猕猴桃酒酿造工艺参数优化及其香气成分分析

通过三因素二次通用旋转组合试验设计，考察了发酵温度、发酵液初始pH值、接种量对酿造猕猴桃酒品质的影响，得出了猕猴桃酒质量的回归模型，结果表明：发酵温度、发酵液初始pH值和接种量对猕猴桃酒质量的影响极为显著(p＜0.01)；主因子效应为发酵温度＞发酵液初始pH值＞接种量。猕猴桃酒酿造的最佳工艺参数为发酵温度20℃，接种量10.3%，pH值3.6；利用气相色谱质谱联用技术(GC-MS)对猕猴桃酒香气成分进行了分析，通过多元回归分析得到了猕猴桃酒中酯类、醇类、酸类和醛酮类香气与工艺参数间的回归模型。     

利用响应面法优化石榴酒发酵工艺条件

攀枝花的石榴品种繁多,籽粒味甜汁多,为了充分利用这一优势资源,本文进行石榴酒发酵,并对其发酵工艺利用响应面分析法进行优化。以酒精度为指标,考虑发酵温度、二氧化硫添加量、酵母接种量对石榴酒发酵酒精度的影响,然后根据中心组合030x—Benhnken）原理采用三因素三水平的分析法,依据回归确定各工艺条件的影响因素,以石榴酒发酵酒精度为响应面和等高线,分析各个因素的显著性和交互作用,结果表明优化得到石榴酒发酵的最佳工艺条件为二氧化硫添加量51．3mg／kg,酵母菌接种量5．33％,发酵温度24．98℃,酒酒精度的理论值为9．58％。通过响应面分析优化发酵工艺,为今后石榴酒发酵的更进一步开发提供一定的理论依据。     

苹果酒酵母融合子W1发酵工艺参数的优化研究

该文利用所构建的苹果酒的模糊综合评判模型，以评判结果为目标，采用响应界面法研究了苹果酒发酵的规律，建立了优质苹果酒发酵的二次多项式数学模型，同时验证了模型的有效性，并考察了接种量、初始pH值和发酵温度对苹果酒品质的影响，优化出最佳发酵工艺参数为接种量5.33%、初始pH值3.37、发酵温度22.14℃。     

黄花梨果酒发酵工艺试验初报

在偏重亚硫酸钾(以SO2计)为80 mg·kg-1,果胶酶为0.2‰的条件下,通过单因素试验探讨发酵温度、酵母接种量、发酵果浆初始固形物含量及发酵时间对黄花梨果酒发酵的影响(以酒精度为评价指标),试验结果表明:最适发酵温度为20~25℃,最适酵母接种量为0.4‰左右,最适发酵果浆初始固形物含量为23%~26%,最适发酵时间为8 d,为下一步正交试验优化发酵工艺提供了合理的参数范围。     

甜高粱茎秆固态发酵生产燃料乙醇的工艺优化研究

为了开发新型生物质能源,研究了用甜高粱茎秆生产燃料乙醇的工艺参数,在单因素试验的基础上用正交试验进行工艺参数的优化。结果表明,发酵温度、pH值、酵母营养盐对甜高粱秆固态发酵乙醇产率、起酵速度和发酵周期有显著影响;而酵母类型和装料系数只影响乙醇产率和起酵速度,对发酵周期无明显影响。试验中当装料系数为80%、pH 3.5、采用丹宝利酵母,添加营养盐2进行发酵时,最佳工艺参数为：发酵温度为22℃或25℃,营养盐添加量为0.02%,酵母接种量为0.08%,在此条件下发酵,最高酒精度可达6.6%（V/V）。该研究结果为中国燃料乙醇的发展提供科学依据。     

酵母菌PA4酿造苹果酒发酵条件的优化

通过三因素二次正交旋转回归实验设计，考察了发酵温度、接种量、发酵液初始pH值对酵母菌PA4酿造苹果酒品质的影响，得出苹果酒质量与影响因素的回归模型。结果表明：发酵温度和接种量对苹果酒质量的影响极显著(p＜0.01)，发酵液初始pH值对苹果酒质量的影响显著(p＜0.05)；菌株PA4酿造苹果酒的最佳工艺参数是发酵温度为24℃，接种量为10%，pH值为3.4。     

枯草芽孢杆菌液体发酵条件优化探究

通过单因素试验对枯草芽孢杆菌液体发酵培养基及发酵条件进行了优化,为实现该菌株的工业化生产提供数据参考。试验结果表明:该菌株培养基各组分的最佳配比为蛋白胨1%,麸皮∶酵母提取物(3∶2)为0.5%,氯化钠1%。最佳发酵培养条件为初始pH值6.0,培养温度为37 ℃,培养时间为24 h、装液量100 mL,接种量为4%,转速为200 rpm·min~(-1)。     

