Keller Judith, Marmit Sven Peko, Bunzel Mirko
Karlsruhe Institute of Technology (KIT), Department of Food Chemistry and Phytochemistry, Institute of Applied Biosciences, Adenauerring 20A, 76131 Karlsruhe, Germany.
J Agric Food Chem. 2022 Jul 13;70(27):8430-8440. doi: 10.1021/acs.jafc.2c02028. Epub 2022 Jun 27.
Dietary fiber fractions of whole seeds from different lupin species were structurally characterized. The low-molecular-weight soluble dietary fiber fraction contains mainly stachyose and verbascose. The soluble dietary fiber fraction is dominated by homogalacturonan and rhamnogalacturonan type I (RGI), with (arabino-)galactans and to a lesser portion arabinans as neutral RGI side chains. Arabinans are preferentially branched in position 2 as demonstrated by methylation analysis and an arabinan profiling approach. Insoluble dietary fiber is mainly composed of cellulose and pectins, but xylans and xyloglucans are present, too. Application of an enzymatic xyloglucan profiling approach demonstrated a substitution degree of 75% and proved the existence of fucosylated xyloglucans. Lignin of all lupin species was analyzed as being rich in guaiacyl units; however, the degree of lignification is low. Alcohol-insoluble residue polysaccharides from both seed coat and embryo/endosperm were analyzed separately, demonstrating tissue-related differences in the portions of cellulose and RGI.
对来自不同羽扇豆品种的全种子膳食纤维组分进行了结构表征。低分子量可溶性膳食纤维组分主要包含水苏糖和毛蕊花糖。可溶性膳食纤维组分以同型半乳糖醛酸聚糖和鼠李糖半乳糖醛酸聚糖I型（RGI）为主，（阿拉伯糖基）半乳聚糖和较少部分的阿拉伯聚糖作为中性RGI侧链。甲基化分析和阿拉伯聚糖谱分析方法表明，阿拉伯聚糖优先在2位分支。不溶性膳食纤维主要由纤维素和果胶组成，但也存在木聚糖和木葡聚糖。酶促木葡聚糖谱分析方法的应用表明取代度为75%，并证明了岩藻糖基化木葡聚糖的存在。分析了所有羽扇豆品种的木质素，发现其富含愈创木基单元；然而，木质化程度较低。分别分析了种皮和胚/胚乳的醇不溶性残渣多糖，结果表明纤维素和RGI的比例存在组织相关差异。
