Sesame seeds roasted

TABLE 12. Changes in the Content (ppb) of Selected Odor-Active Compounds in Sesame Oils with Sesame Seeds Roasted at 160, 180, 200, and 220°C for 20 min (88, 89). 

Sesame seed (roasted) flavor. According to aroma extract dilution analysis, 2-furylmethanethiol, guaiacol, 2-phenylethanethiol (CgHn is, Mr 138.23), and Furaneol have the highest dilution factors in the flavor of roasted sesame seeds, besides 4-vinyl-guaiacol, 2-pentylpyridine (C,oH,5N, Mr 149.24), 2-acetyl-l-pyrroline, 2-acetylpyrazine, and 2-ethyl-3,5-dimethylpyrazine (see pyrazines). 

Sesame Seed (Benne, Benni, Bene Seed). Sesame seed is the whole dried seed of Sesamum indicum L. (PedaUaceae), an annual plant now cultivated in Mexico and Central America, although indigenous to Indonesia and tropical Africa. It may be the oldest condiment known. The seed is small, shiny, and oval shaped, about 0.32 cm long. The unhuUed seeds are dark and the hulled seeds are pearly white. Sesame seeds, when baked, have a pleasant, roasted, nutty flavor. They are used in baked goods and in confections, eg, halvah. 

YOSHIDA H, shigezaki J, TAKAGi s and KAJIMOTO G (1995) Variations in the composition of various acyl lipids, tocopherols and lignans in sesame seed oils roasted in a microwave oven , J Sci Food Agric, 68 (4) 407-16. 

Roasting of white sesame seeds resulted in a material exhibiting an intense roasty, sweet, burnt odor. On the contrary, in the overall odor of black seeds roasted under die same conditions a tallowy, fatty note was predominant, besides the roasty odor. The results of a... 

Comparison of important odorants (FD > 1024) in roasted (180°C, 30 min) black and white sesame seeds [52] ... 

Similar reactions may lead to HDF formation during roasting of coffee, cocoa beans or sesame seeds. However, this has to be proven by further experiments. 

Shimoda, M., Nakada, Y., Nakashima, M., and Osajima, Y. 1997. Quantitative comparison of volatile flavor compounds in deep-roasted and light-roasted sesame seed oil. J. Agric. Food Chem. 45, 3193-3196. 

Yoshida, H. and Takagi, S. 1997. Effects of seed roasting temperature and time on the quality characteristics of sesame (Sesamum indicum) oil. J. Sci. Food Agric. 75, 19-26. 

Isolates from oils from roasted oats (b, c) were quite different in odor compared with those described above. Notes such as roasted, peanut, butterscotch, sesame seeds, creamy, caramel-like were used. Among the compounds identified, furanmethanol (2-furfurylalcohol), 2-methylfurfural, 2,6-dimethylpyrazine and acetylpyrazine were given these pleasant descriptions. Moreover, the stability of oils extracted from roasted oats were better than that of oils extracted directly from crude oats (Fors Eriksson, submitted for publication 1988). 

Sesame Oil Sesame oil has traditionally been used in eastern Asian countries, especially China, Japan, Korea, and Taiwan. It has been prized for its nutritive and health-promoting values. Sesame oil, prepared from roasted sesame seeds, has a distinctive flavor and a long shelflife (86). Several studies have been reported on the flavor components of sesame oil (87-91). The amount of volatile flavor compounds in sesame oil is greatly affected by the roasting process. It has been reported that the ratio of the amount of volatile components in deep-roasted oils was increased by 2-7 times in deep-roasted oil as compared with that of light-roasted oils (90). 

Perhaps the most important compounds identified in the roasted sesame oils are 2-furfurylthiol and guaiacol. Using aroma extract dilution analysis method, these two compounds have been characterized by Schieberle (92) to be the most odor-active compounds in roasted sesame seeds. 2-Furfurylthiol, having an intense coffee-like odor, increased from 16 ppb in roasted oil processed at 160°C for 30 min to 158 ppb in the oil processed at 200°C for 30 min (Table 12). Guaiacol has a burnt and smoky odor with an extremely low-odor threshold of 0.02 ppt in... 

Sesame oil has a long history of human consumption. The processing of sesame seed to yield sesame oil varies from region to region. The major differences are (1) whether the seed coat is removed and (2) whether the seed is roasted. Figure 9 shows the flow diagrams of the processing of three major types of sesame oils produced worldwide, namely (1) refined sesame oil, which is produced from unroasted sesame seed either with seed coat or without seed coat (2) roasted sesame oil, which is produced from roasted sesame seed and (3) small mill sesame oil, which is produced from roasted dehulled sesame seed. 

