2. • The first major breakthrough for microbial
enzymes in the food industry came in the early
1960s when a glucoamylase was launched.
• It allowed starch to be broken down into glucose.
Since then, almost all glucose production has
changed to enzymatic hydrolysis from traditional
acid hydrolysis.
• For example, compared to the old acid process, the
enzymatic liquefaction process cut steam costs by
30%, ash by 50% and by-products by 90%.
3. • Since 1973, the starch processing industry has
grown to be the largest market for enzymes after
the detergent industry.
• Enzymatic hydrolysis is used to form syrups
through liquefaction, saccharification and
isomerization steps.
• Another big market for enzymes is the baking
industry.
• Supplementary enzymes are added to the dough to
ensure high bread quality in the form of a uniform
crumb structure and better volume.
• Special enzymes can also increase the shelf life of
bread by preserving its freshness longer.
4. • A major application in the dairy industry is to
bring about the coagulation of milk as the first
step in cheesemaking. Here, enzymes from both
microbial and animal sources are used.
• In many large breweries, industrial enzymes are
added to control the brewing process and produce
a consistent beer of a high quality.
• In food processing, animal or vegetable food
proteins with better functional and nutritional
properties are obtained by the enzymatic
hydrolysis of proteins.
• In the juice and wine industries, the extraction of
plant material using enzymes to break down cell
walls gives higher juice yields, improved colour
and aroma of extracts, and clearer juice.
5. Enzyme applications in the food
industry
• Sweetener production
• Baking
• Dairy products
• Brewing
• Distilling
• Protein hydrolysis for food processing
• Extraction of plant material
• Enzymatic modification of lipids
• Reduction of viscosity in general
• Safety
• Enzyme regulation and quality assurance
• Future prospects
8. • The starch and sweetener industry began using industrial
enzymes at an early date.
• Special types of syrup that could not be
produced using conventional chemical hydrolysis were the
first compounds made entirely by enzymatic processes.
• Many valuable products are derived from starch. There has
been heavy investment into enzyme research in this field
and intensive development work on application processes.
• Reaction efficiency, specific action, the ability to work
under mild conditions and a high degree of purification
and standardization all make enzymes ideal catalysts for
the starch industry.
9. • The moderate temperatures and pH values used for the
reactions mean that few by-products affecting flavor and
color are formed.
• Furthermore, enzyme reactions are easily controlled and can
be stopped when the desired degree of starch conversion is
reached.
• The first enzyme preparation (glucoamylase) for the food
industry in the early 1960s was the real turning point.
• This enzyme breaks down starch completely to glucose.
Soon afterwards almost all glucose production changed over
from acid hydrolysis to enzymatic hydrolysis because of the
clear product benefits of greater yields, a higher degree of
purity and easier crystallization.
10. • However, the most significant event came in
1973 with the development of immobilized
glucose isomerase, which made the
industrial production of high fructose syrup
feasible.
• This was a major breakthrough which led to
the birth of a multi-billion dollar industry in
the USA for the production of high fructose
syrups.
11. Enzymes for starch modification
• By choosing the right enzymes and the right
reaction conditions, valuable enzyme products can
be produced to suit virtually any specific need in
the food industry.
• Syrups and modified starches of different
compositions and physical properties are obtained
and used in a wide variety of foodstuffs, including
soft drinks, confectionery, meat products, baked
products, ice cream, sauces, baby food, canned
fruit, preserves and more.
12. Conti….
• Many non-food products obtained by fermentation are derived
from enzymatically modified starch products. For instance,
enzymatically hydrolyzed starches are used in the production of
alcohol, polyols, ascorbic acid, enzymes, monosodium
glutamate (MSG), citric acid, lysine and penicillin.
• The major steps in the conversion of starch are
– liquefaction,
– Saccharification
– Isomerization.
In simple terms,
the further the starch processor goes, the sweeter the syrup
obtained.
13. Tailor-made glucose syrups
• Glucose syrups are obtained by hydrolyzing starch (mainly
from wheat, maize (corn), tapioca (cassava), and potatoes).
