Effect of some pretreatments on popping expansion of rice.

Previous experiments have demonstrated that although 14% moisture content in paddy was optimum for popping expansion, pre-drying in the sun to 9% moisture before finally adjusting to 14% moisture enhanced popping yield by as much as 30%. Soaking paddy in 2% NaCl also increased expansion by about 15%. Effects of these 2 factors were studied in greater detail using Intan var. paddy. Improved popping expansion seemed to originate from improved tightness of husk interlocking and greater grain hardness brought about during pre-drying. Soaking paddy in 2% NaCl solution increased popping expansion, but pre-drying did not further improve popping. Water-soaked paddy had lower popping expansion, due to loosened husk interlocking and a softened endosperm. Pre-drying the water-soaked paddy could not restore subsequent expansion. It is concluded that pre-drying of rice is recommended in the production of popped rice; soaking in salt solution seems less practical and wetting of paddy is to be avoided.