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

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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