The changes in composition and some properties of full-cream and non-fat
UHT milk were examined during storage period of 6 months at room (20-30°C) and in
an incubator at (40±O.5°C) . The attained results showed that a gradual decrease occurred in the pH, TS,
protein, fat and ash content, whereas the acidity values and weight of sediment
gradually increased. The rate of change was more pronounced in non-fat UHT milk
and at incubator temperature than at room temperature. In all UHT milk samples, total N and casein N gradually decreased during
storage, whereas non-casein N and non-protein N and their values calculated as % of
on TN increased to greater extent in non-fat UHT milk. This was more pronounced at
the higher temperature. Browning of milk samples and the prepared acid casein was observed with
advancing storage time especially in non-fat UHT milk and at the higher temperature.