生防地衣芽孢杆菌最佳发酵条件探究

通过单因素试验对地衣芽孢杆菌发酵培养基配方及条件进行优化。结果表明,该菌菌株培养基最佳配比为蛋白胨1%、酵母提取物0.5%、氯化钠1%,最佳培养条件是初始pH值8.5、温度37 ℃、时间36 h、三角瓶装液量125 mL、接种量4%、转速200 r·min~(-1)。该研究为地衣芽孢杆菌的大规模工业化发酵培养提供了有益借鉴。     

苹果渣固态发酵苹果醋工艺研究

以新鲜苹果渣为主要原料,采用果胶酶法对苹果渣的酒精发酵和醋酸发酵工艺进行优化研究,通过正交试验确定最优酿造工艺参数。初步获得的苹果渣酒精发酵条件是果胶酶添加量0.06%、酵母接种量8%、初始糖度16 °Brix;苹果渣醋酸发酵过程的最优工艺条件是干湿苹果渣的配料比为1 ∶ 10、醋酸菌接种量15%、发酵温度32 ℃,此条件下总酸含量增长到38.267 6 g/L。     

干白葡萄酒增香酿造工艺参数优化

试验以一种酿酒葡萄为原料,利用顶空固相微萃取/气相色谱-质谱联用技术(HS-SPME/GC-MS)检测了不同可同化氮含量(200、300、400 mg/L)、酵母多糖(150、250、350 mg/L)、发酵温度(14、18、22℃)、初始pH值(3.3、3.5、3.7)和SO2添加量(40、70、100 mg/L)处理发酵酒样中的挥发性香气化合物,探讨了复合酿造因子对贵人香干白葡萄酒主要香气物质含量的影响关系。结果表明,300 mg/L的可同化氮有利于高级醇、酯类、单萜化合物的积累;酵母多糖添加量为250 mg/L时,单萜化合物质量分数达到最大值(198.54μg/L);发酵温度从14℃升高到22℃时,高级醇含量显著升高,酯类和单萜含量显著降低;提高葡萄汁初始pH有利于单萜化合物的积累,不利于高级醇、酯类的生成;添加70 mg/L的SO2时,单萜化合物质量分数最高(181.73μg/L)。正交试验极差分析表明,发酵温度和SO2添加量对高级醇含量影响较大;发酵温度与可同化氮对酯类香气物质含量的影响较大,酵母多糖和pH值对单萜类香气物质含量影响较大。各处理组间的聚类分析可知,可同化氮和酵母多糖对主要香气化合物的影响关联度较高、葡萄汁初始pH值和SO2添加量关联度较高。较低的发酵温度有利于酒样中香叶醇、异戊醇、苯乙醇、辛酸乙酯的生成,添加中等浓度的可同化氮和酵母多糖可促进乙酸异戊酯、乙酸己酯和己酸乙酯的合成,较高的初始pH值有利于芳樟醇、香茅醇和香叶醇的积累。综合分析,发酵温度18℃、初始pH值3.5、70 mg/L SO2、300 mg/L可同化氮、250 mg/L酵母多糖酿造贵人香干白葡萄酒,可有效促进酒样中主要香气化合物的合成释放。     

红曲中非酿酒酵母的分离鉴定及其对黄酒风味成分的影响

为探究红曲中非酿酒酵母对黄酒风味成分的影响,首先对红曲中的酵母菌株进行分离纯化,并采用分子生物学方法进行鉴定,然后将分离的非酿酒酵母菌株分别与红曲霉相结合,以纯种发酵的方式酿造红曲黄酒,分析各酒样中有机酸、氨基酸、挥发性物质等风味成分的组成及含量。结果表明,分离获得的4株非酿酒酵母CKS-2为威克汉姆酵母(Wickerhamomyces sp.)、CKS-3为季也蒙毕赤酵母(Meyerozyma guilliermondii)、CKS-4为胶红酵母(Rhodotorula mucilaginosa)、CKS-7为德尔布有孢酵母(Torulaspora delbrueckii),其中,CKS-7具有较好的产乙醇和苹果酸能力,发酵酒样中丝氨酸、组氨酸、色氨酸和亮氨酸的含量也较高,并且具有良好的合成2-苯乙醇、异戊醇、棕榈酸乙酯等挥发性风味成分的能力。本研究对红曲黄酒品质提升,以及筛选潜在可应用于红曲黄酒酿造的优良非酿酒酵母菌株具有一定作用。     

