Separation and characterisation of chlorogenic acid‐rich conserves from green coffee beans and their radical scavenging potential

Methanolic extract (Me₁) obtained from low‐grade green coffee beans (LCB), which is one of the major by‐products in the coffee industry, was enriched with phenolics by different methods viz., partitioning in solvents, chromatographic separation using dowex & diaion HP20 resins and precipitation by lead acetate. Separated fractions and Me₁ were analysed for total polyphenol, chlorogenic acid, caffeine and radical scavenging activity (RSA). Chlorogenic acid isomers of Me₁ and the isolated fractions were analysed by HPLC. Me₁ found to contain total polyphenol (16.60 ± 0.4%), chlorogenic acids (CGAs) (29.60 ± 0.9%), caffeine (7.52 ± 0.2%) and exhibited RSA (92.50%) at 100 ppm concentration. Precipitation method resulted significantly (P ≤ 0.05) higher phenolics (46.33 ± 0.5%) as well as CGAs (43.50 ± 0.7%). HPLC analysis indicated that the composition of 5‐Caffeoylquinic acid (5‐CQA) was more in all the isolated fractions.     

Proximate composition and fatty acids profile of green and roasted defective coffee beans

Defective coffee beans are responsible for the depreciation of the quality of roasted coffee consumed in Brazil. The extraction of the oil of defective beans for applications in the food and pharmaceutical sectors is being considered as an alternative use for those beans. The objective of this work was to determine the composition of the fatty acid fraction of the pressed oil and the proximate composition of crude defective beans in order to provide subsidiary information for proposals of alternative uses for these beans. The amounts of oil extracted from the defective beans were smaller than the amounts extracted from healthy mature beans. The fatty acid composition of oils from defective beans was not significantly different than that from healthy mature coffee beans.     

Consumption of green coffee and the risk of chronic diseases

ABSTRACT

Green coffee contains macro nutrients such as carbohydrates, protein, fat, as well as minor components such as caffeine, trigonelin and chlorogenic acid. Phenolics, chlorogenic acids and brown pigments are sources of natural antixodants. High polypehonic materials found in green coffee and especially chlorogenic acid in it have an important place. It is considered that; green coffee has effects on body mass, blood glucose and lipid levels, blood pressure, prevention from cardiovascular diseases which is based on chlorogenic acid consisting antioxidant activity. However, many topics like toxicological effects, doses, amounts, usage in the body, advantages and disadvantages, etc. of these active molecules need to be examined. For these reasons this article was rewieved to evaluate health effects of green coffee.     

德宏州生咖啡风味组分与海拔相关性研究

为了探讨生咖啡风味组分与海拔之间的关系,采用HS-SPME-GC/MS对德宏州13个不同海拔地区的咖啡豆风味组分进行分析,同时利用聚类分析及Pearson相关分析法对相关性进行分析。实验结果表明:德宏州咖啡含量最高5种风味物质分别为异戊醛、异戊醇、正己醇、2,3-丁二醇和异戊酸;按不同海拔咖啡区分,第一主成分累计贡献率为46.572%,第一第二主成分的累计贡献率为74.224%;通过聚类分析可知除样品11外,其它样品分为2大类（900 m以上和900 m以下）,但差异不显著;通过Pearson相关性系数分析可知样品间不存在显著性差异,相关性随着海拔差距而增大。综上可知,海拔是造成风味差异的因素之一,但两者的相关性不强,不存在显著性差异。      

响应面法优化咖啡生豆水提绿原酸工艺研究

以越南Robusta咖啡生豆为原料,采用水提方法提取绿原酸。通过单因素实验对料水比、提取温度、p H、提取时间等提取工艺参数进行研究,并通过响应面法优化提取工艺,建立二次多项数学模型。结果表明,单因素和响应面优化咖啡生豆水提绿原酸的最优工艺参数为:料水比1∶20、提取温度为81℃,提取时间为60 min,p H为3.6,绿原酸提取得率为3.27%。      

咖啡生豆多糖提取及抗氧化活性

目的:为咖啡中多糖成分的研究和天然活性多糖的开发提供基础数据。方法:研究了云南小粒咖啡生豆多糖(GBP)的水提工艺和抗氧化活性。应用响应面法对咖啡生豆多糖提取工艺进行优化;运用傅里叶变换红外光谱(FT-IR)和扫描电镜(SEM)共同鉴定和表征咖啡生豆多糖的结构特点。采用DPPH自由基、ABTS自由基清除试验和FRAP法评估咖啡生豆多糖体外抗氧化能力。结果:咖啡生豆多糖水提法的最佳工艺条件：提取温度59℃、提取时间45 min、液料比(V_水∶m_咖啡生豆)21∶1 (mL/g)、浓缩体积1/8及乙醇体积分数75%,该条件下咖啡生豆多糖得率达9.56%。多糖样品经红外光谱和电镜扫描显示咖啡生豆是表面呈不规则的孔状结构的多糖。咖啡生豆多糖对DPPH自由基、ABTS自由基清除能力分别为2.32 mg/mL(IC₅₀)、0.011 mmol Trolox/g GBP,铁还原能力为0.95 mmol Fe²⁺/g GBP。结论:咖啡生豆多糖是具有抗氧化活性的不规则孔状结构多糖,具有进一步研究和开发的价值。     

Genetic diversity and correlation of bean caffeine content with cup quality and green bean physical characteristics in coffee (Coffea arabica L.)

