Biofortified Maize Improves Selenium Status of Women and Children in a Rural Community in Malawi: Results of the Addressing Hidden Hunger With Agronomy Randomized Controlled Trial

Background: Selenium deficiency is widespread in the Malawi population. The selenium concentration in maize, the staple food crop of Malawi, can be increased by applying selenium-enriched fertilizers. It is unknown whether this strategy, called agronomic biofortification, is effective at alleviating selenium deficiency.Objectives: The aim of the Addressing Hidden Hunger with Agronomy (AHHA) trial was to determine whether consumption of maize flour, agronomically-biofortified with selenium, affected the serum selenium concentrations of women, and children in a rural community setting.Design: An individually-randomized, double-blind placebo-controlled trial was conducted in rural Malawi. Participants were randomly allocated in a 1:1 ratio to receive either intervention maize flour biofortified with selenium through application of selenium fertilizer, or control maize flour not biofortified with selenium. Participant households received enough flour to meet the typical consumption of all household members (330 g capita−1 day−1) for a period of 8 weeks. Baseline and endline serum selenium concentration (the primary outcome) was measured by inductively coupled plasma mass spectrometry (ICP-MS).Results: One woman of reproductive age (WRA) and one school-aged child (SAC) from each of 180 households were recruited and households were randomized to each group. The baseline demographic and socioeconomic status of participants were well-balanced between arms. No serious adverse events were reported. In the intervention arm, mean (standard deviation) serum selenium concentration increased over the intervention period from 57.6 (17.0) μg L−1 (n = 88) to 107.9 (16.4) μg L−1 (n = 88) among WRA and from 46.4 (14.8) μg L−1 (n = 86) to 97.1 (16.0) μg L−1 (n = 88) among SAC. There was no evidence of change in serum selenium concentration in the control groups.Conclusion: Consumption of maize flour biofortified through application of selenium-enriched fertilizer increased selenium status in this community providing strong proof of principle that agronomic biofortification could be an effective approach to address selenium deficiency in Malawi and similar settings.Clinical Trial Registration:http://www.isrctn.com/ISRCTN85899451, identifier: ISRCTN85899451.

Proximate composition and sensory characteristics of refractance window dried cowpea composite porridges

Undernutrition is a major public health concern in Uganda. Locally available nutrient dense diets can help reduce the problem of undernutrition. Utilisation of cowpea leaf powder in preparing composite porridge blends depends on sensory acceptance of the consumers. A Nutrisurvey software was used to formulate two composite flour blends, namely maize and millet in a ratio 2:8 and cowpea-maize in a ratio of 1:9 to achieve the daily requirement of protein for children. The study developed a process for the production of composite cowpea flour from finger millet flour and maize flour and followed a one factor design in which maize flour (MF) and millet flour (MMF) was substituted with cowpea leaves flour (CPL). The composites were dried using refractance window drying technology. The proximate composition of the composite flours were determined using standard methods while sensory acceptability of porridges was rated on a five-point Likert scale using an untrained panel. Results indicated a significant (p < 0.05) increase in protein (10.9 to 13.4%), dietary fibre (11.01 to 13.0%) and lipids (4.71 to 5.3%) contents for cowpea-millet composite porridge. For cowpea-maize composite flour, a significant (p < 0.05) increase in protein (5.9 to 7.6%), dietary fibre (1.47 to 3.3%) and lipids (2.84 to 3.3%) was also observed. Sensory evaluation indicated that between the two composite porridges, the cowpea-millet porridge blend was significantly (P≤0.05) more appealing in terms of colour (3.61±0.8), aroma (2.96±0.2), taste (3.24±0.6), texture (3.62±0.6) and general acceptability (3.61±0.8) to the panellists than the cowpea-maize porridge blend. The cowpea-millet and cowpea-maize composite flours can contribute more than 100% of the recommended dietary allowance of protein and carbohydrate requirements for children aged 0-8 years. The study findings indicate that the cowpea-based composite flours have the potential to make a significant contribution to the improvement in the nutritional status of infants and children in developing countries.

