Investigations into the thiamine and riboflavin content of malt and the effects of malting and roasting on their final content
- Authors: Hucker, Barry , Wakeling, Lara , Vriesekoop, Frank
- Date: 2012
- Type: Text , Journal article
- Relation: Journal of Cereal Science Vol.56, no.2 (2012), p.300-306
- Full Text: false
- Reviewed:
- Description: A simple and effective method for the analysis of thiamine (B1) and riboflavin (B2) vitamers, in unmalted and malted grains, by high performance liquid chromatography (HPLC) has been developed. This method makes use of trichloroacetic acid (TCA) as an extraction medium to effectively clean up the sample and analyze the vitamer content with high accuracy (R2 > 0.9992; %RSD < 5%). This method was employed in the routine analysis of a wide range of malted and unmalted grains, and it was found that lighter colored malts contain higher concentrations (2–5 times higher) of thiamine and riboflavin vitamers compared to darker colored malts. The malting process has no effect on the overall riboflavin content; however, both steeping and kilning processes cause increases in thiamine vitamer content. Roasting profiles show that thiamine and riboflavin vitamer concentrations are significantly effected when the temperature reaches 120 °C, which explains why roasted products have lower vitamer content than paler malts.
- Description: A simple and effective method for the analysis of thiamine (B
Vitamins in brewing : Effects of post-fermentation treatments and exposure and maturation on the thiamine and riboflavin vitamer content of beer
- Authors: Hucker, Barry , Vriesekoop, Frank , Vriesekoop-Beswick, Arielle , Wakeling, Lara , Vriesekoop-Besick, Hamish , Hucker, Amy
- Date: 2016
- Type: Text , Journal article
- Relation: Journal of the Institute of Brewing Vol. 122, no. 2 (2016), p. 278-288
- Full Text: false
- Reviewed:
- Description: Post-fermentation processes and maturation are important steps in beer production as they help to shape the organoleptic properties and stabilize the final product. Brewers can use a variety of processing aids (e.g. isinglass, PVPP, etc.) and processes (e.g. pasteurization, bottle conditioning, etc.) to achieve a desired final product with a desirable shelf life; however, these processes can have detrimental effects on the vitamin content of the beer. This research found that heat treatments have a marked influence on the decrease in the thiamine diphosphate vitamer, while PVPP and silica treatments have a greater influence on the decrease in riboflavin vitamers. Refrigeration, filtration or centrifugation have no, or only very limited, influence on thiamine or riboflavin vitamers, while application of isinglass, bentonite, tannic acid and SO2 causes a decrease in both thiamine and riboflavin vitamers. Storage of beer at refrigerated temperatures appears to provide protection against significant degradation of both thiamine and riboflavin vitamers; however, storage of filtered beer at elevated temperatures shows a decrease in thiamine diphosphate and riboflavin. Storage of bottle-conditioned beer at elevated temperatures shows a marked decrease in yeast viability, accompanied by a decrease in thiamine diphosphate and free riboflavin, and a marked increase in free thiamine. These findings provide an insight into the reason why there is a significant variation in the vitamer content of beers, even within a single beer style. © 2016 The Institute of Brewing & Distilling.