Improving the quality of instant tea with low-grade tea aroma

Refuse tea is industrially identified as broken mixed fannings (BMF). It is a primary raw material for instant tea production. The aroma escape during the process affects the quality of instant tea used for application in the food and beverage industries. Capturing and adding back aroma to the instant tea is commercially important to overcome this drawback. Hence, the study was focused on profiling the aroma of BMF and respective instant tea based on low country (0–300 m MASL) and upcountry (>600 m MASL) elevation categories of Sri Lanka to identify the impact of growing elevation on aroma profiles to explore blending proportions for better aroma profiles. Furthermore, volatiles that escaped with steam during the instant tea production process were condensed, and this aroma extract was added back to the tea concentrate prior to spray drying to produce the aroma blended instant tea sample (ABIT). Solid-phase microextraction followed by gas chromatography–mass spectrometry was used to identify the volatile compounds in the headspace of instant tea, BMF and ABIT samples. BMF samples significantly contained linalool (9.94 ± 2.94 %), cis-linalool oxide (Furanoid) (4.69 ± 1.80 %), geraniol (2.47 ± 1.44 %), and 3-hexen-1-ol (3.46 ± 2.06 %); however, the volatile profile of instant tea samples had high amounts of hydrocarbons (51.60 ± 9.34 %) that did not contribute to creating a pleasant aroma for the product. Hexanal, geraniol, citral, cis-jasmon, α-ionone, nerol and E-2-Z-4-hexadienal are characteristic in upcountry BMF and were absent in the low country tea, indicating a difference in the aroma profiles with elevation. ABIT sample showed that there is a clear improvement in the aroma profile by retaining compounds such as linalool (5.48 %), geraniol (0.95 %), hotrienol (0.92 %), and γ-muurolene (0.22 %), which give a pleasant flowery aroma to the product. This study concluded the possibility to improve the aroma profile of instant tea to give the unique aroma of Ceylon tea as per customer requirements in an economically viable manner and this technology can be applied globally.     

茶叶中有机氯农药的质谱确证分析

中国曾大量使用过以DDT和六六六为代表的有机氯农药,近年来,在对茶叶的检测中已很少检测到六六六,但仍经常检出DDT,甚至DDT超标的现象时有出现。本文建立了分析茶叶中DDT的GC-MS-TIC和GC-MS-SIM方法。目前国内实验室仍多采用GC／ECD分析茶叶中的DDT,本文不仅对使用GC／ECD检出的DDT进行了GC-MS确证分析,而且对GC／ECD分析茶叶中DDT的可靠性进行了初步探讨。     

液膜富集─火焰原子吸收法测定茶中微量铜、铁、钴、锌、镉

茶中微量元素的含量是评价茶叶质量的重要指标。由于这些微量元素的含量很低，通常在测定前要进行预富集。本文提出一个用液膜法富集的方法，其富集倍数可达１００倍，回收率在９５％～１０３％之间，５种元素的火焰原子吸收法测定结果，均令人满意。实验条件的选择用正交试验法，较一般常用的因素轮换法更为准确，也更为省时省力。     

以热力学和动力学性质差异连续高敏测定磷和砷及其比较研究

提出以非离子表面活性剂使磷钼酸、砷钼酸－孔雀绿缔合物在水相增敏、增溶、增稳并根据磷（Ⅴ）、砷（Ⅴ）的氧化性差异及形成上述缔合物速率差异，分别建立了以热力学和动力学性质差异在水相不经分离、连续、简便、高敏测两组分的光度法，并对此两法进行了比较研究。摩尔吸光系数ε６５０分别为１．１１×１０５（磷）和１．２２×１０５（砷）Ｌ·ｍｏｌ－１·ｃｍ－１；服从比尔定律的浓度范围相应为０～０．２４和０～０．４８μｇ／ｍＬ。已成功地用于测定四种钢样（相对误差：热力学法皆不大于±５％，动力学法通常皆不大于±１０％）和两种茶样（回收率：热力学法为９８～１０２％，动力学法为９３～１１１％）。     

建瓯“北苑贡茶”品牌茶产业的复兴——以生态经济学为视角

结合经济建设和生态环境之间的关系,分析"北苑贡茶"的兴衰过程及对其衰败原因;从生态经济学角度,提出以"北苑贡茶"为主打品牌的建瓯茶产业的复兴构想。     

几种茶叶中Cu含量的研究

通过对茶叶中Cu含量的研究表明不同茶叶品种中Cu含量差异较大,其中成都特级花茶中Cu含量相对较高。超声波萃取不同茶叶品种Cu的能力差异极大。随着浸泡茶叶的次数和时间延长,茶汤中的Cu含量越来越低,一泡茶汤中Cu含量较大,但均低于《地表水环境质量标准》中Cu的限量标准,因此通过浸泡方式饮茶摄入的重金属Cu含量较低,对人体健康不会造成伤害。     

Interferences elimination in ion chromatography by inclusion of the interfering ion into the mobile phase—Analysis of fluoride in chloride rich dietary samples

New approach to the chloride interferences elimination by addition of the interfering ion to the mobile phase is proposed and evaluated. Different eluents for the non-suppressed ion chromatographic analysis of fluorides in chlorides rich samples were tested and compared with eluent recommended by the column manufacturer. The limit of detection, linearity range and resistance to matrix effects caused by chlorides were the comparison criteria. The applicability of the selected eluent was demonstrated through the analysis of the edible salts and various tea samples. The employment of the proposed eluent shorten the time of the analysis since the only required preparation steps for edible salts were the dissolution and appropriate dilution of the samples. The recovery test was employed to verify the obtained results.     

《茶馆》中的会话含义推导

在现实交际中，人们常常传达一种与话语字面含义不同的另一种意义，这就需要对会话含义进行推导。对《茶馆》中的会话含义，可以利用量的准则、质的准则进行推导，也可以利用关系准则、方式准则等方法进行推导。     

茶叶中有效组分的提取工艺及条件的研究

提出了一种可用于工业规模综合提取茶叶中有效成分的工艺方法，确定了最佳的工艺条件，并对多酚组分进行了分离和鉴定。     

纳米纤维在分析菊酯类农药残留中的应用

以电纺聚苯乙烯纳米纤维作固相萃取材料,对茶叶样品中的拟除虫菊酯农药进行分离富集,用气相色谱-电子捕获器进行检测,并对影响纤维萃取效率的因素进行优化,联苯菊酯、氯菊酯、氰戊菊酯、溴氰菊酯和甲氰菊酯在纳米纤维柱上的最大吸附量分别为7.8、7.5、7.2、6.6、7.0μg/mg,5种农药的3种标准混合液通过纳米纤维小柱后回收率为65.5%～89.0%,RSD为1.2%～3.0%。测定喷洒5种农药后的茶叶样品添加回收率为61.3%～87.1%,RSD为0.9%～2.8%,方法的测定下限为1.0×10-4～1.0×10-2mg/kg。该方法可以满足茶叶中拟除虫菊酯类农药残留检测的要求。