Critical roasting level determines bioactive content and antioxidant activity of Robusta coffee beans
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Indonesian Lampung Robusta coffee green beans were roasted at eight roasting levels (green bean, early yellow, brown, 1st crack done, very light, light, medium, and dark), followed by grinding and brewing. The physical properties of ground coffee and chemical properties of brewed coffee were analyzed. The resulting data were mapped in order to investigate the critical roasting level. It was observed that major alterations for physicochemical properties of coffee happened after “first crack” roasting level (when water activity (Aw) of bean decreased from 0.22 to 0.15). This cracking is defined as popping sound of the bean during roasting. Continuous formation of melanoidins under low Aw (< 0.15) was followed by slow degradation of chlorogenic acid (5-CQA) and total phenolic compounds. Caffeine was stable during roasting, while antioxidant activity slightly decreased. The “first crack” was determined to be the critical roasting level to produce roasted coffee beans containing high concentrations of phenolics.
KeywordsRoasted coffee Roasting Water activity Bioactive compounds Antioxidant activity
The authors thank the Ministry of Research, Technology and Higher Education of the Republic of Indonesia for financial support [grant numbers 079/SP2H/LT/DRPM/II/2016, February 17th 2016]. The authors also acknowledge Aneka Coffee Industry-Indonesia for providing Robusta coffee beans and a roaster machine.
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Conflict of interest
The authors whose names are listed above state that they have no conflict in terms of either financial interest or non-financial interest.
- AOAC. Official Methods of Analysis of AOAC Intl. 19th ed. Method 979.12. Association of Official Analytical Chemists, Maryland, USA (2012)Google Scholar
- BeMiller JN, Huber KC. Carbihydrates. In: Damodaran S, Parkin KL, Fennema OR (Ed.), Fennema’s food chemistry. CRC Press, Inc., Boca Raton, pp. 83–154 (2008)Google Scholar
- Gloess AN, Vietri A, Wieland F, Smrke S, Schönbächler B, López JAS, Petrozzi S, Bongers S, Koziorowski T, Yeretzian C. Evidence of different flavour formation dynamics by roasting coffee from different origins: on-line analysis with PTR-ToF-MS. Int. J. Mass Spectrom. 365–366: 324–37 (2014)CrossRefGoogle Scholar
- International Coffee Organization. Total production by all exporting countries. http://www.ico.org/prices/po-production.pdf. Accessed Dec 6, 2017.
- Massini R, Nicoli MC, Cassara A, Lerici CR. Study on physical and physico-chemical changes of coffee beans during roasting. Note 1. Ital. J. Food Sci. 3: 123–32 (1990)Google Scholar