Oenological influences on the D/H ratios of wine ethanol

Within the European Union the determination of chaptalization of wine involves the comparison of the D/H ratios of ethanol with the ratios of authentic wine samples that are similar to the suspect wine in terms of geographical origin, grape variety, and vintage. In the frame of a databank project comparison, wines are produced under official control on a small scale. To clarify the influence of the different production conditions between commercial wines and these databank wines, wines that were produced under varying conditions were investigated by the (2)H NMR method. None of the parameters under investigation, such as yeast strain, fermentation temperature, or wine fining, showed a significant influence on the (D/H)(I) ratio of wine ethanol, which is the most indicative parameter for the determination of the addition of extraneous sugar to wine. For the (D/H)(II) ratio, different values were found for different yeast strains used for fermentation and a slight decrease was observed with increasing fermentation temperature. At increasing points of fermentation yield an increase of the D/H ratios was found in the present alcohol. The total increase of the (D/H)(I) ratio throughout the fermentation was approximately 1 ppm, so that with a fermentation yield of more than 50% no statistical difference could be observed.     

优选非酿酒酵母胞外酶增香酿造干白葡萄酒效果

为了研究非酿酒酵母胞外酶促进葡萄酒发酵产香的效果,该文在爱格丽葡萄汁酒精发酵12 h后,分别添加优选胶红酵母(Rhodotorula mucilaginosa,RM)胞外酶液,优选发酵毕赤酵母(Pichia fermentans,PF)胞外酶液和商业糖苷酶制剂(almondβ-glucosidase,AG)(10 mU/mL),以不添加酶制剂的酿酒酵母纯发酵为对照,发酵过程中每24 h取样,采用HS-SPME-GC/MS(headspace solid-phase microextraction-gas chromatography/mass spectrometry)监测挥发性成分的生成变化。葡萄酒含糖量低于2 g/L时终止发酵,低温满罐密封储存,次年4月,进行葡萄酒香气仪器和感官量化分析。胞外酶液共测得6种风味酶活性,其中RM酶液中的β-D-葡萄糖苷酶、α-L-鼠李糖苷酶、β-D-木糖苷酶活性均显著(P<0.05)高于PF中的,而α-L-阿拉伯糖苷酶和酯酶在PF酶液中活性更高(P<0.05)。发酵过程中,胞外酶处理显著促进了(P<0.05)品种香气和发酵香气物质的生成,其中RM酶液显著提高了萜烯类物质和苯乙基类化合物含量,其作用效果分别比商业酶处理高41.7%和31.8%,PF酶液显著促进了发酵香气化合物的生成,尤其是脂肪酸乙酯含量约为对照的2倍。酒样感官分析结果显示,两株酵母的胞外酶处理表现出各自增香酿造的优势,其中RM酶液促进温带酸果类香气的效果突出,PF酶液显著提升了柑橘类香气。研究结果为酵母风味酶应用于葡萄酒的增香酿造提供了理论和实践指导。     

腌制叶用芥菜发酵菌分离鉴定及应用研究

为获得发酵性能优良的菌株,生产优质的发酵叶用芥菜,本研究从自然发酵的芥菜中分离发酵用菌株,通过测定乳酸菌的生长、产酸和亚硝酸盐降解能力以及酵母菌的产气、产酯能力和蛋白酶活性等发酵特性进行筛选,并对筛选获得的优良发酵菌加以应用。结果表明,筛选获得的2株乳酸菌L8短乳杆菌(Lactobacillus brevis)、L9植物乳杆菌(Lactobacillus plantarum)和1株酵母菌Y9酿酒酵母菌(Saccharomyces cerevisiae)在腌制叶用芥菜中的发酵性能优良。与自然发酵的叶用芥菜相比,接菌发酵叶用芥菜的pH值和亚硝酸盐含量分别减少了2.22%和88.13%;总酸含量、氨基酸态氮含量分别增加了9.02%和28.09%。接菌发酵提高了腌制芥菜的营养品质和安全性。本研究丰富了叶用芥菜的发酵菌种,为蔬菜发酵加工产业奠定了技术基础。     

Effect of different strains of Saccharomyces cerevisiae on production of volatiles in Napa Gamay wine and Petite Sirah wine

