The first step in K-YBGL procedure is solubilisation/pre-hydrolysis in concentrated hydrochloric acid, therefore a sample should be in a powder form. We recommend freeze-drying of liquid samples prior to the actual analysis. However if the sample is completely dissolved (clear solution) it can be analysed as is, by mixing sample and concentrated HCl to the final concentration of 1.5M of acid and boiling for 2 hours. After neutralisation with 2M KOH, further dilutions might be required. It depends on the expected level of beta glucan (and starch/alpha-glucan) if known.
The starch and alpha-glucan in such samples could be completely hydrolysed with just AMG/invertase incubation.