1. Lactose intolerance and the production of lactose-free milk
Ein Beitrag im Rahmen des Projekts
Lactose intolerance and the production of lactose-free milk
Durchgeführt und präsentiert von den Chemisch-Technischen Assistenten an der

2. Index Incidence of lactose intolerance Cause of lactose intolerance
Symptoms of lactose intolerance
Help for lactose intolerant persons
Lactose-free milk and milk products
Large-scale production of lactose-free milk
Lab-scale production of lactose-free milk
References
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3. Lactose intolerance
Many people have problems with the digestion of milk and milk products:
Drinking a glass of milk will have unpleasant side effects for them.
Germans
10-20%
Austrians
20-25%
Slovenes
24%
Spaniards
30%
North Italians
52%
Sicilians
71%
Worldwide more than 80% of adults cannot digest the milk sugar lactose:
This condition is called lactose intolerance.
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4. Occurence of lactose-intolerance
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5. Babies are lactose tolerant
Yet, lactose-intolerant adults began their lives drinking milk from a bottle or breast and digesting it completely.
Babies produce the enzyme lactase in their small intestine. This enzyme breaks down lactose.
Therefore:
Babies are lactose tolerant
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6. Lactase Lactase acts as a pair of molecular scissors:
It snips the disaccaride lactose in two simple sugars, galactose and glucose:
Lactose tolerant individuals produce lactase for life. For them, a bar of milk
chocolate is a pleasant experience.
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7. 80 % of adults worldwide do not produce lactase
For them, the pleasure of eating chocolate, a scoop of dairy ice cream or some cheese has unpleasant consequences.
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8. Symptoms of lactose intolerance:
bloated feeling,
stomach cramps
diarrhoea
nausea, vomitting
flatulence
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9. „Help“ for people with lactose intolerance Undigested lactose in the small and large intestine is the common cause for the nasty discomforts suffered by lactose intolerant persons.
lactase–tablets
to be taken with lactose containing meals
lactose-free milk products
produced by breaking down lactose using lactase
sour milk products
lactose converted to lactic acid using microbes
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10. Market for lactose-free products on the rise
Increasing demand from developing countries
Increasing range of healthy and tasty lactose-free milk products
ice cream
yoghourts
cheese
pudding
cream in coffee
Most of these are produced by OMIRA
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11. Large-scale industrial production of lactose-free milk
Lactose is split into glucose and galactose by adding the enzyme lactase to milk
Production of lactase enzyme is expensive:
It is manufactured by microorganisms and has to be purified from these.
Key to economic production of lactose-free milk: Immobilization of lactase
Lactase is included within a matrix; milk is continuously pumped through it
No residual lactase in milk
Enzyme can be re-used frequently
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12. Lab-scale in vitro production of lactose-free milk: Immobilization of Lactase by Na-alginate
Enzyme solution is prepared
and mixed with the Na-alginate solution
Mixture is dropped into a solution of calcium chloride
to harden the alginate beads
The lactase-beads are collected.
They can be re-used for about a month.
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13. The lactase-beads are added to conventional cow‘s milk, whey, or lactose-solution
MinusL +
Cleavage of lactose into galactose and glucose is detected by glucose test strips
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14. Results Lactose cleavage by lactase as a function of time
judged by Glucose test sticks
Glucose content (%)
Time elapsed after lactase addition
0 min
5 min
10 min
20 min
40 min
80 min
24 h
Milk (4.8% lactose)
0,05
0.2
0.4
0.7
1,0
5,0
Whey
0.1
0.5
1.0
2.0
4.0
4.8% Lactose-solution
0.6
1.5
5.0
4.8% Saccharose-solution
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15. Results Cleavage of lactose by lactase was also confirmed by HPLC:
Lactose + Lactase
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16. References:
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