Detection of dilution of milk with the help of glass transition temperature by differential scanning calorimetry (DSC)

Abstract

Glass transition temperature of pure milk, milk diluted with water, and pure milk in which sugars like glucose,
fructose and sucrose were investigated by differential scanning calorimetry (DSC). The glass transition
temperature Tg of pure milk (containing 89.2 kg water and 10.8 kg total solids per 100 kg milk) varied between -
114 to -118 o
C. Effect of change in composition of the milk varying the amounts of water and total solids
content (77.47, 81.56, 83.81, 84.31, 85.76, 86.69, 89.43, 92.15, 93.16, 95.71 and 96.38 kg water to make each 100
kg milk sample) on the glass transition temperature of milk showed a linear relationship between glass
transition temperature and composition of the milk expressed in %moisture content (w.b.). The addition of
sugars (glucose, froctose and sucrose) also showed a significant change in glass transition temperature.
Under applied conditions, adulterations in milk by dilution with water only and water and sugars were
detectable even at 0.5 and 5 % respectively