Improving iron and zinc bioaccessibility through food-to-food fortification of pearl millet with tropical plant foodstuffs (moringa leaf powder, roselle calyces and baobab fruit pulp).

Essential mineral (iron and zinc) deficiencies are still prevalent in the Semi-arid Tropics, where many people consume monotonous, predominantly cereal-based diets. This study aimed to evaluate the potential of including tropical plant foodstuffs high in iron and zinc (moringa leaves and roselle calyces) or mineral availability enhancers (baobab fruit pulp) in a pearl millet-based food containing a plant food-based provitamin A source, with the aim of preventing iron and zinc deficiencies in the Semi-arid Tropics. Mineral bioaccessibility was assessed by dialysability assay. Moringa, roselle and baobab considerably increased iron and zinc bioaccessibility when added at 10 parts:100 parts pearl millet (dry basis). These foodstuffs, increased the contribution to the absolute iron requirements of women of reproductive age by 2.5, 2.1 and 2.3 times for moringa, roselle and baobab, respectively and to their absolute zinc requirements by 2.4, 2.1 and 2.7 times, respectively. Combining these plant foodstuffs could contribute up to 28% and 41% of the women's absolute iron and zinc requirements, respectively, from a single meal. Moringa, despite having the highest iron content, when added at a very high level (30 parts:100 parts pearl millet) decreased bioaccessible iron and zinc, most probably primarily due to its high calcium content. Food-to-food fortification of staple cereal foods with moringa leaves, roselle calyces or baobab fruit pulp plus a provitamin A source can potentially sustainably improve iron and zinc bioavailability in the diets of at-risk communities in the Semi-arid Tropics.

Malting Period Effect on the Phenolic Composition and Antioxidant Activity of Finger Millet (Eleusine coracana L. Gaertn) Flour.

The present study examined the influence of malting on the phenolic composition of two cultivars of finger millet using an ultra-performance liquid chromatography mass spectrometer. Total polyphenols and antioxidant activities of the grains were also evaluated using sorghum as an external reference. Catechin, epicatechin, quercetin, taxifolin, and hesperitin were isolated flavonoids, whereas protocatechuic acid was the phenolic acid detected in finger millet malt. Increases in the content of catechin, epicatechin, and protocatechuic acid were observed for 72 h and 96 h for brown finger millet and sorghum malt. Complete loss of taxifolin and hesperitin were observed with the malting period for finger millet cultivars. A similar loss was noted in the proanthocyanidin A1/A2 and catechin content of sorghum with malting time. The grain malt exhibited 2,2-diphenyl-1-picrylhydrazyl,2,2'-azinobis-3-ethylbenzthiazoline-6-sulfonic acid (ABTS) radical scavenging and iron reducing activities. Increased ABTS and iron reducing activity with malting time were observed for the finger millet cultivars. The study demonstrates the presence of hesperitin in finger millet, and also shows that 72 h and 96 h of malting enhanced the catechin, epicatechin, and protocatechuic acid content, in addition to the antioxidant activity of the grain.

Enrichment of maize and triticale bran with recombinant Aspergillus tubingensis ferulic acid esterase.

Ferulic acid is a natural antioxidant found in various plants and serves as a precursor for various fine chemicals, including the flavouring agent vanillin. However, expensive extraction methods have limited the commercial application of ferulic acid, in particular for the enrichment of food substrates. A recombinant Aspergillus tubingensis ferulic acid esterase Type A (FAEA) was expressed in Aspergillus niger D15#26 and purified with anion-exchange chromatography (3487 U/mg, Km  = 0.43 mM, Kcat = 0.48/min on methyl ferulate). The 36-kDa AtFAEA protein showed maximum ferulic acid esterase activity at 50 °C and pH 6, suggesting potential application in industrial processes. A crude AtFAEA preparation extracted 26.56 and 8.86 mg/g ferulic acid from maize bran and triticale bran, respectively, and also significantly increased the levels of p-coumaric and caffeic acid from triticale bran. The cost-effective production of AtFAEA could therefore allow for the enrichment of brans generally used as food and fodder, or for the production of fine chemicals (such as ferulic and p-coumaric acid) from plant substrates. The potential for larger-scale production of AtFAEA was demonstrated with the A. niger D15[AtfaeA] strain yielding a higher enzyme activity (185.14 vs. 83.48 U/ml) and volumetric productivity (3.86 vs. 1.74 U/ml/h) in fed-batch than batch fermentation.

