| Abstract [eng] |
Membrane filtration processes are widely applied for a variety of industries. These processes are used by the food industry, particularly in the dairy industry. However, increased interest in these processes is in vegetable raw materials, in order to reduce transport costs by eliminating unnecessary materials or purification of components. Membrane filtration process are several: microfiltration, ultrafiltration, nanofiltration and reverse osmosis. These processes take place is characterised by a high pressure and a special membrane. In particular membrane, depending on the chemical composition of the fluid and the particle size is limited by the fouling of processes, i. e. the formation of cake layer and thus slowing the specific process. In order to evaluate some of the plant-based raw materials influence on the filtering parameters, the juices of lingonberry and sea buckthorn berry were selected. During the process, there was determined that the formation of fouling had negative effect on the filtration of lingonberry raw material. Then, the fractionation of juice were performed using microfiltration and ultrafiltration and fractions were evaluated by various methods. Total phenolic compounds and antioxidant activity were assessed comparing fractions obtained from fractions of lingonberry and sea buckthorn. It was found that the highest total phenolic compounds is in lingonberry juice retentate (BSR) and the lowest fraction of lingonberry juice permeate (BSP2). The highest total phenolic compounds set buckthorn juice fraction, and the smallest in the permeate fraction of sea buckthorn juice. It was found that the best DPPH• free radicals scavanged by fraction of lingonberry juice retentate. Applying gas chromatography with mass spectrometry was compared juice and fraction composition of the chemical compounds from headspace. Lingonberry juice fractions had 15 volatiles compounds. 23 volatile compounds were found at the fractions of juice of sea buckthorn. The powders of obtained lingonberry juice and their retentate fractions were applied in the yogurt production technology. Sensory, physico-chemical and microbiological properties were assessed by the different ways produced yogurts samples. |
