Scientific journal NRU ITMO
Series "Processes and Food Production Equipment"
Registration certificate ЭЛ № ФС 77 – 55245 - 04.09.2013
registered by the Federal Inspectorate Service for Communication, Information Technologies and Communication Media
ISSN:2310-1164

June 2022 (published: 14.06.2022)

Number 2(52)

Home > Issue > Molecular transfer processes in liquid nutrient media in the yeast and beer industries. 1. Study of the density of aqueous solutions of molasses and concentrated beer wort

UDC 66.098.4

Molecular transfer processes in liquid nutrient media in the yeast and beer industries. 1. Study of the density of aqueous solutions of molasses and concentrated beer wort

Suzdaltseva O.A., Fomina E.A., Alexander G. Novoselov, Sorokin S.A., Baranov I.V., Kravcova E.V., Gulyaeva Yu. N.

The article is a research work in the field of processes and apparatuses of biotechnological productions, aimed at a comprehensive study of the processes of transfer of momentum, thermal energy and mass in nutrient media of yeastand brewing industries. The ultimatum of research is to establish the relationship between the transfer coefficients in the relevant physical processes, namely, the coefficients of kinematic viscosity, thermal diffusivity, and molecular diffusion. The rationale for the need to conduct complex experimental studies of one of the most important dynamic characteristics of matter – the density distribution of the matter mass in its volume – is presented. The objects of research were aqueous solutions of beet molasses and beer wort concentrate, mass concentration of soluble solids (DM) being 77.7 and 81% DM respectively. Six aqueous solutions of beet molasses were made with the concentration of DM of 16.2, 32.5, 40.2, 51.9, 60.2, and 69.9% DM. For seven aqueous solutions of beer wort concentrate used in the experiment the concentration of DM was 10.2, 20.6, 30.1, 40.3, 50.1, 59.6, and 72.4% DM. The range of temperature variation was 293K–363K for aqueous solutions of molasses and 283K–353K for aqueous solutions of beer wort concentrate. Measurements of the density of all research objects were carried out using an Excellence D4 Mettler Toledo density meter, the concentration of soluble solids in aqueoussolutions was measured using a PTR46 refractometer manufactured by Index Instruments Ltd. As a result of the studies carried out, graphical and mathematical dependences of the density of all studied objects on the SW concentration and temperature were obtained. Comparison of the numerical values for the density of molasses aqueous solutions and beer wort concentrate, with comparable values of the content of solids in them and temperatures, showed a complete match. This made it possible to identify aqueous solutions of molasses and beer wort concentrate, despite the fact that both of theseproducts are produced from different feed stocks: molasses is a waste product of sugar production, and beer wort is a semi-finished product in the process of obtaining beer products from grain raw materials. The only original parameter differentiating one type of analysis from another is mass concentration of soluble solids. As the parameter corresponds totechnological properties more than physical ones, we had to determine the values of density over a wide range of solids’ concentrations and temperatures, which are widely used both for hydraulic and for thermal calculations.
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Keywords: aerobic processes; density of nutrient media; an aqueous solution of molasses; beer wort concentrate, solids concentration

DOI 10.17586/2310-1164-2022-15-2-28-39

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