Effect of heating and cooling on phase transitions of chocolate

V diplomskem delu smo z metodo DSC ugotavljali vpliv različnih časovno temperaturnih režimov na fazne in strukturne prehode različnih čokolad. Ugotovili smo, da razlike v sestavi čokolad vplivajo na fazne prehode. Pri testiranju vpliva temperature zadržanja med hlajenjem (30 min) smo ugotovili, da ima 30-minutna prekinitev hlajenja pri temperaturah 15 in 17,5 °C največji vpliv na temperaturo faznega prehoda čokolade med gretjem. Podvojen čas zadržanja pri 15 °C je še dodatno vplival na potek faznega prehoda vzorca čokolade med gretjem. Med različnimi hitrostmi hlajenja se je za najbolj primerno izkazala najnižja, in sicer 1 °C/min. Te ugotovitve bi, ob nadaljnjih in podrobnejših raziskavah, lahko bile uporabne v oskrbovalni verigi, kjer je možnost nenadnih sprememb temperature velika. Za zagotavljanje ustreznih pogojev je potrebno nameniti pozornost razlikam v faznih in strukturnih lastnostih čokolad. Ob vse večji globalizaciji in daljših oskrbovalnih verigah, je pomen dejavnikov v naši raziskavi lahko pomemben za zagotavljanje optimalnih lastnosti čokolade med izdelavo ter za ohranjanje prvotnih lastnosti.In the thesis we tested the effect of time-temperature regimes on the thermal stability of different chocolates, using the DSC method. We established, that the differences in chocolate composition affect their phase transitions. We tested the effect of holding temperatures during cooling (30 min) and established, that temperatures 15 and 17,5 °C have the biggest impact on the melting temperature. When we doubled the holding time at 15 °C, the phase transition temperature of the chocolate sample increased. Among different cooling rates, the lowest (1 °C/min) was found to be the most appropriate. These conclusions could be useful in the food supply chain where sudden temperature changes are common, if more thorough analysis would be done. In order to provide the appropriate conditions, the differences in phase and structural properties must be taken into consideration. Since globalization is on the rise and food supply chains are becoming longer, the subject of our research is important in guaranteeing the optimal properties of chocolate in the manufacturing process and later in preserving its original properties