Orange Maize Research Articles

Genetic analysis of grain yield and related traits of extra-early orange maize inbred lines and their hybrids under drought and rain-fed conditions

Genetic analysis of grain yield and related traits of extra-early orange maize inbred lines and their hybrids under drought and rain-fed conditions

Effect of Traditional Processing and Storage on Retention of Xanthophyll Antioxidant Carotenoids in Malawi’s Orange Maize

Xanthophyll carotenoids (lutein and zeaxanthin) from pigmented maize offer a good source of dietary antioxidants. However, during storage and processing, carotenoids can degrade, giving rise to smaller compounds without antioxidant properties. Therefore, this study was aimed at investigating the impact of traditional processing techniques on the retention of carotenoids with antioxidant properties in orange maize farmed in Malawi.

Performance and Stability Analysis of Extra-Early Maturing Orange Maize Hybrids under Drought Stress and Well-Watered Conditions

The consistently low yield turnout of maize on farmers’ fields owing to drought and the nutritional challenges attributable to the consumption of white endosperm maize pose a major threat to food and nutritional security in Sub-Saharan Africa (SSA). The objectives of this study were to assess the performance of newly developed extra-early maturing orange hybrids under managed drought and well-watered conditions, compare the outcomes of multiple-trait base index and multi-trait genotype–ideotype distance index selection procedures, and identify drought-tolerant hybrids with stable performance across contrasting environments for commercialization in SSA. One hundred and ninety orange hybrids and six checks were evaluated under managed drought and well-watered conditions at Ikenne for two seasons between 2021 and 2023. A 14 × 14-lattice design was used for the field evaluations under both research conditions. Drought stress was achieved by the complete withdrawal of irrigation water 25 days after planting. Results revealed significant differences among the hybrids under drought and well-watered conditions. Grain yield, ears per plant, and plant aspect under managed drought were correlated to the same traits under well-watered conditions, suggesting that the expression of these traits is governed by common genetic factors. Twenty-nine hybrids were identified as top-performing drought-tolerant hybrids by the multiple-trait base index and the multi-trait genotype–ideotype distance index. Of the selected outstanding 29 hybrids, 34% were derived from crosses involving the tester TZEEIOR 197, demonstrating the outstanding genetic potential of this inbred line. Further analysis of the 29 selected hybrids revealed TZEEIOR 509 × TZEEIOR 197 as the hybrid that combined the most drought-tolerant adaptive traits. However, the hybrids TZEEIOR 526 × TZEEIOR 97, TZEEIOR 384 × TZEEIOR 30, TZEEIOR 515 × TZEEIOR 249, TZEEIOR 510 × TZEEIOR 197, TZEEIOR 479 × TZEEIOR 197, and TZEEIOR 458 × TZEEIOR 197 were identified as the most stable hybrids across drought and well-watered conditions. These hybrids should be extensively tested in multi-location trials for deployment and commercialization in SSA.

The effect of herbal Lippia javanica extracts on the bioactive content, functional properties, and sensorial profile of biofortified-orange maize based fermented maheu

Lippia javanica is commonly used to treat respiratory ailments because of its rich phytochemical profile, however its importance as a food additive in maheu production is not known. The study was aimed at determining the effect of herbal Lippia javanica extract (L.J.E) on the bioactive content, functional properties, and sensorial profile of biofortified-orange maize based fermented maheu. The prepared orange maize gruels were mixed with 5 %, 10 %, and 15 % v/w L.J.E and fermented spontaneously for 24 h. Total polyphenols (TP), antioxidant activity (AOA), β-carotene, vitamin A and vitamin C content were analysed using Folin-Ciocalteu reagent, 2,2-diphenyl-1-picrylhydrazyl free radical scavenging activity, ABTS (2,2′-azinobis-3-ethyl-benzothiazoline-6-sulphonate), HPLC, retinol activity equivalent (RAE) conversion, and dichlorophenolindophenol titration method respectively. Physiochemical properties, mineral content and product acceptability were analysed using standard AOAC methods. The β-carotene, vitamin A, and vitamin C range was 0.8–1.1 µg/g, 3.55–3.90 µREA/100g and 6.3–11.1 mg/100g respectively. TP, AOA, total antioxidant activity range was 8.2–19.4 mg GAE/g, 28.1–41 EC50mg/L and 31.3–48.3AE/100g respectively. The pH, total soluble sugars, and titratable acidity was 3.6–3.9, 4–4.5 % and 0.08–0.16 %. Minerals present in maheu were zinc (0.8–1.1mg), iron (2.6–3.1mg), magnesium (93.2–97.1mg), calcium (80.1–89.4mg), and potassium (72.5–82mg). Maheu with 15 % v/w L.J.E had better improved bioactive content, functional properties and sensorial profile.

