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Advisor(s)
Abstract(s)
Optimal thermal processes were designed for white beans in glass jars heated in a
still and end-over-end rotary pilot water cascading retort. For this purpose, isothermal
kinetics of thermal softening of white beans were studied in detail using a tenderometer
and a texturometer. The fractional conversion model was applied in both cases to model
the texture degradation. The Arrhenius equation described well the temperature
dependence of the reaction rate constant. With regard to the heat transfer, heat
penetration parameters (fh and jh) were experimentally determined from 100 containers
under static as well as rotational (end-over-end) conditions at 4, 7, 10, and 15 rpm.
Theoretical optimal temperatures, maximizing volume average quality retention, were
calculated using a computer program valid for conduction heating foods. Experimental
verification of the calculated results was conducted. Considering the finite surface
heat transfer coefficient, theoretical and experimental optimal temperatures were of
the same order of magnitude, around 130 °C, while for an infinite surface heat transfer
coefficient the calculated optimum temperature was much lower than the experimental
value. The type of reaction kinetic model, fractional conversion or first-order models,
does not significantly affect optimal sterilization temperatures. Although some
differences were found, the developed theoretical approach was successfully applied
to convective and mixed heating mode products. The use of the correct surface heat
transfer coefficient is crucial to design optimal processing conditions.
Description
Keywords
Pedagogical Context
Citation
ÁVILA, Isabel M.L.B...[et al.] - Development of a Novel Methodology To Validate Optimal Sterilization Conditions for Maximizing the Texture Quality of White Beans in Glass Jars. Biotechnology Progress. ISSN 1520-6033. Vol. 15, n.º 3 (1999), p. 565-572
Publisher
American Chemical Society and American Institute of Chemical Engineers