Optimization of the Vibration - Aided Infrared Heating Process Using Response Surface Methodology: An application to the drying and parboiling of high moisture paddy

Abstract

The response surface methodology (RSM) was used to derive an optimum drying cum parboilingconditions for high moisture paddy using infrared energy. Considering less penetration power of the infraredradiation spectrum, a vibratory drying bed was used rather than a static bed to facilitate uniform exposure ofgrains to the radiation. A laboratory set-up capable of modulating both frequency and amplitude of vibration ofthe grain bed was developed to study the parboiling and drying characteristics of high moisture paddy. Theexperiments were conducted using five levels of radiation intensity (5514, 4520, 3510, 2520 and 1509 W/m2)and four levels of grain bed depths [3 mm (single kernel thickness), 6 mm, 12 mm and 25 mm]. The responsesanalyzed were head yield (HY), L-value, percent-gelatinized kernel (PK) and specific energy consumption (SE),which are important quality attributes of parboiling cum drying process. Analysis of variance (ANOVA)revealed that both the radiation intensity and the grain bed depth affected L-value, HY, PK and SE either at 1 orat 5% levels of significance. A contour plot for each of the response was used to generate an optimum areathrough superimposition. Optimum radiation intensity of 3100 to 4290 W/m2 and 12 to 16 mm grain bed depthis recommended in obtaining the maximum or minimum levels of response parameters.