Effects of Roasting Condition on the Quality Characteristics and Oxidative Stabilities of Rice Germ

볶음 조건이 쌀눈의 품질 특성 및 산화안정성에 미치는 영향

  • Ko, Soon-Nam (Department of Food and Nutrition, College of Health Sciences, Korea University) ;
  • Kim, Chul-Jin (Korea Food Research Institute) ;
  • Kim, In-Hwan (Department of Food and Nutrition, College of Health Sciences, Korea University)
  • 고순남 (고려대학교 병설 보건대학 식품영양과) ;
  • 김철진 (한국식품개발연구원) ;
  • 김인환 (고려대학교 병설 보건대학 식품영양과)
  • Published : 2003.06.01


In order to compare quality characteristics and oxidative stabilities of rice germs prepared under different roasting conditions, sensory evaluation, color value, tocols (tocopherol+tocotrienol) contents, and peroxide value were investigated. Optimum roasting temperatures for the best acceptability were 20, 10, and 6 min at 170, 180 and 190, respectively. Hunter color a values of rice germ increased as roasting temperature and time increased, whereas L value decreased. Peroxide values of unroasted, and roasted rice germs at $170^{\circ}C$ for 20 min, $180^{\circ}C$ for 10 min, and $190^{\circ}C$ for 6 min were 2.0, and 145.6, 169.5, and 182.9 meq/kg, respectively, after 9 days storage at $60^{\circ}C$. Four tocopherol and three tocotrienol isomers were identified, whereas no ${\beta}$-tocotrienol was detected. The major tocopherol and tocotrienol isomers in rice germ were ${\alpha}$-tocopherol and ${\alpha}$-tocotrienol, respectively. ${\alpha}$-Tocopherol content in roasted rice germ decreased significantly during storage, whereas those of ${\beta}$- and ${\gamma}$-tocopherols slowly decreased. ${\delta}$-Tocopherol had the highest stability among tocopherol isomers in roasted rice germ. Similar trends were observed in tocotrienol isomers.


hunter color;peroxide value;rice germ;roasting condition;sensory evaluation;tocopherol;tocotrienol


  1. Juliano, B.O. Polysaccharides, proteins, and lipids of rice, pp. 59-174. In: Rice: Chemistry and Technology. Juliano, B.O. (ed.). The American Association of Cereal Chemists, Inc., St. Paul, Minnesota, USA (1994)
  2. Chung, R.L., Chen, J.C., Chu, J. and Tzen, J.T. Characterization of seed oil bodies and their surface oleosin isoforms from rice embryos. J. Biochem. 120: 74-81 (1996) https://doi.org/10.1093/oxfordjournals.jbchem.a021396
  3. Shin, D.H. and Chung, J.K. Changes during storage of rice germ oil and its fatty acid composition. Korean J. Food Sci. Technol. 30: 77-81 (1998)
  4. Kim, I.H., Kim, C.J., You, J.M., Lee, K.W., Kim, C.T., Chung, S.H., and Tae, B.S. Effect of roasting temperature and time on the chemical composition of rice germ oil. J. Am. Oil Chem.Soc. 79: 413-418 (2002) https://doi.org/10.1007/s11746-002-0498-2
  5. AOCS. Official Methods and Recommended Pratices of the American Oil Chemist's Society. 4th ed. AOCS press, Champaign, IL, USA (1990)
  6. Kim, Y.E., Kim, I.H. and Lee, Y.C. Effects of roasting process and antioxidants on oxidative stability of perilla oils. Korean J. Food Sci. Technol. 29: 379-382 (1997)
  7. Orthoefer, F.T. Rice bran oil: Healthy lipid source. Food Technol. 50(12): 62-64 (1996)
  8. Kim, H.W. Studies on the antioxidative compounds of sesame oils with roasting temperature. Korean J. Food Sci. Techno!. 32: 246-251 (1997)
  9. Moreau, R.A., Hicks, K.B. and Powell, M.J. Effects of heat pretreatment on the yield and composition of oil extracted from com fiber. J. Agric. Food Chem. 47: 2867-2871 (1999)
  10. Kawabata, K., Tanaka, T., Murakami, T., Okada, T., Murai, H., Yamamoto, T., Hara, A., Shimizu, M., Yamada, Y., Matsunaga, K., Kuno, T., Yoshimi, N., Sugie, S. and Mori, H. Dietary prevention of azoxymethanc-induced colon carcinogenesis with ricegerm in F344 rats. Carcinogenesis 20: 2I09-21I5 (1999)
  11. Ryu, K.C., Chung, H.W., Lee, G.D. and Kwon, J.H. Color changes and optimization of organoleptic properties of roasted polygonatum odoratum tea. J. Korean Soc. Food Sci. Nutr, 26: 83I-837 (1997)
  12. Park, K.D., Choi, J.H. and Sung, H.S. Color evaluation of commercial dehydrated tea-products by hunter-lab tristimulus colorimeter. J. Korean Soc. Food. Nutr. 11: 25-30 (1982)
  13. Shin, D.H. and Chung, J.K. Chemical composition of the rice germ from rice milling and its oil stability during storage. Korean J. Food Sci. Technol. 30: 241-243 (1998)
  14. Choi, O.K., Yun, S.K. and Hwang, S.Y. The chemical components of Korean rice germ. Korean J. Dietary Culture 15: 253-258 (2000)
  15. SAS Institute, Inc. SAS User's Guide. Statistical Analysis Systems Institute, Cary, NC, USA (1990)
  16. Lioyd, B.J., Siebenmorgen, T.J. and Beers, K.W. Effects of commercial processing on antioxidants in rice bran. Cereal Chern. 77: 551-555 (2000) https://doi.org/10.1094/CCHEM.2000.77.5.551
  17. Lane, R.H., Quereshi, A.A. and Salser, W.A Tocotrienols and tocotrienol-like compounds and methods for their use. U.S. Patent 5,591,772 (1997)
  18. Yamamoto, A., Fuji, Y., Yasumoto, K. and Mitsuda, H. Product specificity of rice germ lipoxygenase. Lipids 15: 1-5 (1980) https://doi.org/10.1007/BF02534108
  19. Ministry of Agricultural and Forestry. Agricultural and Forestry Statistical Yearbook, Vol. 2002, pp. 232. National Agricultural Products Quality Management Service (NAQS) of the Ministry of Agriculture and Forestry (MAF), Seoul, Korea (2002)
  20. Rogers, E.J., Rice, S.M., Nicolosi, R.J., Carpenter, D.R., McClelland, C.A. and Romanczyk, Jr. L.J. Identification and quatitation of $\gamma$-oryzanol components and simultaneous assessment of tocols in rice bran oil. J. Am. Oil Chem. Soc. 70: 301-307 (1993) https://doi.org/10.1007/BF02545312
  21. Qureshi, A.A., Mo, H., Packer, L. and Peterson, D.M. Isolation and identification of novel tocotrienols from rice bran with hypocholesterolemic, antioxidant, and antitumor properties. J. Agric. Food Chem. 48: 3130-3140 (2000) https://doi.org/10.1021/jf000099t