EFFECT OF PECTIN CONCENTRATION AND HOMOGENIZATION PRESSURE ON VISCOSITY AND SEDIMENT PERCENTAGE OF A PLAIN

Document Type : Original Article

Author

Department of Food Technology and Dairying, National Research Centre, Dokki, Cairo, Egypt.

Abstract

Acidic milk was prepared from skim milk powder that reconstituted in water to
give 17% MSNF and the resultant milk was heated before culturing with L. delbmeckii
subsp bulgaricus and S. salvarius subsp. them'ophilus. Pectin solution that used to
stabilize acidic milk drink was prepared by blending pectin with sucrose and dispersed
in water to give known concentration. The dispersion was heated in order to sterilize
ii. The two solutions were mixed in proportions to obtain acid milk drink 8.5% MSNF,
then blended and homogenized at known bar, sir gle stage, to produce drink yoghurt.
The effect of homogenization pressure and pectin concentration on the physical
stability of the product were estimated. Viscosity a.,d % sediment were studied. Pectin
concentration 0.35% was the best concentration that gave minimum % sediment and
high viscosity. Applying a pressure of 50 bar is enough to obtain the full effect. Higher
pressures only give minor improvements.

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