Effects of processing sorghum and millets on their phenolic phytochemicals and the implications of this to the health-enhancing properties of sorghum and millet food and beverage products.

Sorghum and millet grains are generally rich in phytochemicals, particularly various types of phenolics. However, the types and amounts vary greatly between and within species. The food-processing operations applied to these grains, i.e. dehulling and decortication, malting, fermentation and thermal processing, dramatically affect the quantity of phenolics present, most generally reducing them. Thus the levels of phytochemicals in sorghum and millet foods and beverages are usually considerably lower than in the grains. Notwithstanding this, there is considerable evidence that sorghum and millet foods and beverages have important functional and health-promoting effects, specifically antidiabetic, cardiovascular disease and cancer prevention, due to the actions of these phytochemicals. Also their lactic acid bacteria-fermented products may have probiotic effects related to their unique microflora. However, direct proof of these health-enhancing effects is lacking as most studies have been carried out on the grains or grain extracts and not the food and beverage products themselves, and also most research work has been in vitro or ex vivo and not in vivo. To provide the required evidence, better designed studies are needed. The sorghum and millet products should be fully characterised, especially their phytochemical composition. Most importantly, well-controlled human clinical studies and intervention trials are required.

Effect of simulated in vitro upper gut digestion of processed cowpea beans on phenolic composition, antioxidant properties and cellular protection.

The effect of simulated in vitro upper gut digestion on the phenolic composition and antioxidant properties of processed cowpea beans was studied. The samples comprised four cowpea cultivars: a cream, brownish-cream and two reddish-brown cultivars. Dry cowpea seeds were soaked in water, blended into paste and deep-fried in vegetable oil. The fried samples were taken through in vitro upper gut digestion followed by freeze-drying of the supernatant. Phenolic composition of extracts from the supernatants were determined using HPLC-MS. Radical scavenging activities were documented using the TEAC, ORAC and nitric oxide (NO) assays. In vitro digestion of the processed cowpeas resulted in phenolic-peptide complexes that were identified for the first time, and decreased extractable phenolic compounds. However, the radical scavenging activities increased. The processed cowpeas and their digests inhibited cellular NO production, and oxidative DNA and cellular damage. In conclusion, deep-fried cowpeas when consumed, could potentially help alleviate oxidative stress-related conditions.

Antioxidant properties and inhibition of lipid formation in 3T3-L1 adipocytes of in vitro digested mageu, a commercial sample.

Mageu is a fermented, non-alcoholic maize-derived product unique to southern Africa. The aim of this study was to identify the health benefits of a polyphenolic extract of commercially produced mageu related to the antioxidant properties and effects on lipid accumulation in differentiated 3T3-L1 adipocytes. A pooled sample of mageu Number 1 brand (original non-flavored) was subjected to in vitro gastroduodenal digestion (GDD). Reverse phase high-performance liquid chromatography of unfractionated undigested (UD) and GDD mageu revealed that with digestion there was an increased extraction of 1.2, 1.83, 1.45, 4.86, and 3.17-fold of caffeic acid, 3,4-dihydroxybenzoic acid, p-coumaric acid, 4 hydroxybenzoic acid and ferulic acid, respectively. An associated increase in the total phenolic acid content and antioxidant activity in the <3 kDa fraction was obtained. In contrast with digestion, inhibition of advanced glycation end products formation and low-density lipoprotein oxidation was found in the <30 kDa fraction indicating the contribution of larger, possibly feruloylated polysaccharides, to activity. Cellular antioxidant activity in Caco-2 cells was >90% for all UD fractions, but with GDD was reduced. All fractions had low scavenging of nitric oxide in the lipopolysaccharide/murine cell model. Exposure of 3T3-L1 adipocytes to all the UD and GDD mageu fractions (at 1% and 10% concentrations) during differentiation resulted in at least a 35% reduction in lipid accumulation, which was not associated with a loss of cellular viability. In conclusion, mageu, UD, and subjected to GDD contains phenolic acids with beneficial bioactive properties that contribute to antioxidant activity and reduces lipid accumulation in adipocytes. PRACTICAL APPLICATIONS: Mageu is a non-alcoholic fermented maize product which when digested has increased bioactivity. Its reported health benefits are due to its caloric content therefore the practical application of this research is to validate the scientific benefits of this food and encourage increased consumption of this functional food. This is especially important in the context of the South African population where this product is widely consumed as increasing obesity is associated with an increased risk of non-communicable disease. Furthermore, as a non-alcoholic drink, consumption can be promoted for all ages' groups and religions, and a commercialized manufacture processes can be optimized to increase phenolic acid release.

