Food Biochemistry and Food Processing (2 edition)

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33 Biochemistry of Beer Fermentation 643

Table 33.6.Some Selected Applications of Cell Immobilization Systems Used for Beer Production

Carrier Material Reactor Type Reference

Flavor maturation

Calcium alginate beads Fixed bed Shindo et al. (1994)

DEAE-cellulose Fixed bed Pajunen and Gronqvist (1994) ̈

Polyvinyl alcohol beads Fixed bed Smogrovicova et al. (2001) ́

Porous glass beads Fixed bed Linko et al. (1993), Aivasidis (1996)

Alcohol-free beer

DEAE-cellulose beads Fixed bed Collin et al. 1991, Lomni et al. 1990

Porous glass beads Fixed bed Aivasidis et al. (1991)

Silicon carbide rods Monolith reactor Van De Winkel et al. (1991)

Acidified wort

DEAE-cellulose beads Fixed bed Pittner et al. (1993)

Main fermentation

Calcium alginate beads Gas lift White and Portno (1979), Nedovic et al. (1997)

Calcium pectate beads Gas lift Smogrovicova et al. (1997) ́

κ-Carrageenan beads Gas lift Mensour et al. (1996), Decamps et al. (2004)

Ceramic beads Fixed bed Inoue (1995)

Corncobs Gas lift Br ́anyik et al. (2006a)

Gluten pellets Fixed bed Bardi et al. 1997

Polyvinyl alcohol beads Gas lift Smogrovicova et al. (2001) ́

Polyvinyl alcohol Lentikats©R Gas lift Smogrovicova et al. (2001), Bezbradica et al. (2007) ́

Polyvinyl chloride granules Gas lift Moll et al. (1973)

Porous glass beads Fixed bed Virkaj ̈arvi and Kronlof (1998) ̈

Porous chitosan beads Fluidized bed Unemoto et al. (1998), Maeba et al. (2000)

Silicon carbide rods Monolith reactor Andries et al. (1996)

Spent grains Gas lift Br ́anyik et al. (2002, 2004)

Stainless steel fibre cloths Gas lift Verbelen et al. (2006)

Wood (aspen beech) chips Fixed bed Linko et al. (1997), Kronlof and Virkaj ̈ ̈arvi (1999),

Pajunen et al. (2001)

Started in 1971, one of the first ICT systems for the fer-

mentation and maturation of beer was developed by TREPAL

(the R&D Centre of the Konenbourg Brewery and the Euro-

pean Brewery) with INSA (Institut National des Sciences Ap-

pliquees, Toulouse, France) and INRA (Institus National des ́

Recherche Agronomique, Dijon, France) (Moll et al. 1973,

Moll and Dueurtre 1996, Moll 2006). A continuous pilot in-

stallation for fermentation and maturation of beer with a flow

rate of 5 L/h was developed and worked for 9 months without

any microbial contamination. Around the same time, Narziss

and Hellich (1971) developed an ICT process where yeast cells

were immobilized in kieselguhr (which is widely used in the

brewing industry as a filter aid) and a kieselguhr filter was em-

ployed as bioreactor (called the “bio-brew bioreactor”). Their

yeast cell immobilization method was based on a method for

the immobilization of enzymes (Berdelle-Hilge 1966). From

the beginning of the nineteen seventies, various systems have

been developed and some have been implemented on an

industrial scale.

ICT processes have been developed for (i) the flavor mat-

uration of green beer, (ii) the production of alcohol-free or

low-alcohol beer, (iii) the production of acidified wort using

immobilized lactic acid bacteria, and (iv) the continuous beer

fermentation (Branyik et al. 2005, Verbelen et al. 2006, Willaert ́

and Nedovic 2006, Willaert 2007, Verbelen et al. 2010).

Flavor Maturation of Green Beer

The objective of flavor maturation is the removal of di-

acetyl and 2,3-pentanedione, and their precursorsα-acetolactate

andα-acetohydroxybutyrate, which are produced during the

main fermentation (see the preceding text). The conversion

ofα-acetohydroxy acids to the vicinal diketones is the rate-

limiting step. This reaction step can be accelerated by heat-

ing the beer—after yeast removal—to 80–90◦C during a cou-

ple of minutes. The resulting vicinal diketones are subse-

quently reduced by immobilized cells into their less-flavor-active

compounds.

The traditional maturation process is characterized by a near-

zero temperature, low pH and low yeast concentration, resulting

in a very long maturation period of 3–4 weeks. Different strate-

gies have been developed to accelerate diacetyl removal (see

Section “Vicinal diketones”). One of the techniques is the use

of an ICT process to reduce the maturation period to about

2 hours.