Estudo reológico de formulações para sorvetes produzidos com diferentes estabilizantes

Abstract

ABSTRACT MILLIATTI, M. C. Rheological study of ice cream formulations produced with different food stabilizers. 2013. 107 pp. Dissertacao (Mestrado). – Faculdade de Ciencias Farmaceuticas, Universidade de Sao Paulo, Sao Paulo, 1995. Six ice cream formulations were produced with different combinations of food stabilizers: Guar gum, Locust bean gum (LBG) and Gelatin. They were evaluated during different production steps: aging time, after whipping and freezing and after complete freezing. Oscillatory trials during aging time showed that ice cream mixes produced with Gelatin + Guar gum and Gelatin + LBG present strong relationship between aging time and rheologic properties, which was not observed in the formulations containing each of these stabilizers alone, nor in the formulations containing the combination of Guar gum + LBG. These results show the strong interaction between gelatin and galactomannans and, also, aging time is critical to create a continuous and stable network for this combination. After aging time (24 hours), the ice creams were produced and evaluated as soon as they were removed from the ice cream producer machine. The tests conducted this time were aeration capacity (overrun) and maximum force required for extrusion. The combination of two stabilizers produced ice creams with lower overrun, which can be explained by the higher viscosity of these systems, making them difficult to incorporate air. It was perceived a trend of greater force required for extrusion for the ice creams with greater incorporation of air. Both the size of the ice crystals as the volume of the frozen phase may have contributed to increase the hardness of these ice creams. After complete freezing, the ice creams were evaluated by a frequency sweep test at -8oC. Ice creams produced with Gelatin and Gelatin + LBG presented higher G’ values, which is an indicative of larger ice crystals and also greater rigidity. Through the thermo-oscillatory rheology, between -10oC and +5oC, it was possible to evaluate the changes in the structures of the products and their relation to sensory properties. Between -10°C and -1°C it was observed, for all formulations, a large decline in the elastic and viscous modules (G' and G, respectively) due to the lost of the cooperative interactions among the ice crystals, associated with their melting. After melting, the parameter G”, associated with the creaminess of the ice cream was very similar for the six formulations evaluated.MILLIATTI, M. C. Rheological study of ice cream formulations produced with different food stabilizers. 2013. 107 pp. Dissertacao (Mestrado). – Faculdade de Ciencias Farmaceuticas, Universidade de Sao Paulo, Sao Paulo, 1995. Six ice cream formulations were produced with different combinations of food stabilizers: Guar gum, Locust bean gum (LBG) and Gelatin. They were evaluated during different production steps: aging time, after whipping and freezing and after complete freezing. Oscillatory trials during aging time showed that ice cream mixes produced with Gelatin + Guar gum and Gelatin + LBG present strong relationship between aging time and rheologic properties, which was not observed in the formulations containing each of these stabilizers alone, nor in the formulations containing the combination of Guar gum + LBG. These results show the strong interaction between gelatin and galactomannans and, also, aging time is critical to create a continuous and stable network for this combination. After aging time (24 hours), the ice creams were produced and evaluated as soon as they were removed from the ice cream producer machine. The tests conducted this time were aeration capacity (overrun) and maximum force required for extrusion. The combination of two stabilizers produced ice creams with lower overrun, which can be explained by the higher viscosity of these systems, making them difficult to incorporate air. It was perceived a trend of greater force required for extrusion for the ice creams with greater incorporation of air. Both the size of the ice crystals as the volume of the frozen phase may have contributed to increase the hardness of these ice creams. After complete freezing, the ice creams were evaluated by a frequency sweep test at -8oC. Ice creams produced with Gelatin and Gelatin + LBG presented higher G’ values, which is an indicative of larger ice crystals and also greater rigidity. Through the thermo-oscillatory rheology, between -10oC and +5oC, it was possible to evaluate the changes in the structures of the products and their relation to sensory properties. Between -10°C and -1°C it was observed, for all formulations, a large decline in the elastic and viscous modules (G' and G, respectively) due to the lost of the cooperative interactions among the ice crystals, associated with their melting. After melting, the parameter G”, associated with the creaminess of the ice cream was very similar for the six formulations evaluated.