EFFECT OF ROASTING CONDITIONS AND VARIETAL DIFFERENCES ON THE ACCEPTABILITY OF TIHLO PROCESSED FROM BARLEY GROWN IN TIGRAY REGION, ETHIOPIA

Abstract

Barley is one of the most important grains used for making ‘Tihlo’ a special type of food in Tigray, northern Ethiopia. However, its quality is dependent on type of variety, roasting temperature and time. Thus, a study was conducted aimed at investigating the most suitable barley variety/varieties and optimal roasting temperature and time for making quality ‘Tihlo’ product. The study was conducted in a 3*3*3 factorial involving three barley varieties (Burguda, Fetina and Hiryti), three roasting temperatures (140, 160 and 180℃) and three roasting times (2, 4 and 6 minutes) in a completely randomized design. Effect of varietal difference, roasting temperature and time on Tihlo quality acceptability (color, smell, taste, mouth feeling/texture, and overall acceptability) and nutritional composition (crude protein, crude fat, crude fiber, total ash, total carbohydrate, calcium, iron and zinc contents) were studied. The sensory scores showed significant (p<0.05) differences for most of the Tihlo quality parameters. The scores for color ranged from 2.46 to 4.57, flavor from 2.7 to 4.69, smell from 3.15 to 4.57, texture from 2.92 to 4.72, and overall acceptability from 2.91 to 4.80 in scales of 5 points. The interaction effect of barley variety, roasting temperature and roasting time on sensory quality of Tihlo revealed that highest acceptability score was obtained when barley grain of Burguda and Fetina were roasted at 160℃ for 6 minutes and at 180℃ for the 2 minutes. Many attributes of the barley flours were significantly (p<0.05) affected by the interaction of variety, roasting temperature and roasting time. The crude fiber varied from 2.18 to 3.36%, crude protein 16.10 to 25.28%, crude fat 1.49 to 2.80%, and total carbohydrate 57.06 to 69.69%, water absorption capacity from 19.30 to 30.97%, bulk density from 0.35 to 0.47%, swelling power from 5.18 to 7%, Calcium content 18.88 to 25.80 mg/100g, Iron content 13.11 to 8.84 mg/100g and zinc content ranged from 1.78 to 2.87 mg/100g. Variety Fetina was found to be superior in its moisture content, crude protein, crude fat, calcium content, and iron content, while Burguda variety had higher total carbohydrate, water absorption capacity and bulk density. From this study it was observed that variety, roasting temperature and time had significantly (p<0.05) affected the sensory attributes and nutritional composition of Tihlo. It can be concluded that for best Tihlo food production barley grains of Burguda and Fetina have to be roasted at 160℃ for 6 minutes.