33A-28 |
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E. GIANNOCCARO1, Y. -J. Wang, and P. Chen. (1) FOOD SCIENCE, UNIVERSITY OF ARKANSAS, 2650 N YOUNG AVE, FAYETTEVILLE, AR 72704 Soybean is the most readily available and cost-effective source of supplemental protein to human, livestock and poultry producers. The feed value of soybean, however, is limited by the presence of higher molecular-weight oligosaccharides because of flatulence from indigestibility. On the other hand, there is an increasing interest in potential utilization of oligosaccharides as nutraceuticals. One way to improve the oligosaccharides levels in soybean is to use genetic variation in a breeding program. The objective of this project was to develop an analytical method to accurately and efficiently measure the quantity of each soluble carbohydrate, namely glucose, fructose, sucrose, raffinose, and stachyose in soybean seeds. Both solvent and aqueous extractions were compared using pure lines of soybeans with known amounts of different sugars. High-Performance Liquid Chromatography (HPLC) system equipped with a CarboPac PA10 column and two detectors, a refractive index (RI) detector and a pulse amperometric detector (PAD), was employed to separate and measure the five sugars. The enthanolic method required a longer extraction and purification time (20 hr), but it recovered more soluble carbohydrates than did the aqueous extraction method (5 hr). The five sugars of interest were identified and well separated using the HPLC system with both detectors, including glucose, fructose, sucrose, raffinose, and stachyose. However, PAD detected samples with 100 times lower concentration than did RI detector. The results suggested that the enthanolic extraction was more effective but more time consuming, and further optimization will be needed. HPLC-PAD is more sensitive and detects sugars in samples with very low concentrations, thus allowing the use of a small amount of samples for accurate measurement of sugars in soybean seeds.
Session 33A, Carbohydrate: General
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