Hydrolysis and antioxidant activity of starch modified with phenolic extracts from grape pomace and sorghum bran under alkaline conditions.

The effect of modification with phenolic extracts from grape pomace (GPE) and sorghum bran (SBE) under alkaline conditions for 6 and 12 h, with and without washing with aqueous ethanol (post modification) on the enzymatic hydrolysis as measured by viscosity decrease and antioxidant activity of maize starch was studied. Phenolic-modified starches showed lower rate of starch hydrolysis. The DSC of residues after enzyme hydrolysis showed the conversion of type I inclusion complexes in the unwashed to type II inclusion complexes in the washed phenolic-modified starches. FTIR suggests the presence of covalent bonds in the residues of the phenolic-modified starches due to the retention of starch-bound phenolics. Phenolic-modified starches showed ABTS radical scavenging activity. Ultra-fast liquid chromatography showed polymerisation of monomeric and dimeric procyanidins to oligomeric procyanidins in GPE and SBE-modified starches. It can be concluded that phenolic-modified starches with relatively low hydrolysis and antioxidant activity can be produced under alkaline conditions.

Consumer Acceptance and Willingness to Pay for Instant Cereal Products With Food-to-Food Fortification in Eldoret, Kenya.

BACKGROUND: Maize is the major food staple in East and Southern Africa, where food-processing industries are emerging fast. New low-cost extrusion cookers allow small enterprises to enter the market for processed cereals, including instant, fortified, and flavored products. OBJECTIVE: Assess consumers' interest and preferences for the new products. METHODS: Consumers (n = 220) in Eldoret, Kenya, were invited to evaluate 4 new cereal products: (1) sifted maize flour mixed with sorghum, (2) instant sifted mixed flour, (3) instant whole flour, and (4) instant whole flour fortified with natural ingredients and to compare them to conventional sifted maize flour, using 2 preparations: stiff porridge (ugali) and soft porridge (uji). These were followed by economic experiments to estimate consumers' willingness to pay (WTP) for the new products and traits. RESULTS: For ugali, consumers preferred conventional sifted maize flour, while for uji, they appreciated the new products, especially sifted mixed flour (with sorghum) and instant whole mixed flour. Fortification with food-to-food sources was not appreciated, especially for ugali. Comparing WTP for the traits with their production cost showed that mixed, whole, and instant flours were economical, but not fortification. Maize/sorghum mixtures realized a benefit of 24% over conventional maize flour, whole meal 11%, and instant mixtures 5%. CONCLUSIONS: There is a potential market for improved cereal products in Kenya, but more for uji than for ugali, especially with instant, mixed, and whole flour. Acceptable and affordable products, fortified with other foods that are locally available, however, still need to be developed, especially for ugali.

Assaying Sorghum Nutritional Quality.

Sorghum (Sorghum bicolor L. Moench) is a major drought-tolerant cereal crop grown mainly in the semi-arid regions of the world. It is an important basic food cereal in these regions which encompasses most of the developing world in many parts of Africa and Asia. Therefore, sorghum is an important source of nutrients for millions of inhabitants in these regions. In light of this, the nutritional quality of sorghum and how this is assessed is of major research interest. Various assays have been used to determine the contents of macronutrients and micronutrients in sorghum including how digestible and bioaccessible these are. A wide range of indices of sorghum nutritional quality has been generated. Advances in analytical instrumentation have contributed significantly to enhancing the capacity of analysts and researchers to broaden the scope of assays for sorghum nutritional quality and also to improve their accuracy.

