Utjecaj dvaju suplemenata u hranidbi koza na tehnološka svojstva kozjeg mlijeka

Abstract

Goat’s daily diet is usually based on grazing, hay and/or feed supplements. Feed supplements are crucial in the diet of high productive goats to achieve their genetic potential and breeders must choose balanced feeding regime to produce large quantities of milk without affecting the technological quality of milk. In the present study, we evaluated the influence of two commercially available feed supplements on goat milk coagulation properties and rheological properties of yoghurts. Goats of the Slovenian Alpine breed (61) were fed with two feed supplements during the 3-year experiment. Feed supplement 1 (FS1) had higher proportions of barley and alfalfa, while feed supplement 2 (FS2) had added premix of minerals and vitamins and had higher proportions of wheat and sunflower meal. Con¬sequently, FS1 had more crude fibres, which is the most probable reason for approximately 15 % higher firmness, consistency and cohesiveness (P<0.05) of yoghurts in FS1 group, compared to the FS2 group. Moreover, the rennet coagulation time (r) was shorter (P<0.05) in the FS1 group, compared to the FS2 group. Curd firmness 30 min after enzyme addition (a30) was also higher in FS1 group although the results were not statistically significant. Taking together, our results indicate that goats fed with FS1 produced milk with better technological properties compared to those fed with FS2, despite the fact that there were no significant differences in chemical composition of milk from each group. We showed that careful selection of feed supplement’s constituents could improve technological properties of goat milk. However, further studies are needed to evaluate the mechanisms of the observed differences.

Changes in milk fat in milk under the influence of different temperatures

“…Hlađenje mlijeka utječe i na kristalizaciju mliječne masti, odnosno na veličinu i strukturu kristala. Što je brže hlađenje i niža temperatura, to se stvara više kristala (Kirin, 2001).…”

“…Niske temperature ubrzavaju izdvajanje mliječne masti u čemu glavnu ulogu imaju imunoglobulini (IgG1 i IgG2), te utječu na njenu kristalizaciju. Što je brže hlađenje i niža temperatura, to se stvara više kristala (Kirin, 2001). Kada se mliječna mast postepeno hladi na 5 °C, stupnjevito 0,1 °C/min, javlja se sferna (sferulitna) mikrostruktura.…”