Preparation of Whey Powder-Based Biopolymer Films

유청분말을 이용한 생고분자 필름의 제조

  • Cho, Seung-Yong (Department of Agricultural Chemistry, Korea University) ;
  • Park, Jang-Woo (Department of Food Technology and Science, Ansung National University) ;
  • Rhee, Chul (Department of Agricultural Chemistry, Korea University)
  • 조승용 (고려대학교 응용생명환경화학과) ;
  • 박장우 (안성산업대학교 식품공학과) ;
  • 이철 (고려대학교 응용생명환경화학과)
  • Published : 1998.12.01

Abstract

Whey powder, a by-product of milk industry, was utilized to produce biopolymer film with the combination of film matrix supporting material, sodium caseinate. Biopolymer films were prepared from whey powder-sodium caseinate mixtures at several mixing ratios. The effects of pH, plasticizers and cross-linkers on tensile strength (TS) and elongation (E) of films were investigated. The films could be formed by use of whey powder up to 70%. As the whey powder content was increased, TS of the film decreased while E increased. Films containing more than 70% of whey powder could not be formed due to the stickiness of lactose in whey powder. The optimum pH of the film solution was found to be 10. Among the plasticizers tested, sorbitol was found to be the most effective plasticizer while glycerol was inadequate for the film. Tensile strengths of films containing $30{\sim}40%$ whey powder were higher than 10 MPa with relatively high E, when the films were plasticized with 30% (w/w) and 40% sorbitol. TSs of the relatively weak films containing $50{\sim}60%$ whey powders were improved by the addition of small amount of sodium citrate for 30% sorbitol plasticized films, and by the addition of sodium chloride for 40% sorbitol plasticized films. It was concluded that up to 70% of whey powder could be utilized to produce biopolymer films by adding sorbitol and cross linkers at pH 10.

Keywords

whey powder;sodium caseinate;biopolymer film;plasticizer;cross linker