The potential of underutilised and biofortified grains, roots, and tubers in Ghana: A nutrition-sensitive approach for improved health

Abstract The prevalence of micronutrient deficiencies and non-communicable diseases are on the rise in Sub-Saharan Africa (SSA) despite the abundance of indigenous nutritious and biofortified crops. Rapid urbanisation and poor dietary habits have resulted in most Ghanaian households frequently consuming highly processed foods, sugar, salt, and unhealthy fats in place of complex carbohydrates such as whole grains, root and tuber crops, fruits, and vegetables. Existing postharvest and food processing practices may also not help consumers to make healthy food choices that would result in optimal nutrition. Applying a food systems approach will enable stakeholders to consider the solutions to these public health concerns through different lenses along the agricultural value chain. This review examines nutritious indigenous crops in Ghana, that include millet, sorghum, soybean, locust bean, aerial yam, taro, and cocoyam, considering how their nutrient composition could aid in disease prevention and health promotion among the populace. In addition, biofortified crops such as yellow and orange maize, high iron bean, yellow cassava, and orange-fleshed sweetpotato are discussed, highlighting the focal nutrients and their relation to health improvement. This review employs the food systems approach to critically examine how nutrition can be maximised along the various steps of the agricultural value chain. It concludes with recommendations at the individual and policy levels that could result in medium- and long-term positive impacts on nutrition and health status.

Provitamin A retention and sensory acceptability of landrace orange maize (MW5021) food products among school-aged children living in rural Malawi

Landrace orange maize is rich in carotenoids and is thought to be a potentially sustainable solution for Vitamin A deficiency. This study evaluated the acceptability of landrace orange maize food products among school-aged children living in rural Malawi. It also determined the retention of provitamin A carotenoids after storage in an uncontrolled environment, followed by milling and cooking. Sensory evaluations of porridge and nsima (thick porridge) were carried out in school-aged children (n = 160) using a 7-point hedonic scale. Total carotenoid content (TCC) was analysed using a spectrophotometric method and High-Performance Liquid Chromatography (HPLC) was used to identify the specific carotenoid composition of the food products. Sensory evaluation results showed a higher acceptance of landrace orange maize food products in comparison to those commonly prepared from white maize. Plain porridge scored 6.5 ± 1.4 and 5.6 ± 1.9 for orange and white maize, respectively. Similar results were observed with nsima. Orange maize nsima received a score of 6.8 ± 0.7 while white maize was evaluated at 5.8 ± 1.9. After 10 months of storage and processing, there was 89% retention of total carotenoids with 59% accounted for by evaluation of individual carotenoids. Despite the total degradation of beta-carotene, 42% retention of beta-cryptoxanthin with provitamin A activity was observed. Encouraging the production of landrace orange maize appears to be a useful strategy for providing Malawian farmers with carotenoid-rich foods with high palatability. It presents a cost-effective option to reduce dependence on supplementation and fortification.Graphical

Effect of germination and roasting on the proximate, mineral and anti-nutritional factors in finger millet (Eleucine Coracana), Cowpeas (Vigna Unguiculata) and orange maize (Zea mays)

