Reevaluation of brown rice diet by the chemical analysis of functional ingredients in high-hydrostatistic pressure processed rice

2021 Fiscal Year Final Research Report

• Project/Area Number: 19K05911
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 38050:Food sciences-related
• Research Institution: Shinshu University
• Principal Investigator: Fujita Tomoyuki 信州大学, 学術研究院農学系, 教授 (10238579)
• Project Period (FY): 2019-04-01 – 2022-03-31
• Keywords: 高静水圧 / マルターゼ阻害活性 / 玄米

Outline of Final Research Achievements

We have found that when brown rice is heated by adding water under high-hydrostatic pressure, the components of the bran layer (seed coat and germ) are transferred to the endosperm. It was expected that new functional components contained in brown rice could be discovered by isolating and identifying the components that migrate from the bran layer to the endosperm (white rice) during that processing. In this study, the active ingredient was explored from rice bran using the maltase inhibitory activity, which is one of the disaccharide hydrolases. As a result of separation of methanol extract from the rice bran and purifying the active compounds by a variety of chromatographic methods, three kinds of sucrose hydroxycinnamates and feruloyl disaccharide were isolated. This is the first report that these compounds show maltase inhibitory activity, suggesting that they contribute to the blood glucose level reducing effect.

Free Research Field

食品化学

Academic Significance and Societal Importance of the Research Achievements

本研究では米糠に含まれるマルターゼ阻害成分を探索し、３種のスクロース桂皮酸エステルと二糖にフェルラ酸が結合した化合物を単離した。これらの化合物がマルターゼ阻害活性を示すことの報告は初めてであった。種皮や胚芽に含まれる成分を胚乳部に移行させた高圧加工米のヒト介入試験では、高圧加工米摂取による血糖値の改善効果等を明らかにしてきた。今回見い出した化合物は種皮や胚芽などの糠中に多く含まれており、高圧加工処理により胚乳部に浸透移行することから高圧加工米の血糖値低減効果に寄与していることが示唆される。