保糖发酵葡萄酒产品的旋光识别模型建立

通过测定不同浓度的标准葡萄糖、果糖以及它们混和溶液的旋光度，得到了葡萄糖和果糖混合溶液的旋光度方程，并经过系列保糖发酵葡萄酒产品的实际修正，证实保糖发酵葡萄酒中的主要旋光物质是葡萄糖和果糖，建立了保糖发酵葡萄酒旋光识别的上限方程为Yw=-0．0448Xt＋0．0813，下限方程为Yw=-0．0669X，＋0．0722。为检测保糖发酵葡萄酒产品提供了简便快速的识别方法。     

关于葡萄糖异构化过程中DE值下降原因的探讨

从还原力的角度探讨了葡萄糖异构化生产果葡糖浆过程中葡萄糖值下降的原因。在费林氏法测定还原糖的条件下,比较了果糖和葡萄糖的还原力;分别用葡萄糖和淀粉水解糖为原料,研究了异构化过程中DE值与果糖含量的关系。结果表明,对于费林氏溶液,果糖的还原力比葡萄糖低;葡萄糖值随异构化所产生的果糖含量增加而降低。异构化过程中DE值下降的主要原因是果糖的还原力比葡萄糖低。     

糖浓度对酒精酵母GJ2008果糖与葡萄糖利用差异性的影响

在不同糖浓度条件下,以YPDF培养基模拟甘蔗汁进行酒精发酵,测定过程中各参数的变化,并对果糖与葡萄糖消耗过程进行曲线拟合,以拟合方程计算出果糖与葡萄糖代谢一半和代谢完全所需时间.结果表明,糖浓度为90gL～270g/L,酵母GJ2008始终会偏用葡萄糖,果糖利用一直受到葡萄糖的竞争性抑制.糖浓度为90g/L时,细胞生长受糖浓度抑制程度最小,但乙醇产率较低;糖浓度为230g/L,发酵液中葡萄糖含量较低时,果糖受葡萄糖的竞争性抑制得到了解除,果糖的利用急剧加快;糖浓度为250g/L和270g/L,发酵液中葡萄糖含量较低时,果糖受葡萄糖的竞争性抑制得到了解除,但果糖的利用并没有加快,表现为后期酵母数维持值较低.糖浓度对果糖代谢的影响要大于对葡萄糖代谢的影响,较低糖浓度有利于后期果糖与葡萄糖利用差异性的缩小.     

提高转化糖溶液中果糖对葡萄糖的比率

美国专利923858号叙述了提高转化糖溶液中果糖对葡萄糖比率的方法,介绍如下;专利所用的转化糖溶液中含有10—15％的转化糖和可供弱氧化醋酸菌(Acetobacter Suboxydans)深层好气发酵的营养物一氮素,使葡萄糖氧化成葡萄糖酸,而不触动     

用反渗透法分离果糖和葡萄糖

1983年Kim等研究了用醋酸纤维膜(CA膜)和聚乙烯醇膜(PVA膜)反渗透法,从有机溶液中分离各种糖、醇、氨基酸、尿素和表面活性剂的可能性,发现了在CA膜中,葡萄糖和果糖之间有渗透性的差异。作者等考虑了原料的组成和加入一些盐的效应,进一步研究了葡萄糖和果糖的反渗透分离。在含有果糖和葡萄糖的混合物中加入一些无机物质,其中一种糖就能有选择性地形成络     

利用重组葡萄糖脱氢酶提高低聚果糖纯度

用IPTG（诱导基因工程菌）M15／pQE31-gdh表达葡萄糖脱氢酶，纯化，该重组葡萄糖脱氢酶用于高纯度低聚果糖生产研究。以含量为51．11％（低聚果糖／总糖）低聚果糖的产品为底物，葡萄糖脱氢酶（5U／g总糖）作用2h，将低聚果糖含量提高到61，37％，消除了48，81％的葡萄糖。以30％（w／v）蔗糖为底物，利用有果糖基转移酶活性的米曲霉GX0015（15U／g总糖）作用6h后，加入葡萄糖脱氢酶（5U／g总糖）协同作用4h，得到成分为：低聚果糖含量76．87％、葡萄糖11．05％、蔗糖含量5.21％的产品。由果糖基转移酶和葡萄糖脱氢酶组成的系统能够有效降低葡萄糖含量，提高低聚果糖含量。     

