The acylated protein derivatives of Canavalia ensiformis (jack bean):: A study of functional characteristics

Protein concentrate was prepared from jack bean (JNP) and it was modified by acylation using acetic (JAP) and succinic anhydrides (JSP). Proximate analyses revealed that moisture and ash content increased following acetylation and succinylation, while both acetylation and succinylation reduced percentage crude fat and protein. Acetylation and succinylation reduced protein solubility in the acidic pH range below the isoelectric point (4.5) of the protein concentrate but improved the solubility of the unmodified protein concentrate at the isoelectric point and pH range alkaline to the isoelectric point. Both acetylation and succinylation increased the water absorption capacity of unmodified protein concentrates at all levels of ionic strength investigated (0.1-1.0mol/l). Acetylation improved oil absorption capacity whereas the tendency to absorb oil reduced after succinylation. Maximal emulsifying activity of native and modified proteins were obtained at pH 10. Emulsion stability of acylated proteins was higher than those of native proteins in the range of pH 4-10 but lower when the pH was 2. Foam capacity and stability of both native and modified proteins increased with increase in protein concentration. Foam capacity of modified proteins increased progressively with increase in pH from 2 to 10. Also, acylated protein derivatives had improved foam capacity over the native protein except at pH 2. Gelation capacity of both native and modified proteins was maximal at the region of isoelectric point. (c) 2005 Swiss Society of Food Science and Technology. Published by Elsevier Ltd. All rights reserved.