枇杷果酒发酵工艺的优化

[目的]优化枇杷果酒酿造的工艺参数。[方法]以湖北省荆门市当地的枇杷鲜果为原料,采用正交试验和感官评定考察不同发酵温度、酵母接种量、起始糖浓度、p H和发酵时间对枇杷果酒质量的影响。[结果]枇杷果酒发酵的最佳工艺条件是发酵温度15℃,起始糖浓度20 Brix,p H 3.6,酵母接种量0.4%,前期发酵时间6 d。[结论]所得果酒透明清亮,色泽淡黄,酒体醇香,为枇杷的深加工利用提供了参考途径。     

柿子酒液态发酵工艺条件优化研究

[目的]为提高柿子资源利用率,对柿子酒发酵工艺条件进行优化研究。[方法]该试验以柿子为主要原料,探究不同防褐变剂及添加量对柿子浆褐变的影响,并比较固态发酵和液态发酵2种发酵方式酿制柿子酒对其品质的影响。[结果]最佳的防褐变剂为柠檬酸1%;酒精发酵工艺的最佳方法为液态酒精发酵,其最优工艺参数为温度30℃、发酵天数7 d、接种量0.3 g/L、糖度200 g/L和p H 3.5。在此条件下酿造出的柿子酒,色泽明亮橙黄、柿香愉悦、酸味纯正、澄清透明、营养丰富。[结论]研究可为增加柿子的附加值,促进农业经济发展供理论依据。     

1株巨大芽孢杆菌BM05发酵条件的优化

[目的]优化巨大芽孢杆菌BM05的发酵条件,提高其发酵活菌数。[方法]通过单因素试验筛选最佳碳、氮源,通过正交试验筛选最佳C/N比,并研究p H、发酵温度、接种量和转速对发酵的影响。[结果]碳源选用玉米淀粉和葡萄糖,氮源选择牛肉粉,初始p H 7.0,发酵温度35℃,接种量为4%,转速220 r/min为最佳发酵条件。通过发酵条件优化,发酵菌数达4.73×109cfu/m L,比原始配方提高了1.56倍。[结论]优化后的发酵条件大大提高了巨大芽孢杆菌BM05的发酵活菌数。     

一株苹果内生枯草芽孢杆菌BS10的发酵条件优化研究

以苹果内生枯草芽孢杆菌BS10为试验菌株进行发酵培养基的优化,通过单因素试验选出最佳的碳源和氮源,通过正交试验筛选出最佳C/N比,对p H值、发酵温度和接种量进行了研究。结果表明,碳源选用麦芽糊精,氮源选择豆饼粉,初始p H值7.5,温度33℃、接种量为4%为最佳发酵条件,发酵活菌数为1.03×1010cfu/m L,比原始配方提高了1.94倍。     

沙枣果酒加工工艺研究

[目的]优化沙枣果酒加工工艺。[方法]以沙枣为原料,经加水浸提后,调糖、调酸并添加酵母进行发酵;利用单因素试验和正交试验设计研究二氧化硫的添加量、酵母用量、沙枣汁初始糖度及主发酵温度对发酵的影响。[结果]结果表明,沙枣果酒的主发酵最佳工艺条件为：SO2添加量为80 mg/L,主发酵温度在22.5℃,初始糖度18%,酵母接种量0.25%;在该最佳工艺条件下,发酵的沙枣酒酒度为10.0%（V/V）。[结论]该加工工艺研究为沙枣果酒的生产提供了理论依据。     

应用Box-behnken响应面优化柑桔果醋发酵工艺研究（英文）

[目的]采用Box-Behnken设计进行工艺优化,研究柑桔果醋的酒精发酵和醋酸发酵工艺,为柑桔果醋的工业化应用奠定基础。[方法 ]以柑桔为原料,初始糖度、初始pH值、接种量3个因素为主要影响因素,以醋酸产量为为评价指标进行Box-Behnken设计试验,考察最佳工艺。[结果]柑桔果醋的酒精发酵优化工艺参数为:初始糖度为16%、接种量为5%、初始p H为3.5。醋酸发酵优化工艺参数为:接种量为8.52%、初始酒精度为6.02%、发酵pH为3.3,该工艺下醋酸产量53.11 g/L。响应面优化试验中接种量对醋酸的影响极显著,初始酒精度对醋酸的影响显著,发酵pH对醋酸的影响极显著;接种量与初始酒精度的交互作用对醋酸的影响不显著,接种量与发酵pH交互影响醋酸不显著,初始酒精度与发酵p H的交互作用对醋酸的影响显著。[结论]采用BoxBehnken设计优化柑桔果醋的发酵工艺稳定可行,为进一步地柑桔果醋的工业化应用奠定基础。     

无花果酒的发酵工艺及其抗氧化活性分析

[目的]研究无花果酒的发酵工艺及其抗氧化活性。[方法]通过单因素试验和响应面分析法优化发酵工艺条件,并检测无花果酒对DPPH自由基和羟自由基的清除率。[结果]无花果酒的最佳发酵工艺条件为:酿酒干酵母接种量0.03%、SO2添加量85mg·kg-1、发酵温度28℃、发酵天数8d,此条件下无花果酒的酒精度为12.2%vol;与发酵前相比,无花果酒的体外抗氧化活性显著增强,维生素C、多酚、黄酮含量比分别比发酵前分提高了4倍、1.27倍、1.64倍。[结论]无花果酒具有良好的抗氧化活性,可以作为一种抗氧化剂和自由基清除剂。     

