Developing Microalgae-Based Fortified Wheat Flour to Address Iron Malnutrition in India
Cornell University, 2020
Abstract: Iron deficiency anemia affects 1.2 billion people worldwide. Current iron fortificants either suffer from poor bioavailability or negatively affect the sensory profile of foods. In this project, we investigated the potential of defatted microalgae Nannochloropsis oceanica (DGM), a by-product of the biofuel industry, as a novel iron source. To test the iron bioavailability from DGM, diet-induced iron-deficient mice were fed microalgal iron extract (Fe-DGM, 39 mg Fe/kg) for 6 weeks. Previously, the mice were made iron-deficient through consumption of a rice-based control diet without supplemental iron (6 mg/kg Fe). Mice fed the Fe-DGM diet had elevated hemoglobin and liver non-heme iron (all P < 0.05) over the control. Iron-repletion through Fe-DGM diets positively affected the expression of iron metabolic pathway genes in the duodenum and liver (DMT1, DCytB, FPN, HAMP, Tf, TfR, all P <0.05). Subsequently, a safety assessment study was conducted to determine adverse effects from high doses of continuous DGM supplementation. Repeated oral challenge through high doses of dietary DGM (5 or 10%) did not induce any oxidative stress, iron bioaccumulation or inflammation in the liver. Plasma biomarkers of inflammation and tissue damage were insignificant. Lastly, Perls’ staining of tissues (liver, muscle, spleen and ileum) were also toxicologically insignificant. To assess what foods hold most promise for iron fortification, fieldwork in rural communities in India was carried out. As whole wheat flour (WF) is widely consumed and available through the public distribution systems, it may serve as a suitable vehicle for iron delivery. Encapsulation of DGM in emulsions (o/w) using conventional homogenization was applied to mask the sensory attributes of DGM for use in WF fortification. When matched for dietary iron intake, the iron bioavailability from the encapsulated DGM was found to be comparable to non-encapsulated DGM in an iron-deficient mouse model. The addition of up to 17.5 mg Fe/kg of this encapsulated powder to WF prevented the oxidation of ferrous ions present in the DGM, and presented less oxidation on a per fat basis as compared to other treatments, including control (WF). We also conducted two in-home sensory assessments (n > 50, day 0 and day 21 storage samples) with Indian flatbread (roti) made from WF supplemented with encapsulated DGM at a 17.5 or 35 mg Fe/kg fortification rate, and concluded that there was no significant differences between fortified or unfortified chapatis in any of the tested sensory attributes. The work presented in this dissertation provides a novel approach to combat iron malnutrition, and exhibits the vast potential of DGM as an effective and safe iron source.