Effect of plant proteinase from jack fruit (artocarpus integrifolis)‎ on rheological and sensory characteristics of low fat yoghurt as a functional food

Abstract EN

Adding a proteolysis enzyme extraction from Jack Fruit (Art carpus integrifolis) in combination with fermentation process in yoghurts manufacture was tried to improve yoghurt flavour and rheological properties as a functional food.

Four experimental with different levels of plant proteinase )control, 3.9 (T1), 7.8 (T2) and 11.7 (T3) units of plant proteinase / ml milk) were evaluated.

The pH of the product treated with plant proteinase was lower than that of the control.

However, the rate of acidity development during storage slightly increased with increasing the addition of plant proteinase level and progress of storage period of yoghurt.

The proteolysis activity in all yoghurt samples gradually increased until the end of storage period (15 days).

Yoghurt made from milk treated with plant proteinase preparations were less firm compared with control at all storage periods, whereas T3 showed the lowest firmness after 15 days of storage being 20.17 g / 100g.

Generally, increasing units of plant proteinase preparations decreased the firmness.

On the other hand, yoghurt made from milk pretreated with plant proteinase had higher syneresis, and apparent viscosity than the untreated product.

The greatest viscosity was observed in T2 and T3 of 433 and 479 mPa.s, respectively, compared with the control of 299 mPa.s, at 15 days storage.

The results indicated that there is an inverse relationship between the amount of added plant proteinase and susceptibility of yoghurt to syneresis.

The T2 treatment gained the highest of total scores (85 points) followed by the control (81.5 points) after 15 days of storage, whereas yoghurt of T3 showed the lowest score (75 point).

From the foregoing results, it is recommended to use Jack Fruit (Art carpus integrifolis) as a source of plant protein (7.8 units / ml milk) to develop high quality yoghurt.