烘焙提香时间对工夫红茶品质的影响

为提高工夫红茶的甜香度,本文以山东夏季鲜叶加工的工夫红茶初制品为原料,在70℃的烘温下进行不同时间的烘焙提香处理,并通过感官审评、生化成分和香气分析方法研究其对工夫红茶品质的影响,结果表明:烘焙时间的长短不仅影响工夫红茶的香型和高低,而且也影响汤色和滋味,在本试验条件下,烘焙时间以1.0~1.5h的感官品质较好;此外,烘焙时间对工夫红茶各生化成分的影响不同,但对品质有利的生化成分以烘焙1.0h的茶样含量最高;随着烘焙时间的延长,工夫红茶香气的种类、含量以及组分比值发生显著变化,从而可以解释不同烘焙时间工夫红茶香型存在差异的原因。     

Selective elution of tea catechins and caffeine from polyvinylpolypyrrolidone

Desorption of catechins and caffeine from polyvinylpolypyrrolidone (PVPP) was comprehensively investigated. The result showed that caffeine could easily be desorbed from PVPP by the tested solvents except n‐hexane, while catechins could only be thoroughly done by dimethyl sulphoxide (DMSO) and N, N‐dimethylformamide (DMF). Excellent desorption efficiency of DMSO and DMF might be attributed to their high dipole moments and H‐bond potentials. Addition of ethanol was recommended considering the elution efficiency and fluidity, but ethanol volume should be <40% (v/v) for DMSO or 20% (v/v) for DMF. Desorption would get to equilibrium within 1 h and followed the pseudo‐second‐order model. Caffeine and catechins could be separately desorbed through two‐stage elution procedure, that is, water or 20% aqueous ethanol for desorbing caffeine and part of nongalloylated catechins and DMSO/ethanol (8/2, v/v) for eluting the remaining catechins. Highly purified catechins (~95%) with high level (~70%) galloylated catechins would be achieved when the desorption procedure was applied in column chromatograph.     

A strategy for reducing CO2 emissions from buildings with the Kaya identity – A Swiss energy system analysis and a case study

Within the general context of Greenhouse Gas (GHG) emissions reduction, decomposition analysis allows the quantification of the contribution of different factors to changes in emissions as well as the assessment of the effectiveness of policy and technology measures. The Kaya identity has been widely used for that purpose in order to disaggregate carbon emissions into various driving forces. In this paper, it is applied for the analysis of emissions resulting from energy use at three different scales. First, a decomposition analysis of the carbon emissions for the complete Swiss energy system is presented using the future projections from the Swiss Energy Strategy 2050. The Kaya identity is then applied to the Swiss building sector after it is adapted with factors that are more relatable to building parameters, such as floor area instead of Gross Domestic Product (GDP). Finally, the last level of analysis is a small scale community energy system for a unique Swiss village that aims to significantly reduce its emissions. An energy strategy is developed and its effectiveness is assessed with the adapted Kaya identity and benchmarked against the Swiss average values. The presented method demonstrates how the performance of buildings under various retrofitting scenarios can be benchmarked against future emission targets.     

中低档铁观音茶精制加工技术

笔者对安溪某一大型乌龙茶生产企业夏季铁观音精制工艺进行了分析和总结,并取样进行感官审评。中低档乌龙茶精制生产重内质轻外形,产品精制烘焙后,重复了筛分、风选和拣剔工序,提高了品质,保障了安全性。经样品感官审评,符合四级铁观音茶标准。     

两种前处理方法在普洱茶香气成分分析中的对比研究

使用XAD-4树脂顶空吸附和同时蒸馏萃取两种方法对普洱茶的香气成分进行提取,对提取物进行GC—MS分析。从分析结果看出,两种提取方法提取得到的成分有差别,可以分别在不同的研究中应用。     

柑橘萜油微胶囊的开发与制备

以β-环糊精+阿拉伯胶+玉米糖浆为壁材,采用喷雾干燥对柑橘萜油进行微胶囊化,通过正交试验,确定出包裹柑橘萜油的最佳工艺条件为:进风温度200℃,出风温度75℃,芯材∶壁材质量比为1∶50,β-环糊精∶阿拉伯胶∶玉米糖浆质量比为2∶3∶5。并测定了柑橘萜油微胶囊在溶液中的释放性能,为该微胶囊的应用提供了很好的理论指导。     

3种淀粉对鸡肉糜盐溶蛋白特性影响及其配方研究

为获得鸡肉蛋白较好的凝胶特性,从而改善其肉糜的加工品质,探讨玉米淀粉、马铃薯淀粉和磷酸酯淀粉3种常用淀粉与鸡肉盐溶蛋白相互作用对鸡肉糜加工基本特性的影响。以盐溶蛋白析出质量浓度、活性自由巯基含量和相对疏水性为指标,分别研究单因素条件下3种淀粉对鸡肉盐溶蛋白特性的影响,并通过二次通用旋转试验筛选出在5%淀粉添加总量条件下3种淀粉在鸡肉糜中的最佳组合配方。单因素试验表明:所选3种淀粉均对鸡肉盐溶蛋白特性有着复杂影响。3种淀粉最佳配方为:玉米淀粉1.6%、马铃薯1.6%、磷酸酯淀粉1.8%,此时鸡肉糜中盐溶蛋白基本特性参量指标预计为:盐溶蛋白质量浓度24.3mg/mL,活性自由巯基含量0.004μmol/mg,相对疏水性值22.86。     

勐库大叶茶蛋白降血脂肽的酶解制备及活性分析

以碱提酸沉法提取的勐库大叶茶蛋白为研究对象,以牛磺胆酸钠结合能力为考察指标,通过单因素实验和响应面分析法优化勐库大叶茶蛋白降血脂肽的制备工艺,并对最优工艺条件下的酶解物进行降血脂活性评价和氨基酸组成分析。结果表明,勐库大叶茶蛋白降血脂肽的最佳制备条件为胃蛋白酶酶解3 h、pH2.1、底物浓度2.7%、酶底比0.3%、温度37 ℃,此条件下酶解物的牛磺胆酸钠结合率为（70.92%±0.12%）。活性评价结果表明,茶叶蛋白酶解物在牛磺胆酸钠结合能力（EC₅₀=6.466 mg/mL）、胰脂肪酶抑制作用（IC₅₀=0.310 mg/mL）和胆固醇酯酶抑制作用（IC₅₀=1.557 mg/mL）三个体外降血脂活性评价指标方面均表现出良好的活性。氨基酸分析表明,所得勐库大叶茶蛋白降血脂肽含有丰富的必需氨基酸（34.35%）、疏水性氨基酸（31.94%）和酸性氨基酸（41.06%）。     

响应面法优化苏式茶馅饼饼皮配方

研究采用玉米油代替猪油作为起酥油,将绿茶粉添加到饼皮中,制作出一种具有绿茶风味的新型苏式馅饼。在单因素试验的基础上,采用响应面试验得出了饼皮制作的最佳配方参数,为苏式茶馅饼的开发提供理论依据。