No abstract

Studies showed that industrial PA membranes can be used for comprehensive treatment of whey containing substances of value to the food industry and allow separating 80% of the protein components in it. PA membranes have ion-exchange properties that allow separating from 20 to 40% of salt cations and anions from the whey and using them in production of food products.Secondary dairy stock (whey and buttermilk) frequently enter the wastewaters of industrial enterprises together with industrial waters and other production wastes. In pouring secondary dairy stock in the sewage system, we not only pollute the environment, but we also lose the additional commercial product that can be made from it.An analysis of the experience of the leading companies in the sector shows that as a function of the product volumes and lines pressed from whey and buttermilk, the additional profit would be 15-35% of the profit obtained from the basic product. It is thus not possible to underestimate the value of secondary dairy stock as product and raw material whose processing is unusually promising, economically advantageous, and environmentally necessary.Membrane methods, ultrafiltration in particular, are the most promising for processing secondary dairy stock. Despite the unconditional promise of membrane methods, they are not sufficiently utilized in industry due to the low output of membrane equipment.Increasing the specific separating surface per unit of working volume of the equipment has been successfully solved by using hollow fibres with semipermeable walls as membranes [1]. We used semipermeable polyamide (PA) membranes in the form of hollow fibres for separating whey. Proteins and mineral salt ions were separated from whey with PA membranes and the performance characteristics of the membranes were determined the permeability for water and whey, selectivity for protein, and ability to retain mineral salt ions.Whey obtained as the usual product of the dairy industry is a valuable protein-carbohydrate raw material. It basically contains protein nitrogenous compounds, organic acids, mineral salts, and a small amount of carbohydrates, vitamins, lipids, enzymes, and trace elements. Whey can be fractionated by ultrafiltration and food additives with the required composition and properties can be obtained. Ultrafiltration is widely used for production of protein concentrate from whey, which is the most valuable of the existing food proteins.Industrial semipermeable VPU-15-PA membranes made of an aromatic polyamide were used for the first time in the study. Ultrafiltration was conducted on a laboratory setup consisting of a nitrogen tank, a manometer, intermediate and receiving tanks, and ultrafiltration module filled with membranes.Ultrafiltration was conducted under 0.2 MPa pressure and 1.5 liters of product was investigated per cycle. The permeability and selectivity of the PA membranes were determined. The permeability is the amount of filtrate obtained per unit of time per unit of working membrane surface. To determine the permeab...

It was hypothesized that active carbon will play the role of an inert filler and cause the formation of a more developed pore structure in membranes since pores are formed as a result of the counteraction of the forces of contraction and adhesion during phase separation in evaporation of the solvent. The carbon particles perturb the structure of the polymer network. The porosity of the membranes also increases because the filler has a porous structure. Active carbon can be used to improve the performance properties of membranes.One method of increasing the food and biological value of dairy products is to include new kinds of raw materials and additives with a high protein content and scarce amino acids lysine and threonine in the formula. Cheese whey is widely used in practice to manufacture products enriched with protein.Membrane methods, ultrafiltration in particular, are used for processing cheese whey [1]. The ultrafiltration process is based on the membrane retaining dissolved particles larger than the size of the pores in the surface layer of the membrane. Adsorption of the components of the whey by the membranes accompanies ultrafiltration [2]. The efficiency of the ultrafiltration process is determined by the material from which the membrane is made. The search for the appropriate composition for manufacturing membranes is still urgent.Judging by the published data, using membranes made of secondary cellulose acetate (SCA) is promising for ultrafiltration. Such membranes are compatible with food products. They are easy to fabricate and consist of a chemically modified natural, renewable product.We manufactured modified composite ultrafiltration membranes for separating protein-carbohydrate raw material on the example of cheese whey. The membranes were modified by incorporating active carbon to create a more developed pore structure, since active carbon is known to contain pores.We made ultrafiltration membranes from SCA by the pouring method [4] using two fractions of active carbon small (85 μm) and large (160 μm). Active carbon pellets used in medicine and thus compatible with food products were ground and passed through a sieve with mesh of a certain size. The concentration of the initial solution and content of filler in the solution were varied. The calculated amount of active carbon was placed in an acetone solution of SCA, mixed well, and films were poured. Membranes were formed over 24 h at 20°C. The performance and physicomechanical properties, water absorption, and swellability of the membranes obtained were investigated.The graphic dependences of the duration of swelling of the membranes in water on the filler content for different concentrations of the initial solution of SCA in acetone with the filler small and large fractions of active carbon are shown in Fig. 1. In analyzing the curves in Fig. 1, note that the lower the concentration of the initial solution for making the membranes, the shorter the swelling time and the more rapidly the system attains equilibrium. Membranes from a 5% initia...