Micro-Encapsulation
Micro-encapsulation involves the enzyme being attached to an inert particle, like a resin bead. The beads are then packed into a vertical tube, which the substrate can then be poured down. Particular industries, which use this, are in the production of clear juices and glucose isomerase. The fruits in juices almost always contain pectins, which hold the fruit cells together. Due to this, juice can often appear cloudy, but pectinase is often added to fruit juice (apple juice) to make it appear clear. However,
there are many disadvantages to leaving pectinase in the apple juice. For example, some people may be allergic to that particular enzyme; it is expensive to purify and extract the enzymes and it’s also very time consuming. In addition the enzyme is wasted and cannot be used again. Consequently, the technique of enzyme immobilisation is used. The pectinase is embedded into resin beads, which are then packed into the vertical tube. The juice is then poured through and the clear juice is collected as the end product, thus leaving the pectinase still attached to the resin beads ready to be reused. Immobilised glucose isomerase is used for the preparation of high fructose syrups from starches. Fructose is a sugar found in fruits, however, it is sweeter than other sugars like glucose and sucrose, and it contains fewer calories. Fructose is obtained from starch, therefore using the enzyme amylase starch is converted to glucose. The glucose is then converted to fructose using the enzyme glucose isomerase. This particular enzyme is used in the immobilised form because it is relatively expensive to produce, therefore it is easier to recover the enzyme and reuse them.
Enzymes have been employed in the detergent industry for years, they are depended upon to remove proteins, starches and lipids, which can originate from blood, grass, sweat, milk etc. The main enzyme used in the detergent industry initially was protease, which catalyses the breakdown of protein molecules such as blood. However, recent developments have introduced “a cocktail of enzymes” () which included lipase’s and amylases. Lipase’s concentrate on the breakdown of fatty substances such as oils. They hydrolyse the ester bonds in triglycerides, which are a major component of fats. Amylase focuses on the breakdown of starchy deposits, from products such as food. The advantage of using these enzymes is that they are specific, thus removing the desired stain without damaging fabrics. Cellulases were also introduced because when detergents were used “small fibres are raised from the surface of cotton thread, resulting in a change in the 'feel' of the fabric and, particularly, in the lowering of the brightness of colours.” () Consequently cellulase was introduced to remove the small fibres, without damaging surrounding, major fibres. In addition enzymes (amylase and protease) are used in dishwashing detergents as they can remove food particles.
Enzymes play a major role in the brewing industry. The yeast converts sugars into alcohol and carbon dioxide. However, these sugars are stored as starch in plants, consequently this meant the process of malting had to be undertaken. This process was relatively expensive and hard to control, therefore industrial enzymes such as amylases, glucanases and protease’s were introduced to catalyse the malting process and make it easier to control. Thus producing the required sugars for the yeast to react on. In addition enzymes aid the filtration process, because of the polysaccharides; xylans and glucans present in the final beer. This often results in slow filtration. Consequently xylanases and glucanases are added to break down the polysaccharides, therefore increasing the filtration rates.
A number of enzymes are applied in the baking industry. The wheat flour used in bread making naturally contains “enzymes that modify the starch, protein and fibre fraction of the flour when water is added to the flour to make dough.” (www.enzymes.co.uk) In addition the yeast accommodates enzymes, which ferment maltose, which in turn produces carbon dioxide, making the bread rise. Enzymes have
played an important role in bread making and they have developed over time. Enzymes such as xylanase, a-amylase, protease, glucose oxidase and lipase are used for various reasons, such as controlling the taste, loaf volume, crumb texture and staling properties. Consequently correct enzymes must be used, otherwise this could have harmful effects on the dough or finished bread.
Enzymes are used greatly in the food industry; for example rennet is used in cheese production and the many flavours in cheese are a result of protease action. Enzymes aid the processing of cooking; they can enhance flavours and aroma, remove unwanted flavours and modify texture. The main enzyme used in the food industry is protease, however, lipase’s are becoming increasingly common. Enzymes are particularly used in “soy sauce production, gelatin hydrolysis and pet food manufacture.” () However, enzymes can cause “quality impairment when they continue to work beyond the point of perfection.” (Biological Sciences Review May 1998) Flavours, colour and texture can change as a result of this. For example “the loss of colour in fruits can be due to hydrolysis of anthocyanins and changes in carotenoid pigments.” (Biological Sciences Review May 1998)
Enzymes also have parts in pharmaceuticals and diagnostic industries, however, the applications of enzymes have not been as extensive as other industries. The most successful applications are extracellular enzymes, which means that they are secreted by the micro-organism which creates them. Enzymes have been used to treat genetic disorders, when some people are unable to produce the required enzymes.
Enzymes are used in a wide variety of industries, for example to enhance flavour and as additives in detergents and the brewing industry. They provide many advantages for different industrial processes. They have also benefited industries in terms of cost, with the introduction of techniques such as enzyme immobilisation. Enzymes have been widely used in the food industries making them more competitive and they have helped in medicine and pharmaceuticals. Consequently, enzymes will be used further in the future as technology progresses. In addition they are a vital part of a number of diverse industrial processes.
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