The fermentation of goat's milk with prebiotic supplement

In this work the fermentation of cow’ s and goat’ s milk with and without inulin addition is investigated. Each type of milk was divided in two parts and in one part 1, 5% inulin was added. Milk was fermented with 2% DVS culture Lactobacillus acidophilus La5 (Christian Hansen’ s, Denmark). Fermented samples were stored in refrigerator (5„aC) for 28 days. On 1st, 7th, 14th, 21st and 28th day pH was measured and microbiological and sensory analysis were performed. The fermentation of goat’ s milk was shorter (825) than cow‘ s milk fermentation (1030). This is probably because more content of proteins in cow’ s milk. In samples from cow’ s milk pH values decreased slowly, but at the end of fermentation in this samples was significantly more viable count of La5 (log N=9, 07) than in goat’ s milks (log N=8, 74). During 4 weeks of storage pH value was unchanged in all samples, while the La5 survival in goats milk was significantly weaker (ƒ´log N=2) than in cow’ s milk. Despite that, after 4 weeks of storage viable cell count in all samples was over 106 which is essential for probiotic drinks production. Sensory evaluation of produced drinks was performed once a week during one-month period. The taste of products fermented with La5 culture was very poor, insipid, with no acid. Samples with inulin possessed better consistency and higher viscosity. The inulin addition showed no influence on cow’ s milk taste, while the specific flavour of goat was less expressed. Sineresis in goat’ s fermented milk samples with inulin was negligible compared with samples without inulin. This observation has shown great effect of inulin on stability of coagulum. The same observation was noticed at 28th day of storage. Casein (ƒŃ, ƒŇ and ƒŰ), lactoglobuline and lactalbumine ratio in row milk and in fermented samples was investigated too. The results showed that goat’ s milk had significantly less ƒŃ-casein and more ƒŇ-casein than cow’ s milk. No difference between samples with and without inulin is detected. However it was showed that in samples with La5 culture a quantity of ƒŇ-casein was slightly lower.