การใช้คลื่นความถี่วิทยุเพื่อควบคุมมอดฟันเลื่อย (Oryzaephilus surinamensis) ในข้าวสารพันธุ์ขาวดอกมะลิ 105

Abstract

The Objectives of this experiment are to use radio frequency (RF) for controlling sawtoothed grain beetle (Oryzaephilus surinamensis) in milled rice cv. Khao Dawk Mali 105 and to examine rice quality after treated by radio frequency with appropriate rate which performed completely kill insects. Insect mass rearing in rice cv. Khao Dawk Mali 105 with moisture content at 14 perecnt was conducted in laboratory condition. In experiment 1, all stages of insect, egg, larva, pupa and adult were treated by 27.12 MHz radio frequency which provided 55oC for 90 seconds. The result showed that adult stage of sawtoothed grain beetle was the most tolerance to RF heat treatment because adult mortality was the lowest (78.09 perecnt), followed by the mortality of pupal, larval and egg stages which were 90.90, 94.34 and 96.46 percent respectively. In experiment 2, adult stage of sawtoothed grain beetle,the most tolerant to RF heating was exposed to RF at 55, 60, 65 and 70 oC for 90, 120, 150 and 180 seconds at each treatment. The result found that RF treatment at 70 °C for 120 seconds was able to get effective control of sawtoothed grain beetle since there was the minimal combination rate of RF heat and there was no insect progeny found in milled rice. In experiment 3, quality of milled rice which treated by RF treatment at 70 °C for 120 seconds has been estimated. a Moisture content was decreased from 13.65 percent to 12.85 percent. Lightness (L*) was increased from 66.10 percent to 68.25 percent. Yellowness (b*) was increased from 15.88 percent to 17.64 percent. Whiteness index was increased from 62.56 percent to 63.67 percent. Amylose content was increased from 16.83 percent to 17.82 percent. Protein content was decreased from 7.38 percent to 7.12 percent. The amount of 2-acetyl-1-pyrroline (2-AP), the aroma compound which always found from fragrant rice was decreased from 2.82 ppm to 2.40 ppm after the RF heat treatment on Khao Dawk Mali 105 milled rice.