Finger millet (Eleucine coracana), cowpea (Vigna unguiculata), and bio-fortified vitamin A “orange” maize (Zea mays) are three nutrient dense crops currently being promoted in Zimbabwe. The effect on nutrient content of processing these specific crop varieties has not been investigated. Therefore, this study was designed to determine the effects of germination and roasting on the proximate, mineral, and anti-nutritional factors in finger millet, cowpeas and orange maize. Finger millet grains were germinated for 48hrs, cowpeas and orange maize for 24hrs, at room temperature (20-23oC). Both raw and processed samples were dried and milled into flour for the determination of proximate and mineral and anti-nutritional composition. Protein content of finger millet increased significantly after processing from 6.53±0.25 mg/100 g to 11.27±0.15 mg/100 g in germinated finger millet flour (P<0.05). Germination of finger millet resulted in significantly increased minerals (mg/100 g); calcium from 345.53±0.55 to 352.63±0.21, zinc from 3.59±0.15 to 8.71±0.01, sodium from 49.89±0.16 to 57.78±1.20 and iron content from 3.75±0.05 to 4.52±0.01 whilst magnesium and potassium decreased significantly from 198.09±0.07 to 69.08±0.06 and 487.08±0.03 to 144.78±0.27 respectively. Processing of cowpeas resulted in slight but significant increase in protein content (20.47±0.21 to 28.50±0.10), increased calcium (138.18±0.12 to 148.18±0.12 mg/100 g), magnesium (14.23±2.00 to 19.18±0.31 mg/100 g), potassium (232±4.00 to 443.41±0.02 mg/100 g) and iron (4.85±0.03 to 4.86±0.04 mg/100 g). Conversely zinc and sodium decreased from 4.5±0.30 to 2.9±0.10 mg/100 g and 31.85±0.03 to 11.64±0.02 mg/100 g, respectively. Notably for orange maize, protein content did not change from 10.06±0.04 to 10.04±0.04 g/100 g before and after processing. Calcium increased from 47.02±2.82 to 57.99±8.85 (mg/100 g), magnesium from 90.91±0.11 to 108.30±0.53 (mg/100 g), potassium from 2.13±0.04 to 4.33±0.25 (mg/100 g), sodium from 0.50±0.02 to 0.70±0.02 (mg/100 g) and iron from 0.50±0.02 to 1.25±0.05 (mg/100 g). Zinc decreased from 6.2±0.2 to 3.53±0.55 (mg/100 g). Tannins, oxalates and phytates decreased significantly after processing of all three crops. Results showed that germination and roasting increased the nutritional profile and decreased anti-nutrient content in finger millet, cowpeas and orange maize. Therefore, it is important to consider germinating and roasting these grains during processing to increase the nutritional potential of the end food product. Further studies are required to investigate the decrease in some nutrients after germination and roasting and possibly establish optimum processing parameters for improved nutrient profile of these food crops. Key words: Traditional grains, millet, orange maize, biofortification, germination, roasting, nutrients, anti-nutrients

Home Gardening of Yellow Cassava and Orange Maize for the Prevention of Nutritional Blindness in Children: An Economic Evaluation and Value of Information Analysis

ObjectivesVitamin A deficiency is the leading cause of childhood blindness worldwide, affecting mostly Sub-Saharan Africa. We aimed to predict the cost-effectiveness of home gardening (HG) of yellow cassava and orange maize to prevent nutritional blindness in children below 5 years and to assess the likely value of obtaining additional information in reducing uncertainty surrounding its cost-effectiveness. MethodsWe developed a Markov model and carried out probabilistic sensitivity analysis with a value of information analysis. We costed resources from a societal perspective and outcomes were measured in disability-adjusted life years (DALYs). ResultsHG was estimated to cost an additional Intl$395.00 per DALY averted, with a 72.27% likelihood of being cost-effective at a threshold of Intl$2800 per DALY. The expected value of information was estimated to be Intl$29 843.50 for 1 child or Intl$925 billion for 31 million Nigerian children affected by the decision. Further research is only worthwhile for 1 parameter (relative risk of low serum retinol; expected value of perfect parameter information Intl$29 854.53 per child and Intl$925 billion for 31 million children). ConclusionHG of yellow cassava and orange maize is expected to be highly cost-effective in preventing nutritional blindness in Nigerian children. Worthwhile further research includes a cost analysis of the intervention and a high-quality randomized trial to assess the effectiveness of HG on serum retinol levels in young children.

Integrated metabolite analysis and health-relevant in vitro functionality of white, red, and orange maize (Zea mays L.) from the Peruvian Andean race Cabanita at different maturity stages.

