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1.
    
Zusammenfassung In zwei unterschiedlich gerösteten Robustakaffees und vier handelsüblichen Röstkaffees wurden die Phenole in bezug auf Struktur und Quantität untersucht. Nach speziellen Extraktions- und Reinigungsverfahren erfolgte die Identifizierung und Quantifizierung nach gaschromatographischer Trennung der Trimethylsilylether mit Hilfe der GC-MS-Kopplung. Die Gehalte der 35 identifizierten Phenole lagen in einem Bereich von unter 0,1 bis über 1000 mg/kg. 16 Phenole wurden erstmals im Kaffee nachgewiesen.
Determination of phenols in coffee
Summary The structure and quantity of phenols, occurring in two different roastedRobusta coffees and in four samples of roast coffee, were investigated. Identification and quantification were carried out after special extraction procedures and clean-up methods by gas chromatography/mass spectrometry. The quantities of 35 phenols investigated ranged from below 0.1 mg/kg to more than 1000 mg/kg. Sixteen phenols were identified in coffee for the first time.


Herrn Dr. H. Lange zum 60. Geburtstag gewidmet  相似文献   

2.
为探究烘焙工艺对咖啡豆口感的影响,本文研究了烘焙程度对咖啡豆中有机酸含量的影响。采用新建立超高效液质联用法(UPLC-MS/MS)测定不同烘焙条件下7种有机酸的含量。结果表明:7种有机酸化合物在0.5~20.0 mg/kg范围内线性关系良好,决定系数均大于0.990。7种有机酸的加标回收率在81.9%~104.7%,RSD为0.53%~6.64%。洪都拉斯咖啡豆样品检测结果显示随烘焙程度增加,苹果酸和柠檬酸含量下降,富马酸含量先升后降,琥珀酸、酒石酸、莽草酸和奎尼酸含量上升。轻度烘焙下苹果酸与柠檬酸总量最高,达到1201.5 mg/kg,酸度最佳;奎尼酸含量最少,为1363.7 mg/kg,涩度最低。肯尼亚、印尼、巴西、萨尔瓦多咖啡豆中有机酸在相同烘焙条件下表现相似。  相似文献   

3.
Green coffee contains a large quantity and variety of polyphenols and flavonoids. The roasting affects the composition of the polyphenols in coffee, due to the formation of compounds generated by Maillard reaction, which can have anti-inflammatory or antioxidant potential. The anti-inflammatory and antioxidant effects of aqueous extracts of green (AGCa) and roasted (ARCa) coffee beans were investigated in animal models and using a DPPH radical scavenging test. In the formalin test the extracts reduced licking activity only in the late phase. The inhibitory values of oedema at 3 h post-carrageenan were 53% and 74% for 100 and 300 mg/kg of the AGCa extract and 36% for ARCa (300 mg/kg). Leukocyte recruitment into the peritoneal cavity was inhibited by the extracts. The antioxidant activities of the extracts were higher than the reference antioxidants, ascorbic acid and butylated hydroxytoluene. These results indicate that coffee extracts exhibit anti-inflammatory and antioxidant properties.  相似文献   

4.
The characteristic volatiles of light, medium, and dark roasted Turkish-style boiled coffee brews were studied by headspace solid-phase micro extraction/gas chromatography-mass spectrometry and sensory flavor profile analysis. Sixty-five volatile compounds, including furans, pyrazines, pyrroles, phenols, pyridines, ketones, oximes, alcohols, aldehydes, thiophenes, benzenes, and terpenes, were isolated from Turkish-style boiled coffee samples. The flavor profile analysis showed Turkish coffee brews as roasted/burnt, spicy, bitter, acidic, sweet, salty, astringent (dry), woody, fermented, earthy, and tobacco-like flavor characteristics. It was concluded that Turkish coffee was rich in furans, pyrazines, pyrroles, and phenols giving its roasted/burnt, spicy, woody, and fermented flavor characteristics.  相似文献   

