NOMOGRAMS FOR DETERMINING THE THERMO-PHYSICAL PROPERTIES OF FRUIT JUICES

Oybek Ismailov; Doniyor Ganijonov; Fozilbek Shomansurov; To’ychi Pirimov; Ganisher Rakhimov

doi:10.55251/jmbfs.12745

Authors

Oybek Ismailov
Doniyor Ganijonov
Fozilbek Shomansurov Fozilbek Shomansurov is a Senior Lecturer at the Institute of General and Inorganic Chemistry, Academy of Sciences of the Republic of Uzbekistan. His research focuses on the study of thermo-physical properties of food products, particularly fruit juices, the optimization of heat exchange processes, and the design of food processing technologies. He actively participates in projects aimed at improving energy efficiency and technological quality in the food industry. https://orcid.org/0009-0006-0610-8858
To’ychi Pirimov
Ganisher Rakhimov

DOI:

https://doi.org/10.55251/jmbfs.12745

Keywords:

dissolved solids, density, viscosity, thermal conductivity, specific heat capacity, nomogram

Abstract

Accurate thermophysical property data are indispensable for heat-transfer calculations, equipment sizing, and reliable control of thermal treatments in juice processing. Yet these properties depend jointly on temperature and soluble-solids content and can vary by cultivar, creating a gap between laboratory tabulations and day-to-day engineering needs. This study quantifies those dependencies for directly pressed apple juices from the Golden Rangers and Simirenko cultivars and introduces compact nomograms that enable rapid, instrument-free estimation of key properties during design and operation.

Experimental measurements covered density (kg·m⁻³), kinematic viscosity (mm²·s⁻¹), thermal conductivity (W·m⁻¹·K⁻¹), and specific heat capacity (kJ·kg⁻¹·K⁻¹) across 20–90 °C and soluble-solids levels of 12–15%. The soluble-solids content in the tested juices was 12.7–14.3%, corresponding to 11.5–13 °Brix, consistent with single-strength apple juice. Nomograms were constructed from the experimental surfaces using separable temperature–solids mappings to ensure linear, parallel scales for temperature, solids, and the target property, providing accurate read-off within the measured domain.

The data show that, within the studied range, higher soluble-solids content produces an average 3.2% rise in density. At 20 °C, kinematic viscosity was 1.45 mm²·s⁻¹ for Golden Rangers and 1.38 mm²·s⁻¹ for Simirenko; heating from 20 to 90 °C reduced viscosity by up to a factor of 3.1. Increasing soluble solids from 12% to 15% decreased thermal conductivity by up to 3.2%, whereas raising temperature from 20 to 90 °C increased specific heat capacity by about 3.7% (≈3% overall at 12.7–14.3% solids). Across compositions, specific heat varied by roughly 3–5% relative to the solids fraction.

Practically, the nomograms allow engineers to (i) interpolate properties quickly for energy and duty calculations, (ii) compute Reynolds and Prandtl numbers for heat-exchanger design and verification, and (iii) evaluate how moderate shifts in °Brix or operating temperature affect residence time and thermal load during pasteurization (notably in tubular exchangers). The tools are intended for use within the measured bounds (20–90 °C; 12–15% solids); extension to broader °Brix ranges and additional fruit matrices represents a natural avenue for future work.