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.
