Influence of Seed Roasting Process on the Changes in Volatile Compounds of the Sesame (Sesamum Indicum L.) Oil

Abstract

Sesame (Sesamum indicum L.) seeds and sesame oils have traditionally been used in eastern Asian countries, especially Korea, China and Japan. Sesame seeds have been prized for their high nutritive value. Sesame oil, prepared from roasted sesame seeds, has a distinctive flavor and long shelflife (Kikugawa et al., 1983; Manley et al., 1974). Several studies have been reported on the flavor components of sesame oil (Yamanishi et al., 1960, 1967; Yoko et al., 1969, Yen, 1990, Shimoda et al., 1996, 1997). The condition of roasting process is the key step in manufacturing sesame oil, significantly influencing the color and flavor quality of sesame oil. Yen (1990) reported that sesame oils prepare at roasting temperatures between 180°C and 220°C have no apparent differences in characteristics, such as acid value, saponification value and refractive index. Yoshida et al. (1994) reported that the oxidative stability of the sesame oil was due to the synergism between the endogenous antioxidants and the browning substances produced during roasting. On the other hand, higher roasting temperatures have usually been employed to obtain a strong flavor but it results in sesame oil of poorer quality (Yen et al., 1986). Thus, in order to make good quality sesame oil, the optimum roasting conditions should be established. This research was designed to investigate the effect of the roasting process, with an emphasis on the roasting temperature and time, on the changes in volatile components of sesame oil.