Influence of infrared (IR) heating parameters upon the hull adherence and cotyledon integrity of whole pigeon pea (Cajanus cajan L.) grain

Abstract

Traditionally, pigeon pea (Cajanus cajan L) grains require repeated pitting, moistening and drying during milling. The process is not continuous and is quite cumbersome, it requires a lot of time and the milling losses are also high. Experiments were conducted to study the effect of infrared radiation at different voltages (V; 203, 210, 220, 230 and 237 V) and for different time (T; 1.3, 2, 3, 4 and 4.7 min) intervals at varying grain moisture (MC; 8.6, 10, 12, 14 and 15.4 per cent, wet basis) content on the strength of hull adhesion (Hs) and cotyledon integrity, in terms of cotyledon adhesion strength (Cs) and shear strength (Ss) of pigeon pea grains. The experiments were designed using CCRD while the analysis of the results were carried out through RSM. Second order polynomial model was used to understand the effect of variable on the responses. It was observed that MC had a significant (p < 0.01) inverse effect on Cs and Ss; it was otherwise for Hs. Two-tailed paired t-test revealed that the model predicted and experimental values did not differ significantly (p < 0.01). Marked reduction in Hs was observed post IR treatment (2.37 N/mm2) as compared to untreated grain (8.80 N/mm2).