Effect of variable warm soaking on moisture uptake of paddy rice and models comparison using Stat-Ease 360 RSM
Abstract
One of the most important parameters in processing Paddy Rice (PR) is the amount of water present in the PR. In this work, effect of variable warm Soaking Parameters (SPs) and models comparison on Moisture Uptake (MU) of three samples of PR was examined. The sampled PR examined were Desi Red, FARO 44 and FARO 61 obtained from rice farmers in Akure, Ondo state, Nigeria. The initial and final weights of PR were determined before and after soaking in water using digital weighing balance of model SF-400. The amount of MU was determined using Agricultural Engineering Standard. Four different soaking temperatures (55, 60, 65 and 70OC) were used. Data analysis was done using Stat-Ease 360 model and Excel 2013 model. Central Composite Design was employed as experimental design method. The independent variables were soaking temperature and soaking time while dependent variable was the amount of MU. The suggested working models were Mean, linear, 2FI, Quadratic, and Cubic models. Model selection depends on sequential p-value, coefficient of determination (R2), Predicted R² and the Adjusted R². Models selected to explain the effect of SPs were significant on MU of Desi Red (P < 0.05; R2 = 90.02 %) and FARO 44 (P < 0.05; R2 = 48.79 %) but slightly significant on FARO 61 PR (P = 0.0520; R2 = 78.21 %). Quadratic model was the best model to explain the interaction between SPs and MU of Desi Red and FARO 61. While linear model was the best to explain the interaction between SPs and MU of FARO 44. Research findings are adequate to navigate design space and can be used for design characterisation of paddy rice MU.
Keywords: Paddy Rice, Stat-Ease 360, Soaking parameters, Moisture uptake, CCD, Models
