Abstract
The effect of the roasting conditions of sesame seeds on the mechanical properties of gomatofu was investigated. Gomatofu was prepared with Muki (hull-less) and Arai (white and black, with hull) seeds (unroasted and roasted at 160, 170, 180, 190 and 200°C) in an electric oven for 15 min. Surface structures and vertical sections of Arai and Muki seeds were observed by SEM. The fracture stress and strain for gomatofu were the smallest when the seeds were roasted at 170°C, and were the highest when the seeds were roasted at 190°C ( ρ<0.01). The average particle size in the sesame milk of seeds roasted at 170°C (21.5-40.4μm) were smaller than that at 190°C (86.4-110.3μm). Thus, it was considered that the particle size of gomatofu which is prepared with seeds roasted at 190°C became smaller (2.0-6.0μm) by mixing during preparing of gomatofu. The mouthfeel of gomatofu prepared with seeds roasted at 190°C was not smooth, as they had a slight bitterness or “Zaratuki.” In terms of the total acceptance by Kramer's test, gomatofu made from Muki ( ρ<0.01) and Arai ( ρ<0.05) was determined to have best palatability when the seeds were roasted at 170°C.
