发酵型枸杞黄酒生产工艺以及护色方法的研究

研究了原料配比、发酵温度及时间对发酵型枸杞黄酒的生产工艺的影响,优化了枸杞黄酒的酿造工艺,即枸杞用量为19%,酵母用量为0.09%,发酵温度为29℃,发酵7 d;并且进一步探讨了枸杞黄酒的护色工艺,考察了2种护色剂——护色剂1和护色剂2,以及杀菌温度和时间对枸杞黄酒色泽的不同作用,优化后的护色条件为:护色剂1用量为0.6 g/L,护色剂2用量为4.0 g/L,杀菌温度为85℃,杀菌时间为10 min。     

Modification of pectin polysaccharides during ripening of postharvest banana fruit

Pectin is one of the major components of the primary cellular walls and middle lamella in plant tissues. In this study, water-soluble pectin (WSP) and acid-soluble pectin (ASP) fractions were isolated from pulp tissues of banana fruit at various ripening stages. Their monosaccharide compositions, glycosyl linkages and molecular mass distributions were evaluated. As ripening progressed, fruit firmness decreased rapidly, which was associated with the increase in the WSP content and the decrease in the ASP content. Meanwhile, the molecular mass distributions of WSP and ASP fractions exhibited a downshift tendency, indicating the disassembly of pectin polysaccharides. Moreover, galactose and galacturonic acid as the major monosaccharide compositions of pectin polysaccharides increased in WSP fraction but decreased in ASP fraction during fruit softening. GC–MS analysis further revealed that pectin polysaccharide had a 1,4-linked galactan/galacturonan backbone with different types of branching and terminal linkages in WSP and ASP fractions. During banana fruit ripening, the amount of 1,4-linked Galp residues of ASP fraction decreased significantly whereas 1,3,6-linked Galp, 1,2-linked Manp and 4-linked Araf residues disappeared, which was related to depolymerization of pectin polysaccharides. Overall, the study indicated that the modifications in polysaccharide compositions and glycosyl linkages, reduced molecular mass distributions and enhanced depolymerization of pectin fraction during banana ripening were responsible for fruit softening.     

烟台干红葡萄酒发酵过程中酵母种类鉴定

利用WL培养基对分离自烟台葡萄果皮和干红葡萄酒发酵过程中的117株酵母菌进行归类,采用26S rDNA D1/D2区序列分析进行分子鉴定,共得到6属8种。并对发酵过程不同时期的酵母种类进行分析,结果表明发酵过程中酵母种类持续减少。     

皂土和壳聚糖对青梅发酵酒澄清效果的比较研究

研究了皂土和壳聚糖对青梅发酵酒的澄清效果,并通过正交试验及综合评比分析,结果表明壳聚糖的澄清效果明显好于皂土,经壳聚糖处理的青梅发酵酒透光率达98.5%,确定了最佳澄清工艺条件：壳聚糖用量0.5g/L,pH为3.2,温度26℃,澄清时间24h。澄清后的发酵酒澄清透明,稳定性增加。     

Enhancement of urea uptake in Chinese rice wine yeast strain N85 by the constitutive expression of DUR3 for ethyl carbamate elimination

Most of the fermented alcoholic beverages, particularly Chinese rice wine, contain the potentially human carcinogenic compound ethyl carbamate (EC). As a major EC precursor in Chinese rice wine, urea in fermentations can be transported into the yeast cell by urea permease and finally metabolized by urea carboxylase and allophanate hydrolase in vivo. To eliminate EC in Chinese rice wines, the present study constructed high urea uptake yeast strains N1‐D, N2‐D and N‐D, by introducing a strong promoter (PGK1p) into the urea permease gene (DUR3) of the industrial Chinese rice wine yeast N85, and by the restoration of the URA3 gene at the same time. With these self‐cloned, high urea uptake strains, the urea and EC in the terminal Chinese rice wine samples were reduced to different extents. With two copies of overexpressed DUR3, the N‐D strain could reduce the urea and the EC by 53.4 and 26.1%, respectively. No difference in fermentation characteristics was found between the engineered strains and the parental industrial yeast strain N85. These results could help to optimize the genetic manipulation strategy for EC elimination in Chinese rice wine production. Copyright © 2015 The Institute of Brewing & Distilling     