The high maize (Zea mays L.) diversity in Peru has been recognized worldwide, but the investigation focused on its integral health-relevant and bioactive characterization is limited. Therefore, this research aimed at studying the variability of the primary and the secondary (free and dietary fiber-bound phenolic, and carotenoid compounds) metabolites of three maize types (white, red, and orange) from the Peruvian Andean race Cabanita at different maturity stages (milk-S1, dough-S2, and mature-S3) using targeted and untargeted methods. In addition, their antioxidant potential, and α-amylase and α-glucosidase inhibitory activities relevant for hyperglycemia management were investigated using in vitro models. Results revealed a high effect of the maize type and the maturity stage. All maize types had hydroxybenzoic and hydroxycinnamic acids in their free phenolic fractions, whereas major bound phenolic compounds were ferulic acid, ferulic acid derivatives, and p-coumaric acid. Flavonoids such as luteolin derivatives and anthocyanins were specific in the orange and red maize, respectively. The orange and red groups showed higher phenolic ranges (free + bound) (223.9-274.4 mg/100 g DW, 193.4- 229.8 mg/100 g DW for the orange and red maize, respectively) than the white maize (162.2-225.0 mg/100 g DW). Xanthophylls (lutein, zeaxanthin, neoxanthin, and a lutein isomer) were detected in all maize types. However, the orange maize showed the highest total carotenoid contents (3.19-5.87 μg/g DW). Most phenolic and carotenoid compounds decreased with kernel maturity in all cases. In relation to the primary metabolites, all maize types had similar fatty acid contents (linoleic acid > oleic acid > palmitic acid > α-linolenic acid > stearic acid) which increased with kernel development. Simple sugars, alcohols, amino acids, free fatty acids, organic acids, amines, and phytosterols declined along with grain maturity and were overall more abundant in white maize at S1. The in vitro functionality was similar among Cabanita maize types, but it decreased with the grain development, and showed a high correlation with the hydrophilic free phenolic fraction. Current results suggest that the nutraceutical characteristics of orange and white Cabanita maize are better at S1 and S2 stages while the red maize would be more beneficial at S3.

Provitamin A Carotenoid–Biofortified Maize Consumption Increases Pupillary Responsiveness among Zambian Children in a Randomized Controlled Trial

Background: Impaired dark adaptation is an early functional indicator of vitamin A deficiency that may be prevented by regular dietary intake of foods containing provitamin A carotenoids.Objective: We tested the impact of provitamin A carotenoid–biofortified maize consumption (∼15 μg β-carotene/g) on dark adaptation in Zambian children.Methods: We used a cluster-randomized trial of children aged 4–8 y (n = 1024) in Mkushi District, Zambia, and compared the regular consumption (2 meals/d, 6 d/wk for 6 mo) of biofortified orange maize (OM) to white maize (WM). The primary outcome was the serum retinol response. In a random sample (n = 542), we used a digital pupillometer to test pre- and postintervention responses to graded light stimuli (−2.9 to 0.1 log cd/m2) in a dark-adapted state.Results: At baseline, 11.7% of the children had serum retinol <0.7 μmol/L, 14.4% had impaired dark adaptation (pupillary threshold ≥ −1.11 log cd/m2), and 2.3% had night blindness. The mean ± SD pupillary responsiveness to light stimuli was poorer at baseline in the OM group (16.1% ± 6.6%) than the WM group (18.1% ± 6.4%) (P = 0.02) but did not differ at follow-up (OM: 17.6% ± 6.5%; WM: 18.3% ± 6.5%). Among children with serum retinol <1.05 μmol/L at baseline, there was greater improvement in pupillary responsiveness in the OM group (2.2%; 95% CI: 0.1%, 4.3%) than the WM group (0.2%; 95% CI: −1.1%, 1.5%; P = 0.01), but there were no differences in children with adequate baseline status. We found no effect of treatment on pupillary threshold or night blindness.Conclusions: The regular consumption of provitamin A carotenoid–biofortified maize increased pupillary responsiveness among children with marginal or deficient vitamin A status, providing evidence of a functional benefit to consuming this biofortified crop. This trial was registered at clinicaltrials.gov as NCT01695148.

Genetic Analysis of Zinc, Iron and Provitamin A Content in Tropical Maize (Zea mays L.)