• This process cleaves the bonds linking the dextrose units in
the starch chain.
• The method and the extent of hydrolysis (conversion)
affect the final carbohydrate composition and
therefore many of the functional properties of starch
syrups.
• The degree of hydrolysis is commonly defined as
the dextrose equivalent
14. Dextrose equivalent (DE)
• Glucose (also called dextrose) is a reducing sugar.
• Whenever an amylase hydrolyzes a glucose-glucose
bond in starch, two new glucose end-groups are
exposed.
• Therefore the degree of hydrolysis can be measured
as an increase in reducing sugars. The value obtained
is compared to a standard curve based on pure
glucose - hence the term dextrose equivalent.
15. Tailor-made glucose syrups (Conti..)
• Originally, acid conversion was used to produce glucose
syrups. Today, because of their specificity, enzymes are
frequently used to predetermine exactly how the hydrolysis
will take place. In this way, tailor-made glucose syrups
with well-defined sugar spectra are manufactured.
• The sugar spectra are analyzed using different techniques,
two being high-performance liquid chromatography
(HPLC) and gel permeation chromatography (GPC).
HPLC and GPC data provide information about the
molecular weight distribution and the overall carbohydrate
composition of the glucose syrups.
• These are used to define and characterize the type of
product, e.g. high maltose syrup.
16. Processing and enzymology
• Modern enzyme technology is used extensively in
the maize wet-milling sector. Current research
focuses on refining the basic enzymatic
conversion processes in order to improve process
yields and efficiency.
• An overview of the major steps in the conversion
of starch is presented in Figure . The enzymatic
steps are briefly explained after that
17.
18. Liquefaction
• Maize starch is the most widespread raw material used,
followed by wheat, tapioca and potatoes.
• As native starch is only slowly degraded using alpha-
amylases, a suspension containing 30-40% dry matter
needs to be first gelatinized and liquefied to make the
starch susceptible to further enzymatic breakdown.
• This is achieved by adding a temperature-stable alpha-
amylase to the starch suspension.
• The mechanical part of the liquefaction process involves
the use of stirred tank reactors, continuous stirred tank
reactors or jet cookers.
19.
20. Cont…
• In most plants for sweetener production, starch liquefac-
tion takes place in a single-dose, jet-cooking process as
shown in Figure.
• The alpha-amylase Termamyl is added to the starch slurry
after pH adjustment, and the slurry is pumped through a
jet-cooker. Live steam is injected here to raise the
temperature to 105°C, and the slurry’s sub-sequent passage
through a series of holding tubes provides the five-minute
residence time necessary to gelatinize the starch fully.
• The temperature of the partially liquefied starch is then
reduced to 90-100°C by flashing, and the enzyme is
allowed to react further at this temperature for 1-2 hours
until the required DE is obtained.
21. • The enzyme hydrolyzes the alpha-1,4-glycosidic
bonds in
pregelatinized starch, whereby the viscosity of the
gel
rapidly decreases and maltodextrins are produced.
• The process may be terminated at this point, the
solution purified and dried.
• They are used as functional ingredients in the food
industry as fillers, stabilizers, thickeners, pastes
and glues in dry soup mixes, infant foods, sauces,
gravy mixes, etc.
22. Saccharification
• When maltodextrins are saccharified by further hydrolysis
using glucoamylase or fungal alpha-amylase, a variety of
sweeteners can be produced.
• These have dextrose equivalents in the ranges 40-45
(maltose), 50-55 (high maltose), 55-70 (high conversion
syrup).
• By applying a series of enzymes including beta-amylase,
glucoamylase and pullulanase as debranching enzymes,
intermediate-level conversion syrups with maltose contents
of nearly 80% can be produced.
• A high yield of 95-97% glucose may be produced from
most starch raw materials (maize, wheat, potatoes, tapioca,
barley and rice).
23. Isomerization
• Glucose can be isomerized to fructose in a reversible
reaction (see Fig. next slide).
