Microwave esterification of sunflower proteins in solvent-free conditions.
The esterification of storage proteins from sunflower seeds renders these molecules more hydrophobic and increases internal plasticization, facilitating their use in the fabrication of materials by thermo-mechanical processes. The reaction was carried out in solvent-free conditions to simplify the process and to reduce costs. Optimization of esterification by the classical method, heating in a thermostat-regulated oil bath, resulted in 84% esterification for a reaction time of 4 h (amount of catalyst = 3.9 meq 5 N HCl/g protein, T = 90 degrees C). Microwave heating was then used to reduce the reaction time and the hydrolysis of protein chains. A similar level of esterification (89%) was obtained in 18 min (amount of catalyst = 3.4 meq 5 N HCl/g protein, microwave power (P) = 560 W). High yields were obtained with this method, demonstrating that this process limited hydrolysis.
Laboratoire de Chimie Agro-industrielle, UMR 1010 INRA/INP-ENSIACET, 118, route de Narbonne, F-31077 Toulouse 04, France. olivier.orliac@ensiacet.fr
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D004951:Esterification; D006368:Helianthus / Q000737:chemistry*; D007700:Kinetics; D008872:Microwaves; D010940:Plant Proteins / Q000737:chemistry*; D012995:Solubility; D013696:Temperature
D010940:Plant Proteins