Partial Substitution of Malted Barley by Raw Barley in Brewing Technology

Alemu, Molla Assefa (2016) Partial Substitution of Malted Barley by Raw Barley in Brewing Technology. Masters thesis, Addis Ababa University.

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Abstract

The effect of commercial enzymes on quality of wort developed from replacement of malted barley with raw barley as adjunct of 40 % and 60 % was investigated for yield of extract, Free Amino Nitrogen, Degree of fermentation, pH, VDK, colour…. The wort pH is relatively stable with no significant changes at all levels of replacements. The colour is lighter with increment in proportion of the raw barley as it appears as colour diluents. The wort produced tends to be turbid which affects the utilization of the wort. The total soluble nitrogen and free amino nitrogen value increased with the use of commercial enzymes while the yield increases with enzymes. The use of ceremix Plus and Ondea Pro have been found to be relatively more effective in the preparation of beer wort as observed for the result obtained in proportions of raw barley and malt barley. The use of high percentage raw barley as adjunct with commercial enzymes are found to be useful in production of high quality wort with low cost and profitability. The use of barley instead of malt in the brewing process is interesting with respect to costs. However, in cost calculations it is important to consider that barley has a considerable enzyme deficit and requires the addition of microbially produced enzymes during the brewing process. Owing to the improving knowledge about brewing with barley using microbial enzyme cocktails during recent years, it is possible to brew beverages with a barley content of up to100 % without technological process problems in the brewery. However, there are different opinions with respect to the influence of unmalted barley on beer quality and flavour. Previous investigations showed a decrease in the colour, bitterness and free amino nitrogen (FAN) content and poor results in sensory analyses. Additionally, increasing b-glucan content was observed using barley. The aim of this study was to investigate the influences of unmalted barley on the brewing process and the quality of the resulting product, with the main focus on the Yield of extract & free amino Nitrogen. For the investigation, brews with 40 % & 60 % raw barley proportion brews with a colour malt addition, to compensate for a lower colour using barley, were produced. In general, it can be said that beers with a proportion of up to 54.57 % barley achieved a comparable or higher extract yield and final attenuation owing to the combined effectiveness of the malt and microbial enzymes. Although all analytical values were within the normal range according to EBC, a slight decrease in total polyphenols and free amino nitrogen content was observed (Table 10).

Item Type:	Thesis (Masters)
Subjects:	H Social Sciences > HD Industries. Land use. Labor > HD28 Management. Industrial Management Q Science > QD Chemistry S Agriculture > S Agriculture (General) T Technology > TP Chemical technology
Divisions:	Africana
Depositing User:	Andriamparany Edilbert RANOARIVONY
Date Deposited:	01 Nov 2018 08:57
Last Modified:	01 Nov 2018 08:57
URI:	http://thesisbank.jhia.ac.ke/id/eprint/7245

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