ARS | Publication request: Profiling Sugars in Tall Fescue and Kentucky Bluegrass Extracts Assayed for Total Water- and Ethanol-Soluble Carbohydrates: Relationship of Chromatographic to Spectrophotometric Data

Submitted to: Southern Pasture and Forage Crop Improvement Conference Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: May 4, 2009
Publication Date: May 10, 2009
Citation: Kagan, I. 2009. Profiling Sugars in Tall Fescue and Kentucky Bluegrass Extracts Assayed for Total Water- and Ethanol-Soluble Carbohydrates: Relationship of Chromatographic to Spectrophotometric Data. 63rd SPFCIC. pg 79.

Technical Abstract: Water-soluble carbohydrates (WSC) and ethanol-soluble carbohydrates (ESC) of herbage are often quantified by spectrophotometric assays. To determine if quantifying individual sugars from chromatograms could yield results comparable to those obtained by the assays, WSC and ESC were extracted from freeze-dried tall fescue (E+ and E-) and Kentucky bluegrass, profiled by high-performance liquid chromatography (HPLC), and quantified both from chromatograms and from standard spectrophotometric assays. The chromatograms demonstrated that ESC extracts contained mostly glucose and fructose. WSC extracts, before being hydrolyzed for the assay, contained glucose, fructose, and putative fructans. Hydrolysis removed the putative fructans and increased both glucose and fructose concentrations, indicating that glucans as well as fructans may have been present in the extracts. Quantifying WSC and ESC from peak areas on chromatograms yielded trends similar to those obtained by colorimetric assays.