改变转化糖溶液中果糖和葡萄糖之间比例的方法

本专利系由英国J&JColman公司提出申请的。本发明提供一种改变转化糖中果糖和葡萄糖之间比例的方法,它包括将一个含有氮营养物的10~15%转化糖溶液处于需氧深层发酵,发酵是用一种能够将葡萄糖氧化成葡糖酸而又不和果糖起反应的醋酸杆菌处理,温度用室温     

超声波对糖溶液物化特性的研究

研究了果糖、葡萄糖、蔗糖、麦芽糖、乳糖五种糖溶液的声速-浓度关系,结果表明:糖溶液中声速与浓度呈极显著正相关,得到的二次回归方程的回归系数大于0.9970。同时比较了声参量和密度对糖类型的辨别性,结果表明:超声检测方法对糖的种类具有更好的辨别性。探讨了声特性与糖分子结构以及糖分子与水分子的水合作用与超声参量之间的关系,表明超声参量可用于对糖溶液物化特性的研究。     

干制条件对杏果中糖含量变化的影响

以新疆赛买提杏为原料,研究热风干制和自然晒制过程中糖含量变化规律,包括果糖、葡萄糖、蔗糖、果胶和粗纤维等。结果表明,杏果实中葡萄糖含量大于果糖含量,干制过程中果糖、葡萄糖及还原糖含量降低,且热风干制温度越高,还原糖降解幅度越大。热风温度处理有利于杏果中蔗糖和可溶性总糖在干制初期的积累。随着干制温度升高,蔗糖与果糖、葡萄糖、还原糖的相关性由极显著负相关水平逐渐向正相关水平转化,说明热作用下蔗糖又降解成果糖和葡萄糖等还原糖类物质。干制过程中可溶性果胶含量增加,原果胶和粗纤维含量降低,说明在干制过程中杏果存在后熟软化的现象。因此,通过控制干制条件在一定范围内能够调控杏果中糖的组分和含量,改善杏干的品质。     

离子色谱法同时测定蛋白胨中葡萄糖、果糖、蔗糖、麦芽糖、乳糖含量

目的建立离子色谱法同时检测蛋白胨中葡萄糖、果糖、蔗糖、麦芽糖、乳糖的分析方法。方法样品用水作为提取剂,用OnGuard Ⅱ RP柱和OnGuard Ⅱ H柱净化,50mmol/LNaOH溶液作为流动相,用Carbopac PA20柱进行离子色谱分析。结果在该条件下5种糖都能得到较好分离,线性良好,葡萄糖、果糖、蔗糖、乳糖和麦芽糖的检出限为0.002、0.004、0.011、0.007、0.018 mg/L,平均回收率为90.59%～97.68%(n=9)。结论该方法操作简便、灵敏度高,可用于作为蛋白胨中葡萄糖、果糖、蔗糖、麦芽糖、乳糖的检测。     

对虾育苗中过氧化钙膨润土混合物的应用

将过氧化钙膨润土混合物在对虾育苗生产中进行了应用研究和生产试验,结果表明,过氧化钙膨润土混合物能增加水体中的溶解氧含量;促使对虾脱皮,增加幼虾的活力;吸附沉淀有机悬浮物、氨氮及硫化氢等,改善育苗池底质状况。     

Continuous production of very enriched fructose syrup by the conversion of glucose to ethanol from glucose-fructose mixtures in an immobilized cell reactor

