Production of Gluten-Free Beer from Pearl Millet Cultivar
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Date
2014-03
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Addis Ababa University
Abstract
Pearl millet starch has featured in many foods recipes and industrial applications. However its
use as a raw material in brewing has not received much attention. This work therefore sought to
establish the suitability of pearl millet starch as a raw material substitute for barley in
production of gluten-free beer. Two type of beer were produced, one with caramel and another
without caramel. It is produced mainly from pearl millet grain (Pennisetum typhoideum) and the
process of brewing involves malting, mashing, fermentation and packaging. Chemical analyses
were carried out on both drinks, which not gave a significant (p≤0.05) difference. Pearl millet
beer had a total acidity of 0.562±0.03, fixed acidity of 0.203±0.001, Volatile acidity 0.360±0.02,
PH 3.92, specific gravity 1.042±0.003, total dissolved solids 1.12×105ppm, total suspended
solids 1.65×105ppm, ethanol content of 4.45±0.03% respectively .The gelatinization temperature
of pearl millet starch samples were determined and results ranged between 80 and 85°C. Other
key parameters evaluated were wort perfect primaries, gravities and pH, attenuation limits,
colour, and bitterness, Head retention (HR) and carbon dioxide (CO2) content of finished
product were also determined. Results showed that the present gravities (PG), pH, bitterness
(BU) and colour (EBC) obtained for the pearl millet starch wort samples ranged from, 65.64-
68.36°P, 5.39 – 6.09 PH, 24.25 – 25.65BU and 4.25 – 5.65 EBC respectively. In addition to the
above parameters, two additional parameters, original gravities (OG) and alcohol by volume
(abv) were measured for the pearl millet starch green beer with the following results, (OG)
58.24. – 60.78°P, (pH) 4.2 – 4.4, (BU) 20.5 – 19.6 BU, (abv) 4.45.6 – 4.56%. Results for head
retention and carbon dioxide for finished products were, (HR) 77 – 83sec, (CO2) 3.08 – 3.43g/l.
Sensory evaluation showed that the 25% pearl millet starch substituted sample was the most
preferred based on estery flavor, tingly mouth feel, colour and bitterness. The microbial count
for pearl millet beer had no growth of E.coli, streptococcus and staphylococcus but aspergillus
was present from the 4th day and heaviest on the 8th day. While the drink which was made of
barely with the same processing method had growth of staphylococcus and aspergillus which
was seen from the 2nd day and heaviest on the 4th day but E.coli and streptococcus was absent.
From the results, the drink which was made of pearl millet could keep for a longer period of time
than the barely beer. Thus, the grain nature could extend the shelf-life of pearl millet beer longer
than the barely beer at normal circumstance brewed.
Keywords: pearl millet, bitterness, colour, attenuation limit, Fermentation time, Head retention.
Description
Keywords
Pearl Millet, Bitterness, Colour, Attenuation Limit, Fermentation Time, Head Retention