5.
A survey on the potential intake of caffeine was carried out in Campinas, SP, Brazil, in the summer of 1993. The survey was based on a representative sample of 600 individuals, 9-80 years old, who were asked about their habitual usage of coffee, tea, chocolate products and carbonated beverages. Caffeine levels in the products were determined by high performance liquid chromatography with a UV-visible detector at 254 nm. Individual daily intakes (mg/kg b.w.) of caffeine were calculated from the consumption data generated by the survey and the caffeine content of the analysed products. Of all those interviewed, 81% consumed soft drinks regularly, 75% coffee, 65% chocolate products and 37% tea. Of the analysed products, coffee showed the highest amount of caffeine. The average and median potential daily intake of caffeine by the studied population were, respectively, 2.74 and 1.85mg/kg b.w. Coffee, tea, chocolate products and carbonated beverages accounted for median individual daily intakes of 1.90, 0.32, 0.19, and 0.19mg/kg b.w., respectively. These data show that coffee is the most important vehicle for caffeine intake within the studied population.  相似文献   

6.
Coffee is one of the most popular drinks across the world and its enormous commercial and social importance is obvious. The levels of nine bioactive amines and five minerals, as well as pH, color, total ash and dry matter characteristics, were determined in different brands of ground and brewed Turkish coffees for the first time. Turkish coffee is a method of preparation, not a kind of coffee. Furthermore, this paper reported the estimated daily mineral intake of five elements. The amines were extracted with trichloroacetic acid (TCA) and quantified by reversed-phase high performance liquid chromatography (HPLC), pre-column derivatization with benzoyl chloride. Of the nine bioactive amines under study putrescine, cadaverine, tyramine and serotonin were detected in all coffee samples. Serotonin was the prevailing bioactive amine in both ground and brewed coffees. The total amine levels in the ground coffee varied from 126.0 mg/kg to 352.2 mg/kg. The total amine levels in the brewed coffee varied from 5.679 mg/L to 48.88 mg/L. The concentrations of five minerals (Mg, Mn, Zn, Na, K) were determined after dry mineralization of both ground and brewed coffee samples. The total mineral contents were analyzed by high-resolution continuum source flame atomic absorption spectrometry (HR-CS-FAAS). Potassium was the prevailing mineral in both ground and brewed coffees. The mean total mineral contents of ground and brewed coffees were 12673.2 mg/kg and 1014.8 mg/L, respectively. Significant differences were obtained between bioactive amines, minerals (except Na), color values (L*, a*, b*), total ash and total dry matter contents of ground and brewed Turkish coffee samples (P < 0.05).  相似文献   

7.
赤砂糖的特性及其变化规律的研究   总被引:1,自引:0,他引:1  
对赤砂糖的特性及其质量变化规律进行研究,结果表明赤砂糖中的酚类物和含氮物含量较大,分别为436.83mg/kg、2127.79mg/kg;可溶性硅酸盐量较小,仅为2.91mg/kg;铁离子含量为68.2mg/kg;丙糖糊在较高温度下存放易出现色值升高、纯度降低的现象,赤砂糖长时间贮存后色值升高明显;赤砂糖晶体分层色值从内向外递增,糖块的色值远高于其正常晶形与糖粉的色值。  相似文献   

8.
5-Hydroxymethylfurfural has become a substance of interest since recent results showed a possible carcinogenic potential in consequence of a metabolic activation by sulfotransferases. 5-Hydroxymethylfurfural is formed either by acid catalysed degradation of reducing sugars or via the Maillard reaction. This work provides an overview of foods potentially containing high amounts of 5-hydroxymethylfurfural. It comprises dried fruits with a high sugar content that were exposed to heat for a long time. The concentration ranges from very low in, e. g. figs (1 mg/kg) to plums that contained up to 2,200 mg/kg. Several types of roasted coffee were analysed that contained from 300 to 2,900 mg/kg of 5-hydroxymethylfurfural. In a small human study with seven healthy volunteers the urine excretion of unmetabolised 5-hydroxymethylfurfural was investigated. After uptake of 20 g of plum jam containing 24 mg of 5-hydroxymethylfurfural, 163 microg (mean) were excreted within 6 h, an equivalent of 0.75% of the ingested 5-hydroxymethylfurfural.  相似文献   

