Enzyme Technology
Glucose oxidase and catalase in the food industry
Glucose oxidase is a highly specific enzyme (for
D-glucose, but see Chapter 8), from the fungi Aspergillus niger and
Penicillium,
which catalyzes the oxidation of b-glucose to glucono-1,5-lactone (which
spontaneously hydrolyses non-enzymically to gluconic acid) using molecular
oxygen and releasing hydrogen peroxide (see reaction scheme [1.1]). It
finds uses in the removal of either glucose or oxygen from foodstuffs in order
to improve their storage capability. Hydrogen peroxide is an effective
bacteriocide and may be removed, after use, by treatment with catalase (derived
from the same fungal fermentations as the glucose oxidase) which converts it to
water and molecular oxygen:
catalase
2H2O2
2H2O + O2 [4.4]
For most large-scale applications the two enzymic
activities are not separated. Glucose oxidase and catalase may be used together
when net hydrogen peroxide production is to be avoided.
A major application of the glucose oxidase/catalase system
is in the removal of glucose from egg-white before drying for use in the baking
industry. A mixture of the enzymes is used (165 U kg−1) together with additional
hydrogen peroxide (about 0.1 % (w/w)) to ensure that sufficient molecular oxygen
is available, by catalase action, to oxidise the glucose. Other uses are in the
removal of oxygen from the head-space above bottled and canned drinks and
reducing non-enzymic browning in wines and mayonnaises.
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This page was established in 2004 and last updated by Martin
Chaplin on
6 August, 2014
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