Preparation of Edible Films from Soybean Meal

대두박을 이용한 가식성 필름의 제조에 관한 연구

  • Yang, Sung-Bum (Department of Food Technology, Korea University) ;
  • Cho, Seung-Yong (Department of Food Technology, Korea University) ;
  • Rhee, Chul (Department of Food Technology, Korea University)
  • 양성범 (고려대학교 식품공학과) ;
  • 조승용 (고려대학교 식품공학과) ;
  • 이철 (고려대학교 식품공학과)
  • Published : 1997.06.01

Abstract

Effect of extraction pH on mechanical properties such as tensile strength (TS) and elongation (E) and on water vapor permeability (WVP) of soybean protein isolate (SPI) edible films extracted from soybean meal was investigated. Five pHs, acidic range (pH 2.0 and pH 3.0), neutral range (pH 7.0) and alkalic range (pH 10.0 and 12.0), were used to extract SPI. TS of the film extracted at pH 7.0 was the lowest, and WVP of $SPI_3$ (SPI extracted at pH 3) film was the lowest value among the films. The WVP of $SPI_3$ films was $3.349\;{\times}\;10^{-10}\;g{\cdot}m/m^2{\cdot}s{\cdot}Pa$ and increased to $3.871\;{\times}\;10^{-10}\;g{\cdot}m/m^2{\cdot}s{\cdot}Pa$ as film thickness increased from $55\;{\mu}m$ to $72\;{\mu}m$ thickness. Three different plasticizers (glycerol, polyethylene glycol and propylene glycol) were used for $SPI_2$ (SPI extracted at pH 2) film. TS of $SPI_2$ films was 12.297 MPa and decreased to 1.356 MPa for glycerol and showed the same trend in other two plasticizers. The SPI films extracted at acidic range were shown higher mechanical properties and lower water vapor permeabilities than those of extracted at neutral and alkalic ranges. The difference of SPI film properties seemed to be attributed by 11S/7S ratio as well as protein content.

Keywords

soy protein isolate;plasticizer;film;tensile strength;elongation;water vapor permeability