Starch nanoparticles stearate

Acylation of starch nanoparticles using SP>525 The acylation of AOT-coated starch nanoparticles with vinyl stearate was performed as described above except that the catalyst (CALB) was incorporated within the microsphoes instead of as part of heterogeneous Novozyme-435 beads. 

The reaction between vinyl stearate and AOT-coated starch nanoparticles was performed for 24hrs, at 40 C, with a 3 1 mol/mol ratio of vinyl stearate to glucose residues. The peak positions and assignments are listed in the... 

Figure 1. DEPT-135 (75 MHz) spectra recorded in DMSO-d6 of A) native starch nanoparticles(l) B) vinyl stearate modified starch nanoparticles (4) with D.S. =0.8 (showed the carbon signals for sugar ring)...

Reaction progress with time The effect of reaction time on the D.S. for acylations of AOT-coated starch nanoparticles with vinyl stearate, CL, and maleic anhydride are shown in Figure 2 and discussed below. Acylation with vinyl stearate starts after a 2 h lag period and by 24 h reached D.S. 0.7. Extending the reaction time to 48 h showed at most an increase in the D.S. to 0.8. The lag period observed for stearate acylation is likely due to the immiscibility of hydrophobic vinyl stearate and hydrophilic starch molecules. However, once a low degree of stearate ester formation occurred the solubility of vinyl stearate in the hydrophobically modified starch nanoparticles increases thus accelerating the reaction. In contrast, a lag period was not observed for the reaction with CL. This is consistent with a relatively higher miscibility of CL than vinyl stearate with the starch nanoparticles. 

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