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

Index

1. Incidence of lactose intolerance 2. Cause of lactose intolerance 3. Symptoms of lactose intolerance 4. Help for lactose intolerant persons 5. Lactose-free milk and milk products 6. Large-scale production of lactose-free milk 7. Lab-scale production of lactose-free milk 8. References 20 October 2009 Klasse 2BKC2

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 Austrians Slovenes Spaniards North Italians Sicilians 10-20% 20-25% 24% 30% 52% 71% Worldwide more than 80% of adults cannot digest the milk sugar lactose: This condition is called

lactose intolerance

.

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Occurence of lactose-intolerance

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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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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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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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Symptoms of lactose intolerance:

bloated feeling, stomach cramps diarrhoea flatulence 20 October 2009 Klasse 2BKC2 nausea, vomitting

„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 20 October 2009 Klasse 2BKC2

Market for lactose-free products on the rise

Increasing demand from developing countries Increasing range of healthy and tasty lactose-free milk products yoghourts cheese pudding ice cream Most of these are produced by OMIRA 20 October 2009 Klasse 2BKC2 cream in coffee

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 20 October 2009 Klasse 2BKC2

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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• The lactase-beads are added to conventional cow‘s milk, whey, or lactose-solution

+

• Cleavage of lactose into galactose and glucose is detected by glucose test strips

Minus L

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Results

Lactose cleavage by lactase as a function of time judged by Glucose test sticks Time elapsed after lactase addition Milk (4.8% lactose) Whey 4.8% Lactose-solution 4.8% Saccharose-solution 0 min 0 5 min 0,05 0 0.1

0 0 0.1

0 Glucose content (%) 10 min 20 min 40 min 0.2

0.4

0.7

0.5

0.7

1.0

0.2

0 0.5

0 0.6

0 80 min 1,0 2.0

1.5

0 24 h 5,0 4.0

5.0

0 20 October 2009 Klasse 2BKC2

Results

Cleavage of lactose by lactase was also confirmed by HPLC:

Lactose Lactose + Lactase 20 October 2009 Klasse 2BKC2

References: http://www.familiesonline.co.uk/article/articleview/1399/1/22/ http://www.spiegel.de/img/0,1020,122495,00.jpg

http://valiblog.files.wordpress.com/2008/08/babyflasche.jpg46

http://en.wikipedia.org/wiki/File:LacIntol-World2.png

http://www.foodreactions.org/colic/ http://www.meuterei2008.de/fileadmin/templates/_gfx/sponsor_minusl.jpg

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