- Title
- The presence and role of Thiamine and Riboflavin in the malting and brewing industries
- Creator
- Hucker, Barry
- Date
- 2013
- Type
- Text; Thesis; PhD
- Identifier
- http://researchonline.federation.edu.au/vital/access/HandleResolver/1959.17/58647
- Identifier
- vital:4895
- Abstract
- Thiamine and riboflavin vitamers are present in a wide range of foods including beer. They play critical roles in a variety of enzymatic complexes and can promote and maintain metabolism. Currently, the presence and role of these vitamers in the malting and brewing industry has not been widely explored. This research has investigated the effects of various malting and brewing processes on the final thiamine and riboflavin vitamer content of finished beer. In order to achieve this, a highly accurate and reproducible HPLC (spike recovery > 95 %; RSD < 5.0 %) method was developed that allowed the separation of thiamine diphosphate (TDP), thiamine monophosphate (TMP), thiamine, riboflavin 5-phosphate (FMN) and riboflavin in various sample matrices. This method was utilised to determine the vitamer content of various cereals and malts and it was found that malting vastly alters the thiamine content of malted barley, while it has minimal effect on riboflavin content. When malted barley is roasted, all vitamers are rapidly degraded. The mashing process releases the various vitamers into a solution and this release is dependent on temperature and enzymatic activity, while wort boiling significantly reduces the vitamer content of the wort. During fermentation, the thiamine content of wort is quickly utilised within the first six hours of standard fermentations and the uptake of this vitamin is not affected by increases in wort gravity. Meanwhile riboflavin is only poorly utilised during these fermentations. Post-fermentative additives, such as the addition of tannic acid and potassium metabisulphite, negatively affect the vitamin content of the final product while phosphorylated forms of these vitamins are greatly affected by the addition of many post-fermentative processing aids/additives. The presence of both thiamine and riboflavin can enhance the spoilage of beer by known brewery spoilage organisms, and the incorrect storage of bottle-conditioned beer can negatively affect the vitamin and organoleptic properties of the final product. These various steps involved in the production of beer greatly affect the final vitamin content, and this knowledge helps to explain the large variation in the thiamine and riboflavin vitamer content of a survey of 204 commercially available beers. This survey concluded that despite the large variations within particular styles of beer, lagers contain the least amount of thiamine compared to ales, stout/porters and wheat beers. However the average riboflavin content of the tested beers was statistically similar (p = 0.608) across all of the styles. This is due to the limited utilisation of this vitamin during fermentations.; Doctor of Philosophy
- Publisher
- University of Ballarat
- Rights
- Open Access
- Rights
- This metadata is freely available under a CCO license
- Subject
- Thiamine; Riboflavin; Beer; Malting; Brewing
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