• Under industrial conditions, the equilibrium point is
reached when the level of fructose is 50%.
• The reaction also produces small amounts of heat that must
be removed continuously.
• To avoid a lengthy reaction time, the conversion is
normally stopped at a yield of about 45% fructose.
• The isomerization reaction in the reactor column is rapid,
efficient and economical if an immobilized enzyme system
is used.
• The optimal reaction parameters are a pH of about
7.5 or higher and a temperature of 55-60°C.
24.
25. • These parameters ensure high enzyme activity,
high fructose yields and high enzyme stability.
• However, under these conditions glucose and
fructose are rather unstable and decompose easily
to organic acids and coloured by-products.
• This problem is countered by minimizing the
reaction time in the column by using an
immobilized isomerase in a column through which
the glucose flows continuously.
• The enzyme granulates are packed into the column
but they are rigid enough to prevent compaction.
26. • The immobilized enzyme loses activity over time.
Typically, one reactor load of glucose isomerase is
replaced when the enzyme activity has dropped to 10-15%
of the initial value.
• The most stable commercial glucose isomerases have half-
lives of around 200 days when used on an industrial scale.
• To maintain a constant fructose concentration in the syrup
produced, the flow rate of the glucose syrup fed into the
column is adjusted according to the actual activity of the
enzyme.
• So towards the end of the lifetime of the enzyme,
the flow rate is much slower.
27. Sugar processing
• Starch is a natural component of sugar cane. When the
cane is crushed, some of the starch is transferred into the
cane juice where it remains throughout subsequent
processing steps.
• Part of the starch is degraded by natural enzymes already
present in the cane juice, but if the concentration of starch
is too high, starch may be present in the crystallized sugar
(raw sugar).
• If this is to be further processed to refined sugar, starch
concentrations beyond a certain level are unacceptable
because the filtration of the sugar solution will be too
difficult.
• In order to speed up the degradation of starch, it is general
practice to add concentrated enzymes during the
evaporation of the cane juice.
28. • Due to its extreme thermal stability,
Termamyl may be added at an earlier stage of the multi-
step evaporation than conventional enzymes. Termamyl is
therefore the product preferred for starch degradation.
• Another polysaccharide, dextran, is not a natural compo-
nent of sugar cane, but it is sometimes formed in the sugar
cane by bacterial growth.
• This happens in particular when the cane is stored under
adverse storage conditions (high temperatures and high
humidity).
29. • Dextran has several effects on sugar processing:
clarification of the raw juice becomes less efficient;
filtration becomes difficult; heating surfaces become
“gummed up”, which affects heat transfer; and finally,
crystallization is impeded resulting in lower sugar yields
• These problems may be overcome by adding a dextran-
splitting enzyme at a suitable stage of the process.
• Enzyme called Dextranase for this application.
• It should be added that dextran problems may also be
encountered in the processing of sugar beets, although the
cause of the dextran is different. In this case, dextran is
usually a problem when the beets have been damaged by
frost. The cure, however, is the same: treatment with
Dextranase.
31. • Enzymes such as malt and fungal alpha-
amylases have been used in bread making.
• Rapid advances in biotechnology have
made a number of exciting new enzymes
available for the baking industry.
• The importance of enzymes is likely to
increase as consumers demand more natural
products free of chemical additives.
32. • The dough for white bread, rolls, buns and
similar products consists of flour, water,
yeast, salt and possibly other
ingredients such as sugar and fat.
• Flour consists of gluten, starch, non-starch
polysaccharides, lipids and trace amounts of
minerals.
33. • The yeast starts to work on the fermentable
sugar transforming them into alcohol and
carbon dioxide, which makes the dough
rise.
• The main component of wheat flour is
starch. Amylases can degrade starch and
produce small dextrin for the yeast to act
upon.
34. • There is also a special type of amylase
which modifies starch during baking to give
a significant anti-staling effect.
