Caroubin: A Gluten‐like Protein Isolated from Carob Bean Germ

ABSTRACT In 1935, Bienenstock and coworkers claimed the presence of gluten‐like material in the germ of the carob seed. The viscoelastic properties of the water‐insoluble proteins isolated from carob germ, which we propose to call caroubin, have been confirmed by dynamic (G′ and G″) and static rheological measurements (texture profile analysis, viscoelastogram). Biochemical analyses showed important similarities (high glutamic acid content, size‐exclusion HPLC profile, PAGE patterns of reduced and unreduced proteins) as well as large differences (high arginine and low cysteine and proline content of caroubin, carbohydrate composition) between caroubin and wheat gluten. Besides potential new industrial uses of carob seed, caroubin could be a valuable material to help us understand the physicochemical basis of the viscoelastic properties of plant protein complexes like wheat gluten.