Effect of Process Variables on Heat-Transfer Rates to Canned Particulate Newtonian Fluids During Free Bi-axial Rotary Processing

Abstract

Effect of process variables on overall (U) and fluid-to-particle (h fp ) heat-transfer coefficients in canned particulates suspended in Newtonian fluids (glycerin solutions at concentrations of 80-100%) undergoing free axial rotation was evaluated in a pilot-scale rotary autoclave. Six influencing factors affecting U and h fp were selected using L 16 Taguchi model for detailed evaluation. With the significant factors identified, a response surface methodology and two full-factorial experimental designs of experiments were used to relate U and h fp to the various process and product variables in each mode of rotation (fixed and free axial modes). The analysis of variance showed that the rotational speed, glycerin concentration (contributing to fluid viscosity), retort temperature, particle material (contributing to particle density), particle concentration and particle size were significant factors (p<0.05) for h fp and U. Headspace was not significant in the range of 5 to 10 mm studied. With an increase in rotational speed, particle density, and retort temperature, there was an increase in the associated h fp and U values; however, increasing the glycerin concentration resulted in the opposite. An increase in particle concentration showed an initial increasing trend in h fp and U values which, subsequently, decreased with a further increase in particle concentration. T tests revealed that both U and h fp were significantly higher ( p<0.01) in the free axial mode as compared to the fixed axial mode.

Effects of Packaging Geometry on Heat Penetration Time in Retortable Semi-Rigid Plastic Trays

“…The geometry benefit seen at 6 RPM is negatively impacted as rotational speed is increased with a tip over point somewhere between 6 and 11 RPM. Ramaswamy and Dwivedi (2011) showed that rotation speed has a significant impact on the overall heat transfer coefficient in a retort environment, further confirming these results.…”

“…If a product was processed in a traditional retort process, nutrients could be degraded as microorganisms were eliminated to render the food commercially sterile. In this example, one possible alternate to maintain preserve some nutrient integrity would be to use higher temperatures at shorter processing times (Ramaswamy and Dwivedi, 2011). In an effort to further minimize quality impact on retorted foods, the thermal processing industry has continued to develop retorts and thermal processes which optimize sterilization times and retain the maximum amount of food quality (Singh et al, 2014) Another possible strategy for delivering optimized heating to a food product could be the use of packaging type and geometry.…”

An Analysis of the Influence of Multiple Processing Factors on the Characteristics of Bioactive-Loaded Beads Prepared by Extrusion–Spheronisation

“…As RSA and Taguchi analysis methods (using ANOVA with orthogonal fractional factorial designs) have different advantages and disadvantages; they can be both used to provide different information on a given system, as done for instance by Ramaswamy and Dwivedi (2009).…”

An Empirical Methodology for Evaluating the Fluid to Particle Heat Transfer Coefficient in Bi-axially Rotating Cans Using Liquid Temperature Data

“…Statistically, a good model will have a large predicted R 2 and a low RMS. With the new approach developed to measure the U and h fp in free axial mode, a simple full factorial design (3×3 factorial) was used to test their response to input variables (a more detailed evaluation of factors affecting U and h fp in free axial mode is detailed in the accompanying paper, Ramaswamy and Dwivedi 2008). Statistical analyses used to obtain means, SD of means, and analysis of variance were performed through the statistical package of SAS.…”