The yeast Saccharomyces cerevisiae ATCC 36859, which preferentially utilizes glucose in glucose-fructose mixtures, was immobilized and used for the continuous production of very enriched fructose syrup. A syrup containing fructose as 99% of the reducing sugars was produced from a 10.1% w/v glucose and 9.8% w/v fructose mixture at a dilution rate of 0.106 h⁻¹. Later in this process when the dilution rate was increased to 0.366 h⁻¹ the ethanol productivity was 12.7 g 1⁻¹ h⁻¹. This is 16% less than the value attained in a similar medium containing only glucose as the carbohydrate. The fructose content was also increased from 55 to 95% of the reducing sugars in a food grade mixture of high fructose corn syrup and Jerusalem artichoke juice. Purification of the product with activated carbon and ion-exchange resin produced a stable, colourless and very enriched fructose syrup suitable for human consumption.     

PC钢棒在混凝土电杆中的应用分析

针对国内很多混凝土电杆生产企业将PC钢棒作为纵向受力钢筋用于混凝土电杆生产的状况作出相应的理论计算,并对使用PC钢棒的电杆进行力学性能试验。结果显示,PC钢棒作为预应力钢筋使用时,为达到预应力电杆抗裂使用要求,在电杆加工时需进行张拉操作,使PC钢棒处于受力状态,从而在电杆后期养护时,钢筋镦头出现断裂脱落,具有延迟断裂现象;PC钢棒用于纵向非预应力钢筋时,电杆的使用强度可以满足,但是裂缝宽度和杆顶挠度均超过标准要求,因此不建议将PC钢棒应用于混凝土电杆的生产。     

Characterisation of pile salting with sodium replaced mixtures of salts in dry-cured loin manufacture

Salting, one of the fundamental operations in Spanish cured loin manufacturing, is essential to preserve the product throughout its processing and storage. However, elevated blood pressure has been identified to be the major adverse effect associated with increased sodium intake. The partial replacement of NaCl with other chloride salts such as KCl, CaCl₂ and MgCl₂ has been proposed as a possible strategy to reduce the sodium content of these products. The aim of this study was to determine the salting time needed to reach the same chloride content as commercial dry-cured loins and, to characterise the first step in dry-cured loin production (salting), in loins salted with sodium partial replaced salts. The results indicated a reduction in the salting time when using KCl as NaCl substitute and an increase in the salting time when adding CaCl₂ and MgCl₂ to the mixture. Further studies need to be done in order to fully understand the influence of these low sodium mixtures of salts on the following manufacturing steps and the final quality characteristics of the product.     

弱筋小麦SRC特性与饼干品质关系的研究

SRC值是评价弱筋小麦品质的简易快速的指标。本文选用11种弱筋小麦品种．分别测定其4种溶剂SRC值和酥性饼干品质特性，分析了弱筋小麦SRC特性与饼干品质的关系。结果表明，各SRC值与饼干的高度．硬度，脆性和韧性的相关系数较小；蒸馏水、50％蔗糖和5％碳酸氢钠3种SRC与饼干直径皆呈显著负相关，相关系数分别为-0．6037，-0．6524，-0．6904；5％乳酸SRC与饼干直径呈极显著负相关．相关系数为-0．8170；50％蔗糖SRC与饼干吸水率呈极显著正相关，相关系数为0．7497。以饼干品质评价结果对11个弱筋小麦样品品质排序．排序结果与现有的研究结果有很好的吻合性，表明用SRC值作为饼干品质的筛选指标是有效而可行的。     

电杆用钢筋张拉断裂原因分析及对策

根据用户的生产数据分析了用同强度级别的 4.8mm钢丝代替 5 .0mm钢丝制作电杆时张拉易断裂的原因 ,提出钢丝生产厂应先了解电杆厂是否适用所订强度级的 4.8mm螺旋肋钢丝 ,然后再供货 ;建议电杆厂在满足使用要求的前提下 ,下料时最好不进行矫直 ,避免钢丝性能被破坏 ,使钢丝张拉后留有足够的屈服强度储备 ,降低钢丝张拉断裂几率 ,提高产品质量     

Inhibition of acrylamide formation in asparagine/d-glucose model system by NaCl addition

