Evaluating Sweet Potato as an Intervention Food to Prevent Vitamin A Deficiency

Genome-wide identification and expression analyses of CYP450 genes in sweet potato (Ipomoea batatas L.)

BACKGROUND

Cytochrome P450 monooxygenases (CYP450s) play a crucial role in various biochemical reactions involved in the synthesis of antioxidants, pigments, structural polymers, and defense-related compounds in plants. As sweet potato (Ipomoea batatas L.) holds significant economic importance, a comprehensive analysis of CYP450 genes in this plant species can offer valuable insights into the evolutionary relationships and functional characteristics of these genes.

RESULTS

In this study, we successfully identified and categorized 95 CYP450 genes from the sweet potato genome into 5 families and 31 subfamilies. The predicted subcellular localization results indicate that CYP450s are distributed in the cell membrane system. The promoter region of the IbCYP450 genes contains various cis-acting elements related to plant hormones and stress responses. In addition, ten conserved motifs (Motif1-Motif10) have been identified in the IbCYP450 family proteins, with 5 genes lacking introns and only one exon. We observed extensive duplication events within the CYP450 gene family, which may account for its expansion. The gene duplication analysis results showed the presence of 15 pairs of genes with tandem repeats. Interaction network analysis reveals that IbCYP450 families can interact with multiple target genes and there are protein-protein interactions within the family. Transcription factor interaction analysis suggests that IbCYP450 families interact with multiple transcription factors. Furthermore, gene expression analysis revealed tissue-specific expression patterns of CYP450 genes in sweet potatoes, as well as their response to abiotic stress and plant hormones. Notably, quantitative real-time polymerase chain reaction (qRT‒PCR) analysis indicated the involvement of CYP450 genes in the defense response against nonbiological stresses in sweet potatoes.

CONCLUSIONS

These findings provide a foundation for further investigations aiming to elucidate the biological functions of CYP450 genes in sweet potatoes.

Effects of Food-Based Approaches on Vitamin A Status of Women and Children: A Systematic Review

Vitamin A deficiency (VAD) increases risk for morbidity and mortality. Food-based approaches offer one strategy to improve vitamin A status. This systematic review assessed evidence of the effects of food-based approaches on the vitamin A status of women and children under 5 y. VAD was defined as clinical ocular symptoms, such as loss of vision, and/or retinol plasma or serum concentration <0.70 μmol/L. Searches on food-based approaches to improve vitamin A status were conducted for the period 2011-2022 on PubMed, CINHAL, Web of Science, and Google Scholar using PRISMA guidelines. English-language publications were included. Case studies, unpublished dissertations, and non-peer-reviewed studies were excluded. This review comprises 24 of 27,322 identified studies; 23 included studies focused on provitamin A carotenoids. There were 17,214 participants across the 24 studies with sample sizes ranging from 8 to 3571 individuals. Intervention studies spanned from 3 wk to 2 y. Fifteen (63%) studies were randomized control trials, 7 were cross-sectional, and 2 were longitudinal studies. Most studies (N = 21) used biochemical measurements, for example, serum retinol, to assess vitamin A status; other studies used clinical symptoms (for example, xerophtalmia) or dietary intake. Thirteen (54%) studies reported a statistically significant effect of food-based interventions (N = 8) or an association of diet (N = 5) on vitamin A status. This systematic review indicated that some food-based interventions improved vitamin A status, thus offering a safe and effective delivery mechanism for vitamin A. There appeared to be significant association between vitamin A status and consumption of foods with high concentrations of preformed vitamin A and provitamin A carotenoids. Differences across studies in regard to the period of evaluation, food approaches used, and statistical power may explain the lack of effectiveness of food-based approaches on vitamin A status in some studies.

