Abstract:
Yoghurts were prepared with incorporating pea fibre, “Kitul”
flour, carrageenan and alginate as stabilizers to determine the best replacer
for gelatine. They were organoleptically evaluated and stored at 7±1˚C.
Further the yoghurt were examined for colour and texture as physical
properties and were subjected to chemical analyses such as pH, titratable
acidity (TA) and water holding capacity (WHC) for 9 days with a three days
interval. Colour attributes of prepared yoghurts were measured using a
colour reader, which gives L*, a* and b* values directly. Texture profile and
the gel strengths of the samples were measured using a digital penetrometer
which was coupled to a dynometer with a load cell of 5kN and cross head
speed of 1 mm/s and equipped with a 1.27 cm flat faced cylindrical Teflon®
plunger. Maximum force needed to cut the surface of the sample was
determined. Enumeration of lactic acid bacteria (LAB) and Coliforms were
done in order to compare the microbiological properties of yoghurts. Pea
fibre and 0.5% of pea fibre (out of 0.5%, 0.6%, 0.7%, 0.8% and 0.9%
incorporation levels) stabilised yoghurts were rated best based on the
sensory evaluations as the best replacer for gelatine while being the most
suitable level of incorporation. In pH and TA, there was a significant
difference between all the treatments and the length of storage. WHC values
were significantly different between treatments and “Kitul” flour obtained
the highest WHC at 6th day. Lowest L* highest a* and lowest b* values
(p<0.05) were obtained from “Kitul” flour added yoghurts. Carrageenan
obtained the highest (p<0.05) score for gel strength and in the texture
analysis of yoghurts carrageenan incorporated yoghurts received the highest
score. In the viability counts of LAB, there was a significant difference
between all the treatments and the length of storage. Pea fibre 0.5% added
yoghurts were free from Coliforms. Results from the present study suggests
pea fibre as the probable alternative stabilizer for gelatine and 0.5% of pea
fibre as the best incorporation level in set-yoghurt preparation in order to
obtain proper sensory and rheological properties to be accepted by
consumers.