Breeding maize with high contents of zinc, iron and provitamin A (PVA) could be effective in mitigating micronutrient deficiency in developing countries with a high reliance on maize-based diets. Information on the mode of inheritance of zinc, iron, PVA and grain yield (GY) would facilitate the development of varieties with enhanced contents of these nutrients. Twenty-four yellow to orange maize inbred lines and their 96 F1 hybrids generated using North Carolina Design II, were evaluated alongside four checks for two years at two locations in Nigeria. The effects of environment, hybrid and inbred line were significant for GY and contents of zinc, iron and PVA. The GY, and contents of zinc, iron and PVA of the hybrids ranged from 1.49 to 6.05 t ha−1, 22.51 to 33.33 mg kg−1, 20.04 to 29.65 mg kg−1 and 3.55 to 15.28 µg g−1, respectively. Additive gene effects controlled the accumulation of PVA and Fe, whereas both additive and non-additive gene effects controlled the inheritance of Zn and GY. Inbred lines with high general combining ability for GY and single or multiple micronutrients were identified, and could be used to develop hybrids and synthetics that combine high GY with high micronutrient content. Six hybrids combined high GY with high contents of all three micronutrients, and are recommended for further evaluation and possible release. Our study revealed the feasibility of enriching maize with multiple micronutrients without compromising grain yield.

Successful reintroduction of landrace orange maize in rural Malawi is not related to the nutritional knowledge of women in farming families

Vitamin A deficiency is a global health challenge, particularly in the developing world. Diet based approaches, using locally available foods, are recommended for providing long term, sustainable solutions. The ProFarmer project, initiated in Malawi, encouraged local farmers to re-adopt landrace crop varieties. Orange maize was used as a case study. Over time, reintroducing this carotenoid-rich crop is predicted to increase provitamin A content in the Malawian diet. Furthermore, it is considered a relatively simple, cost-effective approach that has the potential to reduce dependence on food fortification. This study was aimed at evaluating the impact of the reintroduction of landrace orange maize on nutrition knowledge, attitudes and behaviours (KAB) in women of farming families that currently cultivate the crop. Women were selected, as they are largely responsible for food preparation and providing healthy foods for their families. Additionally, the overall diet adequacy in women living in rural Malawi was assessed. A total of 336 females took part in the cross-sectional study. Before the study, the participating farming families underwent a training program run by local Agriculture Extension workers prior to receiving seeds for cultivation. The training included an explanation of the rationale behind reintroducing landrace maize and nutrition education regarding the health aspects of providing provitamin A through locally grown foods. Families that had recently joined the project and families that had already harvested the crop in previous years were included in the study sample. A semi-structured questionnaire was used to determine KAB regarding orange maize. Diet quality was also assessed using the FAO Minimum Dietary Diversity questionnaire (MDD-W) designed for women. Independent t-tests and Chi-square tests were performed where appropriate. Positive attitudes towards growing and consuming landrace orange maize were recorded. However, only 32% of the women understood the nutritional benefits. Dietary Diversity scores, a proxy for nutrient adequacy, were low with only 34% of women consuming a sufficiently diverse diet. Despite low levels of nutritional knowledge, landrace orange maize was well accepted by families in rural Malawi and presents an affordable, sustainable option for increasing dietary sources of provitamin A. Nutrition education emphasizing the advantages of eating orange maize and expanding diet diversity is recommended in Malawi. Key words: landrace orange maize, Vitamin A, nutrition knowledge, Malawi, carotenoids, diet diversity, women, sustainability

A Comparative Study of Physicochemical Attributes of Pigmented Landrace Maize Varieties

Maize has been cultivated and continues to be cultivated for its usability in calorie supply to humans and livestock. There has been great interest in pigmented landrace maize varieties (PLMVs) due to their importance in the pharmaceutical industry. Landraces are to a large extent a repository of the gene pool that enriches biodiversity and maintains but also stabilizes the ecosystem in a sustainable way. PLMVs are still being cultivated by smallholder farmers in smaller portions of their fields and home surroundings despite the high adoption of white hybrid maize. This study examined the ash, moisture, mineral, crude protein, fat, and carbohydrate content of three different PLMVs from central (Ntcheu and Dedza districts) and northern (Mzimba district) Malawi. The mineral content of soils from fields where PLMVs were grown was also analyzed. The study areas experience a warm temperate climate and higher rainfall in summer than in winter but they differ in that Ntcheu has the highest average annual temperature of 20.3°C while Dedza receives the highest annual precipitation of about 1010 mm. Mzimba’s average annual temperature and precipitation are 20.1°C and 915 mm, respectively. The study showed that orange maize from Dedza had a significantly higher content of calcium (71.00 ± 0.58 mg·kg−1), magnesium (819.00 ± 0.58 mg·kg−1), and phosphorus (2720.35 ± 0.03 mg·kg−1). Significantly higher contents of zinc (54.61 ± 0.43 mg·kg−1) and potassium (808.58 ± 0.27 mg·kg−1) were observed in purple maize from Dedza and Ntcheu, respectively. Red maize from Dedza had a significantly higher content of iron (59.80 ± 0.26 mg·kg−1). Purple maize from Dedza has significantly higher carbohydrate content (65.52 ± 0.07%). The findings also revealed that red maize from Dedza provenance had a high content of crude protein (12.57 ± 0.07%) and fat (10.73 ± 0.14%). Moisture (17.30 ± 0.21%) and ash (2.28 ± 0.02%) were significantly higher in orange maize from Dedza. Dedza’s provenance revealed a high content of the analyzed attributes in PLMVs. Mineral analysis showed different levels of mineral bioavailability in different PLMVs and in the soils where maize was grown. It can, therefore, be concluded that production location and maize variety have an influence on the attributes of PLMVs. Understanding the physicochemical attributes of PLMVs and its maximum utilization have the potential of improving food and nutrition security in Sub-Saharan African countries and globally.

