Enzymes also play a valuable part in many different industries. One of the main ones is Breadmaking.
Bread baking involves lots of different enzymes, which are important to the proper development of the bread from the mixture into the basic food we eat.
The wheat flour included in the ingredients has naturally occurring enzymes that modify the starch, protein and fibre in the flour when water is added to the flour to make the dough. The breadmaking process is like an ancient form of fermentation by a combination of enzymes from yeast and wheat, followed by baking. (5)
In order to produce consistent products for the consumer and to make operations more efficient, enzymes are used as supplements in the bread making process. These include α-amylase, protease, glucose oxidase and lipase. These are blended into the dry flour and are activated when the water is added to make the dough. These supplements enable better handling of dough, and control of characteristics in the finished bread such as taste, loaf volume, crumb texture, and anti-staling properties. (1)
A feature of baking enzymes is that they are usually required to be thermo-labile. This means they are denatured to inactive protein during the baking process. (2)
During dough formation a portion of the starch is degraded by β-amylase to maltose which is utilised by the yeast to form carbon dioxide which causes the dough to rise. However, the amount of degradation is very limited and can be increased by the addition of α-amylase. Use of α-amylase can also help prolong freshness.
Chemical oxidants are used in baking to strengthen the gluten. Enzymes such as glucose oxidase can replace such chemical oxidants. This enzyme oxidises sulphydryl groups in the gluten chemical structure to make the dough stronger.
If too much enzyme is put in the bread usually results in a loss of structure, resulting in bread that does not rise properly or that will cause problems in bakery machinery because it is too sticky. (1)
As well as bread, enzymes are well known for their use in the brewing industry. Most of the sugar present in plant materials is in the form of complex polysaccharides such as starch and cannot be readily utilised. Traditionally these nutrients are "released" by the process of malting whereby barley is allowed to partly germinate during which endogenous enzymes are released which degrade starch and protein to simple sugars and amino acids which can be utilised by the yeast cells.
The malting process is a relatively expensive way of manufacturing enzymes and is not always easy to control. Industrial enzymes such as amylases, glucanases and proteases can be added to unmalted barley resulting in the same simple sugars and amino acids that malting would produce but under more control. (3)
Apart from food and drink, enzymes are important in many other industries, especially textiles.
The main applications of enzymes in the leather industry are proteases which help in the dehairing of the animal hides and lipases are used for degreasing. (5)
Modern fabrics are reinforced with an adhesive called "the size" before weaving. This prevents breaking of the warp threads. Harsher chemicals such as alkalis or acids have been traditionally used for desizing, but are now being replaced by enzymes. Apart from the environmental benefit of replacing harsh chemicals with biodegradable enzymes, enzymes have turned out to be less harsh on the fabric as well. In the modern textile industry enzymes are used increasingly in the finishing of fabrics and clothes. Whilst most of the fibres are arranged as long, straight chains some small fibres can protrude from the yarn or fabric. The correct application of a cellulase enzyme can remove these rough protruberances giving a smoother, glossier brighter coloured fabric. This technique has become known as Biopolishing and results in not only a softer fabric but also improved colour brightness. The same process has recently been adapted and included in some laundry . (1)
The main enzyme activity in biological laundry detergents is protease, which acts on organic stains such as grass, blood, egg and human sweat. However, it has become more common in recent years to include a mixture of enzymes including lipases and amylases. Lipases are effective on stains resulting from fatty products such as oils and fats whilst amylases help remove starchy food deposits. (5)
There are many ways in which enzymes are used today, and many more ways that are being developed. Without enzymes being used in industry, it would be much more difficult for many industries to continue, especially with such high quality products. It would also be harder to prevent and diagnose diseases, and to treat them once they have been diagnosed. Therefore enzymes are very important to our way of living.
Bibliography:
Internet:
- www.enzymes.co.uk
- www.biology-online.org
Books:
- ‘Merit Students Encyclopedia’ Published in 1970 by Crowell-Collier Educational Corporation
CD ROM:
- Microsoft Encarta 1998 Deluxe
- Letts A Level Biology