QUALITY OF YOGHURT MADE FROM COW'S MILK FORTIFIED WITH WHEY PROTEIN ISOLATE

Public Titles

Authors

Department of Dairy Sci. and Technol., Faculty of Agriculture, Menoufia University, Shibin ElKom, Egypt.

Abstract

 Fiveyoghurt treatments were made to study the effect of fortifying cow's milk with whey
protein isolate on the quality of yoghurt, control yoghurt was made by adding 3% non-fat dry
milk to cow's milk while the other four treatments were made by fortifying cow's milk with 0.5,
1.0, 1.5 and 2.0% whey protein isolate respectively and 3.0% nonfat dry milk to each treatment.
All yoghurt treatment was stored in refrigerator for 12 days and was sampled when fresh and at 3,
6, 9 and 12 days for chemical, rheological, microbiological analysis and sensory evaluation. The
obtained results indicated that adding whey protein isolate to cow's milk caused a significant
increase of total solids, total protein, ash contents and titratable acidity, while decreased pH values
and whey syneresis of yoghurt treatments and these effects were proportional to the rate of adding
whey protein isolate. Also, the values of Hardness, adhesiveness, cohesiveness, springiness and
gumminess of the resulting yoghurt had increased and this increase was proportional to the rate of
fortification. Adding whey protein isolate up to 1.5% increased the scores of organoleptic
properties and treatment that made with adding 1.5% whey protein isolate was the most
acceptable yoghurt treatments. Total solids, total protein, ash and fat contents of all yoghurt
treatments did not change significantly, (P > 0.05) during storage period, while titratable acidity
increased. Whey separation decreased during storage period up to the sixth day of storage period
then increased up to the end of storage period, while the scores of organoleptic properties were
almost stable up to the ninth day of storage period. 

Keywords

Egyptian Journal of Dairy Science
Volume 49, Issue 2
December 2020
Pages 77-87

Files

Share

How to cite

Statistics