Impact of Provenance on Phytochemical Attributes of Pigmented Landrace Maize Varieties

Maize is one of the most diverse cereal crops that contribute highly in calorie supply to human diet. Pigmented maize secondary metabolites which are phytochemicals of healthy importance include carotenoids and phenolics which act as precursors of vitamin A and antioxidants respectively. Pigmented landrace maize is cultivated by smallholder farmers in their localities. Three different pigmented maize varieties from different growing districts were analysed for total carotenoids content (TCC) and total phenolic content (TPC), using spectrophotometer. The districts experience a warm temperate climate and higher rainfall in summer than in winter but they differ in that Ntcheu has highest average annual temperature of 20.3°C while Dedza receives the highest annual precipitation of about 1010 mm. Mzimba has an average annual temperature of 20.1°C and receives about 915 mm of precipitation annually. Individual carotenoids were analysed using high performance liquid chromatography (HPLC). TCC were significantly higher (p &lt; 0.05) in Ntcheu and Mzimba provenances compared to Dedza. Lutein (22.84 ± 1.25 µg/g) and Zeaxanthin (23.16 ± 2.44 µg/g) were highest in landrace orange maize from Ntcheu. Mzimba provenance showed highest beta-cryptoxanthin (8.60 ± 2.15 µg/g). TPC were not significantly different between Dedza (204.29 ± 0.35 mg/Kg) and Mzimba (207.65 ± 0.22 mg /kg) red maize. Ntcheu provenance showed the least TPC (184.06 ± 0.61 mg/Kg). It seems provenance influenced phytochemical attributes of pigmented landrace maize varieties in some instances. This study also revealed that post-harvest handling of pigmented landrace maize affects phytochemical content. Care should, therefore, be taken in handling pigmented landrace maize to avoid phytochemical loses. Farmers and all other stakeholders in Malawi are encouraged to produce and include pigmented landrace maize varieties in their diets in order to gain the associated health benefits. Further studies are needed for complete characterisation of phenolic compounds of pigmented landrace maize of Malawi.

Simultaneous dissection of grain carotenoid levels and kernel color in biparental maize populations with yellow-to-orange grain.

Maize enriched in provitamin A carotenoids could be key in combatting vitamin A deficiency in human populations relying on maize as a food staple. Consumer studies indicate that orange maize may be regarded as novel and preferred. This study identifies genes of relevance for grain carotenoid concentrations and kernel color, through simultaneous dissection of these traits in 10 families of the US maize nested association mapping panel that have yellow to orange grain. Quantitative trait loci were identified via joint-linkage analysis, with phenotypic variation explained for individual kernel color quantitative trait loci ranging from 2.4% to 17.5%. These quantitative trait loci were cross-analyzed with significant marker-trait associations in a genome-wide association study that utilized ∼27 million variants. Nine genes were identified: four encoding activities upstream of the core carotenoid pathway, one at the pathway branchpoint, three within the α- or β-pathway branches, and one encoding a carotenoid cleavage dioxygenase. Of these, three exhibited significant pleiotropy between kernel color and one or more carotenoid traits. Kernel color exhibited moderate positive correlations with β-branch and total carotenoids and negligible correlations with α-branch carotenoids. These findings can be leveraged to simultaneously achieve desirable kernel color phenotypes and increase concentrations of provitamin A and other priority carotenoids.

