Prethodno priopćenje
Rheological changes during fermentation of goats and cow's milk using Lactobacillus acidophilus
Predrag Novaković
Jasna Kordić
Vedran Slačanac
; Prehrambeno-tehnološki fakultet, F. Kuhača 20, 31000 Osijek
Tihomir Moslavac
Sažetak
The changes of rheological properties during goat's and cow's milk fermentation using Lactobacillus acidophilus were observed in this paper. Rheological properties of curd are one of the basic parameters of fermented milk products quality. Milk curdling occurs as a consequence of the pH-value lowering during milk fermentation and it is the result of caseinat complex demineralisation and water molecules discharge from the lactic caseinate owing to the increase of H+-ions concentration. The differences in the curd structure between goat's and the cow's acidophilus milk were attended in the aim to compare those differences with fermentation velocities. Both of them, goat's and cow's acidophilus milk, are nonnewton fluids progressively obtaining characteristic properties of pseudoplastic (ticsotropic) type of fluids during fermentation. Goat's and cow's milk curdling starts in the third hour of fermentation. It was shown that extensive changes of goat's milk rheological properties were starting with the significantly lower pH-value than cow's milk and the increase of apparent viscosity is more steady in goat's acidophilus milk and it is proportional to pH-value fall during fermentation. At the end of the fermentation goat's acidophilus milk has lower apparent viscosity than cow's acidophilus milk at 22 °C. During three storage days at 4 °C Theological properties of goat's acidophilus milk were considerably improved (goats acidophilus milk became more consistent). During storage the consistency change of cow's acidophilus milk is minor.
Ključne riječi
goat's and cow's milk; acidophilus; fermentation; reological changes
Hrčak ID:
94898
URI
Datum izdavanja:
12.5.1997.
Posjeta: 1.277 *