Functional Aspects of Carob Flour

PUPPO, M. C.; RIBOTTA, P. D.

Functional Properties of Traditional Foods. ISEKI Food Series

SPRINGER

Año: 2012; p. 413 - 450

The protein system from carob germ, named caroubin by some authors (Feillet & Roulland, 1998; Wang et al., 2001), consists of a mixture of different proteins with a molecular weight ranging from several thousands Da to more than one million (Feillet & Roulland, 1998). Bengoechea et al. (2008 b) obtained from carob flour an isolate with protein content higher than 95%, applying the procedure of alkaline solubilization followed by isoelectric precipitation. The isolate presented, as in flour, high content of aspartic and glutamic acids, and arginine amino acids. The limiting amino acids were methionine + cysteine and phenylalanine + tyrosine. The isolate presented proteins with low electrophoretic mobility and were mainly stabilized by high molecular mass aggregates. These aggregates were formed by the 131 and 70 kDa subunits linked by non-covalent bonds, and other peptides strongly bounded by disulfide interactions. Both, aggregates and subunits were formed mainly by 100 and 48 kDa monomers linked by disulfide bonds. A considerable content of high molecular mass peptides strongly bounded were also found. These peptiedes were not dissociated by the combined effect of the SDS and DTT. No differences in the nature of proteins present in the acid or alkaline isolates were observed. Nevertheless, proteins presented higher denaturation temperature and became more denatured at acid pH (pH 2) than at pH 10. Carob is a legume whose composition, protein nature and protein thermal properties varied from results obtained by other authors for other leguminous crops as soybean, pea and lupine. The knowledge of the nature of proteins that form carob materials like germ flours and isolates, and its thermal properties would be important from the point of view of the application of this crop as ingredient in formulated foods.