Napa Gamay grapes were fermented with four different strains of the yeast Saccharomyces cerevisiae (VL1, MI16, Fermirouge, and RA17). Petite Sirah grapes were fermented with seven different strains of the same yeast (BM45, Fermirouge, RA17, NI, CX3079, A350, and A796). Volatile compounds formed in the wines were analyzed by gas chromatography/mass spectrometry. Volatile compounds found in both wines were alcohols, esters, and acids, as well as some miscellaneous compounds. Isoamyl alcohol was the compound found in the highest relative amount with all four yeast strains in the Napa Gamay wines, followed by 2-phenyl ethanol, monoethyl succinate, and hexanoic acid. The relative amounts of isoamyl alcohol ranged from 30.84% (VL1) to 43.28% (RA17). Major volatile compounds found in Petite Sirah wines were isoamyl alcohol, 2-phenyl ethanol, 2-hydroxy ethyl propanoate, monoethyl succinate, and octanoic acid. The several esters, including 2-hydroxyethyl propanoate, may contribute to the fruity flavor of Petite Sirah wines. Overall, the S. cerevisiae yeast strains used to ferment Napa Gamay grapes and Petite Sirah grapes produced the same major components, with certain variations in formation levels.     

Grape contribution to wine aroma: production of hexyl acetate, octyl acetate, and benzyl acetate during yeast fermentation is dependent upon precursors in the must

Wine is a complex consumer product produced predominately by the action of yeast upon grape juice musts. Model must systems have proven ideal for studies of the effects of fermentation conditions on the production of certain wine volatiles. To identify grape-derived precursors to acetate esters, model fermentation systems were developed by spiking precursors into model must at different concentrations. Solid-phase microextraction-gas chromatgraphy mass spectrometry analysis of the fermented wines showed that a variety of grape-derived aliphatic alcohols and aldehydes are precursors to acetate esters. The C6 compounds hexan-1-ol, hexenal, (E)-2-hexen-1-ol, and (E)-2-hexenal are all precursors to hexyl acetate, and octanol and benzyl alcohol are precursors to octyl acetate and benzyl acetate, respectively. In these cases, the postfermentation concentration of an acetate ester increased proportionally with the prefermentation concentration of the respective precursor in the model must. Determining viticultural or winemaking methods to alter the prefermentation concentration of precursor compounds or change the precursor-to-acetate ester ratio will have implications upon the final flavor and aroma of wines.     

Sensory and analytical study of rose sparkling wines manufactured by second fermentation in the bottle

The sensory and analytical characteristics of five rose sparkling wines manufactured by the traditional method have been determined. Moreover, the changes that take place in the nitrogen and volatile fraction of the wines during the second fermentation and the aging with the yeasts have been studied. Each of these wines was made from a single industrial rose base wine of the Garnacha Tinta variety, with five selected yeasts strains. The base wine had a low content in free amino acids, 16 mg/L, and the yeast consumed more peptides than free amino acids during second fermentation. From the application of the two-way analysis of variance, yeast strain, and aging time factors to the data of volatile compounds, it has been found that most of the differences between these sparkling wines are due to the aging time. It has been verified that these rose sparkling wines have foam of good quality and that the grape variety Garnacha Tinta is suitable for the production of rose sparkling wines.     

Selection of yeast starter culture strains for the production of marula fruit wines and distillates

Juice of the Sclerocarya birrea subsp. caffra (marula) fruit was fermented by indigenous microflora and different commercial Saccharomyces cerevisiae yeast strains at different temperatures, namely, 15 and 30 degrees C. Volatile acids, esters, and higher alcohols were quantified in the wine and distillates, and the results were interpreted using a multivariate analysis of variance and an average linkage cluster analysis. Significant differences between 15 and 30 degrees C and also among yeasts with respect to volatile compounds were observed. Yeast strains VIN7 and FC consistently produced wines and final distillates significantly different from the other strains. A panel of tasters and marula and brandy producers was asked to select wines and distillates that had an acceptable and typical marula "nose". They were also asked to detect the differences among wines and distillates fermented with the same yeast strain at different temperatures.     

Effect of the stone content on the quality of plum and cherry spirits produced from mash fermentations with commercial and laboratory yeast strains

To evaluate the influence of stone content on spirit quality from stone fruit, cherry and plum mashes were prepared and fermented with a commercial and a diploid laboratory yeast strain. Fermentation parameters such as sugar content and ethanol production were followed. Despite an initial lag phase in cherry spirits, both yeast strains performed similarly, as substantiated by the determination of specific flavor compounds, ethyl carbamate, and methanol in the mashes and after distillation. The spirits produced were subjected to sensory analyses by trained panels of at least 25 judges. Although mashes retaining the stones could be clearly distinguished from those where the stones had been removed, no significant preference could be attributed to either spirit, indicating that qualities added by the presence of stones during fermentation are largely a matter of personal taste. Interestingly, the yeast strain used for fermentation seemed to have little influence on the spirit quality.