The present work opens new outlets for the valorization of plant proteins by chemical modification. Sunflower and wheat gluten proteins were esterified by n-octanol in the presence of an acid catalyst. By varying reaction parameters (temperature, catalyst concentration, reaction time), the optimum reaction conditions of esterification were defined. The esterification yield for each type of proteins was obtained with a maximum for sunflower proteins. The difference was attributed to their own structure and composition. Furthermore, an increase of amino groups was observed indicating a hydrolysis phenomenon of proteins. The esterification was accompanied by a loss of weight due to a loss of small peptides in solution. However, the reaction leads to chemically-modified proteins with new functional properties. In both cases, the esterified proteins were less soluble at basic pH compared to native proteins, indicating thus a hydrophobation effect.
KeywordsFatty Alcohol Plant Protein Catalyst Concentration Fatty Esterification Hydrophobation Effect
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