Nutritional supplements from plant raw materials and influence of water on their physicochemical properties

Resumo

Physicochemical properties of nutritional supplements, such as apple, Jerusalem artichoke, and black currant cryogenic powder, were studied by adiabatic calorimetry in the range of 80–320 K and differential thermal analysis in the range of 80–400 K. Temperatures of relaxation transitions and influence of water on these transitions were determined. In thermograms, completely dehydrated samples demonstrated several relaxation transitions (γ-, β-, α₁ and α₂), which are caused by the presence in the studied nutritional supplements of some polysaccharides. The water has a plasticizing effect on nutritional supplements and lowers their relaxation transition temperature. By melting enthalpy of the water phase, which is insoluble in cryogenic powder, the concentration of the saturated solution of water in cryogenic powder at the melting point of water using a calorimetric method was determined (22 ± 1 mass % H₂O in cryogenic powder from apple; 19 ± 1 mass % H₂O in Jerusalem artichoke; 24.1 ± 0.1 mass % from black currant). The diagram of physical states of cryogenic powder from an apple–water system was constructed and analyzed in a wide temperature range and over the entire range of concentrations of ingredients.