Furan fatty acid concentrations in tea infusions prepared from green,black, and herbal teas

Furan fatty acids (FuFAs) are valuable antioxidants with highly effective radical scavenging properties which are widely distributed at low levels in food. Previous research indicated that tea is a valuable source of FuFAs. However, tea is only consumed in form of infusions. To fill this gap, we prepared infusions from different herbal, green, and black teas. Initial measurements with GC-MSMS of tea verified previous findings that 11-(3,4-dimethyl-5-penylfuran-2-yl)-undecanoic acid (11D5) was the prevalent FuFA in tea matrix. Therefore, 11D5 was quantified in tea infusions by means of UHPLC-MSMS equipment after mild alkaline hydrolysis. While herbal tea infusions were low or free of FuFAs, 11D5 was detectable in all samples of green and black tea infusions. Amounts of 11D5 were higher in green tea than in black tea. Moreover, Darjeeling tea infusions were by ~30% richer in 11D5 than black and green teas from other regions. Each cup of green and black tea infusion may provide 20–60 μg 11D5, which is about 5% of the amounts found in tea samples. Spread over the day, regular tea consumption may contribute to the intake of valuable FuFAs.     

基于跨临界CO2热泵的茶叶生产能源系统负荷削减潜力

乡村产业中的化石能源设备逐渐被电能技术替代，引起了乡村负荷波动增大、部分时段产生集中高负荷的问题。为了解决以上问题，将低品位清洁能源应用至乡村的茶叶生产中，针对烘茶全过程的工艺要求提出了跨临界CO₂热泵烘茶技术；并以某茶叶生产乡村为对象，对其代表台区的全年日用电量及产茶日负荷进行了分析，得出采用CO₂热泵烘茶后其负荷得到大幅度削减，整体可降低至原负荷的39.6%~46.8%，峰值负荷与平时负荷的比值由原本的13.6降至5.4~6.2。跨临界CO₂热泵应用至农产品生产中可有效缓解乡村供电压力。     

基于魅力工学的传统器物设计评价应用研究

目的 在传统器物的创新设计中,最重要的环节是了解消费者对所使用产品的不同感受与意向并转换为具体的设计要素.研究消费者心理的感性因素与传统器物设计元素之间的联系,确定设计要素,从而对产品进行创新设计,为提升传统器物附加值作出贡献.方法 以中国传统器物茶宠为例,首先对8位相关的茶宠专家进行访谈,通过魅力工学中的评价构造法整理并提取魅力因子,设计出问卷调查表;然后以访谈内容为依据,使用问卷调查法得到大众对茶宠的魅力评价,共回收84份有效问卷;最后应用数量化一类分析茶宠魅力因子影响权重.结果 得到了数量化一类统计表,选取了其中影响因素较大的魅力因子作为茶宠设计前的风格定调考量.结论 通过茶宠的研究案例证明了该理论的可行性,为未来传统器物的设计提供了更多元且新颖的设计依据.     

Autolysis and the endogenous proteinases characterised in beardless barb (Anematichthys apogon) muscle

Beardless barb is a common fish species used in fermentation of fish paste Ka-pi-plaa. Autolytic profile of beardless barb muscle showed the maximum autolysis was at 50 °C, at both acidic and alkaline pH values. With augmentation concentration of NaCl, autolytic activity slightly decreased. Endogenous proteinases isolated from fish muscle in crude extract forms were also characterised. The acidic proteinases had optimum activity at pH 3.0 and 50°C, and they showed higher proteolytic activity than the alkaline proteinases which were optimally active at pH 9.0 and 50 °C. Proteinases in peak at pH 3.0 were inhibited by pepstatin A, but those in peak at pH 9.0 were highly inhibited by PMSF, TLCK and soybean trypsin inhibitor, suggesting that both aspartic and serine proteinases were existed in beardless barb muscle. The proteinases were stable in pH range of 2.0-5.0 but unstable at the temperatures higher than 40 °C. NaCl suppressed the proteolytic activity, ATP activated the proteinase activity, while CaCl₂, MgCl₂ and CoCl₂ exhibited no influence on the activity. The results implied that cathepsin D is the predominant proteinase responsible for autolysis in beardless barb. The findings were useful to improve the processing and qualities of Ka-pi-plaa product using beardless barb as raw material.     

