Effect of Standardizing Milk Base Using 5 Fold Ultrafiltered Cow Skim Milk Retentate on Quality Characteristics of Plain Set Yoghurt

Abstract

Plain set yoghurts were prepared by varying milk solids levels viz. 13.5%, 13.9% and 14-3% (w/w) in the yoghurt milk base, while maintaining the fat content at 3.3% by the addition of calculated amount of 5 fold ultrafiltered cow skim milk retentate and cow milk cream, respectively. Whey syneresis was observed only in yoghurts made using milk base standardized to 13.5% milk solids and was not statistically different (p>o.<?5) between treatments. Water holding capacity (WHC) and all the textural attributes, namely, firmness, stickiness, Work of Shear (WoS) and Work of Adhesion (WoA) of yoghurts increased significantly (pco.os) with increasing milk solids level in the yoghurt milk base. Flavour, acidity and overall acceptability scores of the yoghurts made from milk standardized to 13.5 and 13.9% milk solids were similar, while at 14.3% milk solids level was the lowest. Body and texture score of the yoghurt made from milk standardized to 13.9% milk-solids was the highest. The optimized yoghurt (13.9% milk solids in the yoghurt milk base) was compared with conventionally made yoghurt. Whey syneresis was not observed in any of the yoghurts. Acetaldehyde concentration, WHC, textural attributes, body & texture and overall acceptability scores were significantly (p<0.05) higher in optimized compared to conventionally made yoghurt. Scores of other sensory attributes did not show any significant difference between 2 types of yoghurts. Use of ultrafiltered skim milk retentate is successful in manufacturing high quality yoghurt in terms of improved sensory attributes especially, body & texture and overall acceptability without the use of stabilizers.