Changes in carbon allocation and subplastidal amyloplast structures of specialised Ipomoea batatas (sweet potato) storage root phenotypes

Vitamin A deficiency (VAD) in Low and Medium Income countries remains a major health concern. Ipomoea batatas, orange sweet potato (OSP), is one of the biofortification solutions being implemented by the World Health Organisation (WHO) to combat VAD. However, high provitamin A (β-carotene) content has been associated with a reduction in dry matter, reducing calorific value and having adverse effects on consumer traits. Both starch and carotenoid formation are located in amyloplasts and could potentially compete for the same precursors. Hence, five different sweet potato storage root phenotypes were characterized through spatial metabolomics and proteomics at the sub-plastidal level. The metabolite data suggested an indirect correlation of starch and carotenoids through the TCA cycle and pentose phosphate pathway. Furthermore, a change in lipid composition was observed to accommodate the storage of carotenoids in the hydrophilic environment of the amyloplast. The data suggests an alteration of cellular ultra-structures and perturbation of metabolism in high β-carotene producing sweet potato roots. This corroborates with previous gene expression analysis through biochemical analysis of sweet potato root tissue.

Effect of Orange-Fleshed Sweet Potato Purée and Wheat Flour Blends on β-Carotene, Selected Physicochemical and Microbiological Properties of Bread

Partial substitution of wheat flour with orange-fleshed sweet potato (OFSP) purée in bread can increase vitamin A intake among consumers. The study investigated the influence of wheat flour substitution with 20–50% of OFSP purée on proximate composition, color, β-carotene, water activity, and microbial keeping quality. The moisture content, crude protein, crude fat, total ash, crude fiber, and carbohydrate in bread ranged from 28.6–32.7%, 9.9–10.6%, 5.0–5.5%, 1.9–3.2%, 1.4–1.8%, and 79.1–80.9%, respectively. β-carotene, total ash, and crude fiber contents in bread, and Hunter color values a*, b*, chroma, and ∆E significantly increased with the addition of OFSP purée. Total viable counts (TVC), yeast, and molds in bread ranged from 2.82–3.64 log10 cfu/g and 1.48–2.16 log10 cfu/g, respectively, on the last day of storage. Water activity, TVC, and fungal counts were low in sweet potato composite bread as compared to white bread. Total β-carotene in OFSP bread ranged from 1.9–5.4 mg/100 g (on dry weight). One hundred grams of bread portion enriched with 40% and 50% OFSP purée provides more than 50% of vitamin A dietary requirements to children aged 4–8 years. Incorporation of up to 50% OFSP purée in wheat flour produces a relatively shelf-stable, nutritious, and health-promoting functional bread.

Nutritional evaluation of complementary porridge formulated from orange-fleshed sweet potato, amaranth grain, pumpkin seed, and soybean flours

Supplementing breastmilk with poor energy and nutrient-dense complementary foodstuffs for young children and infants has resulted in malnutrition, poor growth, and retardation of infant development in many sub-Saharan African countries. Ensuring nutrient adequacy for infants because of their lower consumption requires energy and nutrient-dense food. In this context, the nutritional composition of porridge from complementary flour blends of locally available foodstuffs (orange-fleshed sweet potato, pumpkin seeds, amaranth grains, and soybeans) was carried out. Complementary flours formulated from flour blends of pumpkin seeds, extrusion cooked soybean, and orange-fleshed sweet potato, as well as germinated and extrusion cooked amaranth grains, resulted in varieties of complementary porridges (SAPO1-SAPO5). From these, proximate composition, mineral content (sodium, iron, magnesium, calcium, phosphorus, and zinc), vitamin contents (A and C), and nutrient density of the formulated complementary porridge were determined. Results showed that all the formulated complementary porridge were able to meet the stipulated standards of energy and nutrient (zinc, iron, vitamin A, and protein) densities. Flour blend ratio, germination process, and extrusion cooking significantly (p < .05) influenced the targeted nutrients of interest, as well as the nutrient and energy densities of the formulated complementary porridge. Specifically, the formulated complementary porridge with 40% amaranth grain, 25% orange-fleshed sweet potato, 20% soybean, and 15% pumpkin seed composite mixture had 76.92% compliance level with recommended standards, which assure adequate nutrient complementation to breastfeeding. The present study provides a valuable insight that complementary foods from locally obtainable foodstuffs are potential solutions for mitigating childhood malnutrition and adequate complementation to breastfeeding by proffering the needed energy and nutrient densities required for the immunity, well-being, growth, and development of young children and infants, without fortification.

