Abstract:To promote the consumption of whole-grain oat rice，enrich the nutritional content of rice，improve its nutritional composition，and provide convenient food，this study used self-made whole-grain oat rice with 9.82% dehulling rate and rich in aleuron layer and commercial rice as raw materials. The effects of soaking conditions，oat rice proportion，and rice-water ratio on the quality of composite rice were studied. The optimal steaming process for composite rice was determined by texture analysis and sensory evaluation. The effects of baking powder addition，steaming temperature，and freezing temperature on the processing quality of freezedried instant mixed rice were further studied. The rehydration characteristics and sensory quality of the prepared convenient rice were evaluated，and the changes of its flavor and nutritional quality were analyzed. The results showed that the composite rice prepared under the conditions of soaking temperature 25-40 ℃，soaking time 20-30 min，oat proportion 30%（mass fraction），rice-water ratio 1∶1.5-1∶2.0（g/mL），and steaming time 22 min had good quality，good taste and was conducive to digestion and absorption. Under the conditions of 0.5% baking powder addition，120 ℃ steaming，and freezing at -20 ℃，the rehydration performance was the best，which could optimally change the microstructure of oat rice and rice. Compared with fresh mixed rice and commercial instant rice，the freeze-dried instant mixed rice had richer nutrition and aromatic components.