R-100.04.030 [2016-03] Protein Content in Adjuncts – KJELDAHL
The use of adjuncts is allowed for the production of beer which is not brewed according to the beer purity law – as long as they comply with national guidelines for beer production [1].
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The analysis methods listed below are suitable for all types of starch products added during the mashing process (rice, corn grits, etc., in various processed forms such as flakes or grits), as well as for sugar and syrup samples which are added during wort boiling.
Those using corn or corn products as adjuncts in the brewing process should be aware of the possibility that they could receive genetically modified material in their adjuncts due to lack of monitoring or testing or through accidental or unplanned mixture. In Europe, professional brewing organizations in each member state have developed procedures to help prevent contamination with these materials, designed to ensure that only non-GMO products enter grain mills or breweries. For related quality control testing and fulfillment of defined quality standards, qualitative and quantitative PCR analysis methods are performed in special, accredited laboratories at the individual production stages between agricultural producers and breweries.
References
- MEBAK Band Mikrobrauereien, Selbstverlag der MEBAK, S. 101–124, Freising 2015, ISBN: 978-3-9815960-5-2
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Application/Purpose
This method describes how the protein content in adjuncts is determined.
Scope of Application
Unmalted grains, such as rice, corn (maize), sorghum, barley or starch products, subjected to various degrees of processing (e.g., grits, flakes), which are to be added at certain points in the processes of beer or other beverage production
Principle
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R-110.41.030 Nitrogen Content (Raw Protein) in Barley – KJELDAHLThe determination of nitrogen content according to Kjeldahl is divided into the following steps:
a. Digestion of the sample (oxidation of substances H2O, CO2, NH3)
b. Distillation (distillation of NH3 over into a boric acid solution)
c. Titration (determination of the amount of NH3 present in the receiver after distillation)
a. Digestion → 2 NH3 + H2SO4 → (NH4)2SO4
b. (NH4)2SO4 + 2 NaOH → Na2SO4 + 2 NH3 + 2 H2O
3 NH3 + H3BO3 → (NH4)3BO3
c. 2 (NH4)3BO3 + 3 H2SO4 → 3 (NH4)2SO4 + 2 H3BO3
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