Smart Combination of Heating Modes for Improved Quality, Speed and Safety of Food Processing Ashim K. Datta, Cornell University Laurie D. Hall, Cambridge University

Introduction Aim: Faster Cooking Microwaves Non-Uniformity Combination Heating Speed and Quality

Goals  How to combine the various modes of heating (microwave, infrared, hot air) in what sequence to obtain a desired temperature or moisture profile, thus relating to the quality of the cooked food?  How do the combinations change as we change the composition, size and other characteristics of the food material?

Methodology  Microwave Heating Model  Combination Heating Model (Microwave with Infrared and/or Jet Impingement)  MRI Measurement of Temperature and Moisture after combination heating  Validation  Optimization

Preliminary Results Combination microwave-infrared oven  Specifications  Infrared from top and bottom  Microwaves from the side Advantium TM from General Electric, Louisville, Kentucky

Temperature Contours  Microwave Heating –Edge –Internal  Infrared Heating –Surface  Combination Heating –Uniform

Combination microwave-jet impingement oven  Specifications  Infrared from top and bottom  Microwaves from the side Thermador CJ302UB Double Jet from Enersyst Development Center, Dallas, Texas

Temperature Contours  Microwave Heating  Jet Impingement Heating  Combination Heating

Heating Non-Uniformity Duration of Heating: 1 minDuration of Heating: 2 min MicrowaveJetCombination Mean RiseDifference/ Rise MicrowaveInfraredCombination Mean RiseDifference/ Rise

Oven 3 Mode Heating Method BroilUpper Element Speed Broil Upper Element, Fan, Microwave Bake Upper Element, Lower Element, Fan Speed Bake Back Element, Fan, Microwave GE Profile TM Single Wall Oven (Model JT930BHBB)

Oven 3 Ithaca, New York  Microwave modeling  Temperature measurements  Property measurements Cambridge, UK  MRI of temperature and moisture Synthesis of the models and experiments

Gel Heating  TX151 powder mixed with water (1: 10), preconditioned  NaCl added to change dielectric properties  Gel samples heated in a 250 ml beaker on the oven middle rack  4 different heating modes: convection broil, bake, speed broil and speed bake

Computational Model SchematicMesh  Tetrahedral Elements  Total: 117,394 nodes  Food: 19,221 nodes  Difficulties –Complex Waveguide system –Solver node restrictions

Magnetic Resonance Imaging  3-D temperature maps using Phase Mapping  2 Tesla, 100 cm bore magnet  Matrix: 32 X 128 X 32  Resolution: X X mm  Scan time: 51.2 s  Procedure: Heating Temperature Contours MRI

Experimentations- Properties  Thermal properties (KD2, Decagon Devices)  Dielectric properties (HP85070 Probe, 8722ES Network Analyzer, Agilent Technologies)  Heat transfer coefficients (HFS-3 Heat flux sensors, Fiber Optic Probe, FISO) Microwave-Infrared OvenMicrowave-Jet Impingement Oven

Results- Comparison of Modes  30 s of heating  Sample without salt BroilSpeed Broil Computed MRI

Effect of Composition Bake (sample with salt)Bake (sample with no salt)  Conventional Heating-- No effect Speed Bake (no salt)Speed Bake (salt)  Microwave heating: Corners and bottom  Effect aggravated when salt is present

Preliminary publication  Datta, A. K., S.S.G. Geedipalli and M. Almeida Microwave combination heating. Food Technology. 59(1):  Refereed journal publications are coming

Future Work  Moisture: Model Development & MRI Experimentation

Thank You !!!