Pasting, flow, thermal and molecular properties of maize starch modified with crude phenolic extracts from grape pomace and sorghum bran under alkaline conditions.

This study determined the effects of phenolic extracts from grape pomace and sorghum bran, reaction time and washing with aqueous ethanol on the pasting, flow, thermal and molecular properties of maize starch. The starch modification was carried out under alkaline conditions. The phenolic extracts increased the peak viscosity of the starch. Reaction time had no significant effect on starch properties. Washing with aqueous ethanol significantly increased the peak, final, and setback viscosities of the phenolic modified maize starches. DSC of phenolic modified starches showed higher enthalpy (ΔH) before and after washing with aqueous ethanol in comparison with starch without phenolic extract. FTIR spectra suggested the possible formation of hydrogen and ether (covalent) bonds between starch and phenolic compounds. It can be concluded that the pasting, flow and thermal properties of maize starch can be modified with phenolic extract under alkaline conditions to produce "clean label" starch-phenolic complex.

Effect of malting period on physicochemical properties, minerals, and phytic acid of finger millet (Eleusine coracana) flour varieties.

BACKGROUND: Deficiency of essential minerals is a widespread nutritional disorder in the world, particularly in developing economies. Poor mineral accessibility from foods is a major contributing factor to deficiency and associated health problems. This study investigated the effect of malting on minerals, phytic acid, and physicochemical properties of finger millet varieties. Sorghum was used as external reference. Mineral composition was analyzed using an inductively coupled plasma atomic emission spectroscopy (ICP-AES) and mass spectroscopy (ICP-MS). RESULTS: Data showed that finger millet is rich in macroelements and trace elements. Malting for 24 hr reduced mineral content of the grains except sodium. Increase in the minerals was observed beyond 48 hr of malting particularly at 96 hr. Successive decrease in phytic acid of the grains was not observed with malting time. Malting did not result in any significant change in the physicochemical properties of the grains. CONCLUSION: ICP-AES/MS showed that finger millet contain a variety of minerals in amounts that were not previously reported, and malting the grain for 72 to 96 hr positively affected the minerals. Changes in phytic acid suggest that phytate undergoes dissociation during malting rather than a degradation of phytic acid. Potential exists for utilization of finger millet as functional ingredient to augment important minerals in weaning, geriatric, and adult foods for health promotion.

Phenolic composition and antioxidant properties of koose, a deep-fat fried cowpea cake.

Koose, a West African delicacy, is a side dish prepared by deep frying thick cowpea paste. The current research determined the effect of deep-fat frying of cowpea paste on its total phenolic content (TPC), phenolic composition and antioxidant properties. Four cowpea cultivars comprising two reddish-brown, a brownish-cream and cream phenotypes were used. Liquid chromatography-mass spectrometry was used to determine phenolic composition of the samples. TPC was determined using Folin-Ciocalteu method while radical scavenging capacities were by Trolox equivalent antioxidant capacity, oxygen radical absorbance capacity and nitric oxide scavenging assays. The phenolic acids identified included benzoic and cinnamic acid derivatives. The predominant flavonoid classes were flavan-3-ols and flavonols. Deep-fat frying of the cowpea pastes decreased their TPC, radical scavenging capacities and total quantified flavonoids. The koose inhibited radical-induced oxidative cellular and DNA damage. It is concluded that koose is a potential functional food that can contribute to alleviating radical-induced oxidative stress.

Sorghum-cowpea composite porridge as a functional food, Part II: Antioxidant properties as affected by simulated in vitro gastrointestinal digestion.

The effect of compositing red non-tannin sorghum with brownish-cream cowpea and in vitro gastrointestinal digestion on total phenolic and flavonoid contents and antioxidant properties of a sorghum-cowpea composite porridge was studied. Maize-soybean composite porridge was used as a reference sample. Antioxidant properties were studied using radical scavenging activities against the 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid), peroxyl and NO radicals as well as inhibition of low density lipoprotein (LDL) oxidation and oxidative damage of vector DNA. Hydroperoxide content of the samples was also measured. All the samples demonstrated radical scavenging activity. Simulated duodenal digests of the porridges had hydroperoxides and therefore caused LDL oxidation. The undigested porridges and simulated gastric digests inhibited LDL oxidation. Compositing the cereals with legumes increased total phenolic and flavonoid contents and NO scavenging activity of their porridges. In vitro gastrointestinal digestion of the porridges increased their total phenolic and flavonoid contents, radical scavenging activities and LDL oxidation inhibitory activity.