9.
 Pentosidine, a crosslink amino acid in which one arginine and one lysine residue are linked together by a pentose, has been detected in foods for the first time using ion-exchange chromatography with direct fluorescence detection and subsequent ninhydrin derivatization. The method allows the simultaneous quantification of pentosidine along with all other amino acids of acid hydrolyzates at levels lower than 50 μg kg protein. Levels of pentosidine in all food samples investigated were very low (milk products between not detectable and 2–5 mg/kg protein; roasted coffee and some bakery products up to 35 mg/kg protein), indicating that pentosidine does not play a major part in the polymerization of food proteins. Received: 26 March 1996  相似文献   

10.
Detection and quantification of pentosidine in foods   总被引:1,自引:0,他引:1  
 Pentosidine, a crosslink amino acid in which one arginine and one lysine residue are linked together by a pentose, has been detected in foods for the first time using ion-exchange chromatography with direct fluorescence detection and subsequent ninhydrin derivatization. The method allows the simultaneous quantification of pentosidine along with all other amino acids of acid hydrolyzates at levels lower than 50 μg kg protein. Levels of pentosidine in all food samples investigated were very low (milk products between not detectable and 2–5 mg/kg protein; roasted coffee and some bakery products up to 35 mg/kg protein), indicating that pentosidine does not play a major part in the polymerization of food proteins. Received: 26 March 1996  相似文献   

11.
The evaluation process involved data collected by Official Food Control Laboratories during the period 1995 until 1999. A total of 613 samples analysed for ochratoxin A and complying with a detection limit lower than 0.6 microg/kg were evaluated. With the assistance of statistical process analysis the median concentrations for green coffee (0.4 microg/kg), for roasted coffee (0.6 microg/kg), for decaffeinated roasted coffee along with low-acid decaffeinated roasted coffee (0.4 microg/kg) as well as for soluble coffee (0.7 microg/kg) were determined. The result is a mean daily total intake per consumer of 9 ng OTA.  相似文献   

12.
The aim of this study was to assess the influence of different winemaking technologies on the chemical characteristics and, in particular, on the phenolic fraction of Aglianico, Montepulciano, Nero di Troia and Sangiovese wines produced in Apulia, Southern Italy. Four different winemaking technologies were compared: control (traditional, 5 days of maceration at 25 °C with three daily punching-down), prolonged maceration (10 days), addition of ellagic tannins and cryomaceration (24 h at 5 °C using dry ice), without any other oenological treatment. Results showed that the different technologies slightly influenced the phenolic fraction of Aglianico, which is known to be naturally rich of phenols. On the contrary, the prolonged maceration led to an increase of total phenols (TP) in Nero di Troia (2,592 mg/kg vs. 2,115 mg/kg of control) and a decrease in Sangiovese (869 mg/kg vs. 1,013 mg/kg); the addition of tannins led to an increase of TP in Montepulciano (1,358 mg/kg vs. 1,216 mg/kg) and to a decrease in Sangiovese (916 mg/kg vs. 1,013 mg/kg); and cryomaceration led to a decrease of anthocyanins in all cultivars (about 15%). Phenols extraction from grapes was found to be mostly dependent on the grape variety rather than on the applied winemaking technology.  相似文献   

13.
In the presented study the effects of key brewing parameters (temperature, holding time and storage conditions of coffee powder) on 12 alkylpyrazines in coffee beverages were investigated. The results show that the alkylpyrazine profiles of coffee beverages are similar to those of the coffee used. In total, 70–82% of the alkylpyrazines (113.3 ± 3.5 to 132.6 ± 0.6 mg/kg), depending on the brewing method, passed into beverages during the brewing process. At temperatures higher than 50 °C the alkylpyrazine contents of coffee beverages were almost independent of the brewing temperature. During a 30 min holding time at room temperature the alkylpyrazine contents of a freshly brewed cup of coffee decreased by about 10%. Furthermore, storing coffee in closed systems for up to 29 days at +4 °C, −20 °C or room temperature (+22 °C) had minor effects on the alkylpyrazine contents of beverages produced from the coffee. The results show that under customary conditions more than 70% of the alkylpyrazines present in ground coffee are transferred to beverages during the brewing process. Estimated total amounts of alkylpyrazines ingested by the consumer per cup of coffee beverage are in the milligram range, sufficient to have significant potential health effects.  相似文献   

