Analysis of molecular structure of polysaccharides from beans and research on physical properties in foods

2018 Fiscal Year Final Research Report

• Project/Area Number: 17H06538
• Research Category: Grant-in-Aid for Research Activity Start-up
• Allocation Type: Single-year Grants
• Research Field: Food science
• Research Institution: Ibaraki University
• Principal Investigator: Nakamura Akihiro 茨城大学, 農学部, 准教授 (00803735)
• Project Period (FY): 2017-08-25 – 2019-03-31
• Keywords: 多糖類 / 食品 / 原子間力顕微鏡 / 分子構造 / 物性機能 / 機能改変 / ナノテクノロジー

Outline of Final Research Achievements

In this study, we focused on lentils and kidney beans for comprehensive analysis of the structure and function of legume polysaccharides. Analysis of basic physical properties of lentil polysaccharide (LPS) and kidney bean polysaccharide (KPS), structural analysis by atomic force microscope (AFM), and stabilization function for acidified milk beverages were studied.
The molecular weight of LPS was estimated to be 0.83 million (pH 4 extraction) and 1.1 million (pH 8 extraction), while that of KPS was estimated to be 2.5 million. Those are low-viscosity polysaccharides readily dispersible in water, and exhibit Newtonian fluid behavior. The structure analyzed by AFM was that LPS showed multi-branched and LPS showed linear with branching. Both LPS and KPS were acidic polysaccharides containing galacturonic acid as a component sugar, and had the function as a dispersion stabilizer which suppresses aggregation of milk protein particles under acidic conditions.

Free Research Field

食品科学

Academic Significance and Societal Importance of the Research Achievements

本研究の結果、ダイズ、レンズマメ、インゲンマメのマメ類種子の細胞壁を構成する水溶性多糖類は、分子量50万～250万の分岐構造を持つ多糖類であり、増粘やゲル化の物性機能は示さないがタンパク質など電荷を持つ粒子を増粘を伴わず微細分散する機能を有する事が明らかになった。食品の加工と保存において物性機能素材は不可欠である。一方、マメ類種子はそのまま食材として利用されるだけでなく、デンプン、油脂、タンパク質などの構成成分が分離されて活用される。ところが約40%を占める繊維は飼料として活用されるに留まっている。本研究成果は、繊維から新規な食品の物性機能素材を創出するものであり、学術的、社会的意義は深い。