Drought, Low Nitrogen Stress, and Ultraviolet-B Radiation Effects on Growth, Development, and Physiology of Sweetpotato Cultivars during Early Season

Drought, ultraviolet-B (UV-B), and nitrogen stress are significant constraints for sweetpotato productivity. Their impact on plant growth and development can be acute, resulting in low productivity. Identifying phenotypes that govern stress tolerance in sweetpotatoes is highly desirable to develop elite cultivars with better yield. Ten sweetpotato cultivars were grown under nonstress (100% replacement of evapotranspiration (ET)), drought-stress (50% replacement of ET), UV-B (10 kJ), and low-nitrogen (20% LN) conditions. Various shoot and root morphological, physiological, and gas-exchange traits were measured at the early stage of the crop growth to assess its performance and association with the storage root number. All three stress factors caused significant changes in the physiological and root- and shoot-related traits. Drought stress reduced most shoot developmental traits (29%) to maintain root growth. UV-B stress increased the accumulation of plant pigments and decreased the photosynthetic rate. Low-nitrogen treatment decreased shoot growth (11%) and increased the root traits (18%). The highly stable and productive cultivars under all four treatments were identified using multitrait stability index analysis and weighted average of absolute scores (WAASB) analyses. Further, based on the total stress response indices, ‘Evangeline’, ‘O’Henry’, and ‘Beauregard B-14’ were identified as vigorous under drought; ‘Evangeline’, ‘Orleans’, and ‘Covington’ under UV-B; and ‘Bonita’, ‘Orleans’, and ‘Beauregard B-14’ cultivars showed greater tolerance to low nitrogen. The cultivars ‘Vardaman’ and ‘NC05-198’ recorded a low tolerance index across stress treatments. This information could help determine which plant phenotypes are desirable under stress treatment for better productivity. The cultivars identified as tolerant, sensitive, and well-adapted within and across stress treatments can be used as source materials for abiotic stress tolerance breeding programs.

Performance, Variance Components, and Acceptability of Pro-vitamin A-Biofortified Sweetpotato in Southern Africa and Implications in Future Breeding

In sub-Saharan Africa (SSA), vitamin A deficiency (VAD) is a major cause of blindness in children under 5 years. Sweetpotato (Ipomea batatas L.) is widely grown in this region, and pro-vitamin A varieties could help to combat such problems. Fourteen newly introduced orange-fleshed sweetpotato (OFSP) varieties from the International Potato Centre (CIP) and two local checks were evaluated at four environments using a 4 × 4 triple-lattice design for total tuber yield, marketable yield, unmarketable yield, total tuber numbers, marketable tuber numbers, unmarketable tuber numbers, dry matter content, and sensory characteristics on boiled sweetpotato. Since varieties were previously tested intensively by CIP under diverse conditions, the focus of the current study was to determine their acceptability by farmers. Across-environment ANOVA showed highly significant differences (P < 0.001) for environments, genotypes, and genotype × environment interaction (GE) for all traits studied. Variety Cecelia outperformed the rest in three environments. Cecelia, Erica, Ininda, and Lourdes were found to be the top four most stable and high-yielding varieties. Genetic gains of the top four varieties over the preferred local check Mai Chenje ranged from 135 to 184%, and across-environment broad-sense heritability was 60% for tuber yield. Furthermore, farmers accepted the dry matter content (which was >25%) and taste of all the introduced OFSP varieties. Since there was a high acceptability by farmers, introductions from CIP could help improve human nutrition. Despite the appropriate design, the error variance component was the highest for all traits, and proper field plot techniques were proposed in future breeding and testing activities.

Untargeted metabolomics of purple and orange-fleshed sweet potatoes reveals a large structural diversity of anthocyanins and flavonoids

Anthocyanins are economically valuable phytochemicals of significant relevance to human health. Industrially extracted from multiple fruit and vegetable sources, anthocyanin yield and profiles can vary between sources and growing conditions. In this study, we focused on three purple-fleshed and one orange-fleshed cultivars of sweet potato—a warm-weather, nutritious crop of substantial interest to growers in northern, cooler latitudes—to determine the yield and diversity of anthocyanins and flavonoids. Acidified ethanol extraction of lyophilized roots yielded ~ 800 mg average anthocyanins/100 g dry weight from all three cultivars. UHPLC-DAD-Orbitrap analysis of sweet potato extracts identified 18 high-confidence, mostly acylated peonidin and cyanidin derivatives contributing to > 90% of the total anthocyanin signal. Further assessment of the untargeted Liquid Chromatography–Tandem Mass Spectrometry data using deep learning and molecular networking identified over 350 flavonoid peaks with variable distributions in different sweet potato cultivars. These results provide a novel insight into anthocyanin content of purple-fleshed sweet potatoes grown in the northern latitudes, and reveal the large structural diversity of anthocyanins and flavonoids in this popular crop.

