Upload
mia-crawford
View
226
Download
2
Embed Size (px)
Citation preview
Lactose intoleranceand the production of lactose-free milk
Ein Beitrag im Rahmen des Projekts
Durchgeführt und präsentiert von den Chemisch-Technischen Assistenten an der
20 October 2009 Klasse 2BKC2
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 intoleranceMany 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.
20 October 2009 Klasse 2BKC2
Occurence of lactose-intolerance
20 October 2009 Klasse 2BKC2
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
20 October 2009 Klasse 2BKC2
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.
20 October 2009 Klasse 2BKC2
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.
20 October 2009 Klasse 2BKC2
Symptoms oflactose intolerance:
bloated feeling,stomach cramps diarrhoea
flatulencenausea, vomitting
20 October 2009 Klasse 2BKC2
„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 riseIncreasing demand from developing countries
Increasing range of healthy and tasty lactose-free milk products
yoghourts
ice cream
cream in coffee
pudding
cheese
Most of these are produced by OMIRA
20 October 2009 Klasse 2BKC2
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 lactaseLactase 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.
20 October 2009 Klasse 2BKC2
• 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
MinusL
+
20 October 2009 Klasse 2BKC2
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 0,05 0.2 0.4 0.7 1,0 5,0
Whey 0 0.1 0.5 0.7 1.0 2.0 4.0
4.8% Lactose-solution 0 0.1 0.2 0.5 0.6 1.5 5.0
4.8% Saccharose-solution 0 0 0 0 0 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.jpghttp://valiblog.files.wordpress.com/2008/08/babyflasche.jpg46http://en.wikipedia.org/wiki/File:LacIntol-World2.pnghttp://www.foodreactions.org/colic/http://www.meuterei2008.de/fileadmin/templates/_gfx/sponsor_minusl.jpg