In order to find alternative
protein sources in African regions where
protein deficiency in nutrition is prevailing, solubility, in-vitro digestibility,
amino acid composition and chemical score of Balanites aegyptiaca Del. kernel
proteins were investigated as a function of different processing steps including defatting, air classification, wet sieving and aqueous
ethanol treatment. Air classification delivered a fine fraction of 58.1% of the total
protein. Applying a wet sieving process, a
protein concentrate of 72.9%
protein content was achieved but the recovery was very low (35.6%). However, in case of isoelectric precipitation followed by aqueous
ethanol treatment both
protein content (78.2%) and recovery (53.7%) were high. Data concerning the chemical score revealed, that
lysine content of the defatted kernel flour amounted to 74.2% of the recommended FAO/WHO standard level. In-vitro
protein digestibility was found to be higher than of legume
proteins. The digestible
protein of the full fat flour, defatted flour, air classified and wet sieved fine fractions and
protein concentrate were 91.9, 93.7, 82.0, 86.4 and 94.2%, respectively. The sapogenin content per 100
g protein of the investigated
protein preparations was significantly lower (46% to 62%) than of the initial material (oilcake).