Radio Frequency Heat Treatment: An Alternative Phytosanitary Processing Method for the Control of Sitophilus oryzae in Milled Rice
Pratchaya Vassanacharoen, Wanwarang Pattanapo, Wolfgang Lücke, Suchada Vearasilp
Book of Abstract. Tropentag 2007: International Research on Food Security, Natural Resource Management and Rural Development, Utilisation of diversity in land use systems: Sustainable and organic approaches to meet human needs, October 2007, Witzenhausen
2007
บทคัดย่อ
Radio Frequency Heat Treatment: An Alternative Phytosanitary Processing Method for the Control of Sitophilus oryzae in Milled Rice
Sitophilusoryzae(L.) (Rice weevil) infestation of milled rice during storage is one of the biggest problems leading to huge losses of rice worldwide. The weevils destroy the whole kernel. Contaminated rice usually loses flavour and palatability. This study was set up to determine the efficacy of radio frequency (RF) heat treatment as an alternative to conventional chemical fumigation and to establish the lethal doses of RF heat treatment which can be used in controlling S. oryzae in milled rice. Milled rice cv. ``KhaoDok Mali 105'' (KDML105) with 12% moisture content, infested with S. oryzae were heat-treated with RF at 27.12 MHz with a power input of 30% of the maximal output power of 2800 W. Target temperatures were 45, 47.5, 50, 52.5 and 55°C for 1 minute. A further experiment was carried out using a temperature of 50C for 0, 1, 3, 5, 10, 15 and 30 minutes. Results showed that using RF at 50°C and higher could effectively be used to control S. oryzae.
The Rice weevil was completely eliminated at 50°C using durations of either 15 or 30 minutes. The weevil was also eliminated at 52.5 and 55°C using one minute treatment duration. Therefore, the use of RF heat treatment is effective in controlling S. oryzae using a target temperature between 50 and 55°C. Further studies will be carried out to investigate the effect of temperature and duration of treatment on survival of S. oryzae eggs, larvae and pupae in milled rice during storage. It will be important as well to establish the effect of RF treatment on rice grain quality.