14.
The bioactive composition of coffee, as one of the most popular beverages in the world, has attracted interest as a potential source of beneficial bioactive compounds, especially polyphenols and caffeine. Since the content of these compounds is affected by the processing conditions, the objective of this study was to determine the content of polyphenolic compounds and caffeine in four different coffee varieties: Minas and Cioccolatato (Coffea arabica), and Cherry and Vietnam (Coffea canephora syn. Coffea robusta), roasted by three varying degrees (light, medium and dark). The content of the polyphenolic compounds and the antioxidant capacity of coffees were determined using UV/Vis spectrophotometric methods, while the content of chlorogenic acid derivatives was determined using HPLC analysis. The caffeine content was determined by means of two spectrophotometric methods, as well as HPLC analysis. Additionally, raw caffeine was also obtained by an isolation procedure with chloroform. Cherry coffee, a variety of C. canephora exhibited the highest overall content of total phenols (42.37 mg GAE/g), followed by Minas coffee, while Cioccolatato contained the lowest TPC (33.12 mg GAE/g). Cherry coffee also exhibited the highest content of individual classes of polyphenols (flavan-3-ols, procyanidins and tannins), while the highest content of chlorogenic acid (CQA) derivatives was determined in Minas and Cioccolatato coffees (C. arabica). The highest content of total and individual polyphenolic compounds was determined in coffees roasted in both light and medium roasting conditions, which was also observed for the content of CQA derivatives and antioxidant capacity of roasted coffees. The highest caffeine content in the coffee samples was determined by employing the HPLC analysis (0.06–2.55%). Light roasted Cherry coffee contained the highest overall content of caffeine among all coffees, which exhibited a decrease with intensified roasting.  相似文献   

15.
云南不同地区烘焙咖啡豆主要成分分析及类黑精组成成分   总被引:1,自引:0,他引:1  
刘亚玲  谭超  龚加顺 《食品科学》2017,38(2):176-183
以云南3个咖啡主产区(普洱、怒江、德宏)的生咖啡豆为原料,通过不同程度(轻度、中度、重度)烘焙,对其主要成分进行分析,并提取类黑精,采用热裂解-气相色谱-质谱(pyrolysis-gas chromatography-mass spectrometry,Py-GC-MS)联用技术分析咖啡类黑精的化学组成。结果显示:随着烘焙程度加深,咖啡豆的蛋白质和粗脂肪含量增加,总氨基酸含量降低,其中蛋白质含量最高为重度烘焙后的普洱咖啡豆(16.3 g/100 g),氨基酸含量最高为普洱生咖啡豆(9.41%),粗脂肪含量最高为中度烘焙后的德宏咖啡豆(13.85 g/100 g),矿物质元素中含量较高的为K、Mg、P、Ca,普洱咖啡豆经重度烘焙后K含量最高(2.2 g/100 g)。Py-GC-MS分析结果表明:不同产地、不同烘焙程度咖啡豆的类黑精组成差异明显,但也存在共性特征,咖啡因和酸类相对含量最高,其次是胺类、酯类、酚类、吡咯类、呋喃类、吡啶类、醛类、醇类、酮类等。  相似文献   

16.
目的:研究茶薪菇提取物的酚类物质对体外和体内抗氧化活性的影响.方法:在分析茶薪菇水提物、丙酮提取物、乙醇提取物的总酚、总糖含量以及体外抗氧化的基础上,以阿魏酸、维生素E为阳性对照组,以生理盐水为空白对照组,检测连续灌胃10 d茶薪菇水提物[以总酚含量计,12 mg/(kg bw·d)]对正常小鼠的抗氧化功效,采用D-半...  相似文献   

