The Quantitative Analysis of Thiamin and Riboflavin and Their Respective Vitamers in Fermented Alcoholic Beverages

Abstract

This research aimed to develop a simple and effective method for analyzing thiamin (B(1)), riboflavin (B(2)) and their respective vitamers by high performance liquid chromatography (HPLC) in fermented alcoholic beverages. The method developed here employs a phosphate buffer/methanol gradient elution on a single reverse phase column, coupled with independent fluorescent detection regimes. It also employs a precolumn derivatization to convert thiamin to thiochrome via an alkaline potassium ferricyanide solution. The method described here allowed a spike recovery of better than 97%, with a typical linear detection range (R(2) ≥ 0.9997) between ≤ 5 and ≥ 500 μg/L for all vitamers studied. Lager style beers were found to contain significantly (p < 0.001) less thiamin than other tested styles of beers (lager, 35.7 μg/L; ale, 88.3 μg/L; stout/porters, 104.4 μg/L; wheat beers, 130.7 μg/L), which may be due to the raw material and extensive processing that occurs for this style. There was no statistical difference (p = 0.608) between the riboflavin content of each beer style. Furthermore, wines and ciders contain less thiamin and riboflavin than beer, which is also likely to be due to the base materials used and the differences in processing steps to produce these beverages.

Investigations into the thiamine and riboflavin content of malt and the effects of malting and roasting on their final content

“…All vitamin standards were prepared by dissolving 10 mg of each vitamer into 100 mL of 18 MU water and were stored at 4 C in amber bottles, with all working standards freshly prepared by diluting with 10 mM phosphate buffer (pH 6.5) on the day of use. The thiamine derivatization reagent was prepared by dissolving 1 g of potassium ferricyanide (Mallinckrodt, Griesheim, Germany) in 15 g of sodium hydroxide (Chem Supply, Adelaide, Australia) in 100 mL of 18 MU water and was stored in amber bottles at 4 C for up to one week as reported by Hucker et al (2011). 1.33 M phosphoric acid neutralizing solution used in the thiamine analysis was prepared by dissolving 15.33 g of 85% phosphoric acid (Chem Supply, Adelaide, Australia) in 100 mL of 18 MU water.…”

“…The analysis of thiamine, riboflavin and their respective vitamers was conducted using a Varian (Varian Inc, USA) HPLC system as reported elsewhere (Hucker et al, 2011). All samples were milled to a powder through a FOSS Cyclotec 1093 sample mill (FOSS, Denmark).…”

“…The solution was finally diluted to 10 mL with 10 mM phosphate buffer and filtered through a 0.45 mm regenerated cellulose (RC) filter (Phenomenex, USA) prior to analysis. Following filtration the samples for riboflavin were injected directly into the HPLC and samples for thiamine analysis underwent conversion to their respective highly fluorescent thiochrome esters (Hucker et al, 2011).…”

“…We recently reported that different styles of beer contain significantly different amounts of thiamine and riboflavin vitamers (Hucker et al, 2011). This may be directly due to the malt content, malt style, the malting process, or even the brewing process used in the production of beer.…”

Morpho-Nutritional Response of Lettuce (Lactuca Sativa L.) to Organic Waste Extracts Grown Under Hydroponic Condition

“…Further, the samples were examined for vitamins, i.e., Thiamin, Riboflavin, Niacin, and Ascorbic acid. Thiamine and riboflavin were found by quantitative analysis as described by Hucker et al (2011), Niacin was investigated by colorimetric method (Kawila, 2011) and Ascorbic acid (Vitamin C) was found through dichlorophenol Indophenol dye reduction method (Smirnoff, 2000). Kjeldhal method was adopted to find crude protein through determining nitrogen contents of food material.…”