Use of Dry Milk Molasses with Lactulose in the Yogurt Production Technology with Ultrasonic Treatment

Abstract

Dry milk molasses with lactulose is a product of processing by-products in the lactose production. Its use in the fermented milk drinks technology offers new opportunities to expand the food product range with a prebiotic effect. The research aims at studying the use possibility of dry milk molasses with lactulose in yogurt production technology, as well as to distinguish the ultrasonic treatment impact on the quality characteristics of finished products. The authors revealed that the use of dry milk molasses with lactulose in the yogurt production in an amount of 3 % of the total mass of the milk mixture enables to intensify the fermentation process and obtain a prebiotic fermented milk drink with high consumer properties. The study results demonstrated that the use of ultrasonic treatment with a frequency of 24 kHz and a specific power of 840–860 W/dm3 enables to obtain a finished product with improved quality characteristics in the production technology of yogurt with milk molasses with lactulose. Ultrasonic treatment facilitates a more finely dispersed structure formation of the milk mixture: at the end of the lag phase of the lactic acid cultures growth, the average diameter of protein particles and fat balls in a mixture with ultrasonic treatment is 1.47 and 2.89 times smaller, respectively, in relation to the fermented system without the ultrasound use. The results of microscopy, rheological and organoleptic properties determination of yogurt enable to conclude that there is a more homogeneous mesh protein matrix in the milk clot, the effective viscosity coefficient value increases (by 1.3–3.9 times), the appearance and consistency of the finished product improve during ultrasonic treatment.