Abstract

Various drying techniques were tested on two rice cultivars (Plai Ngahm Prachin Buri and Prachin Buri 2) that typically have severe chalkiness and milling quality problems. The main aims were: (1) to apply multi-stage intermittent drying technique using superheated-steam and hot-air as drying media to reduce the chalkiness and low head-rice yield problems of chalky rice and (2) to compare the quality of different rice products to that of single-stage drying and conventional parboiling process. The results showed that the head-rice yields improved from below the national standard (6.19% for Plai Ngahm Prachin Buri and 29.46% for Prachin Buri 2) to high milling quality levels (up to 61.38% and 68.22%, respectively) by applying hot water soaking together with multi-stage intermittent drying technique. The textural characteristics of the rice dried using multi-stage intermittent drying technique were similar to those for conventionally parboiled rice; however, the rice hardness was significantly lower by 33% and 20% for Plai Ngahm Prachin Buri and Prachin Buri 2, respectively. This study demonstrated that the hot water soaking combined with multi-stage intermittent drying method using superheated-steam drying followed by either hot-air drying at 50 °C or fluidized-bed drying at 80 °C resulted in parboiled rice products whose quality was comparable or superior to that from conventional parboiling and the commercial parboiled rice product.

摘要

在两个通常存在严重白垩和碾磨质量问题的水稻品种（Plai Ngahm Prachin Buri 和 Prachin Buri 2）上测试了各种干燥技术。主要目的是：（1）应用以过热蒸汽和热风为干燥介质的多级间歇干燥技术，以减少白垩稻的垩白和低头稻产量问题；（2）比较稻米的质量。与单级干燥和传统预煮工艺不同的大米产品。结果表明，通过应用热处理，大米产量从低于国家标准（Plai Ngahm Prachin Buri 6.19% 和 Prachin Buri 2 29.46%）提高到高碾米质量水平（分别高达 61.38% 和 68.22%）。水浸结合多段间歇干燥技术。采用多级间歇干燥技术干燥的大米的质地特征与常规蒸谷米的质地特征相似；然而，Plai Ngahm Prachin Buri 和 Prachin Buri 2 的大米硬度分别显着降低了 33% 和 20%。本研究表明，热水浸泡结合使用过热蒸汽干燥的多级间歇干燥方法，然后在 50 °C 下热风干燥或在 80 °C 下流化床干燥，得到的蒸谷米产品的质量相当或优于传统蒸谷米和商业蒸谷米产品。Plai Ngahm Prachin Buri 和 Prachin Buri 2 的大米硬度分别显着降低了 33% 和 20%。本研究表明，热水浸泡结合使用过热蒸汽干燥的多级间歇干燥方法，然后在 50 °C 下热风干燥或在 80 °C 下流化床干燥，得到的蒸谷米产品的质量相当或优于传统蒸谷米和商业蒸谷米产品。Plai Ngahm Prachin Buri 和 Prachin Buri 2 的大米硬度分别显着降低了 33% 和 20%。本研究表明，热水浸泡结合使用过热蒸汽干燥的多级间歇干燥方法，然后在 50 °C 下热风干燥或在 80 °C 下流化床干燥，得到的蒸谷米产品的质量相当或优于传统蒸谷米和商业蒸谷米产品。