Original scientific paper
Influence of milk heating intensity on consistency of yoghurt
Ivica Denona
; Dukat - Mljekara Zagreb d.d., Marijana Čavića 9, 10000 Zagreb
Abstract
The study refers to the influence of heat treatment intensity of milk used for making yoghurt on its consistency. Working hypothesis implied that milk heating intensity had positive influence on yoghurts consistency and quality due to coagulation of whey proteins. The same raw, bulk milk was used in experiments carried out under industrial conditions. For production of ten groups of yoghurt samples 100 000 litres of raw bulk milk was used. Each sample consisting of 10 000 litres of homogenized (150 bar/65 °C), pasteurized (85 °C/20 seconds) and standardized milk to a finished milk fat content of 2.8 % and added 1 % of nonfat milk powder, was divided in four parts, each part was heated to 85 °C, 90 °C, 95 °C and 100 °C during 5 minutes. Milk was cooled to 45 °C, inoculated with 3% of yoghurt culture, and incubated in incubating room (45 °C). Viscosity of yoghurt samples was determined the first, the third and the seventh day after production and storage in cold room under the same conditions. As a rule, viscosity of yoghurt increased from, the first to the seventh day after making. This increase followed the intensity of milk heating. Differences in viscosity of yoghurt were usually significant. Results of investigation and statistical data confirmed the working hypothesis that intensity of milk heating influence consistency and quality of yoghurt.
Keywords
intensity of heating milk for yoghurt making; consistency and quality of yoghurt
Hrčak ID:
95438
URI
Publication date:
20.1.1992.
Visits: 1.417 *