Original scientific paper
Lactulose in milk
Nada Vahčić
; Prehrambeno-biotehnološki fakultet Sveučišta u Zagrebu, Pierottijeva 6, 10000 Zagreb
Mirjana Hruškar
Ksenija Marković
Abstract
Lactulose is ketose derived from lactose during heating and storage of milk and dairy products. This carbohydrate is a slightly sweeter and more soluble than a lactose. The presence of lactulose in an artificial infants nutrition iniciate the development Bifidobacterium bifidum microorganism in the intestinal flora. The aim of this work was twofolded. As it is well known that a development of lactulose occurs during a thermal processes, in this work the influence of a different thermal regimes on lactulose content was analysed. For this purpose, a lactulose content in raw milk samples, milk samples obtained by three different pasteurization regimes as well as after sterilization process on three different sterilizer types, was established. Secondly, a lactulose content in sterilized milk samples from different dairy industries supplied from Zagreb market was established. Lactulose content was determined by enzimatic method. Thermal processing increased lactulose content from an average 0,91 mg/100 g in raw milk samples up to the level between 3.972 to 4.987 mg/100 g for pasteurized milk samples. The values from 27.069 to 29.225 mg/100 g were established in sterilized milk samples. Higher lactulose content arose in milk samples treated at higher pasteurization temperature. The type of sterilizer used had no influence on lactulose content, although the higher values were obtained in tubular sterilizer followed by infusion and plate sterilizers. Lactulose content ranged from 0.984 to 53.578 mg/100 g in sterilized milk samples supplied from market.
Keywords
lactulose; milk; thermal processin
Hrčak ID:
93077
URI
Publication date:
15.3.2000.
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