Calcofluor Fluorescence Assay for Wort β‐Glucan in a Microplate Format

The level of β-glucan in worts produced from malted barley is a critical malting quality parameter. Measurement of wort β-glucan levels allows maltsters to determine whether production malts meet commercial specifications, helps brewers avoid production problems due to slow lautering, and enables barley breeders to develop lines with the potential to meet commercial needs. Many laboratories performing routine wort β-glucan analyses use flow injection analysis (FIA) methods or related segmented flow analysis (SFA) methods that measure the increase in fluorescence with Calcofluor binding to β-glucan. Such automated systems are attractive due to low per-sample reagent costs, relatively high sample throughput, and a minimal number of sample processing steps prior to automated analysis, limiting the need for manual operations. However, FIA or SFA methodology requires significant capital investment for instrument acquisition, discouraging its use outside dedicated quality assurance laboratories. Laboratories that routinely analyze relatively few samples often find kits for enzymatic or colorimetric analysis of β-glucans more attractive. Such kits require relatively simple laboratory instrumentation, reducing capital costs, but may involve multiple sample manipulations, increasing the level of technical support necessary to perform the analyses. Per-analysis reagent costs may also be greater for the kits. In this work, we have adapted the Calcofluor fluorescence method to a microplate reader to achieve a simple and cost-effective assay for wort β-glucan that avoids the acquisition costs of FIA or SFA instrumentation.