THE EFFECTS OF ASCORBIC ACID, pH, AND EXOGENOUS IRON ON THE CHEMICAL IRON PROFILE OF A SOY PROTEIN CONCENTRATE

Publisher Website
Google Scholar
Abstract
The effect of pH, ascorbic acid (Asc) and exogenous iron on the chemical iron profile in a typical soy protein concentrate was investigated. Graded levels of Asc were added to a soy protein concentrate slurry (SC) to produce various pH levels. In order to separate the effect of Asc on pH versus reduction and/or chelation, controls were included which contained appropriate amounts of concentrated HCl to match the acidity of the corresponding Asc samples. In addition, iron was added with and without Asc. Addition of 10–50 mM Asc produced statistically significant increases in percent soluble and ferrous iron over the corresponding acid controls. Results suggest that the ability of Asc to decrease the iron binding capacity of soy protein was predominantly a function of its reducing capabilities, rather than its effect on pH and/or chelation. Also, it was noted that excessive amounts of iron added to the SC produced significant differences in chemical iron profile as compared to the control. This suggests that care must be taken in assuming the presence of a common pool of non-heme iron when both exogenous and endogenous iron are present.