ジャポニカ米56品種で新規ヒドロキシ脂肪酸エステル同定~色素米品種に含まれる生理活性脂質の解明~

2026-06-03 北海道大学

北海道大学のボメ ゴウダ シッダバサーブ ゴウダ准教授らの研究グループは、全国56品種のジャポニカ米(玄米・赤米・緑米・黒米)を対象に非標的リピドミクス解析を実施し、米では世界で初めて新規生理活性脂質であるFAHMFA(ヒドロキシ脂肪酸エステル)およびLNAPEを含む196種類の脂質分子を同定した。研究ではLC-Orbitrap-MSを用いた網羅的解析により、品種ごとの脂質組成を詳細に比較し、着色米ごとに特徴的な「脂質指紋」が存在することを明らかにした。特に黒米と緑米では、多価不飽和脂肪酸と飽和脂肪酸のバランスが良好で、動脈硬化リスク指標やコレステロール代謝指標に優れた傾向が認められた。また、デンプン分解速度が遅く推定グリセミック指数(GI)が低いことから、食後血糖値の急上昇を抑える可能性も示された。これらの結果は、黒米や緑米が心血管疾患や2型糖尿病の予防に寄与する機能性食品となる可能性を示しており、健康志向食品や高付加価値米製品の開発に向けた重要な基盤情報を提供する成果となった。

ジャポニカ米56品種で新規ヒドロキシ脂肪酸エステル同定~色素米品種に含まれる生理活性脂質の解明~
研究の概要図

<関連情報>

56品種のジャポニカ米における脂質プロファイリング及びヒドロキシ脂肪酸由来の新規脂肪酸エステルの同定 Lipidomic profiling of 56 japonica rice cultivars and identification of novel fatty acid esters of hydroxy fatty acids

Lipsa Rani Nath, Siddabasave Gowda B. Gowda, Divyavani Gowda, Perumalsamy Parasuraman, Wei Qin, Shu-Ping Hui
Food Research International  Available online: 13 November 2025
DOI:https://doi.org/10.1016/j.foodres.2025.117895

Highlights

  • Lipidomics of 56 japonica rice cultivars revealed 196 lipid molecules.
  • Discovery of novel bioactive lipids like FAHFAs and LNAPEs in rice grains.
  • Black and green rice showed favorable lipid profiles and health-promoting potential.
  • Pigmentation and farming practices influence lipid composition in rice.
  • Findings support breeding nutritionally superior rice for health benefits.

Abstract

Pigmented japonica rice cultivars are a rich source of nutritionally significant lipids, yet their comprehensive lipidomic profiles remain poorly characterized. In this study, we performed untargeted liquid chromatography-mass spectrometry-based lipidomics on 56 japonica rice cultivars from Japan to examine the influence of grain pigmentation on lipid composition. A total of 196 lipid molecules across five major lipid classes were annotated. Most importantly, we report for the first time in rice the presence of a novel group of bioactive lipids, fatty acid esters of hydroxy medium-chain fatty acids (FAHMFAs), belonging to the fatty acyl category. These lipids were abundant in brown and green pigmented rice cultivars and were confirmed by MS/MS spectral analysis and comparison with authentic standards. Additionally, N-acyl-lysophosphatidylethanolamines (LNAPEs), a class of phospholipids, were characterized and found to be enriched in black rice. Pigmented cultivars also exhibited favorable lipid-based nutritional indices, particularly those enriched in polyunsaturated fatty acids. Multivariate statistical analysis revealed distinct lipid signatures differentiating organic from conventional cultivation, primarily driven by fatty acyls and glycerophospholipids. The estimated glycemic index (eGI) of selected cultivars was also assessed, with black rice showing the lowest eGI, indicating its potential benefits for blood glucose regulation and metabolic health. This study provides the first comprehensive evidence of FAHMFAs and LNAPEs in rice, revealing the diverse bioactive lipid composition of pigmented japonica cultivars and their potential for functional food development. However, the findings are limited to japonica varieties and warrant further validation across broader rice types.

1202農芸化学
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