预处理和干燥方式对方便米饭品质的影响

Effects of Drying and Pretreatment Methods on Quality of Instant Rice

研究不同蒸煮方式、干燥方式和预处理方式对方便米饭质构、体外消化率、血糖指数等因素的影响.实验结果表明,电饭锅蒸煮制备的方便米饭硬度和黏度要高于常规制备的方便米饭.-20℃冷冻+80℃热风干燥和4℃水洗+-20℃冷冻干燥方式制备的方便米饭品质最接近新鲜米饭.热风干燥方便米饭的复水率为2.71,复水时间为8 min;冷冻干燥方便米饭的复水率为3.32,复水时间为5 min.2种干燥方式制备的方便米饭体外消化率均高于新鲜制备的米饭,其饱和浓度C∞、水解指数HI和血糖指数GI等指标也相应的增高.感官评价结果表明,2种干燥方式制备的方便米饭均具有较好的品质,口感良好;其中,4℃水洗+-20℃冷冻干燥制备的方便米饭感官评价更高.

In this paper,the effects of cooking,drying and pretreatment methods on textural properties,in vitro digestibility and glycemic index parameters of instant rice were fully investigated.The experimental results showed that fresh and instant rice prepared by the electric rice cooker had higher values of hardness and viscosity than that of instant rice prepared by conventional boiling method.The qualities of instant rice prepared by freezing treatment at-20^followed by hot air drying at 80 and 4 X.water washing treatment followed by-20^freeze-drying were found to be near to the freshly cooked rice.A rehydration rate of 2.71 and rehydration time of 8 min were observed for instant rice prepared by hot-air drying;whereas the rehydration rate and rehydration time was 3.32 and 5 min,respectively,for the sample prepared by freezing treatment.The in vitro digestibility of instant rice was higher than that of freshly prepared rice,as well as saturation concentration Cw,hydrolysis index(HI)and glycemic index(GI).It was also found that both the instant rice prepared by these two drying methods had well sensory quality with good taste,while instant rice prepared by 4 Xl water washing with-20^freeze-drying had better sensory evaluation.