35. • Gluten is a combination of proteins which
forms a large network during dough
formation. This network holds the gas in
during dough proofing and baking.
• The strength of this gluten network is
therefore very important for the quality of
all bread raised using yeast.
36. • Enzymes such as hemicellulases, xylanases,
lipases and oxidases can directly or
indirectly improve the strength of the gluten
network and so improve the quality of the
finished bread.
37. Flour supplementation
• Malt flour and malt extract can be used as
enzyme supplements because malt is rich in
alpha-amylases.
• Commercial malt preparations can differ
widely in their enzyme activity, whereas an
industrial enzyme is supplied with a
standardized activity.
38. • The alpha-amylases degrade the damaged
starch in wheat flour into small dextrin,
which allow yeast to work continuously
during dough fermentation, proofing and the
early stage of baking
• The result is improved bread volume and
crumb texture.
39. • In addition, the small oligosaccharides and
sugars such as glucose and maltose
produced by these enzymes.
• Enhance the Maillard reactions responsible
for the browning of the crust and the
development of an attractive “baked” flavor.
40. Dough conditioning
• Flour contains 2.5-3.5% non-starch
polysaccharides which are large polymers (mainly
pentosans)
• Play an important role in bread quality due to their
water absorption capability and interactions with
gluten.
• Addition of certain types of pentosanase or
xylanase at the correct dosage can improve dough
machinability, yielding a more flexible, easier-to-
handle dough.
41. • Consequently, the dough is more stable and gives
better oven spring during baking resulting in a
larger volume and improved crumb texture.
• Normal wheat flour contains 1-1.5% lipids, both
polar and non-polar. Some of these lipids,
especially the non-polar lipids such as
triglycerides, are bound with gluten, impeding its
functionality.
42. • The addition of a functional lipase modifies
the triglycerides.
• Modification of their interaction with
gluten, and this results in a stronger gluten
network.
• This ensures a more stable dough in case of
over-fermentation, a larger loaf volume and
significantly improved crumb structure.
43. • Chemical oxidants such as bromates,
azodicarbonamide and ascorbic acid have
been widely used to strengthen the gluten
when making bread. As an alternative,
oxidases
• Glucose oxidase can partially replace the
use of these chemical oxidants and achieve
better bread quality.
44. • Glucose oxidase and fungal alpha-amylase
can be used not only to replace bromate but
also to give a larger bread volume.
45. The synergistic effects of enzymes
• Each of the enzymes used in baking has its
own specific substrate in wheat flour dough
• For example, lipases work on the lipids,
xylanase works on the pentosans and
amylases work on the starch.
• Overdose of enzymes will have detrimental
effect on either the dough or on the bread.
46. • An overdose of fungal alpha-amylase or
hemicellulase/xylanase may result in a
dough that is too sticky to be handled by the
baker or baking equipment.
• Use a combination of lower dosages of
alpha-amylase and xylanase with low
dosages of lipase or glucose oxidase to
achieve optimum dough consistency,
stability and bread quality.
47. • Another example is to use maltogenic alpha
amylase in combination with fungal alpha-
amylases and xylanase or lipase to secure
optimum crumb softness together with
optimum bread quality in terms of crumb
structure, bread volume, etc.
49. Application in Dairy
• The application of enzymes in the processing of
milk has a long tradition.
• In ancient times, calf rennet was used
for coagulation during cheese production. The
rennet contains the enzyme chymosin.
• Proteases are also used for accelerating cheese
ripening, for modifying the functional properties
of cheese
50. • Cow’s milk contains 5% lactose and in
order to break it down we need the enzyme
lactase.
• Lactase (beta-galactosidase) is used to
hydrolyze lactose in order to increase
digestibility or to improve the solubility or
sweetness of various dairy products.
51. • Cheese making process rennet (the milk-
clotting enzyme) and calcium chloride are
added to promote the milk protein clotting
reaction that forms a gel.
• Proteases are enzymes that are added to
milk during cheese production, to hydrolyze
caseins, specifically kappa casein.