The peptides in oat and malt extracts that are preferentially absorbed by Lactobacillus plantarum and stimulates its proliferation in milk

Lactobacillus plantarum proliferates inefficiently in milk, mainly because of its lack of cell envelope proteases and its inability to hydrolyse proteins in milk. Our previous study showed that this strain could grow well in milk with the addition of oat and malt extracts. To investigate the usage and preference for polypeptides and oligopeptides for this strain, sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE), o-phthaldialdehyde (OPA), high-performance liquid chromatography (HPLC), plate counting and other methods were used in this study. The results showed that proteins in fermented milk cannot be absorbed and utilised by L. plantarum, whereas polypeptides and oligopeptides provide available nitrogen sources for their growth. Short-chain peptides were more conducive to absorption and utilisation than long-chain peptides. In particular, peptides with molecular weights in the range of 200–1400 Da in the oat extract and 100–700 Da in the malt extract were preferentially absorbed and utilised.     

茶多酚对羊肉肌原纤维蛋白凝胶特性的影响

研究茶多酚对羊肉肌原纤维蛋白凝胶特性的影响，将不同添加量（0.00%、0.01%、0.05%、0.10%、0.50%、1.00%）的茶多酚加入到羊肉肌原纤维蛋白中，测定肌原纤维蛋白表面疏水性、乳化性能、保水性、质构特性，观察羊肉肌原纤维蛋白凝胶微观结构。结果表明，与对照组相比，茶多酚添加量为0.10%时，羊肉肌原纤维蛋白的表面疏水性最小，疏水基团暴露程度最轻，乳化活性指数达到最大（4.88 m2/g），乳化稳定性指数（86.54%）和保水性（95.22%）均达到最佳；随着茶多酚添加量的增加，羊肉肌原纤维蛋白凝胶的硬度、咀嚼度、胶着度均显著上升（P＜0.05），弹性、内聚性、回复性整体呈下降趋势（P＜0.05）。结论：添加适量茶多酚可以显著改善羊肉肌原纤维蛋白的凝胶特性，并且凝胶的微观结构更加致密、空隙更小、形状规则且分布均匀；茶多酚与肌原纤维蛋白的非共价结合和共价结合可能会影响蛋白质的功能特性，并且这种作用强度随着茶多酚添加量的变化而变化。     

文冠果茶与文冠果金花散茶的香气分析

目的分析文冠果茶与文冠果金花散茶的香气成分。方法采用同时蒸馏萃取法(simultaneous distillationandextraction,SDE)提取香气物质,用气相色谱-质谱(gaschromatography-massspectrometry,GC-MS)测定各香气成分,并分析各成分的相对含量及其差异。结果 2者香气物质丰富,分别有123和118种;文冠果茶中以醇类、醛类和酮类为主要香气成分,其相对含量达到了总香气物质的84.65%,其中含量较高的组分是α-松油醇、反,反-2, 4庚二烯醛、香叶基丙酮及6-甲基-5-庚烯-2-酮等;文冠果金花散茶以醛类和酮类为主要香气物质,其相对含量达到了总香气物质的51.98%,其次是醇类和酸类,且醇类明显减少,而醛类和酸类明显增加,其含量最高的组分是反,反-2, 4庚二烯醛等烯醛类物质,对菌花香有积极作用。结论工艺的差异会形成不同风味的文冠果茶。     

不同水分工夫红茶贮藏过程中主要内含成分及感官品质变化研究

目的研究不同水分工夫红茶贮藏品质变化规律,为工夫红茶贮藏的适宜水分条件提供理论参考。方法系统比较不同水分工夫红茶(国家标准范围内)在自然贮藏条件下其主要内含成分及感官品质的变化。结果 1年贮藏期内,初始水分含量越低,含水率增长速度越快,总体上,茶叶初始水分含量高低决定贮藏过程中水分的高低。在短期贮藏(≤6月)时含水量越高的红茶中茶多酚、水浸出物保留量越多;长期贮藏(6月)时水分较低的红茶中茶多酚、水浸出物保留量越多。咖啡碱、可溶性糖在短期贮藏(≤6月)中水分含量适中的红茶中下降速度越慢;长期贮藏(6月)含水量较高的保留量越高。氨基酸含量在含水量越低的红茶中越高。初始水分含量高的红茶L*、a*、b*值均稍高于水分低的红茶。结论从综合品质的变化来看,本实验中以处理3含水率为5.93%的处理最好,处理2含水率为4.1%次之,处理1含水率为2.33%最差。