香格里拉产区特色非酿酒酵母及自然发酵葡萄酒香气成分的研究

以香格里拉产区澜沧江流域4个不同海拔葡萄园（布村、溜筒江、斯农和阿东）的酿酒葡萄赤霞珠为试材,对各地葡萄酒特色非酿酒酵母进行分离鉴定,并采用气质联用（GC-MS）法对各地自然发酵葡萄酒的香气成分进行分析。结果表明：各地赤霞珠自然发酵葡萄酒中共分离鉴定到非酿酒酵母9个属10个种,其中,葡萄汁有孢汉逊酵母（Hanseniaspora uvarum）在各地均有分离到;黏红酵母（Rhodotorula glutinis）在布村、溜筒江和阿东均有分离到;出芽短梗霉（Aureobasidium pullulans）、汉逊德巴利酵母（Debaryomyces hansenii）和美极梅奇酵母（Metschnikowia pulcherrima）为斯农独有;而核果梅奇酵母（Metschnikowia fructicola）、季也蒙毕赤酵母（Meyerozyma guilliermondii）和克鲁维毕赤酵母（Pichia kluyveri）为阿东独有;浅黄隐球酵母（Cryptococcus flavescens）为溜筒江独有。这些非酿酒酵母使得各地自然发酵葡萄酒的香气各具特色,其中以醇类、酯类和芳香族类香气种类与含量的差异最为突出。     

On-line HPLC–MS–DPPH assay for the analysis of phenolic antioxidant compounds in fruit wine: Antidesma thwaitesianum Muell.

A reversed phase high performance liquid chromatography (RP-HPLC) separation coupled with an electrospray ionisation mass spectrometry detection (ESI-MS) and the 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay was used for the screening of multiple antioxidant compounds in Antidesma thwaitesianum Muell. fruit wine. The active compounds were identified by comparison with authentic standards and published mass spectra. With the help of the multidimensional information of LC–ESI-MS/MS and DPPH assay, the compounds with different chemical structures could be determined in one run successfully. The antioxidant compounds were separated and identified as gallic acid, cyanidin-3-sophoroside, monogalloyl glucoside, delphinidin-3-sambubioside, catechin, caffeic acid, and pelargonidin-3-malonyl glucoside. This result shows that an on-line HPLC–MS–DPPH assay can be a powerful technique for the rapid characterisation of antioxidant compounds in plant extracts.     

黄酒酿造中米浆水回用技术的研究

对浸米过程中米浆水的变化情况及不同添加浆水量对黄酒质量的影响进行了分析.结果表明,随浸米时间的延长,米浆水中总酸和COD含量逐渐增加;浸米温度越低,酸含量越少.黄酒发酵过程中用新鲜米浆水替代部分投料用水,可以起到"以酸制酸"的作用,最适宜的浆水添加量为40%.     

Factors influencing quantities of sugars and organic acids in blackcurrant concentrates

 Use of endogenous non-volatile flavour components, i. e. sugars and organic acids, in fruit juice products is desirable. A study of 133 blackcurrant concentrates from three seasons examined variation in sugars and acids arising from storage of fruit at freezing or sub-ambient temperature, seasonal differences, geographical origin and choice of conventional thermal-evaporative or freeze concentration technology. Compared with freeze concentrates, conventional concentrates had significantly higher contents of total sugars and acids, notably malic acid, and higher fructose/glucose, lower malic/citric acid and similar sugar/acid ratios. Concentrates from frozen fruit generally had smaller amounts of fructose, total sugars and fructose/glucose ratios than those from fresh fruit, as well as less citric, ascorbic and total acids and lower sugar/acid ratios. Principal component analysis of 40 randomly chosen concentrates showed that variance is dominated by differences in fructose, total sugars and ascorbic acid contents and sugar/acid ratios. Geographical origin and concentration technology were major sources of variance but changes in post-production sub-ambient storage could not be excluded. Received: 4 July 1997 /  Revised version: 14 October 1997