The Role of Targeted Nutrition Education of Preschoolers and Caregivers on Sustained Consumption of Biofortified Orange-Fleshed Sweetpotato in Kenya

BACKGROUND

Persistent prevalence of high malnutrition in poor households in developing countries calls for enhancement of cost-effective nutrition interventions among the vulnerable groups. One responsive way is to promote regular consumption of home-grown biofortified foods, particularly in the micronutrient-deficient groups. Previous nutrition interventions have targeted adults with behavior change education, but have rarely explored the potential of nutrition education of preschoolers as change agents.

OBJECTIVES

This study sought to assess the effect of nutrition education targeting preschool children and their caregivers on their consumption of vitamin A-biofortified orange-fleshed sweetpotato (OFSP) in rural farm households in Homa Bay County, Kenya.

METHODS

A total of 431 preschooler-caregiver pairs from 15 village-level clusters were recruited into a randomized controlled trial. The sample was randomized into 1 control (3 villages) and 3 treatment groups (4 villages each). Treatments involved channeling nutrition education to preschoolers through their learning materials (preschooler treatment); the caregivers through their mobile phones (caregiver treatment); and to both preschoolers and their caregivers simultaneously (integrated treatment). Baseline and follow-up household-level surveys were conducted with the caregivers, and consumption data were collected from the preschoolers using a child dietary diversity register. Class teachers sought 24-h consumption recalls of the preschoolers for 19 consecutive schooldays.

RESULTS

The results of a zero-inflated Poisson regression showed that the phone-mediated and multichanneled nutrition education approaches significantly increased the number of days of OFSP consumption. The integrated nutrition education approach significantly increased the preschoolers' likelihood to consume OFSP, number of OFSP consumption days, and likelihood to consume it more than once per week by 11%, 77%, and 20%, respectively.

CONCLUSIONS

Nutrition education through OFSP-branded preschoolers' learning materials and phone-mediated messages provides effective nudges to the caregivers to feed their preschoolers regularly with OFSP. This could have implications for realizing sustainable nutrition programs in biofortified crop-growing areas.

Marketing Healthy Food in an African City: Consumer Motivations for Adopting Orange-Fleshed Sweet Potato in Maputo, Mozambique

Since the late 1990s, the International Potato Center has promoted orange-fleshed sweet potato (OFSP) cultivars in Mozambique as a healthy food, emphasizing its capacity to reduce the prevalence of vitamin A deficiency among mothers and young children. This article seeks to reveal why consumers in Maputo, the capital city of Mozambique, adopt or reject OFSP looking at the role of food systems and consumer characteristics in access and acceptance of healthy food and at the positioning OFSP on the market in terms of lifestyle and need satisfaction.The results of 255 street interviews confirm that OFSP is widely known. Information reaches people mainly via informal channels (relatives and retailers). Nonadoption is the result of the positioning of OFSP as food for young children and sick people. The OFSP appeals most to the hedonistic and conservative lifestyle segments. Adoption is associated with the perception of OFSP as a source of vitamins that builds up muscles and improves physical appearance and self-fulfillment. While women are typically responsible for domestic tasks, male adopters emphasize the role of OFSP in family health and well-being more than female adopters. This first attempt to understand the marketing of healthy food in Mozambique exposes many similarities between the urban consumers in Maputo and those in developed countries. The results indicate that future marketing should exploit informal channels such as vendors and emphasize its nutritious value for all consumers instead of focusing on mothers and young children.