Roasted sesame oil has a strong characteristic flavor of roasted sesame seed. It is the most popular sesame oil consumed in China, Japan, and Korea. It is also believed to be beneficial to health (40). As shown in Figure 9, sesame seeds are roasted at 140 200°C prior to oil extraction. The conditions of the roasting process... 

Effect of Roasting on Antioxidative Activity Roasted sesame oU was reported to be much more antioxidative than unroasted purified sesame oil (71). Yen and Shyu (67) found that roasted sesame oUs prepared from sesame seeds with different roasting temperatures (between 180°C and 210°C) exhibited... 

Effect of Roasting on Different Ciasses of Lipids Roasting of sesame seed not only affects the antioxidative activity and the hgnans of sesame oil, the lipid composition will also be affected. The lipids in sesame seeds consist of neutral lipids, phosphohpids, and glycolipids. The major lipid fraction is neutral lipids, which constitute about 91 96% of the total lipids. Phospholipids and glycolipids represent around 3% and 0.3 6% of the total lipids, respectively (69, 70, 75-78). 

Glycolipids content of sesame seed, on the other hand, increased with roasting temperature and time (75, 78). When sesame seeds were roasted in an electric oven from 120°C to 250°C for 30 min, the glycolipids content was found to increase from 6.9-mg/lOOO-g seeds (0.5% of total lipids) to 262.9-mg/lOOO-g seeds (17.2%... 

The extraction of sesame oil from roasted sesame seed is generally performed with pressing. Solvent extraction is not used because the desirable roasted flavor may be removed during evaporation of solvent. In commercial production, continuous screw-press or hydraulic press is employed (42). The hydraulic press can be vertical or horizontal. The continuous screw may be operated twice in order to increase the oil yield (82). Proper cooking (100°C, 7 min) and addition of water (12.5%) after roasting can also raise the oil yield (83). 

Sesame oil from roasted sesame seed has the characteristic flavor and color of the roasted sesame oil the filtered crude oil is used without further refining. Sesame oil from cold-pressed unroasted sesame seed is also used directly after filtration as a flavored oil. Crude sesame oil from unroasted sesame seeds after screw-press or hydraulic press or solvent extraction, which varies in color from yellow to dark amber, may need further refining. Refined sesame oil is usually pale yellow in color. 

Roasted Sesame Oil Sesame Seed Refined Sesame Oil... 

Three extremely odorous pyrazines, 3-isopropyl-2-methoxypyrazine, 2-s-butyl-3-methoxypyrazine, and 2-isobutyl-3-methoxypyrazine have been shown to be present in green peas, and are likely to be of major significance in the flavor of peas (59). The volatile oil of green bell peppers has been found to contain 2-isobutyl-3-methoxypyrazine as a major component (60,61). The alkylpyrazines in potato chips (62,63) and roasted peanuts (63) have been examined. 2-Isopropyl-3-methoxypyrazine has been characterized in the vacuum steam volatile oil of potatoes (64), 2-ethyl-3-methoxypyrazine in cooked potato (65), and 3-ethyl-2,5-dimethylpyrazine and 2-ethyl-3,5-dimethylpyTazine as the components important to the aroma of baked potato (66). A variety of alkylpyrazines have been identified in roasted sesame seeds (67) and 21 pyrazines have been identified in the aroma components isolated from roasted green tea (68). 

The fatty, tallowy-smelling aroma compound 2-pentylpyridin (56), which has been identified in roasted sesame seeds [77], is formed from the reaction of a fat oxidation product, 2,4-decadienal, with ammonia from the degradation of amino acids like glutamine and asparagine [78] (cf. Fig. 3.33). 

Schieberle P. Studies on the flavour of roasted white sesame seeds. In Progress in flavour precursor studies, Schreier, R, Winterhalter, P. (Eds.), Allured Publishing, Carol Stream, 1993, 343-360. 

Roasting of the rather odourless sesame seeds generates an intense aroma characterised by roasty, burnt, meat-like or sulphurous odour notes. Several studies have been performed to identify the odorants responsible for these notes in roasted white and black sesame [97-99]. The results obtained for moderately roasted white sesame are presented in Table 6.51 as an example. 

On the basis of high OAV, 2-acetyl-l-pyrroline (no. 1), 2-furfurylthiol (no. 2), 2-phenylethylthiol (no. 3) and furaneol (no. 4) are the most important contributors to the overall roasty, caramel-like aroma of the moderately roasted sesame. The two thiols nos. 2 and 3, but not the unstable 2-acetyl-l-pyrroline (no. 1), were also identified as key odorants of white and black sesame seeds which had been longer roasted and which elicited intense burnt or even rubbery odour notes ]97, 98]. 

Schieberle, P. (1994) Important odorants in roasted white and black sesame seeds. In Kuhihara, K., Suzuki, N., Ogawa, H. (eds.) Olfaction and Taste, ISOT XI. Springer, Tokyo, pp. 263-267... 

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