MSc

The present study entitled “Development of fruit blended yoghurts and quality
evaluation” was carried out at College of Agriculture, Vellayani, Thiruvananthapuram
during the period of 2019-2021. The objective of the study was to develop fruit blended
yoghurts from variety of fruits and to ascertain its sensorial quality, chemical and
nutritional composition, and to study the storage stability. Thus, six fruit blended
yoghurts namely Avocado yoghurt, Banana (Robusta) yoghurt, Mango (Moovandan),
Passionfruit yoghurt, Pineapple yoghurt and Soursop yoghurt were developed.
Homogenised toned milk with a fat content of 3g was selected for the study.
Optimum ripened fruits like Avocado, Banana (Robusta), Mango (Moovandan),
Passionfruit, Pineapple and soursop were selected for the development of fruit yoghurts.
The yoghurt culture used was strains of Streptococcus thermophilus and Lactobacillus
bulgaricus. The amount of yoghurt culture (2%) and sugar (12%) were constant in all
the treatments. The fruit yoghurts were processed by the standardized procedure
reported by Remya et al. (2019) after minor modifications. The various treatments
selected for the formulation of fruit yoghurt with milk, fruit pulp, yoghurt culture and
sugar respectively in the predetermined proportions were, T1 (85:15:2:12), T2
(80:20:2:12), T3 (75:25:2:12), T4 (70:30:2:12), T5 (65:35:2:12) and control (100:0:2:0).
The treatments were same for all the fruit yoghurts.
Sensory evaluation of fruit yoghurts exhibited significant difference in
appearance, colour, aroma, texture, taste, and overall acceptability of the treatment
combinations. From the sensory evaluation it was found that T4A, T2B, T3M, T4P, T4PA,
and T4S were the best combinations of fruit yoghurts selected from each fruit. The
selected fruit yoghurts along with control were subjected to nutritional analysis and
stored at refrigerated temperature of 4°C for further study. Storage stability on sensory
attributes and changes in other properties like acidity, moisture, peroxide value, pH,
syneresis, total soluble solids and microbial profile were studied on every 3 days
interval for two weeks.
Among six fruit yoghurt developed pineapple yoghurt revealed higher
carbohydrate (22.66g/100g), dietary fiber (0.72g/100g), iron (0.76 mg/100g), vitamin
C (9.02 mg/100g), calcium(381.30mg/100g) and phosphorus (457mg/100g) content.
Avocado yoghurt found was with highest energy value (114.16 kcal) and fat content
(9.60 g/100g). The β-carotene content was higher in mango yoghurt (143.60 /100gµg).
Pineapple yoghurt was scored maximum (50.14g) total antioxidant activity.
The sensory evaluation of all fruit blended yoghurts and plain yoghurt during
storage revealed decrease in scores obtained for all the sensory parameters. However,
the product was acceptable till the end of two weeks. During storage study, it was found
that there was a gradual increase in acidity of fruit yoghurts with increasing percentages
of fruit yoghurts. The result of this study indicates that, 30% passion fruit pulp flavored
yoghurt had the highest (9.26%) titratable acidity. The moisture content and the
peroxide value and syneresis were increased and pH content was dropped during shelflife study. Banana yoghurt was noted with high rate (88.53%) of moisture content at the
last day of storage. Peroxide value was higher in avocado due to the presents of fat
content in the avocado fruit. Among all the fruit yoghurt passionfruit yoghurt showed
high rate of syneresis. pH was dropped in all the fruit yoghurt including in control, the
minimum (3.30) pH was recorded in pineapple yoghurt at the end day of storage.
In the present study T2B was the most acceptable fruit yoghurt among other
yoghurts based on sensory attributes, while the T4PA was rich in many nutrients. The
microbial profile revealed the presence of bacterial, fungal colonies and yeast mould
count from the initial day itself. The coliform was absent till the end of storage period.
Cost of production of one kilogram fruit yoghurts was Rs 240 (T4A), 150 (T2B), 210
(T3M), 210 (T4P), 190 (T4PA) and 230 (T4S) respectively
This study on development of fruit blended yoghurts and quality evaluation -
concludes that the fruit yoghurts developed from various fruits were higher in nutrients
and had better sensory qualities than the plain yoghurt.