Enzyme Technology Essay, Research Paper
The food and drink industry depends heavily on enzymes.
Enzymes produced by yeast have been used for thousands of years in brewing and
baking. High fructose syrup contains fructose and glucose in roughly
equal proportions. The high fructose syrup is greater in demand than pure
glucose as food and drink sweeteners, because fructose is sweeter than glucose.
Therefore, if glucose can be converted into fructose, its commercial value is
increased greatly. ?Biological systems
are increasingly being used in the provision of goods and services.
Traditionally they have featured in well-established industries such as
brewing, baking, wine-making and cheese manufacture. Modern biotechnology also
now includes the use of biological catalysts in products such as washing
powders and ‘diet’ versions of drinks; the recycling or cleaning of waste and
remediation of land; and the use of DNA technology to develop new crops and
medicines. Enzymatic treatments are a now a major way of producing
sweeteners, including syrups derived from sucrose derived from sucrose or
starch that contain mixtures of glucose, maltose, fructose, and other sugars.
High fructose syrup (HFS) from maize starch has now eclipsed sucrose as the
major sweetener used in US food industry. More than eight million of HFS are
sold annually. What is HFS? HFS stands for High Fructose
Syrup. It is made from a cheap raw material starch. Typically the production of
HFS uses four enzymes in three distinct stages: Liquefaction Starch obtained as by-product after valuable oil and
protein has been extracted from maize. Starch solution (about 33% starch by
mass in water) is boiled and treated with a-amylase, an enzyme from Bacillus licheniformis. At this
temperature the enzyme is denatured after a few minutes, but not it broken some
of the bonds in the starch molecules. Saccharificariton A cocktail of various fungal is added to the
dextrin, depending on the carbohydrate composition required in the finished
product. High glucose contents a mixture of a-amylase or pullulanase with syrup
with amyloglucosidas. After 1-3 days at 60 C, these enzymes break down the
dextrins progressively to glucose syrup. This solution is sweet, but not
sufficiently so to be used in most drinks and other foods. Isomerisation Glucose shares its chemical composition with
fructose but has a different molecular structure. This makes glucose about half
as sweet as fructose. The enzyme glucose isomerase converts glucose to
fructose, thereby increasing the sweetness of the syrup. Several spices of
microbe produce glucose isomerase. Designing
Enzymes ?The conventional
method of manufacturing Invert Sugar involves acid hydrolysis of
sucrose, the popular and cheap sweetener. However, such acid hydrolysis has a
low conversion efficiency, high-energy consumption and thus cost of production
is high. The acid-hydrolysed product also contains impurities introduced by
uncontrollable parameters during inversion. The said conversion can also be
achieved by enzymatic action of invertase on sucrose with a conversion
efficiency of almost 100% without the inherent disadvantages of acid
hydrolysis. The key to the process developed is a specific enzyme for the
continuous production of concentrated Invert Sugar using immobilised
yeast cells in an inorganic insoluble matrix. More
traditional enzyme-mediated industrial processes include the production glucose
syrup from starch. Cereal-derived starch, inexpensively produced in bulk
quantities by modern agronomic techniques, is treated with a combination of amylolytic
enzymes, resulting in its degradation to glucose. The glucose can be used for a
variety of purposes: it may be sold directly in crystalline form, or used a
food ingredient in the production of soft drinks, jams, sweets, confectionary
or ice cream. The Enzymes,
which are used in sweeteners production?
1. a-amyalse: hydrolyses a-1,4 bonds in glucose
polymers, but only within chains, yielding shorter chains(dextrins). Obtained
commercially from bacteria (e.g. Bacillus spp.). 2. B-amylase:? hydrolyses a-1, 4 bonds in glucose
polymers, breaking off successive maltose units from the (non-reducing) ends of
the obtained commercially from barely and malt. 3. ???Amyloglucosidase: breaks a-1,
4, cleaving
glucose units progressively from the (non reducing) ends of the chain but not
slowly. Obtained commercially from the fungi Aspergillus spp. And Rhizopus
oryaze. 4. Pullulanase: hydrolyses a-1,6
bonds. Obtained commercially from the bacteria Bacillus acidopullulyticus and Klebsiella
pneumonia. 5. Glucose
isomerase: transforms glucose into its sweeter-tasting isomers fructose. Are there any improved Enzymes? Over the last decades
scientists have been trying to find better enzymes for HFS production. A Danish
scientist introduced some new bacterial a-amylase from Bacillus licheniformis
that catalysed the breakdown of starch at 100 C in 1974.This led to
significant improvements in the initial liquefaction process. Some other range
of dextrin-degrading enzymes has also been become available to satisfy the
demand for specialised sugar syrup i.e. baby food, diabetic confectionary or
for use in brewing and wine making. These investigations took a lot of time and
many scientists have been working hard in selection of microorganism. Now
scientists are still working trying to find the ideal production strain. ??? Further
Investigations? ??????????? Further
investigations showed that of the hundreds of amino acids residues making up
glucose isomerase, just two were responsible for the weak links. By
substituting these amino acids with others that bound more tightly to their
neighbours, the proteins were able to produce a more stable enzyme. This was
done by altering a small selection of the DNA that coded for glucose isomerase.?
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