Microwave Heating and Mass Transfer Characteristics of White Beans

✍ Scribed by Benjamin Adu; Lambert Otten

• Publisher: Elsevier Science
• Year: 1996
• Tongue: English
• Weight: 222 KB
• Volume: 64
• Category: Article
• ISSN: 0021-8634
• DOI: 10.1006/jaer.1996.0047

✦ Synopsis

The drying characteristics of white bean seeds exposed to constant microwave (2450 MHz) absorbed powers ranging from 0 и 28 to 0 и 44 W / g (dry basis) was investigated with a single-mode ( TE 1 0 ) microwave drying apparatus . The ef fect of absorbed power level on moisture and temperature history during drying are presented . Microwave drying of white beans was found to be a falling rate process . At constant absorbed power , seed temperature increased rapidly during the initial stages of drying to a maximum value and began to decrease gradually during the latter stages of drying . To maintain a constant drying temperature the absorbed power had to be increased progressively with further reduction of moisture content . The gradual decrease in seed temperature when drying rate was decreasing is opposite what is observed during hot air drying . It was considered as resulting from a progressively increasing heat of desorption with drying , a phenomenon common to hygroscopic solids . Thus , the microwave heating characteristics observed for white beans is likely to apply to similar hygroscopic solids .