The effect of lactase and formula reconstitution on milk osmolality.

Hdl Handle:
http://hdl.handle.net/10147/209128
Title:
The effect of lactase and formula reconstitution on milk osmolality.
Authors:
Malone, A J; Kearney, P J; Duggan, P F
Affiliation:
Department of Paediatrics and Child Health, Cork University Hospital, Ireland.
Citation:
Int J Food Sci Nutr. 1999 Sep;50(5):311-7.
Journal:
International journal of food sciences and nutrition
Issue Date:
3-Feb-2012
URI:
http://hdl.handle.net/10147/209128
PubMed ID:
10719561
Abstract:
These experiments investigated the reaction rate of lactase on milk lactose by measuring milk osmolality; and explored the effect of formula reconstitution on milk osmolality. The investigations measured milk osmolality with the Fiske Os, freezing-point osmometer. Lactase (Lactaid) incubated with pure lactose solutions established the validity of the method. Lactase was incubated for 24 hours with four reconstituted milk formulas (Milumil, and Cow and Gate Nutrilon Plus, Farley's First Milk, SMA Gold). Milk osmolality increased most rapidly in the first 4 hours after the addition of lactase. The lactase enzyme completed over 90% of the reaction within 12 hours. The milk osmolalities ranged from 487 to 591 mosm/kg after 24 hours with 2-4 drops of lactase in 240 ml of formula. A clinical guideline osmolality of 400 mosm/kg was reached in 240 ml of formula at 1 to 12 hours depending on the dose of lactase. High milk osmolalities due to prolonged enzyme incubation, or high lactase doses could be reduced to around 400 mosm/kg by dilution of 240 ml of formula with an extra 60 ml of water. The initial osmolality of formula after reconstitution by paediatric nurses varied widely and usually exceeded the manufacturer's quoted osmolality. This initial osmolality was a further influence on the final osmolality reached after the addition of lactase. It is concluded that the recommended incubation time for Lactaid of 24 hours is unnecessary as lactase exerts the majority of its effect in less than 12 hours. Adjustment of Lactaid dose and incubation times will maintain milk formula osmolality within standard guidelines. Dilution with extra water will correct inadvertent high enzyme doses and prolonged incubation times. The normal method of reconstituting milk formulas from powder may be unreliable as the manufacturer's quoted osmolality was not reproduced when milk formulas were reconstituted by paediatric nurses.
Language:
eng
MeSH:
Animals; Humans; Infant; Infant Food/*analysis; Lactase; Lactose/metabolism; Milk/*chemistry/drug effects; Osmolar Concentration; Time Factors; beta-Galactosidase/*physiology
ISSN:
0963-7486 (Print); 0963-7486 (Linking)

Full metadata record

DC FieldValue Language
dc.contributor.authorMalone, A Jen_GB
dc.contributor.authorKearney, P Jen_GB
dc.contributor.authorDuggan, P Fen_GB
dc.date.accessioned2012-02-03T15:13:00Z-
dc.date.available2012-02-03T15:13:00Z-
dc.date.issued2012-02-03T15:13:00Z-
dc.identifier.citationInt J Food Sci Nutr. 1999 Sep;50(5):311-7.en_GB
dc.identifier.issn0963-7486 (Print)en_GB
dc.identifier.issn0963-7486 (Linking)en_GB
dc.identifier.pmid10719561en_GB
dc.identifier.urihttp://hdl.handle.net/10147/209128-
dc.description.abstractThese experiments investigated the reaction rate of lactase on milk lactose by measuring milk osmolality; and explored the effect of formula reconstitution on milk osmolality. The investigations measured milk osmolality with the Fiske Os, freezing-point osmometer. Lactase (Lactaid) incubated with pure lactose solutions established the validity of the method. Lactase was incubated for 24 hours with four reconstituted milk formulas (Milumil, and Cow and Gate Nutrilon Plus, Farley's First Milk, SMA Gold). Milk osmolality increased most rapidly in the first 4 hours after the addition of lactase. The lactase enzyme completed over 90% of the reaction within 12 hours. The milk osmolalities ranged from 487 to 591 mosm/kg after 24 hours with 2-4 drops of lactase in 240 ml of formula. A clinical guideline osmolality of 400 mosm/kg was reached in 240 ml of formula at 1 to 12 hours depending on the dose of lactase. High milk osmolalities due to prolonged enzyme incubation, or high lactase doses could be reduced to around 400 mosm/kg by dilution of 240 ml of formula with an extra 60 ml of water. The initial osmolality of formula after reconstitution by paediatric nurses varied widely and usually exceeded the manufacturer's quoted osmolality. This initial osmolality was a further influence on the final osmolality reached after the addition of lactase. It is concluded that the recommended incubation time for Lactaid of 24 hours is unnecessary as lactase exerts the majority of its effect in less than 12 hours. Adjustment of Lactaid dose and incubation times will maintain milk formula osmolality within standard guidelines. Dilution with extra water will correct inadvertent high enzyme doses and prolonged incubation times. The normal method of reconstituting milk formulas from powder may be unreliable as the manufacturer's quoted osmolality was not reproduced when milk formulas were reconstituted by paediatric nurses.en_GB
dc.language.isoengen_GB
dc.subject.meshAnimalsen_GB
dc.subject.meshHumansen_GB
dc.subject.meshInfanten_GB
dc.subject.meshInfant Food/*analysisen_GB
dc.subject.meshLactaseen_GB
dc.subject.meshLactose/metabolismen_GB
dc.subject.meshMilk/*chemistry/drug effectsen_GB
dc.subject.meshOsmolar Concentrationen_GB
dc.subject.meshTime Factorsen_GB
dc.subject.meshbeta-Galactosidase/*physiologyen_GB
dc.titleThe effect of lactase and formula reconstitution on milk osmolality.en_GB
dc.contributor.departmentDepartment of Paediatrics and Child Health, Cork University Hospital, Ireland.en_GB
dc.identifier.journalInternational journal of food sciences and nutritionen_GB
dc.description.provinceMunster-

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