中优选1株高产酯酶的酵母,经26S r DNA D1/D2区域序列分析鉴定种属。随后利用模拟葡萄汁进行优选酵母和酿酒酵母的混合发酵,设立同时接种、提前48 h接种和提前96 h接种优选酵母3个实验处理,以两株酵母的纯发酵为对照,研究发酵过程中的酵母生长动力学及不同碳链长度底物(C_2~C_8)对应的酯酶活性变化。结果:优选的非酿酒酵母为发酵毕赤酵母。酵母生长动力学研究发现,单一酿酒酵母的发酵速率最快,但混合发酵中的酵母数量更多,尤其是提前96 h接种。模拟发酵处理中,同时接种处理的酯酶活性累积量最大(574 m U/mL),酯酶活性在C_2~C_8有底物特异性,其中C8酯酶活性累积量最高(178~227 m U/mL),C_2酯酶活性累积量最低(46~66 m U/mL)。结合发酵动力学与发酵中酯酶活性变化,发现酯酶活性与酵母的生长状况有关,当酵母生长达到稳定期,酯酶活性达到最大值。结论:优选酵母与酿酒酵母的同时接种发酵具有较高的C4~C8酯酶活性累积量,有增香酿造的应用潜力。     

Identification of Predominant Aroma Compounds in Muscadine Grape Juice

The aroma components of muscadine (Vitis rotundifolia Michx) grape juice were analyzed by gas chromatography (GC)/mass spectrometry and GC/olfactometry (aroma extract dilution analysis). 2,5-Dimethyl-4-hydroxy-3(2H)-furanone (furaneol), with a burnt sugar-like aroma, was the most intense aroma in the juice. Other predominant compounds included 2,3-butanedione, ethyl butanoate, ethyl 2-methylbutanoate, 2-phenylethanol, and o-aminoacetophenone. These compounds were described as buttery/cream cheese, bubble gum/fruity, green apple/fruity, rosy, and foxy, respectively. Furaneol and o-aminoacetophenone were thought to be responsible for characteristic candy and foxy-like aroma notes of muscadine grape juice. Flavor dilution chromatograms were similar for juices prepared from grapes harvested on different dates and from different locations.     

酵母菌乳酸菌共发酵对荔枝汁品质的影响

本研究以鲜榨荔枝汁为原料,分别对其进行干酪乳杆菌及三种酵母菌(BO213、D254、EC1118)的复合发酵,探索发酵过程中乳酸菌活菌数、pH、可溶性固形物、糖组分、有机酸、DPPH?清除能力以及感官指标等变化。结果表明：发酵后荔枝汁中的乳酸菌活菌数均高于7 lg (cfu/mL),均具有一定的益生功能。复合发酵不仅能促进干酪乳杆菌的生长,还能降低荔枝汁的糖度,且酒精度低于0.50%,符合无醇饮料的标准。随着发酵时间的延长,各组的糖含量均呈现下降的趋势。发酵24 h后干酪乳杆菌单独发酵组的乳酸含量显著低于复合发酵组,从高到低依次为：D254+干酪组(6.62 g/L)>Ec1118+干酪组(6.55 g/L)>BO213+干酪组(2.35 g/L)>干酪组(0.94 g/L)。D254+干酪组、Ec1118+干酪组发酵24 h的荔枝汁体外抗氧化能力(DPPH?清除能力)相比单独发酵组更具优势。发酵后的荔枝汁香气更佳,且复合发酵优于单独发酵,其中BO213+干酪组的香气最好,Ec1118+干酪组次之。综上,通过Ec1118+干酪乳杆菌可制得一款风味良好、营养丰富的发酵无醇益生荔枝饮料。     

二氧化硫对采后葡萄果皮酚类物质合成及其抗氧化能力的调控作用

为探究二氧化硫(Sulfur Dioxide,SO₂)对葡萄果皮酚类物质合成及其抗氧化能力的影响,该试验以木纳格葡萄为试材,采用500μL/L SO₂熏蒸处理2 h,以空气熏蒸为对照,放置于(0±1)℃贮藏44 d。定期测定各酚类物质含量变化,采用高效液相色谱法测定黄烷醇单体含量。结果表明：贮藏结束时,SO₂处理组总酚、总黄烷醇、总黄酮、总花青素、(+)-儿茶素、(-)-表儿茶素、(-)-表没食子儿茶素和(-)-表儿茶素没食子酸酯含量分别是CK组的0.74、1.26、1.33、1.33、1.47、1.79、1.59和1.49倍;1,1-二苯基-2-三硝基苯肼(DPPH)、2,2’-联氮-二(3-乙基-苯并噻唑-6-磺酸)二铵盐(ABTS)自由基清除活性以及铁离子还原能力(FRAP)分别比CK组高13.76%、20.44%和4.98%。SO₂处理在一定程度上诱导了苯丙氨酸解氨酶基因(L-Phenylalanine Ammonia-Lyase,PAL)、肉桂酸-4-羟基化酶基因(Cinnamate 4-...     

酶解处理对葡萄汁芳香物回收工艺的影响

以玫瑰香葡萄为试材 ,采用NOVOferm1 2酶制剂对葡萄中键合态芳香物质进行酶解处理 ,并结合感官评定 ,研究了酶解处理对葡萄汁芳香物回收工艺的增香效果。结果表明 ,酶解处理葡萄汁芳香物回收液中葡萄典型芳香物质总含量比未酶解处理葡萄汁芳香物回收液增长了 30 2 1 4μg/L ;感官分析表明 ,酶解处理对葡萄汁芳香物质回收工艺具有明显的增香调控作用     

葡萄酒的pH值与二氧化硫的关系

控制葡萄酒陈酿时原酒品质,其主要影响因素为原酒的pH值和二氧化硫的用量,根据原酒的不同pH值,对游离二氧化硫的用量加以调节,达到二氧化硫防腐、抗氧化的作用.     

比色法测定啤酒中二氧化硫的含量

介绍了以盐酸副玫瑰苯胺为显色剂测定啤酒中二氧化硫含量的方法。本法无需蒸馏 ,较简便。利用此方法对 2 2种国产啤酒样品进行了检测 ,其含量在 1～ 2 6mg/L。此方法具有较好的回收率与重复性 ,其回收率在 93 8%～ 1 0 1 1 %之间 ,而变异系数为 1 0 %。     

葡萄酒中二氧化硫的几种检测方法对比

详细比较氧化法、蒸馏法、碘量法、盐酸副玫瑰苯胺法4种国标方法和流动注射法测定葡萄酒中二氧化硫残留量的影响因素和重复性,并采用5种方法检测进口葡萄酒样品。结果显示:不同方法的检测结果存在显著差异,氧化法、蒸馏法和流动注射法的检测结果差异性较小(P>0.05),碘量法和比色法的检测结果与其他几种方法的差异较大(P<0.01)。由于该5种方法存在检测和适用性的差异,因此检测时应根据实际样品情况和检测要求选择合适的方法进行,以减少因为方法不同引起的结果差异和评估错误。