綠豆芽與黃豆芽中非消化水溶性多醣之分子結構特徵探討

Abstract

果膠為植物細胞壁中可溶性的酸性多醣，在不同部位具有不同的化學結構，在纖維素微纖維間形成可以水合的膠狀基，其為細胞壁厚度、水合程度、孔洞性、離子交換能力與靜電性質的重要決定因子。綠豆芽與黃豆芽為廣泛食用的芽菜類蔬菜，其熱水萃取物與水溶性多醣被證明具有生物活性，因此本論文選擇此兩種芽菜解析其多醣的分子結構特徵。本研究以酸水解、化學衍生化結合層析法、質譜法、以及對於阿拉伯半乳聚醣親和專一性之Yariv 試劑對於綠豆芽以及黃豆芽之非消化水溶性多醣進行結構解析。結果發現綠豆芽與黃豆芽皆主要以半乳醣、阿拉伯醣與半乳醣醛酸所構成，且兩者主要之醣鍵結形式皆為3,6-半乳呋喃醣、6-半乳呋喃醣與還原端阿拉伯醣，並同時具有3-阿拉伯醣與5-阿拉伯醣之鍵結形式，且結合β-Gal Yariv reagent 對於綠豆芽水溶性多醣與黃豆芽非消化水溶性多糖之結果及免疫調節活性測試證明，兩者上述主要之共同分子特徵為典型之具免疫調節活性之多分支之阿拉伯半乳聚醣二型結構，且黃豆芽非消化水溶性多醣具有促進Bifidobacterium longum 生長趨勢之特性，而兩者所展現出之生理活性反應仍存在差異，而相關生理活性與其阿拉伯半乳聚醣鍵結區塊間的關係仍有待進一步探討，以瞭解植物細胞壁生長初期的多醣分子特徵。

Pectin is a soluble acidic polysaccharide found in plant cell walls, with varying chemical structures in different plant parts. It forms a hydrated gel-like matrix between cellulose microfibrils and is a crucial determinant of cell wall thickness, hydration, porosity, ion exchange capacity, and electrostatic properties. Mung bean sprouts and soybean sprouts are widely consumed sprout vegetables, and their hot water extracts and water-soluble polysaccharides have been shown to possess bioactivity. Therefore, this thesis focuses on analyzing the molecular structural characteristics of the polysaccharides in these two types of sprouts. The study used acid hydrolysis, chemical derivatization combined with chromatography, mass spectrometry, and Yariv reagent, which is specific for arabinogalactan affinity, to analyze the structure of indigestible water-soluble polysaccharides in mung bean sprouts and soybean sprouts. The results showed that both mung bean sprouts and soybean sprouts mainly consist of galactose, arabinose, and galacturonic acid, with the primary glycosidic linkages being 3,6-galactofuranose, 6-galactofuranose, and reducing-end arabinose. Additionally, they both exhibit linkages at 3-arabinose and 5-arabinose. The combination of β-Gal Yariv reagent results for mung bean sprout water-soluble polysaccharides and soybean sprout non-digestible water-soluble polysaccharides, along with immunomodulatory activity tests, indicated that the shared molecular feature of these polysaccharides is a typical highly branched arabinogalactan type II structure with immunomodulatory activity. Moreover, soybean sprout indigestible water-soluble polysaccharides tend to promote the growth of Bifidobacterium longum. However, differences in the physiological activity responses between the two types of sprouts were observed, and the relationship between these physiological activities and the arabinogalactan linkages still requires further investigation to better understand the molecular characteristics of polysaccharides during the early stages of plant cell wall development.