Influence of the Addition of Casein on the Properties of Nutritionally Improved Sweet Spreads

Cilj ovog diplomskog rada bio je ispitati utjecaj dodatka kazeina na svojstva krem-proizvoda proizvedenih bez šećera i s dodatkom kakaove ljuske. Kakaova ljuska za proizvodnju namaza odvojena je od kakaovog zrna nakon prženja, samljevena te je nakon mljevenja prosijavanjem izdvojena frakcija manja od 71 μm koja se koristila u proizvodnji namaza. Krem-proizvodi proizvedeni su u kugličnom mlinu pri temperaturi 50 °C, s 3 kg kuglica i pri brzini okretaja 60 o/min. Šećer koji se koristio u klasičnim recepturama zamijenjen je sa šest različitih omjera ksilitola i kakaove ljuske (50:50, 60:40, 70:30, 80:20, 90:10, 100:0). Svaki od tih namaza proizveden je bez i s dodatkom 1 i 2 % kazeina uz dodatak stevije. Nakon proizvodnje krem-proizvoda provedene su analize sljedećih parametara: boja, tekstura (čvrstoća i mazivost), koloidna stabilnost, specifični volumen, prividna gustoća i aktivitet vode. Ukupna promjena boje se povećavala kako se povećavao udio kakaove ljuske u krem-proizvodima. Koloidna stabilnost je također bila veća u uzorcima s većim udjelom ljuske, ali može se vidjeti i utjecaj kazeina na povećanje koloidne stabilnosti krem-proizvoda. Dodatkom kakaove ljuske u krem-proizvode došlo je do povećanja čvrstoće i otpora smicanju, a povećanjem udjela kazeina i proizvodima došlo je do smanjenja tih vrijednosti.The aim of this thesis was to examine the effect of casein addition on the properties of sweet spreads produced without sugar and with the addition of cocoa shell. The cocoa shell for the production of spreads was separated from the cocoa beans after roasting, ground and sieved to obtain a fraction of less than 71 μm, which was used in the production of spreads. Sweet spreads were produced in a ball mill at the temperature of 50 °C, with 3 kg of stainless steel balls and at a speed of 60 rpm. The sugar used in classic recipes has been replaced with six different ratios of xylitol and cocoa shell (50:50, 60:40, 70:30, 80:20, 90:10, 100:0). Each of these spreads was produced without and with the addition of 1 and 2% casein with addition of stevia. After the production of the sweet spreads, the following parameters were analysed: colour, texture (firmness and spreadability), colloidal stability, specific volume, apparent density and water activity. Total colour change increased as the proportion of cocoa shell in sweet spreads increased. Colloidal stability was also higher in samples with higher content of cocoa shell, but the effect of casein on increasing of colloidal stability of sweet spreads can also be seen. Addition of cocoa shell to sweet spreads increased firmness and shear strenght, and an increase of casein content in the products resulted in decrease of these values