Abstract:
The objective of the current study was to develop a set-type
yoghurt incorporating the juice of three watermelon varieties including
‘Thilini’, ‘Kinaree C28’ and ‘Rocky 475’ which are most commonly
grown in the dry zone of Sri Lanka. “Initially, to identify the best
watermelon variety for set-yoghurt production, the yoghurts were
made separately using each watermelon variety at 25% (v/v) juice
concentration. Next, to determine the appropriate inclusion level,
batches of yoghurt were made using the selected best watermelon
variety at the four concentration levels of 15% (T1), 20% (T2), 25%
(T3) and 30% (T4) (v/v). A batch of yoghurt made without watermelon
was used as the authenticated control. Sensory evaluations were
performed by 30 untrained panelists. Microbiological and
physiochemical properties of the watermelon juice incorporated setyoghurts
were analyzed during the storage period of 21 days at 4 ̊C.
Incorporation of ‘Rocky 475’ variety at 20% level resulted the best
sensory attributes for colour, taste, texture and aroma. Both fat and
protein content of the yoghurts were gradually decreased with the
increased levels of watermelon juice. Highest syneresis was observed
in the T4 yoghurts which contained the highest level of watermelon
juice and the lowest syneresis was observed in the control. In all
treatments, total plate count and yeast and mold counts were within
the acceptable level during the storage period. This study results
revealed that by using up to 20% (v/v) of the juice extracted from the
‘Rocky 475’ watermelon variety, the organoleptic properties of setyoghurt
could enhance while ensuring microbiological safety