Addition of 1, 5 and 10% of NaCl to equimolar mixture of asparagine/D-glucose was applied to study any affects of this food additive on acrylamide formation in the mixture. The samples were heated at 171.17°C for 10 min and the content of acrylamide was followingly determined by GC-MS technique using negative chemical ionization procedure. For comparison purposes, acrylamide formation was studied also in the mixture without NaCl addition at the same conditions. The results proved considerable inhibiting effects of NaCl on the acrylamide formation in all mixtures with addition NaCl, when the acrylamide content was lowered roughly by 32, 36 and 40% in comparison to mixture without NaCl addition. Very important is a fact, that effective lowering of acrylamide content was observed already at 1% of NaCl addition what could make possible to apply this knowledge also in real technological procedures of food processing.     

Textural properties of a model aqueous phase in low fat products. Part 1: Alginate, caseinate and starch in isolation, and in starch containing binary mixtures

Summary The effect of increasing additions of calcium on the textural properties of alginate, caseinate and starch dispersions was investigated to provide a baseline for further work on mixtures of these biopolymers. Increasing concentrations of calcium transformed the alginate solutions into gels having a maximum rigidity at 1000 and 300 p.p.m. Ca²⁺ for 2.0 and 0.5% of the polysaccharide, respectively. Gelation was achieved by cooling which unveiled a two stage process of network formation. Caseinate solutions (12%) showed an increased viscosity with a rising Ca²⁺ concentration up to 2250 p.p.m., above which viscosity decreased. Starch (2.5%) exhibited a slight loss in storage modulus (G') with increasing levels of calcium. The texture of the alginate starch mixture was determined by the alginate component (two stage gelation process), but inverted to that of starch at high levels of added Ca²⁺. In the absence of the counterion, casein had an adverse effect on the strength and cohesion of starch networks. At 400 p.p.m. Ca²⁺, the protein forms a continuous liquid like phase which suspends the starch inclusions thus dictating the textural properties of the mixture. Caseinate continues to dominate up to 1200 p.p.m. Ca²⁺, at which point the starchy matrix influences the system once more. Finally at higher levels of the counterion the sample phase inverts back to a starch continuous gel. Part 2 of this work examines the effect of calcium on the remaining preparations in order to facilitate the formulation of improved low fat products.     

火焰原子吸收光谱法测定奶粉中的钙镁铜铁含量

本文采用灰化法和湿法硝解对奶粉进行处理 ,用火焰原子吸收法分别测定了其中的钙、镁、铜、铁等金属元素含量。并对两种处理方法的结果进行比较 ,结果表明 :干灰化法较省时 ,方便 ,但有较大的偏差 ,湿法硝解虽花时长 ,却较准确     

Comparison of an individual congener standard and a technical mixture for the quantification of toxaphene in environmental matrices by HRGC/ECNI-HRMS

Both a technical standard and a recently commercially available standard containing 25 congeners were used to quantify toxaphene in a variety of environmental matrices, using high-resolution gas chromatography/electron capture negative ion high-resolution mass spectrometry (HRGC/ ECNI-HRMS). The purpose was to examine the differences between the two standards and to assess how well the congener standard describes the total toxaphene profile. At a resolving power of approximately 11,000 no interferences from other organochlorines were observed. Biotic matrices were enriched in octa- and nonachlorobornanes relative to the technical mixture, whereas abiotic matrices were enriched in hexa- and heptachlorobornanes. The hexa- and heptachlorobornanes were generally overestimated by the weighted response of the technical mixture, whereas the nonachlorobornanes were consistently underestimated. The extent to which the technical mixture over- or underestimates total toxaphene concentrations depends on the distribution of congeners among homologue groups and the abundance of particular congeners. The current 25-congener mixture described only approximately 35-75% of the total toxaphene response: more congeners are needed to adequately describe some matrices. Correction factors were developed that will allow laboratories to report reliable concentrations of individual congeners in samples that were quantified using the technical mixture, but they should be applied with caution, as they may be highly instrument dependent.