| Summary: | As the continuous phase in which other ingredients are distributed, filling fat plays an important role in determining the sensory attributes such as hardness, flavour release and texture of filled confectionery products. For this reason, knowledge on the rheological properties and crystallisation behaviour of filling fat is crucial. Two filling fats, which mainly differ in POP (1,3-dipalmitoyl-2-oleoyl-glycerol) and SOS (1,3-distearoyl-2-oleoyl-glycerol) triacylglycerol compositions, were used in this study. Rheological properties of the two filling fats, namely Creamelt 601 and Creamelt 701, were first studied using oscillatory rheology under static and slow cooling conditions to obtain genuine information about the crystallisation behaviour in which a viscoelastic system was evident for both filling fats. Oscillatory rheology was also used to simulate certain manufacturing conditions in which the filling fats are used to show the effects of processing conditions on the crystallisation behaviour of the filling fats. Application of shear during the cooling process at high and low temperatures indicated an enhancement of the crystallisation process and damage to the crystal aggregates respectively. Nevertheless, there was no evidence of a significant impact of the point at which shear was applied on the final rheological properties. The viscoelastic properties of the filling fats at every step of the processing conditions were assessed using an oscillation frequency sweep. Development of a weak crystal network was shown by a reduced frequency-dependent profile as soon as the filling fats reached the first crystallisation temperature. Similarly, the application of shear at higher temperatures showed enhancement of the crystallisation process by secondary nucleation and rearrangement of the crystal network whereas at lower temperatures, shear application may result in destruction of the network. In addition, other crystallisation techniques of analysis such as x-ray diffraction (XRD), differential scanning calorimetry (DSC) and polarised light microscopy (PLM) were also used to study the crystallisation behaviour of the filling fats.
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