提取方法对茶油中活性成分角鲨烯含量的影响

采用不同的工艺和溶剂从油茶籽中提取茶油,并对经甲酯化处理的茶油进行气相色谱分析、GC-MS联用分析、标准物质共同色谱比对等方法,研究了不同的提取方法对茶油中生物活性物质角鲨烯含量的影响。结果表明,茶油中含有比较多的角鲨烯,其含量随提取方法而不同,直接压榨法、己烷提取法、石油醚提取法、丙酮提取法和三氯甲烷提取法等所得到的茶油中角鲨烯的含量分别为2.98%、7.62%、0.94%、0.29%和0.54%。     

乙醇提取-丙酮沉淀法提取分离茶皂素的工艺研究

以油茶饼粕为原料,采用乙醇提取-丙酮沉淀法对茶皂素进行提取分离。以茶皂素纯度和得率为考察指标,对乙醇体积分数、液料比、提取温度、提取时间、提取次数、提取液浓缩程度和丙酮用量等工艺参数进行了单因素优化。结果表明：体积分数95%的乙醇为提取溶剂,乙醇与预处理过的油茶饼粕液料比为9：1（mL：g）,提取温度为70℃,提取时间为4 h,提取次数为2次,提取液浓缩至刚好有固体析出,丙酮用量为4倍浓缩液体积量时提取分离效果较佳,得到的茶皂素纯度为85.17%,得率为9.82%。不同溶剂打浆对产品纯化效果的比较发现：丙酮、乙酸乙酯、无水乙醇、体积分数95%的乙醇作为打浆纯化溶剂用于提高茶皂素纯度效果均不明显。     

油茶籽油精炼过程中苯并[a]芘风险控制技术研究

研究了油茶籽油加工过程中苯并[a]芘风险控制技术。本文以传统生产工艺的压榨原油、脱色油、成品油和浸提毛油为研究对象,除压力外,模拟油茶籽油加工过程中的精炼工艺流程工况,设计了苯并[a]芘风险控制技术实施方案,并用苯并[a]芘残留量作为评价指标。结果表明：4种试验油均不同程度地存在苯并[a]芘,尤以压榨原油含量最高。常规脱色工艺不致油茶籽油中苯并[a]芘含量增加,而高温脱臭工艺则会使油茶籽油中苯并[a]芘含量显著增加。脱色工艺中用传统的5%活性白土与0.5%硅藻土分别处理均不能去除苯并[a]芘。用1%活性炭与助滤剂硅藻土配伍去除苯并[a]芘效果最好。     

基于脂肪酸和甘三酯组成的茶油掺伪检测参数的确定

本实验研究了测定脂肪酸和甘三酯在检测茶油中掺伪4种其他植物油时的有效性。在本研究中,与脂肪酸和甘三酯指纹图谱向量夹角余弦相似度、亚麻酸相对含量、三亚油酸甘油酯(LLL)相对含量、碳当量数(ECN)42甘三酯的实际与理论含量绝对差(ΔECN42)值、(LLL/ECN42)×100值和ECN46/LLL值相比,(ECN44+ECN46)/LLL值是茶油中掺伪大豆油、葵花籽油和玉米油的最有效检测参数,分别可以检测茶油中掺伪3.35%的大豆油、1.73%的葵花籽油和3.01%的玉米油,亚麻酸相对含量是茶油中掺伪芥花籽油的最有效检测参数,可以检测茶油中掺伪7.55%的芥花籽油。     

基于粗略到精细分类的面部表情识别方法

为了更准确地识别人的表情,在识别人脸7种基本表情（愤怒、厌恶、恐惧、高兴、无表情、悲伤和惊讶）时,采用了局域二值模式技术提取面部特征,进行由粗略到精细的表情分类。在粗略分类阶段,7种基本表情中的2种表情被选为初步分类结果（候选表情）。在精细分类阶段,选用计算加权卡方值确定最终分类结果。采用日本的Jaffe表情数据库来验证算法性能,对陌生人表情的识别率为77.9%,其结果优于采用同样数据库的其他方法,且易于实现。     

