咖啡和绿茶的抗氧化活性研究

茶和咖啡是全世界消费最多的饮料。该工作利用电子自旋共振(ESR)技术和ABTS〔2,2'-Azinobis(3-ethylbenzothiazoline-6-sulfonic acid)〕等方法,研究和比较了3种绿茶(龙井、碧螺春和毛峰)和3种咖啡的抗氧化活性,以及对ABTS 、DPPH、超氧阴离子、羟基自由基、单线态氧的清除作用和对脂质过氧化的抑制作用。利用高压液相色谱(HPLC)分析了绿茶中的抗氧化成分之一EGCG((-)-epigallocatechin gallate)和咖啡中的抗氧化成分之一绿原酸(chlorogenic acid5,CQA)的含量。结果发现,如果按每克剂量比较,对于清除ABTS 的能力而言,茶和咖啡水提取液对ABTS 清除能力各有千秋,咖啡水提取液的比龙井、毛峰水提取液的高,但与碧螺春无显著差异,咖啡B比咖啡A和C强;按每杯茶(3g/200mL)和咖啡(2.4g/200mL)对ABTS 的清除能力进行比较,咖啡的比龙井和毛峰的高但比碧螺春低,咖啡B比咖啡A和C强。对超氧阴离子、羟基和DPPH自由基及单线态氧的清除作用和对脂质过氧化的抑制作用的研究表明,如果按每克剂量比较,茶和咖啡水提取液没有明显区别;按每杯量进行比较时,茶水提取液比咖啡水提取液对自由基的清除能力稍强。HPLC结果表明,EGCG含量在毛峰中最高,5CQA含量在咖啡B中最高。该研究结果表明茶和咖啡中均含有丰富的抗氧化成分,并都具有较强的抗氧化活性和清除自由基能力。     

光照强度对茶树、咖啡、可可叶片组织的影响

探索光照强度对植物叶片组织的影响,是研究多层多种人工胶林群落的一个重要内容。通过人工控制云南大叶茶(Camellia sinensis var assamica)、咖啡(Coffea arabica)、可可(Theobroma cocoa)光照强度试验,揭示植物组织变化规律性,从而为合理配置人工胶林群落中群落成员提供理论依据。 1.材材与方法 本试验是在云南西双版纳中国科学院热带植物研究所人工胶林群落研究室进行。将云南大叶茶树、咖啡、可可分别放置于事先人工布置好的不同透光度的试验场地。光照强度的测定采用半导体照度计(德产),试验的透光度为7％、15％、20％、70％(相当于旷地光照的百分比数)。试验经两年后,采取3     

A COMPARISON OF METHODOLOGY APPLIED TO THE SELECTION OF A PANEL FOR SENSORY EVALUATION OF INSTANT COFFEE

Twenty judges performed a variety of chemosensory tasks in order to select the best scores to form a panel for coffee evaluation. An average of correct responses (P%), one-way analysis of variance (ANOVA) and principal components analysis (PCA) were compared. The tests involved: ability to recognize the four basic tastes, identification and matching of odors, taste intensity evaluation and perception of small differences in taste. P% accounted for 71.17 ± 4.34% and 10 of the judges had scores greater than the final average. ANOVA and PCA resulted in 2 different panels consisting of 9 and 12 judges, respectively. The panel was composed by the nine panelists selected by the three methods. The other three panelists that were doubtful could improve to the point of acceptance with additional training. These methods should be used simultaneously to have more security in the acceptance or rejection of panelists.     

咖啡旋皮天牛幼虫蛀道及蛀道行为的空间特征分析(英文)

研究了咖啡旋皮天牛Acaloleptacervinus (Hope)韧皮部蛀道和木质部蛀道的空间特征 ,揭示了其幼虫的蛀道行为特性。结果显示 ,钻蛀孔集中分布于咖啡树径 4cm处 ,当钻蛀孔处树径大于 4cm时 ,木质部蛀道大多向上发展 ,当小于 4cm时则向下发展 ;钻蛀孔在树干上的垂直分布则显示钻蛀孔多分布于靠近树干基部的区域 ;钻蛀孔多紧临树干上的凸起物旁 ,如侧枝基部、瘤凸旁等 ;较多数的钻蛀孔位于树干的南面。以上结果说明咖啡旋皮天牛幼虫的钻蛀行为具有很强的位置选择性。这一研究有助于我们进一步理解咖啡旋皮天牛幼虫的钻蛀行为 ,进而找到具有针对性的防治措施。     

咖啡天牛幼虫种群的空间分布型及应用

咖啡旋天牛和灭字虎天牛是危害咖啡的重要害虫。本研究表明,咖啡天牛混合种群的空间分布为随机分布１。这是咖啡天牛群的重要生物学科技司。在此基础上,建立了运用被害株度估计平均密度的模型和理论抽样公式。这些模型对咖啡天牛的密度调查有着极其重要的实用价值。     

思茅咖啡天牛种群构成与危害的时空特性研究

通过室内饲养和野外调查,本文对思茅市咖啡天牛种群的构成,发生时期危害的时空特性及幼虫蛀孔部位的选择性进行了研究。结果表明,危害思茅地区咖啡的天牛种群由旋皮天牛和灭字虎天牛构成 ,在不同时间两个种群的构成比例不同。施皮天牛是优势种心化高峰期为４月１８－３０日,灭字虎天牛成虫主要在１０－１２月出现;在咖啡树中天牛幼虫的频数分布具有明显特征,１头虫的分布频数最高;     

