Comparative characteristics of some plants family heather extracts and the effectiveness of methods for their production

The paper presents new data related to the comparative study of water-alcohol leaf extracts of the heather plants family (highbush blueberry, lingonberry, heather). Leaf extracts were obtained by three methods, two of which were using ultrasonic emitters (an ultrasound bath and a submersible ultrasonic probe), the third method, thermal (traditional), was chosen as a comparison. The extracts are characterized by parameters as the total content of extractive substances, the sum of phenolic compounds, flavonoids, the dispersed phase size particles distribution determined by the method of dynamic light scattering, and a quantitative assessment of the integral antioxidant activity is given. It has been established that ultrasonic probing has a highest activity in extracting phenolic compounds and flavonoids from lingonberry leaves and heather grass, and at the same time the level of their antioxidant activity is inferior to the extracts obtained by the traditional method at which the plant raw materials is boiled with the extractant. The traditional thermal method is characterized by the highest values of the sum of extractives for all types of raw materials and average values for the sum of phenolic compounds and flavonoids. There are observed a significant increase in the content of particles with the size <1000 nm for "ultrasonic" lingonberry leaf extracts is compared to the traditional method, however this pattern is not fulfilled for other types of raw materials. All heather herb extracts have a high polydispersity and the greatest tendency to sediment formation during the storage.