Heat-induced structural change in bovine beta-lactoglobulin A
1997
Dhanapati, N. (College of Dairying, Ebetsu, Hokkaido (Japan)) | Ishioroshi, M. | Samejima, K.
The heat-induced structural changes in bovine beta-lactoglobulin A were investigated by circular dichroism, differential scanning calorimetry, spectrofluorometry, spectrophotometry and electrical conductivity methods. The alpha-helices, beta-turns, beta-sheets and random coils of beta-lactoglobulin A were severely altered by heating. The SH content of beta-lactoglobulin A at pH 6.7 was increased on heating up to 80 degrees C and then gradually decreased on heating up to 100 degrees C. Fluorescence intensity, electrical conductivity and absorbance of beta-lactoglobulin A at pH 6.7 were gradually increased on heating from 60 to 85 degrees C. Differential scanning calorimetric study of beta-lactoglobulin A (pH 6.7) showed that the first and second denaturation peaks were at 85.3 and 135,5 degrees C respectively, Heat-induced gel of 5% beta-lactoglobulin A (pH 6.0) was formed by heating above 63 degrees C and the maximum storage modulus was observed 2.7 x 10(3) dyne/square-cm at 85 deg
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