Changes in Gelling Behavior of Whey Protein Isolate and β-Lactoglobulin During Storage: Possible Mechanism(s)

Authors

  • D. RECTOR,

    1. Authors Rector and Kinsella are with the Institute of Food Science Cornell Univ., 115 Stocking Hall, Ithaca, NY 14953. Author Matsudomi's current address: Dept. of Agricultural Chemistry, Yamaguchi Univ., Yamaguchi 753, Japan.
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  • N. MATSUDOMI,

    1. Authors Rector and Kinsella are with the Institute of Food Science Cornell Univ., 115 Stocking Hall, Ithaca, NY 14953. Author Matsudomi's current address: Dept. of Agricultural Chemistry, Yamaguchi Univ., Yamaguchi 753, Japan.
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  • J.E. KINSELLA

    1. Authors Rector and Kinsella are with the Institute of Food Science Cornell Univ., 115 Stocking Hall, Ithaca, NY 14953. Author Matsudomi's current address: Dept. of Agricultural Chemistry, Yamaguchi Univ., Yamaguchi 753, Japan.
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  • Supported by a grant from the National Dairy Board. Technical support from Steven Watkins is greatly appreciated.

ABSTRACT

Dry-heat treatment of a dialyzed whey protein isolate at 80°C for 7 days resulted in a decrease in hardness (from 1.55N to 0.49N) of gels formed from a 12% solution. Partial denaturation and progressive polymerization of protein was observed. The monomeric β-lactoglobulin concentration of the whey decreased from 60.64% to 33.33%after 7 days at 80°C. The rate constants determined at 40 to 80°C were used to calculate an Arrhenius relationship for the polymerization. After one year at 25oC, 18% of monomeric β-lactoglobulin was projected to be converted to higher-molecular-weight material. The polymerization apparently did not involve disulfide cross-links.

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