The Potential of Sweetpotato as a Functional Food in Sub-Saharan Africa and Its Implications for Health: A Review

Increasing urbanization in developing countries has resulted in busier lifestyles, accompanied by consumption of fast foods. The consequence is an increased prevalence in noncommunicable diseases (NCDs). Food-based approaches would be cheaper and more sustainable in reducing these NCDs compared to drugs, which may have side effects. Studies have suggested that consuming functional foods could potentially lower NCD risks. Sweetpotato is regarded as a functional food because it contains bioactive compounds. Recently, sweetpotato has gained attention in sub-Saharan Africa (SSA), but research has focused on its use in alleviating micronutrient deficiencies such as vitamin A deficiency, particularly the orange-fleshed variety of sweetpotato. Some studies conducted in other parts of the world have investigated sweetpotato as a functional food. There is a need to characterize the sweetpotato varieties in SSA and determine how processing affects their bioactive components. This review highlights some of the studies conducted in various parts of the world on the functionality of sweetpotato, its bioactive compounds, and how these are influenced by processing. In addition, the potential health benefits imparted by sweetpotato are expounded. The knowledge gaps that remain in these studies are also addressed, focusing on how they can direct sweetpotato research in SSA.

Yield stability analysis of orange - Fleshed sweet potato in Indonesia using AMMI and GGE biplot

Orange-Fleshed Sweet Potato (OFSP) is an important crop in Indonesia. Yield potential and genotypic adaptability are important factors in varietal development. The purpose of this study was to estimate the stability of yield and to select the best OFSP genotypes across three agroecosystems in West Java, Indonesia. The field trials used were augmented design with 50 F1 Orange-Fleshed Sweet Potato (OFSP) genotypes as treatment, and seven check varieties as controls. The experiments were conducted in three different agroecosystems in West Java (Sumedang, Bandung, and Karawang). Selection was based on physical characteristics of sweet potato tuber, yield and stability across three environments. Data analysis of the yield characters, yield component, and tuber quality were performed by combined variance analysis. Selected genotypes were analyzed for stability yield using the parametric, non-parametric, Additive Main effects and Multiplicative Interaction (AMMI), AMMI Stability Value (ASV), and Genotype and Genotype by Environment (GGE) biplot models. Results identified the top best ten F1 genotypes namely F1-38 (G1), F1-69 (G2), F1-71 (G3), F1-77 (G4), F1-127 (G5), F1-128 (G6), F1-135 (G7), F1-159 (G8), F1-191 (G9), and F1-226 (G10). Location showed a significant effect on yield. Genotypes F1-069, F1-077, F1-226, F1-038, and F1-128 have the lowest ASR based on non-parametric and parametric stability models and there were identified as the most stable. AMMI analysis identified F1-128, F1-135, F1-038, and F1-069 as the most stable genotypes. F1-38 (G1), F1-69 (G2), F1-128 (G6) were found to be the most stable genotypes based on ASV analysis, while GGE biplot identified F1-38 (G1) and F1-69 (G2) genotypes as the stable genotypes. Other genotypes were considered to as location-specific. Based on AMMI, ASV, and GGE Biplot models, F1-038, and F1-069 were identified as stable genotypes. They produced higher yields than other genotypes. Therefore, the F1-038 and F1-069 genotypes can be potentially recommended as superior varieties for West Java, Indonesia.

Effect of food safety training on behavior change of food handlers: A case of orange-fleshed sweetpotato purée processing in Kenya

Sweetpotato purée processing is new to Kenya and a rapidly growing value addition activity among informal, small, and medium-sized food enterprises (SMEs) in sub-Saharan Africa (SSA). Inadequate knowledge of food safety and poor hygiene practices by food handlers, low level of compliance with Good Manufacturing Practices (GMPs), and microbial contamination are major food safety challenges in orange-fleshed sweetpotato (OFSP) purée processing in Kenya. The extent of food safety training in enhancing food safety in rural-based SMEs and food processing environments has not been fully investigated. This study aimed at evaluating the impact of food safety training on food safety knowledge and hygiene practices of food handlers and in control of microbial contamination in OFSP purée processing in Kenya. Pre- and post-food safety training assessments were conducted to determine food handler's (N = 14) knowledge and practices on food safety. Food, water, and swab samples (n = 62) from the processing environment were collected before and two months after the training and analyzed for food hygiene indicator microorganisms. The findings indicate a significant (p < 0.05) improvement in overall food safety knowledge and practices of food handlers after the training. Poor knowledge scores were exhibited on aspects of cross-contamination, cleaning, and sanitation but these significantly (p < 0.05) improved after the training. Similarly, microbial counts on food equipment surfaces, installations, personnel hands, and in the final product (OFSP purée) significantly (p < 0.05) declined to acceptable levels after the food safety training. Total counts, yeasts and molds, S. aureus, Enterobacteriaceae, and total coliforms counts in the packaged OFSP purée were 2.6, 1.8, 1.5, 1.9, and 1.2 LOG CFU/g respectively hence suitable for its current application as an ingredient in baked products. The findings from this study indicate food safety training as an appropriate tool for improving food handler's knowledge and hygiene practices as well as enhancing microbial safety and quality of processed foods in SMEs if necessary food safety support resources are provided.

