The Effect of Heating Rate by Ohmic Heating on Rheological Property of Corn Starch Suspension

Ohmic Heating에 의한 가열속도 변화가 옥수수전분의 물성특성에 미치는 영향

  • Lee, Seok-Hun (Department of Food Science, Chungkang College of Cultural Industries) ;
  • Jang, Jae-Kweon (Department of Food Science, Chungkang College of Cultural Industries) ;
  • Pyun, Yu-Ryang (Department of Biotechnology, Yonsei University)
  • 이석훈 (청강문화산업대학 식품과학과) ;
  • 장재권 (청강문화산업대학 식품과학과) ;
  • 변유량 (연세대학교 생명공학과)
  • Published : 2005.06.30


Granule swelling is essential phenomenon of starch gelatinization in excess water, and characteristic of heated starch dispersion depends largely on size and distribution of swelled starch granule. Although swelling characteristic of starch granules depends on type of starch, heating rate, and moisture content, influence of heating rate on swelling phenomenon of starch granule has not been fully discussed, because constant heating rate of starch dispersion cannot be obtained by conventional heating method. Ohmic heating, electric-resistant heat generation method, applies alternative current to food materials, through which heating rate can be easily controlled precisely and conveniently at wide range of constant heating rates. Starch dispersion heated at low heating rates below $7.5^{\circ}C/min$ showed Newtonian fluid behavior, whereas showed pseudoplastic behavior at heating rates above $16.4^{\circ}C/min$. Apparent viscosity of starch dispersion increased linearly with increasing heating rate, and yield stress was dramatically increased at heating rates above $16.4^{\circ}C/min$. Average diameter of corn starch granules during ohmic heating was dramatically increased from $30.97\;to\;37.88\;{\mu}m$ by increasing heating rate from $0.6\;to\;16.4^{\circ}C/min$ (raw corn starch: $13.7\;{\mu}m$). Hardness of starch gel prepared with 15% corn starch dispersion after heating to $90^{\circ}C$ at different heating rates decreased gradually with increasing heating rate, then showed nearly constant value from $9.4\;to\;23.2^{\circ}C/min$. Hardness increased with increase of heating rate higher than $23.2^{\circ}C/min$.


  1. Ellis HS, Ring SG, Whittam MA. A comparison of the viscous behaviour of wheat and maize starch pastes. J. Cereal Sci. 10: 33-44(1989)
  2. Holmes ZA, Soeldner A. Effect of heating rate and freezing and reheating of corn and wheat starch-water dispersions. J. Am. Diet. Assoc. 78: 352-355 (1981)
  3. De Alwis AAP, Fryer PJ. The use of direct resistance heating in the food industry. J. Food Engin. 11: 3-27 (1990)
  4. Schreier PJR, Reid DJ, Fryer PJ. Enhanced diffusion during the electrical heating of foods. Intl. J. Food Sci. Technol. 22: 249-260(1993)
  5. Kim JS, Pyun YR. Extraction of soybean milk using ohmic heating. Korea Soybean Dig. 12: 33-38 (1995)
  6. Lee SH, Jang JK. The effect of heating rate by ohmic heating on rheological property of starch suspension. J. Korean Soc. Ind. Food Technol. 6: 61-70 (2002)
  7. Miller BS, Derby RI, Trimbo HB. A pictorial explanation for the increase in viscosity of a heated wheat starch-water suspension. Cereal Chem. 50: 271-280 (1973)
  8. Rao MA, Okechukwu PE, Da silva PMS, Oliveira JC. Rheologi-cal behavior of heated starch dispersions in excess water: role of starch granule. Carbohydr. Polymer. 33: 273-283 (1997)
  9. Okechukwu PE, Rao MA. Kinetics of cowpea starch gelatiniza-tion based on granule swelling. Starch 48: 43-47 (1996)
  10. Miles MJ, Morris MJ, Ring SG. Gelation of amylose. Carbohydr. Res. 135:257-69(1983)
  11. Ring SG. Studies on starch gelation. Starch 37: 80-83 (1985)
  12. Lii CY, Shao YY, Tseng KH. Gelation mechanism and Theological properties of rice starch. Cereal Chem. 72: 393-400 (1995)