Lehmapiima rasvakuulikeste suurusjaotust mõjutavad tegurid
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Kuupäev
2016
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Autorid
Ajakirja pealkiri
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Abstrakt
Piimas on rasv varieeruva suurusega rasvakuulikestena. Rasvakuulikeste suurust
mõjutavad mitmed tegurid, näiteks laktatsiooni järk, aastaaeg ja lehma vanus.
Rasvakuulikeste suurus on oluline näitaja piimatoodete valmistamisel, sest mõjutab
nende omadusi.
Magistritöö eesmärgiks oli uurida lehmapiima rasvakuulikeste suurusjaotust ning
erinevate tegurite mõju suurusjaotusele.
Piimaproove koguti 2015. a. märtsist kuni 2016 a. veebruarini Eerika Farm osaühingust.
Rasvakuulikeste suurusjaotuse uurimine tehti Eesti Maaülikooli Veterinaarmeditsiini ja
Loomakasvatuse Instituudi Toiduteaduse ja toiduainete tehnoloogia osakonna
mikromeiereis. Rasvakuulikeste suuruse määramiseks kasutati Gorjajevi mahuühik
kambrit, mikroskoopi ja programmi NIS-Elements. Andmed piima rasvasisalduse,
valgusisalduse ja piima koguste kohta saadi Eesti Põllumajandusloomade
Jõudluskontrolli keskusest. Andmetöötluseks kasutati Microsoft Excelit ja programmi Rprojekt.
Tulemustest selgus, et keskmine rasvakuulikeste diameeter üle kõigi proovide oli 3,2 µm.
Uuringust ilmnes, et laktatsiooni esimesel kahel kuul on rasvakuulikesed suuremad
võrreldes hilisemate laktatsiooni järkudega (r = -0,89; p˂ 0,001). Kevadel on
rasvakuulikeste keskmine läbimõõt suurem võrreldes teiste aastaaegadega (r = -0,76;
p˂ 0,05). Mida vanem on lehm, seda väiksemad on rasvakuulikesed (r = -0,97; p˂ 0,05).
In the milk fat is separated in small globules which vary in very wide scale. The milk fat globule size distribution is affected by different factors, like lactation stage, season and cow´s age. Milk fat globule size affect the parameters of some milk products, so it is important to know the size distribution. Aim of this thesis was to study bovine milk fat globule size distribution and how different factors influence the distribution. Milk samples were collected from March 2015 to February 2016. The experiments were conducted in micro-dairy of the Department of Food Science and Food Technology, Institute of Veterinary Medicine and Animal Sciences of the Estonian University of Life Sciences. Chamber of Gorjajev and program NIS-Elements was used to examine fat globule size distribution. Data about milk fat, milk protein and milk yield of the cows were collected from the Estonian Livestock Performance Recording Ltd. Microsoft Excel and R-program was used for statistical analysis. The results showed that average dimeter of milk fat globules was 3,2 µm. During first two months of lactation the diameter of milk fat globules is larger in comparison with following months of lactation ( r = -0,89; p˂ 0,001). Average diameter of milk fat globule was bigger in spring compared to other seasons of a year (r = -0,76; p˂ 0,05). Cow’s age has decreasing effect on the average diameter of milk fat globules ( r= -0,97; p˂ 0,05).
In the milk fat is separated in small globules which vary in very wide scale. The milk fat globule size distribution is affected by different factors, like lactation stage, season and cow´s age. Milk fat globule size affect the parameters of some milk products, so it is important to know the size distribution. Aim of this thesis was to study bovine milk fat globule size distribution and how different factors influence the distribution. Milk samples were collected from March 2015 to February 2016. The experiments were conducted in micro-dairy of the Department of Food Science and Food Technology, Institute of Veterinary Medicine and Animal Sciences of the Estonian University of Life Sciences. Chamber of Gorjajev and program NIS-Elements was used to examine fat globule size distribution. Data about milk fat, milk protein and milk yield of the cows were collected from the Estonian Livestock Performance Recording Ltd. Microsoft Excel and R-program was used for statistical analysis. The results showed that average dimeter of milk fat globules was 3,2 µm. During first two months of lactation the diameter of milk fat globules is larger in comparison with following months of lactation ( r = -0,89; p˂ 0,001). Average diameter of milk fat globule was bigger in spring compared to other seasons of a year (r = -0,76; p˂ 0,05). Cow’s age has decreasing effect on the average diameter of milk fat globules ( r= -0,97; p˂ 0,05).
Kirjeldus
Märksõnad
piim, piimarasvad, rasvasisaldus, magistritööd