Spectrophotometric determination of the iodine value of brewery spent grain
Brewery spent grain, wet spent grain, dry spent grain
High molecular weight dextrins and starch present in the wort extracted from brewery spent grain are precipitated through the addition of ethanol, centrifuged and dissolved in phosphate buffer, followed by the addition of an iodine solution. Depending on the molecular weight and degree of branching, a red to blue color forms, the intensity of which is measured spectrophotometrically at 578 nm.
This is a mathematical method for calculating the dextrin content as a difference between the total glucose content and the fermentable extract as determined through analytical methods.
Suitable for beer
The dextrin content is calculated through multiplication of the difference between the total glucose content and the fermentable extract by a factor of 0.915.