Iron binding capacity of dephytinised soy protein isolate hydrolysate as influenced by the degree of hydrolysis and enzyme type

Abstract

Soy protein is increasingly used in extended meat products and dairy type products due to the presence of high quality proteins with excellent functional properties. However, it has been shown to inhibit iron bioavailability because of phytic acid present in the protein. This present study investigated the effects of dephytinise from soy protein isolate (SPI) on iron binding capacity and degree of hydrolysis. Also the effects of enzyme type and degree of hydrolysis on iron binding capacity were studied. It was demonstrated that phytase and anion exchange resin could remove effectively the phytate from SPI. The dephytinise would decrease the degree of hydrolysis of SPI. The enzyme type and degree of hydrolysis influenced significantly the iron binding capacity of the hydrolysate. Flavourzyme might be the best choice for producing peptides with iron binding capacity from SPI and middle degree of hydrolysis would be benefitable to this process.

Keywords: Hydrolysis; Iron binding capacity; Phytate; Soy protein isolate.

Fig. 1

Dephytatinise from soy proetin isolate by phytase, anion exchange resin and acid-organic solvent treatments. Each observation is a mean of three replicate experiments (n = 3) and the values with different lowercase differ significantly at p < 0.05

Fig. 2

The degree of hydrolysis (DH) of soy proetin isolate and dephytatinised soy proetin isolate under different proteases hydrolysis. Each observation is a mean of three replicate experiments (n = 3) and the values with different lowercase differ significantly at p < 0.05

Fig. 3

The molecular weight distribution of soy proetin isolate and its hydrolysate with Flavourzyme at degree of hydrolysis (DH) of 6.79%