Tensile, Solubility, and Electrophoretic Properties of Egg White Films as Affected by Surface Sulfhydryl Groups |
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| Authors: | A Handa A Gennadios G W Froning N Kuroda M A Hanna |
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| Affiliation: | Authors Handa and Kuroda are with the Research Institute, Q.P. Corporation, 5-13-1, Sumiyoshi-Cho, Fuchu-City, Tokyo 183, Japan.;Author Gennadios is with the Materials Science Group, Research &Development, Banner Pharmacaps Inc., 4125 Premier Drive, High Point, NC 27265-8144.;Author Froning is with the Dept. of Food Science and author Hanna is with the Industrial Agricultural Products Center and Dept. of Biological Systems Engineering, Univ. of Nebraska, Lincoln, NE 68583-0730. |
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| Abstract: | Films plasticized with polyethylene glycol were cast from alkaline (pH 10.5, 11.0, or 11.5), aqueous egg white (EW) solutions with or without heating (40°C for 30 min). Prior to casting, concentration of surface sulfhydryl (SH) groups was determined and they increased (P < 0.05) (3.81–19.45 μM/g protein) with both pH and heating, presumably due to protein denaturation and cleavage of disulfide (S-S) bonds. Concentration of surface SH groups correlated (P < 0.05) with film tensile strength (r = 0.70), elongation at break (r = 0.86), and film total soluble matter (r =−0.94). Most likely, surface SH groups formed S-S bonds through air oxidation and/or sulfhydryl/disulfide interchange, thus contributing to EW film formation. SDS-PAGE patterns in presence or absence of 2-mercaptoethanol confirmed occurrence of S-S bonding in dried EW films. |
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| Keywords: | egg white protein films edible films sulfhydryl groups tensile strength |
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