Evolution of particle size distribution, flow behaviour and stability during mill ball refining of a white chocolate flavouring paste

Rheological Properties, Particle Size Distribution and Physical Stability of Novel Refined Pumpkin Seed Oil Creams with Oleogel and Lucuma Powder

“…As refining proceeded, the range of size classes of solid particles varied from 0.52-859 to 0.52-211 µm for cream CBS, from 0.52-515 to 0.52-211 µm for cream OS, and from 0.52-586 to 0.52-211 µm for OLS cream. The CBS and OS creams showed remarkably similar unimodal distribution, as also reported in other studies for anhydrous pastes refined in a ball mill refiner [14,22,29], with some differences at high particle size which became less evident as refining proceeded. OLS cream showed a larger particle size distribution curve with a lower particles volume percentage of around 11 µm compared to the other samples.…”

“…Figure 2 reported the evolution of D90 as a function of refining time, where 350 µm corresponded to the fineness of the coarsest fraction of unrefined cream, that is hazelnut paste. Fineness and D90 tended to assume the same value for coarse particles [16,22]. CBS and OS creams refined for 150 min showed similar D90 values (26.4 µm and 24.4 µm) lower than those observed for sample OLS (37.4 µm).…”

“…The physical properties of refined creams are also affected by the physical state of the fat phase. Comparing the fineness of a hazelnut-and-cocoa-based paste, containing a vegetable oil, with that of a white chocolate flavouring paste, containing a blend of vegetable oil and fats, refined in the same way and containing powders of comparable initial granulometry, a similar evolution of fineness over refining time was observed [14,22]. However, those products differed in the type of oil/fat used, so presented a different PSD of creams at 25 • C, probably because in one of them there was also a high fraction of several fats that could crystallise when the temperature changed from 45 (processing in the ball mill) to 25 • C (storage).…”

“…where scan i (h) is the light intensity of the scan acquired at the i-th time instant and a height of h, and Nh is the number of height positions in the selected scanning zone of the tube (top, centre, bottom or global) [22]. The data were analysed by using the software package TowerSoft Ver 1.2 (Formulaction, Toulouse, France).…”

“…For small-scale production, stirred ball mills represent a valid technology for cream production [16][17][18][19][20][21]. Ingredients and balls stirring in the mill tank result in impact and shearing actions that provide a progressive reduction of the no fat solid particles as well as their homogeneous dispersion [22]. The particle size distribution of creams depends on the amount and type of the solid particles and their size before grinding, but also on the oil/powder ratio, because if the oil/powder ratio is too low, the cream will be coarse [23].…”