As you read this, enzymes will be at work within your body. They act as catalysts, controlling chemical reactions involved in digestion, respiration and metabolism. Our own bodies produce many different types of enzyme, as do all living things, right down to the humblest mould and the smallest bacteria.

Enzymes are able to break down, or modify, chemical compounds such as starches and proteins and this ability has been utilised by humans for thousands of years.

Perhaps the best known use of an enzyme in food production is rennet, traditionally derived from the stomach linings of young calves. Rennet contains enzymes that coagulate milk causing it to separate into solids (curds) for cheese production and liquid (whey).

Enzyme production

Enzymes have traditionally been sourced from the tissues of plants and animals, where they occur naturally. However,
micro-organisms such as mould and fungi can also be used to produce vast quantities of enzymes. Some of these microorganisms produce the enzymes naturally, but many more have been genetically modified to produce ‘copies’ of animal or plant enzymes.
Microbial production has many advantages over plant and animal sources. The raw products required – the micro-organisms and the substrate on which they feed – can be supplied wherever they are required. This frees companies from having to rely on a regular supply of enzyme-rich, plant or animal-based materials, which may be expensive to collect and transport, and which will also need processing and purifying.

Bread

No matter what it is, almost all commercially manufactured bread in the UK is made with enzymes.

Enzymes allow manufacturers to pump up loaf volume significantly, adjust texture, produce a better crust colour and prolong shelf life. They make the dough easier to put through machines, increase dough stability and control ‘crumb structure’ – which in a sliced white loaf might be silky and uniform, but in a baguette may be chewy and variable, with large holes. Enzymes can even give bread a whiter appearance.

What most of us would recognise as a modern loaf would be impossible to produce without enzymes. But what does all this mean for the consumer? Andrew Whitley warns that some enzymes are potential allergens, notably the very widely used alpha-amylase
(used in baking to break starches down into sugars, for yeast to feed on). Click here to read more of Andrew's warnings.

Bakery workers can become sensitised to enzymes from bread improvers. Industry experts warn thatliquid or granular preparations of enzymes are safer than powdered forms, because of the allergenic potential of enzyme dust. This should not be a problem to the end consumer if enzymes are destroyed during processing, but Whitley has quoted research from the University of Bochum, in Germany, which shows that up to 20% of the allergenicity of alpha- amylase can survive in the crusts of bread.

Whitley has also revealed that an enzyme called transglutaminase, which may be used to make dough stretchier in croissants and some breads, may render part of the wheat protein toxic to people with a severe gluten intolerance.

Such unintended and unanticipated effects suggest that the safety testing of some enzymes may not be up to scratch, and raises the possibility of other, as yet unnoticed, side affects. However, unless enzymes are fully labelled on ingredients lists, it will be virtually impossible to correlate possible side effects with enzyme use.

Cheese

Enzymes are essential to cheese production. They act by coagulating milk, allowing the ‘solid’ curds to be separated from the ‘watery’ whey. The curds are then pressed and matured to produce cheese.
Traditionally the enzymes would have come from the
stomach linings of young calves, where they are naturally
produced to enable the calf to digest its mother’s milk. Commercially produced preparations of standardised, enzyme-rich matter for cheese production were first made in Denmark in 1874.

Today, over half of the enzymes used in UK cheese production are microbial in origin. The enzymes are produced from genetically modified (GM) yeast and moulds which contain copies of the calf gene for the production of chymosin, the main enzyme involved in milk clotting.

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