EFFECTS OF ASCORBIC ACID AND SUGAR ON PHYSICAL, TEXTURAL AND SENSORY PROPERTIES OF COMPOSITE BREADS

The present study was carried out to demonstrate the combined effects of different maize flour, ascorbic acid and sugar on the physical, textural and sensory properties of composite breads. The composite flour was prepared using 70% of wheat flour and 30% of flour obtained from grain of differently coloured maize - light blue, blue, red and yellow maize flour. Chemical characterization of composite flours made with four different types of maize was also assessed. Furthermore, the content of total phenolics, flavonoids, anthocyanins, phenolic acids and antioxidant capacity in composite flours was determined. The total of 12 breads that were prepared, four of which were control composite breads, four breads with ascorbic acid, and four were breads with ascorbic acid and sugar. The content of total phenolic compounds showed clear differences among all composite flours. The anthocyanins content determined in composite flours was in the following descending order: blue>red>light blue, while in the yellow maize composite flour anthocyanins were not detected. The results showed that the addition of AsA (0.025%) and sugar (5%) negatively affected the volume as well as the specific volume of composite wheat-maize breads. The texture analysis showed that the addition of AsA in amount of 0.025% had no impact on springiness, cohesiveness and resilience of bread crumb, while it increased crumb hardness. However, composite breads made with AsA and AsA and sugar showed a more compact structure, with a larger number of cells and smaller mean cell areas. Bread samples with AsA and sugar in the tested doses had the lowest springiness, which is indicative of brittleness and reflects the tendency of the bread to crumble when slicing. Results of the sensory evaluation revealed that the AsA and sugar addition had a generally positive effect on the investigated sensory attributes.

Kinetics of Phenolic Compounds Modification during Maize Flour Fermentation

This study aimed to investigate the kinetics of phenolic compound modification during the fermentation of maize flour at different times. Maize was spontaneously fermented into sourdough at varying times (24, 48, 72, 96, and 120 h) and, at each point, the pH, titratable acidity (TTA), total soluble solids (TSS), phenolic compounds (flavonoids such as apigenin, kaempferol, luteolin, quercetin, and taxifolin) and phenolic acids (caffeic, gallic, ferulic, p-coumaric, sinapic, and vanillic acids) were investigated. Three kinetic models (zero-, first-, and second-order equations) were used to determine the kinetics of phenolic modification during the fermentation. Results obtained showed that fermentation significantly reduced pH, with a corresponding increase in TTA and TSS. All the investigated flavonoids were significantly reduced after fermentation, while phenolic acids gradually increased during fermentation. Among the kinetic models adopted, first-order (R2 = 0.45–0.96) and zero-order (R2 = 0.20–0.82) equations best described the time-dependent modifications of free and bound flavonoids, respectively. On the other hand, first-order (R2 = 0.46–0.69) and second-order (R2 = 0.005–0.28) equations were best suited to explain the degradation of bound and free phenolic acids, respectively. This study shows that the modification of phenolic compounds during fermentation is compound-specific and that their rates of change may be largely dependent on their forms of existence in the fermented products.

A comparative study of the hydrothermal behavior of four corn flours and their starches in Madagascar

In Madagascar, maize constitutes the third staple food. Traditionally, cereal gruel (made up from rice or maize flour) is the supplementary food for Malagasy children. This work involved a comparative study of the hydrothermal behavior of four maize flours sold on the market and their starches, in order to identify their best use in food systems, especially in infant nutrition. Studies of functional properties such as swelling power, solubility and viscosity were undertaken. At 90°C, the swelling power value range was between 4.81 (g/g) and 8.2 (g/g) for flours and between 6.72 (g/g) and 9.1 (g/g) for their starches. While solubility was 11.8 (%) and 16.4 (%) for flours at the same temperature (90°C), for starches, it was between 12.6 (%) and 22.8 (%). The viscosity peaked at 90°C, ranging from 648 (cP) to 2728 (cP) for flours and from 220 (cP) to 2268 (cP) for starches.

