Tag Archives: particle size

753-758 H. Mootse, A. Pisponen, S. Pajumägi, A. Polikarpus, V.Tatar, A. Sats andV. Poikalainen
Investigation of Casein Micelle Particle Size Distribution in Raw Milk of Estonian Holstein Dairy Cows
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Investigation of Casein Micelle Particle Size Distribution in Raw Milk of Estonian Holstein Dairy Cows

H. Mootse*, A. Pisponen, S. Pajumägi, A. Polikarpus, V.Tatar, A. Sats andV. Poikalainen

Institute of Veterinary Medicine and Animal Sciences, Estonian University of Life Sciences, Kreutzwaldi 56/5, EE51014 Tartu, Estonia; *Correspondence: hannes.mootse@emu.ee

Abstract:

The particle size of milk influences its microstructure and defines many properties of dairy products such as colloidal stability, texture etc. Differences in particle size can significantly affect milk processing especially when membrane technology is used. Aim of this investigation was to estimate casein micelle size in the raw milk of Estonian Holstein dairy cows and its variability concerning individual animals. Milk samples were collected during 12 months with the interval of 25–35 days. DLS analyses were performed using a Malvern Zetasizer Nano ZS (Malvern Instruments Ltd, Malvern, UK). Average mode of casein micelle particles size in raw milk of 44 cows was 171.13 nm with the variation range 70.1 nm and its distribution resembled a normal one. Casein micelles size mode of individual cows varied in a wide range from 148.5 (with variation range 18.2) to 194.1 (with variation range 27.6) nm which may be caused by differences in physiological and health status, stage of lactation and other factors concerning milk production.

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155-164 A. Menind and A. Normak
Study on Grinding Biomass as Pre-treatment for Biogasification
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Study on Grinding Biomass as Pre-treatment for Biogasification

A. Menind¹ and A. Normak²

¹ Institute of Technology, Estonian University of Life Sciences,
56 Kreutzwaldi Str., EE51014 Tartu, Estonia; e-mail: andres.menind@emu.ee
² Institute of Agricultural and Environmental Sciences,
Estonian University of Life Sciences, 5 Kreutzwaldi Str., EE51014 Tartu, Estonia

Abstract:

Six different samples were collected from local farms in Tartu County in Estonia. Based on preliminary results of fibre tests, four samples with different lignin content were chosen for grinding and biogasification experiments. Next, knife mill and laboratory scissors were used for particle size reduction. The knife mill was used with bottom screen sizes 0.5 mm, 4 mm and 10 mm. With scissors the hay was cut into 2…3 cm pieces. Sieve shaker and Easy Sieve software were used for particle distribution analysis. Biogas potential was determined for different hay samples. Cumulative biogas production was calculated by pressure increase in gas phase of bottles according to ideal gas law. We are going to show in what way the cutting impacts biogas yield. Negative correlation between biogas yield, particle size and lignin content is significant for most hay samples analysed.

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