Effect of Heat Treatment on Whey Proteins Denaturation in the Presence and Absence of Lactose


Jasim M.S. Al-Saadi
Food Science Department, Technical College of Agriculture, Halabja, Sulimmania




Abstract:
The effect of lactose on denaturation of whey proteins was investigated in cow
milk, with and without lactose, heated at different temperatures ranged of (65-95)°C for
30 min. Compared with the milk without, the milk containing lactose showed a smaller
increase in pH values and a higher concentration of whey proteins. Whey proteins
percentage in milk samples with and without lactose heated at (65,70,75 ,80,85,90 and
95) °C for 30 min were(90.38,88,86.16 , 67.9,44,23,23.5 and 23.2%) and (82.85,75, 71.14 ,
44.18,25.92,20.52 and 20%) respectively. It was concluded that heating cause formation
new band located below β-Lg band in whey samples of both milk ,with and without
lactose , and the intensity of this band increased with increment of heating temperatures
and heating time.

Keywords: milk proteins, heat treatment, whey proteins , denaturation



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