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Effect of breed and storage on goat milk quality
Hončíková, Barbora ; Potůčková, Miroslava (advisor) ; Michaela, Michaela (referee)
The aim of this diploma thesis was in theoretical part to summarise current knowledge about composition, physico-chemical, technological and sensory properties and cryostability of goat milk including a comparison of this characteristics for dairy goat breeds which are used for industrial and farm dairy production.
Goat milk has high nutritional and therapeutic value. It is suitable for dairy industry processing as well as cow milk. In the Czech Republic, where is traditional cow milk consumption, the interest of consumers in goat milk products increased recently. The main Czech dairy goat breeds are White and Brown-Shorthaired Goats.
In the practical part of diploma thesis were compared the 2 main Czech dairy goat breeds, White and Brown-Shorthaired Goats, with a rare breed Girgentana Goat. Cryostability of goat milk was observed for 16 weeks (0, 1, 2, 3, 4, 8, 12 and 16 weeks) for White and Brown-Shorthaired breed. Characterized parameters were main components (total solid, non-fat solid, fat, lactose, crude proteins and casein), minor components (citric acid, urea, free fatty acids and fatty acid profile), physico-chemical properties (density, freezing point and titratable acidity), technological properties (cheeseability, fermentability and thermostability) and for fresh milk also sensory identity and acceptability.
It was found that milk from Girgentana Goats contains the significantly (p < 0.05) highest amount of total solid, fat and lactose. The highest amount of crude proteins (p < 0.05) was on the contrary observed in Brown-Shorthaired Goat milk H1. These two samples had also the best cheeseability (p < 0.05) but the worst sensory acceptability because of their strong goat flavour and taste. During the storage test of White and Brown-Shorthaired Goat milk samples was found significantly (p < 0.05) negative influence of storage in frozen state only on cheeseability. This could be explain by the negative changes in the conformatin of proteins, especially casein fraction.
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