Assessment of Functional and Pasting Properties of Fresh Orange Maize Hybrids and Open-Pollinated Varieties as Influenced by Genotype, Harvesting Time, and Growing Location

The study evaluates the effects of genotype, maturity, and growing location on the functional and pasting properties of freshly harvested orange maize hybrids and open-pollinated varieties (OPVs). Eight fresh orange maize hybrid and eight fresh maize OPV, including the control, were harvested at three stages: 20, 27, and 34 days after planting (DAP). The freshly harvested maize samples were lyophilized and characterized for the pasting and functional properties using standard laboratory methods. The peak viscosity, final viscosity, and swelling power of the OPVs increased between 20 and 27 DAP. Additionally, the water absorption capacity increased between 20 and 27 DAP for the maize hybrids, with a decreasing trend between 27 and 34 DAP. However, genotypes 2, from the orange maize hybrid, and 5, amongst the OPV, were outstanding with the highest peak viscosities, indicating good final product quality. The combined ANOVA for the fresh orange maize hybrid and OPV showed a highly significant effect (p ≤ 0.01 and p ≤ 0.001) for the maturity and location on the pasting and functional properties except for the pasting temperature, final viscosity, and pasting time which showed no significant effect. In contrast, the location by genotypes by maturity interactions had no significant effects on the pasting and functional properties of the fresh maize hybrid and the orange OPV except only for the setback, which was highly significant at p ≤ 0.001. Nutritionists, food scientists, and maize breeders could use the information from this study to select the best maize genotypes at the appropriate harvesting period suitable for the production of the preferred maize-based products of consumers.

Effect of processing on bioaccessibility of carotenoids from orange maize products

SummaryThis study assessed the effect of processing including boiling, roasting and fermenting on bioaccessibility of carotenoids (lutein, zeaxanthin, β‐cryptoxanthin, α‐carotene and β‐carotene) from orange maize. Bioaccessibility of carotenoids was analysed using a three‐stage in vitro digestion. High‐performance liquid chromatography was used to analyse the contents of carotenoid compounds in the processed orange maize products and digesta. On average, boiled maize had the highest retention rate (79.0%) of carotenoids followed by fermented porridge (73.8%), fermented maize (68.4%) and unfermented porridge (59.0%). Roasted maize had the lowest retention rate of 56.1%. Without further processing, carotenoids recovery from raw orange maize ranged from 73.0% to 100.5%. After treatments, carotenoids recovery showed varying levels of increase except for fermented maize. The average recovery of carotenoids in whole digesta of boiled maize, roasted maize, fermented porridge and unfermented porridge was 108.5%, 116.9%, 101.9% and 110.7%, respectively.

Variability in resistant starch, vitamins, carotenoids, phytochemicals and in-vitro antioxidant properties among diverse pigmented grains

Maize, sorghum, quinoa and rice are important grains which serve as the major source of carbohydrates and micronutrients in the diet. Apart from their normal color, these crops are also cultivated in different colors among diverse regions of the world. In the present study, various pigmented grains including maize, sorghum, rice and quinoa of different color were evaluated for their nutrients, anti-nutrients, phytochemicals and antioxidant activity. Resistant starch, amylose, total starch, and damaged starch contents varied significantly (p < 0.05) among the evaluated samples. Water soluble vitamins, tocols and carotenoids showed wide variability among the grains. The findings showed riboflavin, niacin, pantothenic acid and total folic acid content were found significantly (p < 0.05) higher in red sorghum (177.01 μg/100 g), orange maize (2233.98 μg/100 g), red quinoa (1361.16 μg/100 g) and black quinoa (147.33 μg/100 g), respectively. Total tocopherols and tocotrienols ranged from 35.33 to 192.72 and 17.03 to 231.39 μg/100 g, respectively. Total phenolic, flavonoid and anthocyanin content varied significantly (p < 0.05) and were recorded between 282.12 to 900.54 mg gallic acid equivalents (GAE)/100 g, 120.29 to 174.11 mg catechin equivalents (CE)/100 g and 13.44 to 197.04 mg cyanidin-3-glucoside equivalents (CGE)/100 g, respectively. The total proanthocyanidin content varied significantly among pigmented grains and ranged from 2.11 to 32.18 mg catechin equivalent (CE)/100 g. The free radical scavenging activity evaluated using 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2′-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS) varied significantly among samples and was observed between 13.52 to 56.89% and 32.01 to 65.10%, respectively. Reducing power and metal chelating activity varied significantly among pigmented grains and were observed between 3.04 to 5.98 mol ascorbic acids equivalents (Mol AAE)/100 g and 56 to 67.1%, respectively. Maroon maize had the highest phytic acid content of 609.21 mg/100 g. The bioaccessibility of iron (Fe) and zinc (Zn) was found to be higher for both black and red quinoa. Overall, red and black quinoa had low content of phytic acid and high content of nutrient than other pigmented grains evaluated.