The effects of antioxidants and shelf life conditions on oxidation markers in a sunflower oil salad dressing emulsion (SOSDE).

The effects of levels of antioxidant [gallic acid or ethylene diamine tetraacetate (EDTA)] in a sunflower oil salad dressing emulsion (SOSDE) and shelf life affecting conditions on aroma, anisidine values (AV) and peroxide values (PV) were determined. Aroma differences between products with different concentrations of antioxidants were more apparent for ambient than accelerated stored SOSDEs. Aroma differences were more noted between SOSDEs with different antioxidants than antioxidant concentrations per se. PV differences between accelerated stored SOSDEs with high and low EDTA concentrations were found. AV differences existed between SOSDEs with different gallic acid concentrations for both storage conditions, and for accelerated stored SOSDEs with different EDTA concentrations. The accelerated storage model is more suitable for SOSDEs with metal chelator antioxidants e.g. EDTA, than free radical scavenging antioxidants e.g. gallic acid. PV, AV and aroma of accelerated stored SOSDEs do not clearly predict ambient shelf life.

Emerging Early Actions to Bend the Curve in Sub-Saharan Africa's Nutrition Transition.

BACKGROUND: Sub-Saharan Africa is the last region to undergo a nutrition transition and can still avoid its adverse health outcomes. OBJECTIVE: The article explores emerging responses to "bend the curve" in sub-Saharan Africa's nutrition transition to steer public health outcomes onto a healthier trajectory. METHODS: Early responses in 3 countries at different stages of food system transformation are examined: South Africa-advanced, Ghana-intermediate, and Uganda-early. By comparing these with international experience, actions are proposed to influence nutrition and public health trajectories as Africa's food systems undergo rapid structural change. RESULTS: Arising from rapid urbanization and diet change, major public health problems associated with overweight are taking place, particularly in South Africa and among adult women. However, public health responses are generally tepid in sub-Saharan Africa. Only in South Africa have policy makers instituted extensive actions to combat overweight and associated noncommunicable diseases through regulation, education, and public health programs. Elsewhere, in countries in the early and middle stages of transition, public health systems continue to focus their limited resources primarily on undernutrition. Related pressures on the supply side of Africa's food systems are emerging that also need to be addressed. CONCLUSIONS: Three types of intervention appear most feasible: maternal and child health programs to simultaneously address short-term undernutrition problems while at the same time helping to reduce future tendencies toward overweigh; regulatory and fiscal actions to limit access to unhealthy foods; and modernization of Africa's agrifood food system through job skills training, marketing reforms, and food industry entrepreneurship.

Inactivation of tannins in milled sorghum grain through steeping in dilute NaOH solution.

Steeping milled sorghum in up to 0.4% NaOH was investigated as a method of tannin inactivation. NaOH steeping substantially reduced assayable total phenols and tannins in both Type III and Type II sorghums and with Type III sorghum caused a 60-80% reduction in α-amylase inhibition compared to a 20% reduction by water steeping. NaOH treatment also reduced starch liquefaction time and increased free amino nitrogen. Type II tannin sorghum did not inhibit α-amylase and consequently the NaOH treatment had no effect. HPLC and LC-MS of the tannin extracts indicated a general trend of increasing proanthocyanidin/procyanidin size with increasing NaOH concentration and steeping time, coupled with a reduction in total area of peaks resolved. These show that the NaOH treatment forms highly polymerised tannin compounds, too large to assay and to interact with the α-amylase. NaOH pre-treatment of Type III sorghums could enable their utilisation in bioethanol production.

Sensory and physicochemical analyses of roasted marama beans [Tylosema esculentum (Burchell) A. Schreiber] with specific focus on compounds that may contribute to bitterness.

