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Hygroscopic properties of green coffee transported by sea

Ruszkowska M., Dmowski P., Urbanowicz K.

TransNav : International Journal on Marine Navigation and Safety of Sea Transportation

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2021

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Vol. 15 No. 3

641--647

EN

The aim of research was to evaluate the hygroscopic properties of green coffee beans determining its quality during sea transportation. The research material consisted of seven samples of unroasted bean coffee from different countries of origin (Kenya, India, Ethiopia, Columbia and Guatemala) obtained directly from the coffee producer. The water content of green coffee must not exceed 12% as it then has a tendency to grow mould and become musty. Coffee beans require particular temperature, humidity/moisture and possibly ventilation conditions and therefore, to explore and predict the behaviour during transport of green coffee its equilibrium moisture content must be determined for a range of transport temperatures and relative humidity levels . The present paper focuses on the evaluation of the hygroscopic properties of green coffee from different countries of origin based on isotherms of water vapour sorption and characteristic selected parameters of the surface microstructure determining transport conditions and the microbiological stability of this cargo. While assessing the quality and transport durability of green coffee beans, based on the parameters of monomolecular layer capacity and the specific surface area of sorption, it was found that especially samples of coffee from Guatemala and Ethiopia were the least susceptible to changes in the transport conditions.

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Development and validation of RRLC–UV method for determination of chlorogenic acid in green coffee

Velkoska-Markovska Lenche, Jankulovska Mirjana S., Petanovska-Ilievska Biljana, Hristovski Kristijan

Acta Chromatographica

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2020

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Vol. 32, no. 1

34--38

EN

Coffee is one of the most widely consumed beverages in the world. It contains many bioactive compounds, including chlorogenic acid which possesses various biological properties. In this study, in order to determine concentration of chlorogenic acid in green coffee, a reverse-phase rapid resolution liquid chromatography (RP-RRLC) method with diode-array detection (DAD) was developed. Successful separation was achieved on a Poroshell 120 EC-C18 (50 mm × 3 mm; 2.7 μm) column using acetonitrile–water with 1% phosphoric acid (10:90, v/v) as a mobile phase, at a flow rate of 1 mL/min, and with UV detection at 325 nm. The identification was made with comparison of the retention time of pure analytical standard with the retention time of chlorogenic acid in the analyzed samples. The developed method was validated using the following parameters: linearity, sensitivity, selectivity, precision, and accuracy. Excellent linearity over the range 12.33–143.50 μg/mL was achieved with R2 values greater than 0.99. The intra-day precision was validated with the %RSD values, which confirmed that the method for determination of chlorogenic acid was repeatable. The mean recovery rate of the method ranged between 97.87% and 106.67% with %RSD values lower than 1%. The limit of detection and limit of quantification values under the used chromatographic conditions were 0.29 and 0.96 pg, respectively. This method was successfully employed for quantitative determination of chlorogenic acid in green coffee samples.

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Wpływ prażenia kawy na wybrane parametry jej jakości

Szymanowska K., Wołosiak R.

Aparatura Badawcza i Dydaktyczna

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2014

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T. 19, nr 1

77-83

PL

W badaniach wykorzystano kawę zieloną z Brazylii i Etiopii, którą poddano procesowi palenia. W próbkach pobieranych w trakcie prażenia porównywano suchą masę, kwasowość, zawartość cukrów bezpośrednio redukujących, polifenoli ogółem, przeciwutleniaczy oraz przeprowadzono oznaczenie składników aromatu kawy (GC-MS). Wyniki badań świadczą o silnym wpływie procesu palenia na jakość sensoryczną i fizykochemiczną kaw. W próbkach obu gatunków kaw prażenie powodowało wzrost zawartości cukrów bezpośrednio redukujących i kwasowości. Zauważono niewielki spadek zawartości polifenoli i aktywności przeciwutleniającej. Kawy zielone charakteryzowały się ograniczonym profilem związków lotnych, natomiast na bogaty profil zapachowy kaw palonych wpływały głównie pirazyny, ketony i pochodne furanu.

EN

Green coffee from Brazil and Ethiopia were used for the presented investigations. The coffee samples were received during roasting process. The content of dry weight, acidity, reducing sugars, total polyphenols and antioxidant activity were analysed in the study. The coffee aroma compounds were also determined. The results obtained indicate a strong influence of roasting process on sensory and physicochemical quality of the coffees. For both coffee species roasting resulted in an increase of reducing sugar contents and acidity. A slight decrease of polyphenol contents and antioxidant activity was noted. Green coffees had a limited volatile profile. Rich aroma profiles of roasted coffees were influenced mainly by pyrazines, furan derivatives and ketones.