Abstract:
This study was designed to evaluate some properties of different fruit
yoghurts made from (date pulp, mango, guava and fruit mixture) during
storage.
The results obtained revealed that, the pH was decreasing by time of
storage in all types of fruit yoghurt. Similar pH values were obtained in
mango and date yoghurts on one hand and in guava and mixture yoghurt on
the other hand. Acidity was fluctuating in all types of yoghurt.
The moisture contents showed no significant difference in guava and
mixture yoghurts during all times of storage. However, the moisture was
fluctuating in mango and date yoghurts. Protein contents were similar in
mango, guava and mixture yoghurts and showed no significant changes
during storage periods. On the other hand date recorded the highest amount of
protein. Ash % showed significant differences in all types of yoghurts during
the different periods of storage. Fiber content was not affected by storage time
in mango yoghurt and fluctuating in guava yoghurt, but it was decreasing in
date and increasing in mixture yoghurt by time of storage. The fat content
showed no significant difference in guava and mixture yoghurts and
fluctuating in mango and date yoghurts. Carbohydrates were found to give
significant differences between the different types of yoghurt and along the
times of storage. The total solids % fluctuated by time of storage in all types
of yoghurt except the mixture yoghurt where it showed no significant
difference.
The minerals contents indicated that, Ca was almost not affected by
storage time in date and guava yoghurts, but showed some variations in
mango and mixture yoghurts. Na and K were fluctuating by storage time in all
fruit yoghurts. P was not affected at all by storage time in all types of yoghurt.
III
On the other hand panel tests revealed that, there was no significant
difference by time of storage in mango, guava and mixture, while in date
yoghurt the taste was getting better by the time of storage. The time of storage
was found to make some fluctuation in color in mango, guava and mixture
yoghurts, and no significant difference was observed in date yoghurt. Odor
registered no significant difference by time of storage in mango, date and
mixture yoghurts, while in guava significant difference was observed. With
regard to flavor it was affected by time of storage (become better) in date,
guava and mixture yoghurts, but in mango yoghurt no significant difference
was recorded. Texture recorded the best results after 3 days of storage in all
types of yoghurts.
