Malt intended for use in beer brewing or elsewhere in the food industry
While α-amylase is active in a gelatinized solution of amylopectin, the viscosity of the solution is constantly dropping due to the degradation of the starch molecules, which can be tracked using a rotational viscometer. The change in the reciprocal of the specific viscosity serves as a measure for the activity of α-amylase.
Malt intended for use in beer brewing or elsewhere in the food industry
Through the action of endo-β-glucanase on a β-glucan solution, the viscosity of the solution continuously decreases, due to the degradation of the substrate molecules, which is measured using a rotary viscometer. The change in the reciprocal of the specific viscosity is a measure for the activity of endo-β-glucanase.
Water intended for use as an ingredient in the production of beer (brewing liquor) or other foods
The chromium content is determined by employing a flameless method which utilizes graphite furnace atomic absorption spectrophotometry. This technique is suitable for determining the chromium content of water with very little chromium contamination. Any matrix effects can be eliminated by using the standard additions calibration technique.
An aliquot of the sample is dosed into a graphite tube and is subsequently subjected to a program comprising a three-step temperature regime through electrothermic resistance heating. As the temperature increases in each step, the consecutive steps include drying, matrix pyrolysis (incineration) and thermal dissociation into free atoms (atomization). These can be carried out separately. During the analysis, the graphite tube is under an inert gas atmosphere (argon).
Also important for graphite furnace AAS is background correction, which can be achieved using a continuum radiation source (deuterium) or through the Zeemann effect. Background correction with the Zeemann effect is used for particularly difficult sample matrices.
A hollow-cathode lamp serves as the light source.