Thermo-physical and nutritional changes of dehulled yellow peas during infrared processing (micronization)

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Wray, Sharon Leanne
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Infrared processing, or micronization, is an innovative cooking technique that has many benefits and advantages. Micronization is an energy efficient method that converts almost all of the input power into usable radiation. Infrared radiation has the capability for localized heating of a product which results in quick and uniform cooking. During the heating process, the product undergoes physical changes which increase its nutritional value in addition to enhanci g its flavor. Micronization has the potential to increase the marketability of hard-to-cook pulse crops by decreasing their required cooking time and creating an instant product. Experiments were performed with a stationary infrared micronizer to determine the optimum heat intensity required to process dehulled yellow peas in terms of short processing time and promoting high nutrition. A 23.2 kW/m2 heat intensity at the kernel surface required 60 s of processing time to reach 140C while 16.8 kW/m2 required 80 s. Both of these heat treatments increased dry matter digestibility of the peas by 63.0%; increased the amount of available digestible protein by 7%; and required 93% less enthalpy to gelatinize the remaining starch. A moveable multi-lamp micronizer was designed and fabricated based on these results. Although the heat intensity at the pea surface was 23.0 kW/m2, the maximum average processing temperature was only 105C. The temperatures inside the kernels were, however, maintained above 95C for 45 to 130 s depending on their position relative to the lamp, i.e. the length of time the kernels were maintained above 95C increased with distance from the infrared lamp's initial starting point. To that end, infrared processing is an effective means of processing peas for increased digestibility and decreased cooking time.