Phytochemicals in Leaves and Roots of Selected Kenyan Orange Fleshed Sweet Potato (OFSP) Varieties

This study reports the inherent phytochemical contents in leaves and roots of nine sweet potato varieties from Kenya. Results indicated that vitamin C content varied significantly (P < 0.05) among the sweet potato varieties regardless of the plant part, leaves having significantly (P < 0.05) higher levels than in the roots. Total flavonoids and phenolic compounds differed significantly (P < 0.05) among varieties, higher values were found in leaves than in roots. Flavonoid contents in roots ranged from below detectable limits (Whitesp) to 25.8 mg CE/100 g (SPK031), while in leaves it ranged from 4097 to 7316 mg CE/100 g in SPK4 and Kenspot 5, respectively. Phenolic content was below detectable limits in the roots of whitesp but it was in substantial amounts in orange fleshed varieties. The β-carotene content was significantly (P < 0.05) higher in leaves (16.43-34.47 mg/100 g dry weight) than in roots (not detected-11.1 mg/100 g dry weight). Total and phytic phosphorus were directly correlated with phytate contents in leaves and the roots. Tannins and soluble oxalates varied significantly (P < 0.05) with variety and plant part being higher in leaves. The current information is important for ration formulations and dietary recommendations utilizing sweet potato leaves and roots. Future studies on effects of processing methods on these phytochemicals are recommended.

Bioavailability of Selected Micronutrients in Teff-based Complementary Infant Foods

Background:

The problem of micronutrient malnutrition is affecting millions of infants in the developing countries. One of the major issues that aggravates the problem is lack of appropriately processed complementary foods in which the bioavailability of the major micronutrients is improved.

Methods:

Teff, soybean and orange-fleshed sweet potato were separately processed into their respective flours and blended in a ratio of 70:20:10, respectively, to prepare household- and industrial-level complementary foods. The ingredients and developed complementary foods were analysed for their vitamin A, calcium, iron, zinc and phytate contents. Moreover, phytate: mineral molar ratios of calcium, iron and zinc in the complementary foods were calculated to determine their bioavailability.

Results:

The vitamin A values obtained in the complementary foods were appreciable; they were in the range of 91.89 to 160.97 µgRE/100 g. Phytate content of teff and soybean was significantly (p ≤ 0.05) reduced by the household practices employed for processing them. However, the reduction was not significant (p > 0.05) in the household-level complementary foods because of the small quantity of germinated teff flours used. Calcium, iron and zinc compositions of all complementary foods closely met the recommended levels for 6 to 8 month-old infants. Phytate: mineral molar ratios for calcium and zinc in all complementary foods were below maximum recommended limits indicating their good bioavailability. In case of iron, these ratios were above the critical limit except that of the industriallevel complementary foods.

Conclusion:

Generally, complementary foods with improved compositions and bioavailability of the micronutrients analysed were developed from the teff-soybean-orange-fleshed sweet potato formulations.

Metabolic diversity in sweet potato (Ipomoea batatas, Lam.) leaves and storage roots

Sweet potato (Ipomoea batatas, Lam.) is an important root vegetable in developing countries. After its domestication in Neotropical America, human migration led to the distribution of the sweet potato plant throughout the world. Both leaf and storage root are high in compounds of nutritional value. Yet, the storage roots are of particular value due to their significant content of provitamin A (β-carotene). The breeding effort for elite sweet potato lines led to the reduction of genetic diversity and the potential to improve other traits. The focus of the present study was to assess the metabolic diversity of 27 sweet potato cultivars including landraces and improved varieties. A metabolite profiling approach was optimised for sweet potato leaf and storage root tissue and 130 metabolites identified with three different analysis platforms. The data highlighted a lack of correlation between storage root phenotype and leaf metabolism. Furthermore, the metabolic diversity of storage roots was based on the secondary metabolism, including phenylpropanoids and carotenoids. Three cultivars of three different flesh colouration (yellow, orange and purple) showed a significant difference of the primary metabolism. This data demonstrates the value of metabolite profiling to breeding programs as a means of identifying differences in phenotypes/chemotypes and characterising parental material for future pre-breeding resources.

