국립강릉원주대학교

초록/요약 도움말

This study evaluated the physicochemical quality characteristics of raw as well as physicochemical and flavor characteristics of roasted beans of fully washed specialty bourbon cultivar of Coffea arabica “BM 139" from four geographical sub-regions of Rwanda in comparison with a wet processed typica cultivar from Yirgacheffe, Ethiopia and a dry processed red bourbon cultivar from Cerrado, Brazil. The moisture content of raw coffees ranged from 7.7%–10.2 %. Raw coffee from Brazil had the lowest density (true density = 1.188, bulk density = 0.644 g/cm3) and darker in terms of lightness than samples from other regions. Other samples showed no significant differences in true density. Raw coffee from Nzahaha coffee washing station (CWS), Rusizi district and Kayumbu CWS, Kamonyi district showed the lowest total phenolic content of 38.4 and 38.9 mg/g respectively whereas raw coffee from Nyamyumba CWS, Rubavu district had the highest total phenolic content of 46.8 mg/g on a dry weight basis. DPPH radical scavenging activity ranged from 89.9 % to 91.8 % and varied little between samples. Raw coffee from Yirgacheffe, Ethiopia showed the highest total titratable acidity (2.3 ml of 0.1 N NaOH/g corresponding to 1.48 % citric acid) and total CQA of 82.62 mg/g whereas coffee from Brazil had the highest caffeine content of 18.5 mg/g on a dry weight basis. Raw coffee from Karenge CWS, Rwamagana district was characterized by having the lowest caffeine and trigonelline content (13.4 and 10.33 mg/g respectively). After roasting there was a drop in most physicochemical characteristics. Moisture (1.5–2.6 %), bulk density (0.405–0.486 g/cm3), L* (31.1–39.3), pH (4.72–5.02), TPC (30.62–25.84 mg/g), TTA (1.92–2.59ml/g), trigonelline (10.15–11.92 mg/g) and total CQA (32.74–54.3 mg/g). Raw and roasted coffee samples from Rulindo and Kirorero cws indicated higher bulk densities which might be due to higher altitudes of these two areas. Caffeine and RSA were not affected by the roasting process. Dry processed red bourbon coffee from Brazil was characterized by higher caffeine content in raw as well as roasted forms. After roasting, wet processed bourbon coffees from Rwanda were more acidic than Brazilian and Ethiopian coffees. Typica cultivar from Ethiopia exhibited higher CQA content compared to wet processed Rwanda and dry processed Brazilian bourbon cultivar evaluated. Close flavor characteristics between coffee samples from western and southern sub-regions as well as between northern and eastern sub-regions were observed. This study revealed that the physicochemical characteristics of the bourbon cultivar may vary depending on the environmental conditions, processing as well as agricultural practices applied in different coffee growing areas.