17.
Coffee is one of the most popular beverages in the world, prepared and consumed in many different ways. Taste, aroma and composition of the coffee brew vary depending on the preparation method. Therefore, this study investigates the effect of different brewing methods on the polyphenol and methylxanthine composition and antioxidant capacity of thirteen different coffee brews. The content of total phenols and flavonoids was determined spectrophotometrically and the content of chlorogenic acid derivates (3-CQA, 4-CQA and 5-CQA) and caffeine using the high performance liquid chromatography (HPLC-PDA). Antioxidant capacity of coffee brews was evaluated by using the ABTS (2,2-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid)) and FRAP (ferric-reducing antioxidant power) assays. Instant coffee brews showed the highest values in content of total phenols, chlorogenic acid derivates, caffeine and antioxidant capacity, which significantly decreased by milk addition. The antioxidant capacity of coffee brews was in compliance with the total phenol content and content of chlorogenic acid derivates.  相似文献   

18.
优化了微波预处理亚麻籽降低其压榨饼生氰糖苷含量的条件,并比较了甘肃亚麻籽在最佳微波条件下微波前后压榨油的品质变化,同时对比了另外五个不同品种亚麻籽在最佳微波条件下其压榨饼生氰糖苷含量在微波前后的变化。结果表明:最佳微波条件为功率700 W,时间6 min,亚麻籽水分17%。在此微波条件下,甘肃亚麻籽压榨饼生氰糖苷含量降低至(4.18±0.23)mg/kg,其压榨油的酸价显著升高,过氧化值显著降低,黄色值、红色值均微弱增加。脂肪酸组成、甾醇含量没有显著性变化,总酚含量是直接压榨亚麻籽油的1.42倍;另外五个不同品种亚麻籽仅哈尔滨亚麻籽压榨饼中生氰糖苷的含量为(15.40±0.47)mg/kg,其余四个品种的压榨饼生氰糖苷含量均在5 mg/kg以下。   相似文献   

19.
A study was carried out of the leaching of aluminium from aluminium cooking vessels and packages. Very small or undetectable levels of aluminium leached from packaging materials into foodstuffs. In boiling tests with neutral porridge no migration of aluminium into the test matrix was observed from the pan. When boiling milk, the leaching of aluminium was 0.2-0.8 mg/kg. The aluminium content of tap water in aluminium pans when reaching boiling point was 0.54-4.3 mg/l and increased with increasing boiling time to 6.3-17 mg/l. Aluminium dissolved in foods based on acidic fruit juice rose to levels of 2.9-35 mg/kg when the foods were boiled in aluminium pans. Steaming of currant berries in an aluminium vessel gave aluminium concentrations of 19-77 mg/kg in the resulting juice. The highest aluminium concentration of 170 mg/kg was measured in rhubarb juice prepared in the steaming vessel. Aluminium dissolved in water to levels of 0.81-1.4 mg/l when heated for the first time in new coffee percolators. The aluminium concentration of water heated in older percolators was 0.09-0.78 mg/l.  相似文献   

20.
Three methods, most frequently used in hydrophilic phenols extraction from virgin olive oils (liquid–liquid, solid-phase with C18 and solid phase with diol-bound sorbents), were applied on virgin olive oils enriched with 2.0–10.0 mg/kg of phospholipids (granular de-oiled soy lecithin). Phospholipids addition significantly decreased the total phenols concentration determined colorimetrically. Liquid–liquid extraction showed the best repeatability and recovery, and the lowest decrease of total phenols extracted in the presence of phospholipids. Extraction rate declined with the increase of phospholipids concentration, but showed a kind of saturation behaviour. Addition of phospholipids (5 g/kg) to various commercial extra virgin olive oils resulted in a different degree of total phenols decrease (from 1% to 45%), probably because of different affinity of phospholipids toward different classes of phenolic compounds. During prolonged contact time between phenols and phospholipids (60-days storage), oxidation monitored by K270 and a decrease of total phenols concentration proceeded more rapidly in the presence of phospholipids.  相似文献   

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