Dept. of Agroindustrial Science and Technology, Federal Univ. of Pelotas, 96010-900, Pelotas, RS, Brazil.
J Food Sci. 2019 Aug;84(8):2222-2227. doi: 10.1111/1750-3841.14738. Epub 2019 Jul 24.
The conventional prolonged parboiling process results in high operation cost and grain darkening, which may limit consumption. Moreover, residue generation by rice industries is another challenge. The objective of this study was to evaluate the use of microwave irradiation during soaking and gelatinization stages of parboiling rice. Processing time, colorimetric profile, broken and nongelatinized grains, sucrose and glucose content, free 5-hydroxymethyl-2-furfural, and residual phosphorus were evaluated. As the soaking and gelatinization times during microwave treatments increased, the colorimetric parameters increased; however, the values were lower than those with the conventional process. Regardless of soaking time, a decrease in broken and nongelatinized grains was obtained by using the lowest steaming time (5 min). Additionally, lower residual phosphorus content was found in soaking water (10 and 20 min) when using microwave irradiation. Under favorable conditions, a reduction in the levels of broken and nongelatinized grains, residual phosphorus, and color changes was observed, indicating that microwave irradiation may be more beneficial than conventional parboiling. PRACTICAL APPLICATION: Parboiling requires a high volume of water and soaking time, which leads to high costs, underutilization of infrastructures, and high residue in the water after processing. The rapid parboiling process involves the use of microwaves during the soaking and gelatinization stages. The main advantages of the microwave parboiling process include reduced processing time, ranging from 83% to 95%, higher gelatinization, greater yield, reduced darkening, and reduced residual phosphorus in the effluents by 60%. This report can aid industries in streamlining their processes, thereby providing a high-quality, lower cost, and environmentally safe product.
常规的长时间半蒸工艺会导致高运营成本和谷物变暗，这可能会限制消费。此外，稻米产业产生的残渣也是另一个挑战。本研究的目的是评估在半蒸稻米的浸泡和糊化阶段使用微波辐射。评估了加工时间、比色曲线、破碎和未糊化的颗粒、蔗糖和葡萄糖含量、游离 5-羟甲基糠醛和残留磷。随着微波处理浸泡和糊化时间的增加，比色参数增加；然而，这些值低于常规工艺的值。无论浸泡时间如何，使用最短的蒸制时间（5 分钟）都可以减少破碎和未糊化的颗粒。此外，使用微波辐射时，在浸泡水中（10 分钟和 20 分钟）发现残留磷含量较低。在有利条件下，观察到破碎和未糊化颗粒、残留磷和颜色变化的水平降低，表明微波辐射可能比常规半蒸更有利。实际应用：半蒸需要大量的水和浸泡时间，这导致成本高、基础设施利用不足以及加工后水中残留高。快速半蒸工艺涉及在浸泡和糊化阶段使用微波。微波半蒸工艺的主要优点包括加工时间从 83%到 95%的缩短、更高的糊化度、更大的出米率、变暗程度降低以及废水中残留磷减少 60%。本报告可以帮助企业简化其工艺，从而提供高质量、低成本和环境安全的产品。
