PHYSICO-CHEMICAL CHANGES IN UHT TREATED AND WHOLE MILK POWDER DURING STORAGE AT AMBIENT TEMPERATURE
Saeed Akhtar1, Tahir Zahoor2 and Abdul Moeed Hashmi2
1University College of Agriculture, Bahauddin Zakariya University, Multan. 2Department of Food Technology, University of Agriculture, Faisalabad.
Abstract: We studied the changes in pH, acidity and viscosity of ultra high temperature (UHT) treated and reconstituted whole milk powder (WMP) during storage of 90 days at room temperature. The samples were analyzed at 0, 30, 60 and 90 days intervals for these physico - chemical properties of the milk types. Values indicated an increase in acidity and viscosity with a decrease in pH with the storage time increased both in UHT treated and reconstituted whole milk powder. Apart from many enzymatic changes to deteriorate the milk, these apparent changes in milk characteristics may be one of the reasons that UHT milk cannot be kept unspoiled above 90 days and the quality of WMP is influenced within this time period.
Keywords: Physico-chemical changes, storage stability, UHT milk, whole milk powder.