Bioactive Composition and Free Radical Scavenging Activity of Fresh Orange Maize Hybrids: Impacts of Genotype, Maturity Stages, and Processing Methods.

Bioactive compounds in foods are responsible for their biological activities, but biotic and abiotic factors may influence their levels. This study evaluated the impact of three genotypes (designated 4, 5, and 7), maturity stages (20, 27, and 34 days after pollination) and processing methods (hydrothermal and dry-heating) on the bioactive constituents (carotenoids, phytate, tannins, vitamin C) and 2,2-diphenyl-2-picrylhydrazyl radical (DPPH*) scavenging activity of fresh orange maize hybrids. Freshly harvested maize cobs of each genotype were subjected to hydrothermal processing at 100°C and dry-heating with husks and without husks. Carotenoids (lutein, zeaxanthin, β-cryptoxanthin, α-carotene, and total β-carotene) contents of fresh and processed samples were analyzed using HPLC; other bioactive constituents and DPPH* scavenging ability were determined using spectrophotometric methods. Genotype had a significant effect on the levels of carotenoids (p < 0.001) and vitamin C (p < 0.05), while genotype (p < 0.001), and processing methods (p < 0.001) had significant effects on DPPH* SC50. Maturity stages, processing methods and their interaction also had significant effects (p < 0.001) on the levels of all the bioactive constituents. A positive moderate to strong correlation was observed between (p < 0.001) α-carotene and the following: lutein (r = 0.57), β-cryptoxanthin (r = 0.69), total β-carotene (r = 0.62). However, the relationship between α-carotene and zeaxanthin was positive but weak (r = 0.39). A positive moderate correlation (p < 0.001) was observed between lutein and the following: β-cryptoxanthin (r = 0.57), total β-carotene (r = 0.58), and zeaxanthin (r = 0.52). A positive strong correlation (p < 0.001) was observed between β-cryptoxanthin and each of total β-carotene (r = 0.92) and zeaxanthin (r = 0.63); total β-carotene and zeaxanthin (r = 0.65); while the association between vitamin C and DPPH* SC50 was negative and weak (r = −0.38). Generally, genotype 4 and harvesting at 34 days after pollination had the best combination of bioactive constituents and DPPH* scavenging ability.

Harvesting time and roasting effects on colour properties, xanthophylls, phytates, tannins and vitamin C contents of orange maize hybrid

Biofortified maize varieties form an essential part of a nutritious diet; available evidence suggests that different processing methods may affect the final food products. The study aimed to evaluate the effects of processing (roasting) and harvesting time on the bioactive components (lutein, zeaxanthin, β-cryptoxanthin, phytate, tannin and vitamin C) and colour properties (L*, a*, b*), of biofortified orange maize. The orange maize hybrids used for the study were obtained from the International Institute of Tropical Agriculture (IITA) diverse lines with high provitamin A (PVA) content. The results showed that harvesting time and roasting methods significantly (P ≤ 0.001) affected the colour properties. The positive values of ∆b* 30.7, 36.0 and 38.1 at 20 days after pollination (DAP), 27DAP and 34DAP, respectively showed that the intensity of orange colour increased with delay in harvesting time. In unprocessed freshly harvested orange hybrid maize; lutein, zeaxanthin, β-cryptoxanthin, tannin and vitamin C increased with an increase in harvesting time. For roasted hybrid, the mean concentrations of all the bioactive components increased with increases in harvesting time except for tannin and vitamin C that showed a decrease at 20DAP and 27DAP. The results revealed that processing and time of harvest affect the levels of non-provitamin A carotenoids, tannins, phytic acid, Vitamin C and the colour properties of biofortified maize genotypes.