EFFECTS OF DRYING AND GRINDING IN PRODUCTION OF HEALTHY VEGETARIAN SOUP MIX

The healthy vegetarian soup recipe is full of veggies, it can be made with dried mushrooms, legumes and vegetables. The investigations were carried out to study the effect of drying method (hot air drying temperatures ranging from 50 to 70°C and freeze-drying) on colour and nutritional content of oyster mushroom (Pleurotus otreatus), which is the most widely cultivated in Viet Nam. To describe the hot air drying process, eight mathematical drying models were applied. Soup powder was passed through a sieve shaker for obtaining three different grades (0.25, 0.5 and 1 mm sieve sizes). The method of Principle Component Analysis (PCA) was used to describe the sensory attributes of samples. The results showed that mushroom dried at 70°C was the highest quality as compared to the other temperatures. The colour and nutritional content of freeze-dried samples (moisture content3%, protein31.98%, carbohydrate52.88% and phenolic content 31.13mgGAE/g) favourable in comparison to hot air drying. To establish drying models for mushroom, Wang and Smith model was selected (R 2 >0.9). The PCA was represented 86% of the total variance in the sensory attribute data. The soup mix powder having particle size of 1 mm was found better sensory quality among all other sizes.