Applications of natural ingredients in alcoholic drinks - Natural Food Additives, Ingredients and Flavourings - page 396

Fig. 16.13 Illustration of selectivity of different glucosidase enzymes, showing part of an

amylopectin molecule.

Fig. 16.14 An example of a fl avour compound released from its glycoside in grape must
by glycoside hydrolytic enzymes. β - D -Glucopyranosides (glucosides, as above) of alcohols
are common aroma/fl avour precursors in grapes. Others include 6- O - α - L -rhamnopyranosyl-
β - D -glucopyranosides (rutinosides), 6- O - α - L -arabinofuranosyl- β - D -glucopyranoside
(arabinosyl glucosides) and 6- O - β - L -apiofuranosyl- β - D -glucopyranosides (apiosyl
glucosides). Pectinases also have secondary glycodasic activity (see text).

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are the various pectinases (or pectolases), which catalyse the hydrolytic
degradation of pectins (major structural materials of cell walls), thus facilitating
release of fl avour and colour components into the must. They also have secondary
glycodasic activity (Tamborra et al. 2004). The commercial preparation is usually
a mixture of pectin methylesterase (PME), polymethylgalacturonate lyase
(PMGL), polymethylgalacturonase (PMG) and polygalacturonase (PG), which
together degrade pectin (Fig. 16.15) (McKay et al. 2011e).
Some enzymes are generally used in conjunction with others, especially in the
production of specifi c beer types (Table 16.19) but, for convenience, enzyme
preparations can be purchased as mixtures to perform multiple jobs simultaneously.
Thus Dualase from Murphy & Son (UK) can be used to degrade α - and
β -polysaccharides and Trizyme can be used to degrade these, plus proteins.