TORTILLAS MADE WITH EXTRUDED FLOURS OF BLUE MAIZE AND CHÍA SEEDS AS AN NUTRITIOUS AND NUTRACEUTICAL FOOD OPTION

Tortillas with adequate nutrients and phytochemicals as a recommended option may improve health in older adults. In this research tortillas were prepared with native blue maize (Zea mays L.) and chía (Salvia hispanica) seeds processed by alkaline extrusion. The hypothesis was that alkaline extrusion would generate flours of both seeds with improved nutraceutical and nutritional characteristics compared to traditional products. The aim was then to evaluate extruded defatted chía flour addition on nutritional and nutraceutical properties of tortillas made with extruded native blue maize flour. Tortillas were prepared with a mixture 75% extruded blue maize flour +25% extruded defatted chía flour. Other tortillas from 100% extruded blue maize flour and commercial lime-cooked maize flour (Blue MASECA®) were used as control and reference. Nutritional, antioxidant, antihypertensive and hypoglycaemic properties of tortillas were evaluated in vitro. A completely randomized experimental design with one factor (type of tortilla) was used for data analysis. Tortillas added with extruded chía flour had higher protein, dietary fibre, essential amino acid (EAA) profile, in vitro protein digestibility (IVPD), and calculated protein efficiency ratio (C-PER) than control and reference tortillas. Tortillas with addition of extruded chía flour also had better antioxidant activity [oxygen radical absorbance capacity, (ORAC) 18006 vs 15531 Trolox equivalent, (TE) μmol per 100g of dry weight, (DW) sample], and better antihypertensive [(ACE) angiotensin-converting enzyme inhibition, IC50=0.47 vs 0.65 extract mg mL-1] and hypoglycaemic (IC50=20.07 vs 25.81 extract mg mL-1 to α-amylase inhibition, and IC50=16.25 vs 19.69 extract mg mL-1 to α-glucosidase inhibition) potential than tortillas from 100% extruded blue maize flour. The use of extruded chía flour and blue maize flour allowed obtaining tortillas with enhanced nutritional, antioxidant, antihypertensive, and hypoglycaemic properties. The extrusion process consumes few water volumes without generating polluting effluents. An appropriate public policy in Mexico may promote these tortillas to be used to fight against malnutrition, and to reduce incidences of chronic degenerative diseases such as hypertension or diabetes.

Microbial Profile of Fermented Maize Flour (Ogi) and African Oil Bean (Pentaclethra macrophylla) Seeds

This study assessed the microbial and physicochemical properties of fermented maize flour (Ogi) and Pentaclethra macrophylla seeds (Ugba). The microbial analyses were done based on microbiological standards. The samples were monitored at points of preparation from 0 to 96 hours of fermentation. The physicochemical parameters were performed in accordance to standard procedures. Selected dilutions were inoculated by pour-plate method on appropriate media for isolation of aerobic bacteria, Staphylococci, coliforms, lactic acid bacteria (LAB) and fungi. Molecular identification of the LAB were done using 16s rRNA Sanger sequencing method. The pH decreased steadily from 3.9 to 3.3 for Ogi and from 7.7 to 5.8 for Ugba, with a corresponding increase in titratable acidity from 1.3 to 2.5 for Ogi and from 0.6 ± 0.14ef to 1.2 ± 0.28c for Ugba. Microorganisms isolated from fermented maize flour (Ogi) and ‘Ugba’ were; Lactobacillus brevis, L. plantarum, Pediococcus acidilactici, Staphylococcus species, Escherichia coli, Bacillus species, Micrococus species, Pseudomonas species, Proteus species, Saccharomyces species, Aspergillus species and Candida species. The total bacteria counts showed decrease in both samples, with Ugba having the highest bacteria count (2.7×106±12.00a cfu/g which decreased to 1.0×106 ± 2.00f cfu/g) compared to Ogi with values (1.3×106 ± 3.00c cfu/g to 1.6 ×105± 1.73h cfu/g) from 0 hour to 96 hours of the fermentation period. Fungi counts increased in both samples throughout the fermentation period with Ugba having counts of (1.4 ×103± 2.65i to 2.8 ×104 ± 5.00 a cfu/g), and Ogi (7.7 ×103± 1.53 h to 2.7 ×104± 6.00 b cfu/g). LAB were persistent and most predominant in Ogi while Bacillus species were most predominant in Ugba. The variations in their different levels of values were of significant difference (P ≤ 0.05). This study revealed the distribution of fermentative microorganisms and few contaminants which were not directly associated with fermentation process and that can however, be further reduced through heat preparation treatment of Ogi.

The Interaction between Tribolium castaneum and Mycotoxigenic Aspergillus flavus in Maize Flour

Tribolium castaneum is one of the most common insect pests of stored products. Its presence makes cereals more susceptible to the spread of the fungi Aspergillus flavus, which may produce mycotoxins. The aim of this work was to evaluate the influence of T. castaneum adults on the development of a mycotoxigenic A. flavus strain in maize flour as well as the influence of this fungus on the insects. Maize flour was exposed to T. castaneum, spores of A. flavus or to both. The results revealed an interaction between T. castaneum and A. flavus as the flour exposed to both organisms was totally colonized by the fungus whereas almost all the insects were killed. Aflatoxin B1 (AFB1) revealed a significantly higher concentration in the flour inoculated with both organisms (18.8 µg/kg), being lower when exposed only to A. flavus, suggesting that the presence of insects may trigger fungal development and enhance mycotoxin production. The ability of these organisms to thrive under the same conditions and the chemical compounds they release makes the interaction between them a subject of great importance to maintain the safety of stored maize. This is the first work evaluating the interaction between T. castaneum and A. flavus mycotoxin production.