Abstract: Rehydration characteristics and edible quality of traditional instant rice are the main points of restricting the popularization since its initiation. Therefore people have made unremitting efforts its improvement. The objective of this paper was to make a fresh start with high temperature-high pressure-short time extrusion technology to produce‘ engineering rice’, a further type of reformed instant rice with well rehydration characteristics and better edible qualities and with nutrition-fortified attributes that would be acceptable to different levels of consumers. Effects of glyceryl monostearate(GMS), sodium stearyllactylate(SSL), and lecithin(LC) on physicochemical properties of extruded rice flour and rehydration characteristics of the engineered instant rice showed that the degree of starch gelatinization(DG) and water-soluble carbohydrate(WSC) of the extrudates decrease with the increase of added emulsifier in general. Expansion, warter-soluble protein(WSP), and water absorption index (WAI) of the extruded rice flour, and rehydration rate and hardness of the engineered instant rice increase with the increase in added GMS, but the stickness of instant rice rises with less than 0.8% GMS, decreased with higher than 0.8%. WSP and WAI increased with the increase of added SSL, but expansion of extrudates changed little. Expansion of extrudates and WAI rised with LC increase, but WSP changed little. Rehydration ratio of instant rice rised, but hardness and stickness decreased when LC and SSL less than 0.8% compared with the control sample.

Key words: extrusion processing, instant rice, emulsifier, rehydration characteristics, texture analysis