[Sadaka* et al., 5(9): September, 2016] ISSN: 2277-9655 IC™ Value: 3.00 Impact Factor: 4.116 http: // www.ijesrt.com © International Journal of Engineering Sciences & Research Technology [42] IJESRT INTERNATIONAL JOURNAL OF ENGINEERING SCIENCES & RESEARCH TECHNOLOGY EFFECTS OF INITIAL MOISTURE CONTENT AND HEATING RATE ON WHEAT (OAKES) DRYING KINETIC PARAMETERS Sammy Sadaka 1,* , Gagandeep S. Ubhi 1 and Griffiths Atungulu 2 1 Assistant Professor, Senior Graduate Student, Department of Biological and Agricultural Engineering, University of Arkansas Division of Agriculture, Little Rock, Arkansas, United States. 2 Assistant Professor, Department of Food Science, University of Arkansas Division of Agriculture, Fayetteville, Arkansas, United States. DOI: 10.5281/zenodo.61449 ABSTRACT The goal of this study was to determine the effects of initial moisture content and heating rate on the drying kinetic parameters of wheat under non-isothermal conditions. Wheat (OAKES) samples at initial moisture contents of 20.7%, 18.5%, 16.8%, and 14.8% wet basis (w.b.) were dried using a thermogravimetric analyzer. The analyzer was set at five heating rates (2, 3, 4, 5 and 10 o C/min) to determine the drying kinetic parameters, i.e., activation energy, of the heated samples from room temperature of 30°C to 170 o C. The experimental moisture ratio data were fitted to the four empirical models, namely Page, Newton, Logarithmic, and Henderson models. The goodness of fit criterion was used to determine the best-fitting model. Heating rate and initial moisture content affected the activation energy required for drying wheat. Increasing the heating rate expedited the drying curve. The heating rate of 10°C/min for wheat at an initial moisture content of 14.8% w.b. resulted in the greatest activation energy of 28.174 kJ/mol. The heating rate of 2°C/min for wheat at an initial moisture content of 20.7% w.b. resulted in the lowest activation energy of 14.760 kJ/mol. The Logarithmic and Henderson models were adjudged as best fit models for the entire drying curves by R 2 , RMSE, and X 2 . This study highlighted that the energy required to dry wheat from 20.7% w.b. to acceptable safe level could be minimized by reducing the heating rate. KEYWORDS: Wheat drying; Activation energy; Non-isothermal kinetics; Heating rate; Moisture content. INTRODUCTION Wheat, a major crop in the United States, has diverse usage in the manufacturing of numerous products. According to the USDA ERS’s [23] report, wheat production in the United States reached about 2.0 billion bushels with an average yield of 43.7 bushels per acre. Wheat is usually harvested at a moisture content (MC) less than 25% and must be dried to 13% or below to protect it from molds [9]. Understanding the drying kinetics of wheat is crucial in devising process conditions, which optimize wheat drying to achieve safe storage MC without compromising quality. Drying curves provide useful information to understand the mechanism of water migration from a product [5]. Knowledge of drying kinetics of a product is essential to control the overall drying process and the quality of the final dried product [10]. The key kinetic parameter, which is being studied in various drying processes, is the activation energy. To optimize energy consumption during drying, it is necessary to match the external energy demand of a particular drying operation with that determined by drying kinetics. Various techniques of thermal analysis had been employed to investigate the drying kinetics of a wide range of products. Thermogravimetric analysis (TGA) is one such technique, which measures the amount, and rate of change of mass of a sample with respect to temperature or time under controlled heating conditions [3].