BACKGROUND: Although people began to consume coffee for its stimulating effect, the demand for decaffeinated coffee is increasing and now accounts for 10% of the total amount of coffee consumed in the world. Forty‐two arabica coffee genotypes originating from Ethiopia were tested to assess caffeine content variability among them, and the correlation of caffeine content with cup quality and green bean physical characteristics. RESULTS: Green bean caffeine content was measured using high‐performance liquid chromatography, while cup quality was determined by professional coffee tasters. Caffeine content ranged from 9.1 to 13.2 g kg^?1 on dry mass basis (d.m.b.). Six genotypes—AD0291, AD0591, AD2491, AD2691, AD2791 and AD2891—had a caffeine content of less than 10.0 g kg^?1. Caffeine content showed negative and statistically significant correlations with cup quality attributes. Correlations between caffeine content and green bean physical characteristics were non‐significant. CONCLUSIONS: Simultaneous selection for low caffeine content and good cup quality is possible. Some accessions had low caffeine content, and may serve as a source of desirable genes for variety development of types with relatively low caffeine content. Copyright © 2008 Society of Chemical Industry     

The influence of brewing method on bioactive compounds residues in spent coffee grounds of different roasting degree and geographical origin

The content of bioactive compounds in spent coffee grounds (SGC) was studied. SGC were obtained from Coffea arabica beans of different roasting degrees (light and dark) and different geographical origins (Nicaragua, Columbia and Mexico) processed using four brewing methods (mocha, filtered, drip and infusion). The highest caffeine and chlorogenic acid contents were determined in filtered spent coffee extracts. All extracts of light roasted spent coffee grounds showed lower browning index levels in comparison to that from dark roasted spent coffee grounds. Generally, the highest content of total polyphenolic compounds and highest antioxidant capacity were determined in extracts prepared in drip. In conclusion, the results obtained in this study indicate that the spent coffee grounds produced of domestic levels, especially those obtained from filter coffeemaker, could be considered as a good source of natural antioxidants.     

Effect of packaging materials and storage time on changes of colour,phenolic content,chlorogenic acid and antioxidant activity in arabica green coffee beans (Coffea arabica L. cv. Catimor)

The conditions and storage time of green coffee beans are very important for the commercial quality of coffee. This includes factors such as light, humidity and temperature in the warehouse and also the packaging material used. The aim of this study was to evaluate the effects of type of packaging materials namely high density polyethylene (HDPE) bag and jute sack on moisture content, colour, phenolic contents, chlorogenic acids content and antioxidant activity of Arabica green coffee bean during 15 months of storage. The results show that HDPE bag can preserve the moisture content, colour and chlorogenic acid in green coffee beans (GCB) better than a jute sack during storage. No significant difference of phenolics content in green coffee beans was observed during 4 months of storage in both types of packaging. During initial 10 months of storage the antioxidant activity of GCB stored in HDPE showed higher values than that of GCB stored in jute sack. However, after 1 year of storage, the phenolics content and antioxidant activity in GCB in a jute sack were higher than in HDPE bag. The fluctuation of moisture content could lead to stress condition of green coffee bean and contributing to forming of bioactive compounds. This finding was observed and need further investigation.     

Effects of slope exposure,altitude and yield on coffee quality in two altitude terroirs of Costa Rica,Orosi and Santa María de Dota

This study assessed the effects of slope exposure, altitude and yield on several cup quality criteria of coffees from two altitude terroirs of Costa Rica, Orosi (between 1020 and 1250 m above sea level) and Santa María de Dota (between 1550 and 1780 m above sea level). East‐facing slopes gave beverages with generally superior attributes, probably owing to better exposure to morning sunlight. These beverages were mainly more acid: at Orosi an acidity score of 2.73 out of 5 was obtained (3.64 for Santa María de Dota) for eastern exposures, as opposed to 2.36 on average (3.28 for Santa María de Dota) for other exposures. In addition, a positive relation was found between altitude and taster preferences in both terroirs. A negative relation was also found between yield and beverage acidity at Santa María de Dota, where some coffee trees produced up to 13 kg of coffee cherry. Coffees from Orosi were characterised by a floral flavour, which depended on slope exposure, whilst coffees from Santa María de Dota displayed a chocolate taste, which was more marked at high altitude. In both terroirs the caffeine, trigonelline, fat, sucrose and chlorogenic acid contents were not well correlated with the sensory characteristics. Copyright © 2005 Society of Chemical Industry     

咖啡精油超临界CO2萃取工艺优化及理化特性分析

以云南保山小粒咖啡豆为对象,根据国家标准,测定生、熟咖啡豆的营养成分,在单因素实验的基础上,以响应面优化超临界CO₂萃取咖啡精油的工艺参数;测定生、熟咖啡精油理化指标,并通过气相色谱-氢火焰离子化检测器（GC-FID）分析生、熟咖啡精油的脂肪酸组成。结果表明:经烘焙处理后,熟咖啡豆中水分、水浸出物、咖啡因、总糖、粗纤维和粗脂肪含量与生咖啡豆中的存在显著差异（P<0.05）;超临界CO₂萃取生咖啡精油的最佳工艺条件为萃取压力25 MPa,萃取温度54 ℃,萃取时间150 min,在此条件下咖啡精油萃取得率为13.98%。烘焙处理前后,咖啡精油各常规理化指标无显著差异,且均符合国家标准要求。通过GC-FID分别检测到15和16种脂肪酸,其中亚油酸、棕榈酸、硬脂酸和油酸等为主要脂肪酸,烘焙对咖啡豆脂肪酸组成影响不明显,但各脂肪酸的含量存在一定差异。烘焙对咖啡豆及咖啡精油的各项指标均有一定程度的影响,为云南地区咖啡产业发展提供科学依据。