Effect of the Amount of Balls on the Properties of Dark and Milk Chocolate Produced in a Ball Mill

Cilj ovog diplomskog rada bio je ispitati utjecaj količine kuglica na svojstva tamnih i mliječnih čokolada. Postupak proizvodnje čokolade bio je proveden u laboratorijskom kugličnom mlinu uz primjenu sljedećih uvjeta: temperatura kupelji 55 °C; vrijeme miješanja 3 h; brzina okretaja 60 o/min. Proizvedene su tamne čokolade s 2, 2,5 i 3 kg, te mliječne čokolade s 2, 3 i 4 kg kuglica. Masa čokolade bila je konstantna. Nakon miješanja u kugličnom mlinu čokolade su temperirane, upločene i nakon hlađenja dobivenim čokoladama određeni su sljedeći parametri: boja (nakon hlađenja, 24 h, 48 h i tjedan dana), tvrdoća, veličina čestica i viskoznost. Rezultati su pokazali kako je ukupna promjena boje tjedan dana nakon izrade uzoraka veća kod tamnih nego kod mliječnih čokolada. Tamna čokolada miješana s 2 kg kuglica je imala najveću ukupnu promjenu boje. Tvrdoća se kod tamnih čokolada smanjila smanjenjem količine kuglica, a kod mliječnih čokolada tvrdoća se povećala smanjenjem količine kuglica. Tamna čokolada miješana s 3 kg kuglica imala je najveću tvrdoću. Ista čokolada imala je najveću volumnu distribuciju čestica, tj. najveći udio čestica jednake veličine. Plastična viskoznost tamnih i mliječnih čokolada povećala se povećanjem, a granica tečenja smanjenjem količine kuglica.The aim of this study was to investigate the effect of the amount of the balls on the properties of dark and milk chocolates. The production of chocolate was carried out in a laboratory ball mill under the following conditions: the bath temperature 55 °C; mixing time 3 hours; with the speed of 60 rpm. Dark chocolates with 2, 2.5, and 3 kilograms of balls, and milk chocolates with 2, 3, and 4 kilograms of balls were produced, with the mass of chocolate being constant. After mixing in the ball mill chocolates were tempered, moulded and after the cooling, the following parameters were determined: colour (immediately after cooling, after 24 hours, 48 hours and one week), hardness, particle size and viscosity. According to the results, the total colour change one week after sample production was greater in dark than milk chocolates. Dark chocolate mixed with 2 kg of balls was the chocolate with the greater total colour change. Hardness of dark chocolates decreased by decreasing the amount of balls, and in milk chocolates the hardness increased by decreasing the amount of balls. Dark chocolate mixed with 3 kg balls had the highest hardness. The same chocolate had the highest volume distribution of particles, i.e. the largest proportion of particles of equal size. The plastic viscosity of dark and milk chocolates increased with increasing, and the yield stress with decreasing amount of balls