52. • The most common enzyme isolated from
rennet is chymosin.
• Chymosin can also be obtained from several
other
– Animal,
– Microbial
– Vegetable sources.
53. Cheese
• Cheese has been made in most cultures since ancient
times.
• Cheese is a milk concentrate, the basic solids of which
consist mainly of protein (actually casein) and fat. The
residual liquid is called whey.
• The casein and fat in the milk are concentrated
approximately 10 times in production of hard and some
semi-hard types of cheese
• The moisture content of the cheese serves to distinguish
various categories, such as hard (low-moisture), semi-
hard and soft cheeses
54. Classifications of cheese
• Fresh
• Not aged, mild tasting, whitish color, highly perishable
because moisture is 80 % (Cottage cheese, ricotta, feta)
• Soft
• Ripened for a short time (Brie & Camembert)
• Semi-hard
• Contain 40-50 % moisture content (Muenster, Gouda,
Edam)
• Hard
• Contain 30-40% moisture content (Cheddar, Swiss)
• Very hard
• Aged the longest & have 30 % moisture content
(Parmesan, Romano)
55. Cheese Production Procedure
• Standardization
• Pasteurization (65°C for 30minutes)
• Ripening of milk (Starter culture )
• Addition of Rennet (0.006% rennet)
• Cutting of the curd
• Heating/Cooking of the Curd (37-40°C , whey comes
out)
• Draining of the whey (6.2 pH)
• Salting
• Pressing
• Packaging
56. Milk has two main parts…the water and the solids. There are
other names for these two parts:
As milk separates into the
two parts, we call it
“curdling” .
WHEY is the correct name
for the liquid.
CURDS is the correct name
for the solids.
Curdling happens naturally
as the milk sours, but it is
done intentionally as the
first step in making cheese.
57. 1. Renneting:
The enzyme rennin is
obtained from the
stomach of young
calves. Added to
milk in liquid or
tablet form, it causes
the milk protein
(casein) to
coagulate.
2. Cutting of Curd: The
coagulated milk is cut with
a knife into cubes.
3. Whey Drainage: The liquid whey is
drained off from the curds, which are then
crumbled into pieces.
4. The soft, moist curds are
ready for finishing steps.
58. Procedure Contd.
• Pressing : Assist final
whey expulsion, provide
texture and shape the
cheese
• Salting: (2.5%) Cause
more moisture to be
expelled and retard starter
activity
• Cutting & Packaging
• Aging: 3-4 months time
given for taste
development.
Brine Salting
60. Unlike the hard cheeses, soft cheeses are
“spreadable”. You usually can’t and don’t pick
them up with your fingers.
Some can be eaten with a spoon,
such as cottage cheese. Some are spread with a knife, as in this popular
combination… cream cheese on bagels.
61. Enzymes used in dairy
• Lactase
Lactase is a glycoside hydrolase enzyme that cuts
lactose into it's constituent sugars, galactose and
glucose.
• Lactase is used commercially to prepare lactose-free
products, particularly milk for lactose intolerant
individuals.
• It is also used in preparation of ice cream, to make a
creamier and sweeter-tasting product.
62. Catalase
• Catalase has found limited use in one
particular area of cheese production.
•
• It is used instead of pasteurization, when
making certain cheeses in order to preserve
natural milk.
• Catalases are beneficial to the end product
and flavor development of the cheese.
63. Lipases
• Lipases are used to break down milk fats
and give characteristic flavors to cheeses.
• The flavor comes from the free fatty acids
produced when milk fats are hydrolyzed.
• Animal lipases are obtained from calf and
lamb, while microbial lipase is derived by
fermentation with the fungal species.
64. • Although microbial lipases are available for
cheese-making, they are less specific in fats they
hydrolyze, while the animal enzymes are more
partial to short and medium-length fats.
• Hydrolysis of the shorter fats is preferred because
it results in the desirable taste of many cheeses.
• Hydrolysis of the longer chain fatty acids can
result in either soapiness, or no flavor at all.
