Method development for green coffee analysis and its possible application for group discrimination and correlation of green coffee chemistry with cupping quality

vi, 50 leavesDevelopment of an ion-exchange HPLC method to simultaneously determine certain organic acids and sugars in green coffee is described. Identifying and quantitating flavor relevant compounds in green coffee offers the potential for an objective measure of cup quality. Presently, a panel of trained experts who rely upon sensory discrimination, a subjective measure, determines coffee quality. Accurate quantitation of individual compounds was verified by single component fortification of green coffee samples and determination of recoveries. Typical recoveries were as follows: malic acid 100.7%, quinic acid 86.7%, citric acid 112.8%, lactic acid 100.0%, sucrose 93.6%, fructose 109.3% and glucose 110.2%. This method is the first to report simultaneous determination of two classes of green coffee components, and provides for a relatively quick and accurate means of determination. Future utilization of this method as a measure of coffee cup quality in green coffee has implications for future coffee breeding, flavor manipulation and genetic transformation

Shade coffee in Hawai'i---quality, physiology, and biochemistry

Thesis (Ph.D.)--University of Hawaii at Manoa, 2008.Measurements were made on yields, bean characteristics, specific leaf area, leaf temperature, leaf nutrient levels, nodal growth, organoleptic quality and photosynthetic response. Brewed coffee samples were analyzed using solid phase microextraction-gas chromatography to capture and analyze brewed coffee volatiles. These volatiles were used topredict organoleptic quality and group membership based on location, year of harvest and shade treatment. In addition, application of kaolin was explored using glass plates and slides to determine coverage and light transmittance.Shading did not appreciably affect organoleptic quality. Furthermore, brewed coffee volatiles were not good predictors of organoleptic quality. However, with few to no misclassifications, the volatiles could accurately predict group membership.Shading resulted in statistically different yields in the macadamia (16% of sun) and kaolin (199% of sun) treatments in the second year, although a negative, linear trend was observed with increased shading. The lack of significant differences in yields between the cloth shaded and sun treatments was likely a result of large yield variation. Bean sizes were generally larger in shaded treatments and only the percentage of defects and broken beans were lower for the kaolin treatment in the second year in Kunia. Kona bean sizes were larger in the sun treatment but no differences were observed in bean characteristics. Kaolin treated plants responded similarly to sun plants for most measurements, although the responses tended to be more extreme when compared to the shade cloth and macadamia treatments. Kaolin treated leaves were 3.4°C cooler than sun leaves and photosynthesized 71% more CO2 than sun plants.To explore the effects of shade level and type on coffee in Hawai'i, Coffea arabica L. was shaded with varying degrees of black and aluminized shade cloth, macadamia trees, and a novel, spray-on shade composed mostly of kaolin. These treatments were compared to unshaded coffee. Two locations were used in this experiment: Kunia, O'ahu and Kona, Hawai'i. The shading was imposed after the first major flowering of the season and maintained for 2 complete harvests.Includes bibliographical references (leaves xxx-xxx).Also available by subscription via World Wide Web78 leaves, bound 29 cmTo explore the effects of shade level and type on coffee in Hawai'i, Coffea arabica L. was shaded with varying degrees of black and aluminized shade cloth, macadamia trees, and a novel, spray-on shade composed mostly of kaolin. These treatments were compared to unshaded coffee. Two locations were used in this experiment: Kunia, O'ahu and Kona, Hawai'i. The shading was imposed after the first major flowering of the season and maintained for 2 complete harvests. Measurements were made on yields, bean characteristics, specific leaf area, leaf temperature, leaf nutrient levels, nodal growth, organoleptic quality and photosynthetic response. Brewed coffee samples were analyzed using solid phase microextraction-gas chromatogtaphy to capture and analyze brewed coffee volatiles. These volatiles were used to predict organoleptic quality and group membership based on location, year of harvest and shade treatment. In addition, application of kaolin was explored using glass plates and slides to determine coverage and light transmittance. Shading resulted in statistically different yields in the macadamia (16% of sun) and kaolin (199% of sun) treatments in the second year, although a negative, linear trend was observed with increased shading. The lack of significant differences in yields between the cloth shaded and sun treatments was likely a result of1arge yield variation. Bean sizes were generally larger in shaded treatments and only the percentage of defects and broken beans were lower for the kaolin treatment in the second year in Kunia. Kona bean sizes were larger in the sun treatment but no differences were observed in bean characteristics. Kaolin treated plants responded similarly to sun plants for most measurements, although the responses tended to be more extreme when compared to the shade cloth and macadamia treatments. Kaolin treated leaves were 3.4°C cooler than sun leaves and photosynthesized 71 % more CO2 than sun plants. Shading did not appreciably affect organoleptic quality. Furthermore, brewed coffee volatiles were not good predictors of organoleptic quality. However, with few to no misclassifications, the volatiles could accurately predict group membership

Isotopes as Tracers of the Hawaiian Coffee-Producing Regions

Green coffee bean isotopes have been used to trace the effects of different climatic and geological characteristics associated with the Hawaii islands. Isotope ratio mass spectrometry (IRMS) and inductively coupled plasma mass spectrometry ((MC)-ICP-SFMS and ICP-QMS) were applied to determine the isotopic composition of carbon (δ¹³C), nitrogen (δ¹⁵N), sulfur (δ³⁴S), and oxygen (δ¹⁸O), the isotope abundance of strontium (⁸⁷Sr/⁸⁶Sr), and the concentrations of 30 different elements in 47 green coffees. The coffees were produced in five Hawaii regions: Hawaii, Kauai, Maui, Molokai, and Oahu. Results indicate that coffee plant seed isotopes reflect interactions between the coffee plant and the local environment. Accordingly, the obtained analytical fingerprinting could be used to discriminate between the different Hawaii regions studied