THE SPATIAL CHARACTERISTICS OF LARVAL GALLERIES OF COFFEE STEM‐BORER: ACALOEPTA CERVINUS (COLEOPTERA: CERAMBYCIDAE)*

Abstract The spatial characteristics of larval galleries and mining behaviour of the coffee stem‐borer, Acalolepta cervinus (Hope), were studied on their host plant, Coffea arabica L. Results showed that entry holes were centrally located on stems of 4 cm diameter. Older larvae than third instar preferred tunnelling upward on the stems when diameter at the entry hole is larger than 4 cm, but downward on less than 4 cm. The vertical distribution of entry holes skewed toward lower position of stems. The larvae preferred drilling holes beside protrusions, especially beside the bases of adjacent branches. More entry holes were located on the south‐facing side of stems. Larvae boring hole on stem exhibited a strong location preference. This study helps us to understand larval tunnelling behaviour and to develop the control methods against the target pest.     

DRINKING HOT COFFEE: WHY DOESN'T IT BURN THE MOUTH?

Coffee served at temperatures recommended by the hospitality and food literatures for brewing and holding are above thermal pain and damage thresholds. Yet, consumers do not report pain or damage on drinking coffee at such temperatures. To investigate this discrepancy, the temperature of hot coffee before and during sipping was investigated for 18 subjects. Coffee temperature was continuously monitored by thermocouples in the cup, in the coffee bolus in the oral cavity and on the surface of the tongue. There was minimal cooling as the coffee entered the mouth from the cup, yet the coffee temperature was still above threshold for inducing burn damage. It is hypothesized that during drinking, the bolus of hot coffee is not held in the mouth long enough to heat the epithelial surfaces sufficiently to cause pain or tissue damage.     

HEDONIC R-INDEX MEASUREMENT OF TEMPERATURE PREFERENCES FOR DRINKING BLACK COFFEE

R-index measures were obtained from judges who ranked black coffees for preferred drinking temperature. Preferred temperatures were above thermal pain and thermal damage thresholds. The least preferred temperature was below the oral thermal pain threshold. Similar results were obtained with a ranking for temperatures that judges felt were most likely to be served in a coffee shop. Observations of customers in coffee shops indicated that they began sipping coffee at similar high temperatures.     

咖啡旋皮天牛的初步研究

咖啡旋皮天牛(Dihammus cervinus Bates)为咖啡重要害虫。作者于1957—59年在云南西双版纳调查,为害率轻者13—16％,重者50—70％。此虫在国内分布云南、四川,国外分布于越南、缅甸和印度。文献上记载,为害植物有咖啡(Coffea arabica L.)、水团花属(Adina)、柚木属(Tectona)、醉鱼草属(Buddleia)、臭牡丹属(Clerodendron)及     

SENSORY PROFILING AND PRODUCT POSITIONING OF ROASTED AND GROUND (BREW) COFFEE AND SOLUBLE (INSTANT) COFFEE WITH AND WITHOUT ADDED FLAVOR

Coffee powders available commercially are of different qualities. The quality variations may be due to inherent quality of coffee beans, storage time and packaging materials used. Sensory profiles of brewed and soluble coffees were studied through profiling. Canonical discriminant analysis (CDA) used for positioning the different coffee samples showed that freshly made coffee from plantation arabica (PA), Pea berry (PB), PA with chicory (PAC), PB with chicory (PBC) and their blends viz. PA + PB and PAC + PBC occupied the quadrant where coffee aroma and overall quality rated higher. Other roasted & ground (R&G) coffee (market) samples were positioned where oily, fermented, musty, stale and caramelized notes dominated. In case of soluble coffee, the flavored coffee procured from the western market (S3, S6, S9 and S8) dominated the quadrant where other added flavor and oily notes dominated. The typical soluble (instant) coffee without any added flavor S10, S12 and S13 occupied another quadrant. The soluble coffee powder with spice incorporation took a separate quadrant where other added flavor and bitter taste dominated. The dominant quality attributes for the groups are different and are discussed in relation to the directional vectors.     

中国咖啡锈菌(Hemileia vastatrix)生理小种研究

对我国云南、海南和广东咖啡植区收集到的58个咖啡锈菌菌株标本进行生理小种鉴定,鉴定出小种有7个。各咖啡植区除共同出现Ⅱ号生理小种外,云南咖啡植区还出现Ⅰ,XV,XXIII和XXIV号生理小种;海南则出现VI和XXII号小种;广东咖啡栽培地区未发现有新的生理小种。各咖啡植区新生成的生理小种种类有明显不同。     

中国咖啡锈菌(Hemileia vastatrix)生理小种研究*

对我国云南、海南和广东咖啡植区收集到的58个咖啡锈菌菌株标本进行生理小种鉴定,鉴定出小种有7个。各咖啡植区除共同出现Ⅱ号生理小种外,云南咖啡植区还出现Ⅰ,XV,XXIII和XXIV号生理小种;海南则出现VI和XXII号小种;广东咖啡栽培地区未发现有新的生理小种。各咖啡植区新生成的生理小种种类有明显不同。