Change in texture improvement of low-fat tofu by means of low-fat soymilk protein denaturation

Woo kyoung Shin, Wallace H. Yokoyama, Wook Kim, Louise Wicker, Yookyung Kim

Research output: Contribution to journalArticle

10 Citations (Scopus)

Abstract

BACKGROUND: Tofu made from low-fat soy flour is a nutritional food for consumers and economically benefits the food processor. However, low-fat tofu has poor textural quality, especially insufficient firmness. Stepwise heating (heating at 75 °C, followed by holding at 95 °C) of full-fat soymilk increases gel properties. Therefore we evaluated the two-step heating of low-fat soymilk to improve tofu texture. RESULTS: The denaturation enthalpy and temperature of β-conglycinin and glycinin were higher in low-fat tofu compared to high-fat tofu. The viscosity of low-fat soymilk and texture of tofu by one-step heating were weaker than full-fat soymilk and tofu. However, the two-step heating increased free sulfhydryl groups and viscosity of low-fat soymilk to a value higher or similar to conventional soymilk. The syneresis of low-fat tofu was reduced about 30% and hardness was higher (131.0 N) by the two-step process compared to one-step heating of full-fat tofu (101.4 N) by the one-step process. The microstructure of low-fat tofu became finer, denser and more homogeneous by the two-step heat process. CONCLUSION: Low-fat tofu produced by denaturing the two major soy proteins separately had improved textural qualities similar to full-fat tofu as a result of increased hydrophobic interactions between denatured protein molecules.

Original languageEnglish
Pages (from-to)1000-1007
Number of pages8
JournalJournal of the Science of Food and Agriculture
Volume95
Issue number5
DOIs
Publication statusPublished - 2015 Mar 30

Fingerprint

Soy Foods
Protein Denaturation
tofu
soymilk
texture
Fats
lipids
Heating
heat
protein denaturation
Viscosity
viscosity
Food
glycinin
sulfhydryl groups
Soybean Proteins
soy flour
hydrophobic bonding
Hardness
Flour

Keywords

  • Gelling
  • Low-fat soymilk
  • Low-fat tofu
  • Stepwise denaturation

ASJC Scopus subject areas

  • Agronomy and Crop Science
  • Food Science
  • Nutrition and Dietetics
  • Biotechnology

Cite this

Change in texture improvement of low-fat tofu by means of low-fat soymilk protein denaturation. / Shin, Woo kyoung; Yokoyama, Wallace H.; Kim, Wook; Wicker, Louise; Kim, Yookyung.

In: Journal of the Science of Food and Agriculture, Vol. 95, No. 5, 30.03.2015, p. 1000-1007.

Research output: Contribution to journalArticle

Shin, Woo kyoung ; Yokoyama, Wallace H. ; Kim, Wook ; Wicker, Louise ; Kim, Yookyung. / Change in texture improvement of low-fat tofu by means of low-fat soymilk protein denaturation. In: Journal of the Science of Food and Agriculture. 2015 ; Vol. 95, No. 5. pp. 1000-1007.
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abstract = "BACKGROUND: Tofu made from low-fat soy flour is a nutritional food for consumers and economically benefits the food processor. However, low-fat tofu has poor textural quality, especially insufficient firmness. Stepwise heating (heating at 75 °C, followed by holding at 95 °C) of full-fat soymilk increases gel properties. Therefore we evaluated the two-step heating of low-fat soymilk to improve tofu texture. RESULTS: The denaturation enthalpy and temperature of β-conglycinin and glycinin were higher in low-fat tofu compared to high-fat tofu. The viscosity of low-fat soymilk and texture of tofu by one-step heating were weaker than full-fat soymilk and tofu. However, the two-step heating increased free sulfhydryl groups and viscosity of low-fat soymilk to a value higher or similar to conventional soymilk. The syneresis of low-fat tofu was reduced about 30{\%} and hardness was higher (131.0 N) by the two-step process compared to one-step heating of full-fat tofu (101.4 N) by the one-step process. The microstructure of low-fat tofu became finer, denser and more homogeneous by the two-step heat process. CONCLUSION: Low-fat tofu produced by denaturing the two major soy proteins separately had improved textural qualities similar to full-fat tofu as a result of increased hydrophobic interactions between denatured protein molecules.",
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N2 - BACKGROUND: Tofu made from low-fat soy flour is a nutritional food for consumers and economically benefits the food processor. However, low-fat tofu has poor textural quality, especially insufficient firmness. Stepwise heating (heating at 75 °C, followed by holding at 95 °C) of full-fat soymilk increases gel properties. Therefore we evaluated the two-step heating of low-fat soymilk to improve tofu texture. RESULTS: The denaturation enthalpy and temperature of β-conglycinin and glycinin were higher in low-fat tofu compared to high-fat tofu. The viscosity of low-fat soymilk and texture of tofu by one-step heating were weaker than full-fat soymilk and tofu. However, the two-step heating increased free sulfhydryl groups and viscosity of low-fat soymilk to a value higher or similar to conventional soymilk. The syneresis of low-fat tofu was reduced about 30% and hardness was higher (131.0 N) by the two-step process compared to one-step heating of full-fat tofu (101.4 N) by the one-step process. The microstructure of low-fat tofu became finer, denser and more homogeneous by the two-step heat process. CONCLUSION: Low-fat tofu produced by denaturing the two major soy proteins separately had improved textural qualities similar to full-fat tofu as a result of increased hydrophobic interactions between denatured protein molecules.

AB - BACKGROUND: Tofu made from low-fat soy flour is a nutritional food for consumers and economically benefits the food processor. However, low-fat tofu has poor textural quality, especially insufficient firmness. Stepwise heating (heating at 75 °C, followed by holding at 95 °C) of full-fat soymilk increases gel properties. Therefore we evaluated the two-step heating of low-fat soymilk to improve tofu texture. RESULTS: The denaturation enthalpy and temperature of β-conglycinin and glycinin were higher in low-fat tofu compared to high-fat tofu. The viscosity of low-fat soymilk and texture of tofu by one-step heating were weaker than full-fat soymilk and tofu. However, the two-step heating increased free sulfhydryl groups and viscosity of low-fat soymilk to a value higher or similar to conventional soymilk. The syneresis of low-fat tofu was reduced about 30% and hardness was higher (131.0 N) by the two-step process compared to one-step heating of full-fat tofu (101.4 N) by the one-step process. The microstructure of low-fat tofu became finer, denser and more homogeneous by the two-step heat process. CONCLUSION: Low-fat tofu produced by denaturing the two major soy proteins separately had improved textural qualities similar to full-fat tofu as a result of increased hydrophobic interactions between denatured protein molecules.

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