AFM approach to study the function of PGPR's emulsifying properties in cocoa butter based suspensions

Planar sucrose substrates for investigating interfaces found in molten chocolate

“…Interestingly the surface planes we identify as possibly contributing to the broad GIXRD peaks observed all correspond to faces observed in the growth habit of sucrose [31]. Furthermore the rms roughnesses we obtained by fitting the specular X-ray reflectivity from the bare sucrose thin films in air are consistent with our planar surfaces featuring similar 1 nm height steps to those observed in the AFM studies on single sucrose grains [8,9]. We note that a recent study that focussed on sucrose films of thickness ≤ 33 nm, concluded that their films showed no crystalline character [32]; this is in contrast to our observation of broad GIXRD peaks for the 22 nm film.…”

“…That these planar interfaces have a polycrystalline character makes them comparable to the interfaces imaged with AFM from single sucrose grains extracted from chocolate-like dispersions [8,9]. These AFM images show the surfaces feature steps, 1-2 nm in height, which the authors point out are consistent with the sucrose crystal lattice [8,9]. Interestingly the surface planes we identify as possibly contributing to the broad GIXRD peaks observed all correspond to faces observed in the growth habit of sucrose [31].…”

“…The broad and overlapping nature of these reflections, suggests that the thin film has a polycrystalline character. That these planar interfaces have a polycrystalline character makes them comparable to the interfaces imaged with AFM from single sucrose grains extracted from chocolate-like dispersions [8,9]. These AFM images show the surfaces feature steps, 1-2 nm in height, which the authors point out are consistent with the sucrose crystal lattice [8,9].…”

“…Recently, AFM studies on grains of sucrose extracted from model chocolate suspensions (and then washed with acetone) have suggested that PGPR forms pillow-like deposits, which separate the sucrose particles by steric hindrance [8], whilst lecithin was found to be inhomogeneously distributed across the surface of the sucrose grains in layers up to 38 nm in thickness [9]. AFM studies are unable to resolve the internal structure and composition of these surfactant deposits at the molecular level.…”

Effect of emulsifier type on physicochemical properties of water‐in‐oil emulsions for confectionery applications

“…It can be deduced from the lack of aggregates in emulsions stabilised by PGPR (Fig. 1) that the adsorption of this much larger emulsifier (PGPR molar mass is approximately 4400 g mol À1 (Bastida-Rodr ıguez, 2013), and phospholipids molar mass is approximately 600-900 g mol À1 (Bueschelberger, 2004)) at the interface generates long-range steric forces, and creates repulsive barriers between adjacent droplets that hinder droplets from flocculation, film drainage and coalescence (Claesson et al, 2004;Middendorf et al, 2015).…”