利用异或运算和编码约束的降维LDP人脸识别方法

为了有效表示面部特征,在局部方向模式(LDP)的基础上,提出降维局部方向模式(RDLDP)；首先,修改LDP编码模式约束以完成模式的重构,通过对LDP码进行异或运算来计算每个块的单一码；然后,将所得编码图像划分为生成直方图,连接所有区域的直方图块以形成最终描述符;最后,计算特征向量间的卡方相异性度量值,并使用最近邻分类器完成最终的人脸识别;实验采用了3个公开的标准数据库FERET、扩展YALE-B和ORL,提出的改进方法在3个数据集上的最高识别率分别可高达96.97%、96.10%、97.61%,该结果验证了提出方法的有效性。与其他基于局部描述符的先进方法相比,提出方法在准确度和错误识别率等方面更优。     

Molecular evidence for maternal inheritance of the chloroplast genome in tea,Camellia sinensis (L.) O. Kuntze

BACKGROUND: Tea is the most consumed beverage worldwide after water. Yet very little is known about the genetics of tea in comparison with other crop species. Here we have taken advantage of the polymorphic nature of microsatellite DNA to investigate the mode of chloroplast inheritance in tea, Camellia sinensis (L.) O. Kuntze. This is important for the correct interpretation of phylogeny and introgression data as well as assessing the suitability of chloroplast transformation as a means for transgene containment in tea. RESULTS: The study was based on six Japanese tea cultivars, namely Aj2, CK23, Hatsumomiji, Nka05, Yamanoibuki and Kanayamidori used to generate four informative families. The parental pairs in the crosses differed at a single chlroroplast locus with respect to an imperfect microsatellite repeat of 16 nucleotide bases. In agreement with earlier cytological studies, all 61 progeny displayed a cpDNA profile that was consistent with the maternal inheritance of chloroplasts in tea. CONCLUSIONS: The data generated here provide the first molecular evidence of the plastid inheritance in tea. However, we suggest that additional families and polymorphic markers be screened for increasing the confidence in the observed maternal inheritance of chloroplasts in this important crop species. Copyright © 2011 Society of Chemical Industry     

Food safety knowledge,attitudes and practices of street food vendors and consumers in Ho Chi Minh city,Vietnam

This study had the major objective of evaluating the food safety knowledge, attitudes and practices of consumers and vendors of street foods in Ho Chi Minh City (MCMC), Vietnam. There were three main surveys performed in this study. A total of 120 consumers and 40 street food vendors from four districts [Binh Thanh (BT), Thu Duc (TD), district 3 (D3) and district 8 (D8)] in HCMC contributed to the study on a voluntary basis. The surveyed consumers had adequate levels of food safety knowledge and attitudes. No significant difference (p > 0.05) occurred between the food safety knowledge levels of the consumers on the basis of gender. However, significant differences (p < 0.05) occurred on the basis of age, education level, food safety training status and location. In contrast, the street vendors had poor food safety knowledge and attitude levels. No significant differences (p > 0.05) were observed in the food safety knowledge levels of the vendors on the basis of gender and age. However, significant differences (p < 0.05) were found on the basis of food safety training status and education level. It was also noted that the vast majority (95%) of the vendors had not received any food safety training. With regards to the practices, it was determined that 52.5% of the vending sites were open air stands without any protection from the sun, wind and dust. 52.5% the vending stalls had no direct access to potable water, while 47.5% did not have adequate hand washing facilities and a further 30% lacked proper waste water and food disposal facilities. In addition, 52.5% of the vendors did not separate raw, partially cooked food and cooked food products. These findings highlighted that street food vendors in HCMC generally have poor food handling practices and most are operating under unhygienic conditions. These results should provide the Vietnamese government with even more reasons to increase their current efforts to improve the safety of street foods and food safety awareness of the consumers.     

A review of recent studies in China on the possible beneficial health effects of tea

Tea is one of the most heavily consumed beverages in the world. The relationship between tea drinking and human health is becoming a subject of intense study by scientists throughout the world. In this paper, we first provide a comprehensive analysis of the medical literature on tea published in China during the past 20 years, and then highlight some recent studies in China on the relationship between tea and several human diseases. During the period 1982–2002, 691 research papers related to tea and health have been published in 290 Chinese journals. These studies showed that tea and tea constituents have various biological activities and suggested that tea drinking might be beneficial to human health. Tea has potential in the prevention or adjuvant treatment of several diseases including cancer, cardiovascular diseases and obesity. The trend and future direction in medical research on tea in China are also briefly discussed.     

略论太极拳的修身养性

从太极拳的文化渊源入手 ,探讨了太极拳的功理、得“理”、“法”者 ,才可修身、养性、颐心 ,得出了走正途、练功法 ,以静生动 ,动中求静 ,不欲修 ,则修自来 ,不求养 ,则养自成 ,修身养性 ,则浑然天成的结论