регистрация / вход

Enzyme Technology Essay Research Paper The food

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

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.?

ОТКРЫТЬ САМ ДОКУМЕНТ В НОВОМ ОКНЕ

ДОБАВИТЬ КОММЕНТАРИЙ [можно без регистрации]

Ваше имя:

Комментарий