方便米饭的新型组合干燥工艺

The research on a novel combined drying process of instant rice

提出了一种将热风干燥、微波干燥、渗透处理相结合的新型干燥方法。以蒸煮后的东北粳米为研究对象，以成品色泽、质构、复水性能为指标，对不同干燥方式获得的产品性能进行了比较。经研究确定了最佳组合干燥工艺参数：90℃一次热风干燥80min至物料水分含量40％，2．5W／g微波强度下干燥10min至水分含量20％；常温下以料液比3：2向半干米饭中加入28％葡萄糖＋15％食盐的组合渗透液，搅拌混匀10min，静置30min，最后以90℃二次热风干燥20min得到水分含量15％～20％、Aw0．6左右的产品。结果显示，组合干燥方式生产周期短、能耗低，产品含有中等水分含量、低水分活度，可真空包装贮藏，复水后与新鲜米饭品质相近，是一种工业化生产方便米饭的新途径。

The aim of this research is to establish a new combined drying method which utilizes hot-air drying, microwave drying and osmotic absorption to develop a new type of instant rice. Cooked round-grained rice was chosen as a test material. The color, rehydration ratio and texture were used as the evaluation indexes. Ultimate parameters of the combined drying process were determined as follows： materials were dried for 80 min to moisture content of 40% at 90 ℃ by hot-air drying, then were dried for 10 min to moisture content of 20% under 2.5 W/g microwave, then the combined osmotic solution with 28% glucose and 15% NaCl was added into semi-dried products at solid-liquid ratio of 3：2 at room temperature and the whole system was mixed for 10 min then left to stand for 30 min. Final products with 15% -20% moisture and 0.6 Aw were obtained by 20 min second hot-air drying at 90 ℃ for 20 min. The results showed that the novel processing could contribute to cost reduction as well as keeping the vacuum-packing product with medium moisture and low water activity, which presented similar quality with fresh rice. Thus it could be a new way to process instant rice industrially.