Spinach leaf and chloroplast lipid: a natural rheology modifier for chocolate?

In this study the possibility of replacing current surfactants in chocolate formulations with natural lipids extracted from spinach leaf (SPLIP) or spinach chloroplast (CH.SPLIP) was evaluated. SPLIP and CH.SPLIP were extracted with chloroform/methanol following enzyme deactivation with hot isopropanol. Results showed a higher extraction yield for SPLIP while glycolipids were more concentrated in CH.SPLIP. Sugar/oil suspensions with dispersed volume fractions of 0.28, 0.33 and 0.37 containing 0.1 % to 0.7 % (w/w) surfactant (SPLIP, CH.SPLIP, lecithin and PGPR as commercial references) based on oil phase were prepared and analyzed in shear rheology. Apparent viscosity at 40 s^-1 was significantly lower for the natural surfactants compared to lecithin at 0.5 to 0.7 % (w/w) addition. With regard to yield stress, taken as the shear stress at 5 s^-1, both natural surfactants showed comparable performance to PGPR at 0.3 % to 0.7 % addition. As SPLIP and CH.SPLIP behaved similar (p > 0.05), SPLIP, due to higher extraction yield, would be the preferred choice for application in chocolate matrices.