A study of Some Properties of Different Fruit Yoghurts during Storage

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.