Effect of radio frequency treatments for Sitophilus oryzae control and qualities of vacuum packed rice

• Main Authors: Chih-Cheng Huang, 黃志成
• Other Authors: Su-Der Chen
• Format: Others
• Language: zh-TW
• Published: 2013
• Online Access: http://ndltd.ncl.edu.tw/handle/12374583623586800250

碩士 === 國立宜蘭大學 === 生物資源學院碩士在職專班 === 101 === Rice is the most important grain in Asia; however, insect infestation often occurs. Vacuum packed rice can prevent pest growth to extend shelf life, but the pest eggs in the rice may hatch when the bag was open. When temperature is above 60℃, adults and eggs of rice pest will be heated to die. The objective of this study was to develop the radio frequency (RF) thermal processing to replace chemical fumigation for rice weevils（Sitophilus oryzae）of rice. The energy outputs of RF were linearly decreased from 1.1 kW/kg to 0.8 kW/kg during the RF electrode gaps operating from 4.1 cm to 6 cm. The 2 kg vacuum packed rice reached above 60℃ operating at 60 s RF with gap of 5.5 cm, and the temperature distribution of vacuum packed rice was more uniform than the other shorter gaps. The vacuum packed rice loading 50 Sitophilus oryzae obtained 100% pest mortality after RF 60 s heating, and there was no pest egg hatching during 2 month storage. There was no significant difference on moisture, protein, fatty acid, amylose contents and taste value or sensory evaluation score between 2 kg vacuum packed polished rice or brown rice with height of 3.8 cm or 4.1 cm after RF heating 60 s with 5.5 cm electrode gap and untreated rice. There were no significant difference on color and pasting properties between RF heating 60 s rice and untreated rice after room temperature 6 months storage and 37℃ 2 months storage.