南瓜酒的研制

[目的]探讨以南瓜为原料的发酵酒酿造工艺。[方法]通过单因素试验考察不同的酵母接种量、初始糖度、初始pH、主发酵温度对发酵南瓜酒乙醇含量的影响,再以乙醇含量、总糖度、澄清度、色泽、滋气味等因素的综合评分为依据,通过正交试验对酿造工艺进行优化。[结果]南瓜酒发酵的影响因素从主要到次要依次为酵母接种量、主发酵温度、初始pH、初始糖度;发酵的最佳条件是初始糖度20%、初始pH 3.5、主发酵温度21℃、酵母接种量6%,主发酵时间7 d。主发酵液离心取上清液经10 d后发酵处理,得到成品南瓜酒。南瓜酒的相关理化指标为：乙醇含量11.0%-12.0%（V/V）,糖度4-5 g/L;得到的南瓜酒色泽呈浅橙黄色,酒中带有南瓜清香,甜酸协调适口,酒体透明、无沉淀。[结论]南瓜酒口感柔和,气味独具南瓜果味芬芳,是一种极具市场潜力的保健型果酒。     

深黄被孢霉突变菌株发酵制备花生四烯酸工艺研究

在单因素试验基础上,采用响应面分析法优化深黄被孢霉突变菌株发酵制备花生四烯酸工艺,确定最优发酵工艺条件为:接种量15.66%,发酵温度28.29℃,发酵时间6.58 d,发酵p H 5.96。花生四烯酸产量为3.12 g·L-1,在最优发酵工艺条件下,可提高产量,同时减少接种量,缩短发酵时间,降低生产成本。     

响应面法优化仙人掌酵素的发酵工艺

[目的]利用酵母菌和乳杆菌发酵仙人掌制备仙人掌酵素。[方法]首先以糖的添加量、菌种比例、接种量、发酵温度、发酵时间为因素进行单因素试验,确定超氧化物歧化酶(SOD)活性较大时各因素相应的范围;然后分析试验条件,应用Box-Behnken中心组合设计,以糖的添加量、接种量和发酵温度为因素,以SOD活力的变化为响应值进行试验,运用SAS统计软件对试验数据进行分析,建立二次响应面回归模型,得出重要因素的最佳水平,从而确定最佳的发酵条件。[结果]经响应面法优化获得仙人掌酵素发酵工艺的参数如下:糖的添加量55.0%、接种量4.0%、发酵温度34.0℃,在优化条件下,SOD活力达到323.21 U/g。[结论]该研究可为仙人掌酵素的生产提供科学依据。     

Transformation of a star into a planet in a millisecond pulsar binary

Millisecond pulsars are thought to be neutron stars that have been spun-up by accretion of matter from a binary companion. Although most are in binary systems, some 30% are solitary, and their origin is therefore mysterious. PSR J1719-1438, a 5.7-millisecond pulsar, was detected in a recent survey with the Parkes 64-meter radio telescope. We show that this pulsar is in a binary system with an orbital period of 2.2 hours. The mass of its companion is near that of Jupiter, but its minimum density of 23 grams per cubic centimeter suggests that it may be an ultralow-mass carbon white dwarf. This system may thus have once been an ultracompact low-mass x-ray binary, where the companion narrowly avoided complete destruction.     

Action at a distance along a DNA

A number of ways are known by which an event at one location on a DNA molecule can affect an event at a distant location on the same molecule. Three classes of mechanisms are described for such distal actions: tracking or translocation of a protein along a DNA, the association of two proteins bound at separate sites to form a DNA loop in between, and distal interactions that are affected by the topology of the DNA. The basic characteristics of each type of mechanism are discussed in terms of the known physicochemical properties of DNA. The various modes of action at a distance are often interrelated. Examples include the formation of positively and negatively supercoiled DNA loops by tracking and the strong effects of DNA topology on looping.     

Conversion of a peroxiredoxin into a disulfide reductase by a triplet repeat expansion

Pathways for the reduction of protein disulfide bonds are found in all organisms and are required for the reductive recycling of certain enzymes including the essential protein ribonucleotide reductase. An Escherichia coli strain that lacks both thioredoxin reductase and glutathione reductase grows extremely poorly. Here, we show that a mutation occurring at high frequencies in the gene ahpC, encoding a peroxiredoxin, restores normal growth to this strain. This mutation is the result of a reversible expansion of a triplet nucleotide repeat sequence, leading to the addition of one amino acid that converts the AhpC protein from a peroxidase to a disulfide reductase. The ready mutational interconversion between the two activities could provide an evolutionary advantage to E. coli.     

Development of a receptor on a foreign nerve fiber in a Pacinian corpuscle

When the sensory fiber of a Pacinian corpuscle (in cat mesentery) is transected (at the inferior mesenteric nerve) transduction fails within 30 hours: the nerve ending produces no generator potentials in response to mechanical stimulation. Electrically elicited nerve impulse conduction continues for at least another 18 hours. A transducer mechanism develops on a regenerating nerve fiber when this fiber enters the denervated corpuscle. Such transducer development takes place on myelinated fibers from the inferior mesenteric nerve, which normally supplies corpuscles, as well as on myelinated hypogastric nerve fibers, which normally do not go to corpuscles, including fibers larger than the original corpuscle afferents.     

一个具有非自治性扰动的拟线性椭圆方程非平凡解的存在性

利用变量替换和Ekeland变分原理,在R～N上获得了一类具有非自治扰动的拟线性椭同方程非平凡解的存在性结果.

Abstract：

The existence of a nontrivial solution is obtained for a quasilinear elliptic equations on RN with a non-autonomous perturbation by the change of variable and the Ekeland's variational principle.