sesame seed roasting

Scope: Layer: food. Coarse white sesame seeds from China, 1994 crop (Kadoya Sesame Mills), roasted in an electric oven at 170, 200, or 230°C for 1 to 20 minutes (12 conditions). Taste-related components — free sugars (mainly sucrose) and free amino acids (mainly glutamic acid, aspartic acid, alanine, and others) — were quantified by HPLC and a high-speed amino-acid analyzer.

Note: The total free amino acids and the amount of free sugars decreased consistently as roasting temperature and time increased (for example, total free amino acids fell to 23% of the unroasted level at 170°C for 20 minutes, and to 44% at 230°C for 10 minutes; free sugars, mainly sucrose, had almost disappeared at 230°C for 10 minutes, with a residual rate of 0.2%). The authors discuss these taste-related components as 『甘味を中心に、酸味あるいは苦味とともに呈味に寄与している』 (in translation: "contributing to taste mainly through sweetness, together with sourness or bitterness"), but bitterness was not measured as an independent sensory score (the 5-point sensory evaluation covered color, shape, aroma, taste, and overall impression). No source directly measuring the bitterness of roasted sesame itself was found within the range of this collection.