The role of phenolics and saponins in contributing to bitterness in marama beans, an underutilized legume, especially when roasted, was investigated. Marama beans were roasted at 150°C for 20, 25 or 30 min, then dehulled to separate cotyledons, and pastes were prepared from these. Water extracts were prepared from full fat and defatted flours from roasted and unroasted marama cotyledons. A sensory panel evaluated the sensory attributes of marama pastes and water extracts. Marama water extracts were analysed for total phenolic content, phenolic composition and saponin content. Roasting of marama beans for more than 20 min resulted in negative properties, such as bitterness. The major extractable phenolic acids present in marama water extracts were gallic and protocatechuic acids which increased as a function of roasting time. Saponin content of the water extracts was in the range of 55-63 mg/l. The identified phenolic acids, saponins and other as yet unidentified compounds may contribute to the perceived bitterness.

Does a sorghum-cowpea composite porridge hold promise for contributing to alleviating oxidative stress?

The effect of compositing red non-tannin sorghum with cream-coloured cowpea and porridge preparation on phenolic profile and radical scavenging activity was studied. A maize-soybean composite porridge representing a similar product on the South African market was used as reference sample. UPLC-QToF-MS-ESI was used to determine phenolic composition of the grain flours, their composites and porridges. Total phenolic content was determined using Folin-Ciocalteu method while radical scavenging activity was determined using the ABTS, DPPH and NO radical scavenging assays. Four benzoic acid derivatives and five cinnamic acid derivatives were identified in the samples. The predominant flavonoid subclasses identified in sorghum were flavan-3-ols, flavanones and flavones while cowpea had mainly flavan-3-ols and flavonols with soybean having mainly isoflavones. Compositing the cereals with legumes significantly (p<0.01) increased their total flavonoid content and radical scavenging activities. Sorghum-cowpea composite porridge showed better promise in contributing to alleviating radical induced oxidative stress than maize-soybean composite porridge.

Phenolic composition and inhibitory effect against oxidative DNA damage of cooked cowpeas as affected by simulated in vitro gastrointestinal digestion.

Cowpeas contain phenolic compounds with potential health benefits. The effect of simulated gastrointestinal digestion on phenolic composition of cooked cowpeas and the ability of the digests to inhibit radical-induced DNA damage was determined. A red and a cream-coloured cowpea type were used. The phenolic composition of acetone extracts and enzyme digests of cooked cowpeas was determined using UPLC-MS. Compounds such as p-hydroxybenzoic acid, p-coumaric acid, coumaroylaldaric acid and feruloylaldaric acid were present in the acetone extracts of the cooked cowpeas but were not detected in the enzyme digests. Glycosides of quercetin and myricetin decreased upon in vitro gastrointestinal digestion of cooked cowpeas whereas flavan-3-ols were hardly present except catechin glucoside. The enzyme digest of the red cowpea type was about thrice as effective as that of the cream cowpea type in protecting DNA from oxidative damage. The observation that enzyme digests of cooked cowpeas inhibited radical-induced DNA damage suggests that cowpea phenolics retain some radical scavenging activity after gastrointestinal digestion.

The morama bean (Tylosema esculentum): a potential crop for southern Africa.

The morama bean is an underutilized leguminous oilseed native to the Kalahari Desert and neighboring sandy regions of Botswana, Namibia, and South Africa (Limpopo, North-West, Gauteng, and Northern Cape provinces), and forms part of the diet of the indigenous population in these countries. It is also known as gemsbok bean, moramaboontjie, elandboontjie, braaiboonjie, marama, marumana, tsi, tsin, gami, and ombanui. It is reported as an excellent source of good quality protein (29-39%); its oil (24-48%) is rich in mono- and di-unsaturated fatty acids and contains no cholesterol. Morama is a good source of micronutrients such as calcium, iron, zinc, phosphate, magnesium, and B vitamins including folate. It is also reported to be a potential source of phytonutrients including phenolic compounds (e.g., tannins), trypsin inhibitors, phytates, and oligosaccharides, components which have been shown in other foods to contribute to health in particular, prevention of noncommunicable diseases such as cardiovascular diseases, diabetes, and some cancers. From a nutritional and health perspective, the morama bean has potential commercial value as a cash crop and value-added products, particularly in the communities where it is found.