EFFECTS OF COFFEE HUSK ROASTING CONDITIONS AND ITS CONCENTRATIONS ON PHYSICOCHEMICAL PROPERTIES AND SENSORY ACCEPTABILITY OF HOJJA (A LOCAL HOT DRINK)

Abstract

This study intended to explore the effect of coffee husk roasting conditions and its concentrations on the physicochemical properties and sensory acceptability of hojja. This study set in three factors in a full factorial design with three levels. The factors considered were roasting temperatures (160, 170, and 180°C), roasting times (5, 10, and 15 min), and coffee husk concentrations (4, 7 and 10g) with the same levels of unroasted coffee husks (as a control). The result showed that the increased coffee husk concentrations decreased L*value of colour from 81.32 to 76.31, extraction yield (EY) from 14.83 to 11.44%, PH from 6.54 to 6.21%, water contents from 95.40 to 94.21%, and increased in a* value from 0.46 to 1.81, b* value from 9.66 to 14.92, total dissolved solids (TDS) from 2.33 to 3.32% and titriable acidity from 0.132 to 0.167% were recorded. At the same time, it increased carbohydrate from 12.60 to 15.00%, fats from 6.96 to 8.51%, proteins from 7.44 to 9.23%, ash from 0.59 to 0.88%, and gross energy from 115.13 to 151.33kca/mL respectively. Increased coffee husk concentrations also increased Ca from 3.31 to 3.95mg/100mL, Fe from 0.033 to 0.075 mg/100mL, Mg from 1.30 to 1.76mg/100mL, total phenolic content from 0.40 to 0.79 mgGAE/mL and tannin from 0.11 to 0.50 mg/mL. Additionally increased in sensory score values of colour from 5.16 to 7.33 , in aroma from 5.41 to 7.35, in taste from 5.32 to 7.41, in body from 5.58 to 7.91 and overall acceptability from 5.41 to 7.50 respectively. The increased roasting temperatures and times decreased extraction yield from 13.72 to 10.06%, titriable acidity from 0.123 to 0.076%, water contents from 95.31 to 93.72%, protein from10.83 to 8.94%, and tannin from 0.42 to 0.02mg/mL. However, increased PH from 6.28 to 6.73%, fats from 3.86 to 8.02%, Ca from 3.67 to 4.11mg/100mL, Fe from 0.048 to 0.084 mg/100mL, Mg from 1.58 to 1.92mg/100mL and body score value from 6.50 to 8.49 were recorded. These increased roasting temperatures and times also increased and then decreased a* value from 0.89 to 1.75to 1.00, b* value from 15.22 to 20.27 to 16.35, in carbohydrates from 9.56 to 14.19 to 12.77%, gross energy from 120.52 to 165.68 to 144.18 kca/mL and total phenolic contents from 0.44 to 0.68 to 0.46 mgGAE/mL. Furthermore in sensory score value of colour from 5.08 to 8.08 to 6.08, aroma from 5.11 to 8.18 to 6.26, taste from 5.14 to 8.26 to 6.33 and overall acceptability from 5.00 to 8.25 to 6.25 were recorded. Increased roasting temperatures and times, decreased and then increased L*value of colour from 77.67 to 73.18 to 74.95 and no effects on TDS. It concluded that both main and interactions of coffee husk concentrations, roasting temperatures and times had (P<0.05) significant effects on physicochemical and sensory acceptability of hojja. From all trials of sample brewed from 10g roasted coffee husks at 1700C for 10 minutes was acceptable in many sensory attributes and product properties. Therefore, this hojja has best sensory acceptability of the others.