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Dielectric, thermal, and rheological properties of inulin/water binary solutions in the selected concentration
Author(s) -
Ahmed Jasim,
Thomas Linu,
Khashawi Rawan
Publication year - 2019
Publication title -
journal of food process engineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.507
H-Index - 45
eISSN - 1745-4530
pISSN - 0145-8876
DOI - 10.1111/jfpe.12968
Subject(s) - inulin , rheology , sugar , dielectric , water activity , chemistry , chemical engineering , food science , materials science , water content , composite material , optoelectronics , geotechnical engineering , engineering
Inulin—a prebiotic has many applications in the food and pharmaceutical industries for texture modification and replacement of fat/sugar. In this study, thermal, rheological, and dielectric properties of inulin solutions were studied in a wide range of concentrations (5–50% w/v). Inulin is readily dissolved in water in low concentrations (< 20%), and exhibited Newtonian flow behavior, and the dielectric spectra were close to the pure water. The dielectric constant, ε′ of concentrated inulin (40–50%) showed frequency independency (500–1,150 MHz) whereas the loss factor, ε″ increased with frequency. Oscillatory rheology of concentrated inulin solutions at selected temperatures showed solid‐like behavior ( G ′ > G ″), and the mechanical rigidity increased exponentially with the concentration. During thermal scanning of inulin concentrates (30–50%), two glass‐like transitionsT g ′were detected (−74.98 to −72.28 °C;−24.25 to −23.45 °C), which were independent of the concentration. The obtained information will be useful for product development and structural characterization of inulin‐incorporated food products. Practical applications Incorporation of soluble fiber like inulin into food products has proven health effect. Knowledge of flow behavior and glass transition temperatures of inulin at selected concentrations will provide a better understanding of food formulation, transport, and storage. Dielectric properties of inulin solutions would help to employ microwave/radiofrequency heating of formulated foods. The information presented in the present work should be useful to the food and pharmaceutical industries for early prediction of food quality and process engineering.