Production, Utilization and Nutritional benefits of Orange Fleshed Sweetpotato (OFSP) Puree Bread: A Review

Bread though an exotic food product in sub-Saharan Africa, has been an important cereal product consumed by most individuals among the vast Sub-Saharan African population. Bread formulations in both the local and industrial production have evolved. The latest and emerging technology in bread formulation involve the incorporation of orange-fleshed sweetpotato (OFSP) puree. OFSP puree-based bread is commercially available across sub-Saharan Africa (SSA) and is being promoted due to the potential nutritional benefits that it possesses. Together with OFSP flour based bread, OFSP puree based bread serves as a good food vehicle for β-carotene; this serves to alleviate vitamin A deficiency (VAD) especially among the vulnerable population in SSA. The production of OFSP puree based bread has so far been relying on fresh OFSP puree or cold-chain stored OFSP puree. However, this has presented economic challenges and problems to the sustainability and expansion in OFSP puree bread production. Cold chain stored OFSP puree is capital intensive and has inconsistent supply. With the development of shelf-storable preservative treated OFSP puree, most of these challenges will be overcome without undoing the currently harnessed benefits. The use of OFSP puree in bread baking can then be expanded easily at minimal production costs and maximum retention of nutritional quality. Therefore, the use of the shelf-storable OFSP puree in bread baking needs to be evaluated further to present a substantiated case for its use. The current review has been developed with focus on the scientific advances in the production of OFSP puree based bread from both historical and a forecast perspective. The scientific progress and breakthroughs in the use of OFSP puree in bread are critically reviewed.

Development of a quantitative approach using Raman spectroscopy for carotenoids determination in processed sweet potato

The orange-fleshed sweet potato is a vegetable-rich in carotenoids. The thermic treatment for sweet potato processing can decrease the content of these constituents in the foods, lowering their bioactive properties. Raman spectroscopy has been growing as a fast tool to food analysis, especially for detection of low concentrations of carotenoids and to the monitoring of its degradation profile over time. Therefore, in this work were evaluated two methods of drying, hot air and microwaving with rotary drum, combined with quantitative Raman spectroscopy. The results showed carotenoids degradation around 50% for both types of drying processes studied. PCA plot proved the potential of reproducibility of analyses for microwave drying samples. For samples heated with hot air, the best linear correlation achieved was R² = 0.90 and by microwave was R² = 0.88. Also, partial least squares (PLS) regression models were constructed obtaining a satisfactory coefficient of determination.

Household Consumption of Orange-Fleshed Sweet Potato and its Associated Factors in Chipata District, Eastern Province Zambia

BACKGROUND

The Integrating Orange Project promotes production and consumption of orange-fleshed sweet potato (OFSP) to address vitamin A deficiency among rural populations of Zambia since 2011.

OBJECTIVE

This study assessed household production and consumption of OFSP and identified factors associated with consumption thereof in Integrating Orange Project areas in Chipata district, Zambia.

METHODS

Respondents of 295 randomly selected households were interviewed using a structured questionnaire during the sweet potato harvest season. Associations between OFSP consumption and household factors were assessed using χ² tests.

RESULTS

Frequency of OFSP consumption was categorized as ≥4 days during the last 7 days (30.2%), 1 to 3 days during the last 7 days (49.5%), eats OFSP but not during the last 7 days (7.1%), and never (13.2%). In total, 60.3% of households planted OFSP, and 40.0% bought OFSP, mostly from farmers within the community. Orange-fleshed sweet potato consumption was associated with the presence of children aged less than 5 years in the household ( P = .018), production of OFSP ( P < .001), purchasing of OFSP ( P < .001), and respondent having knowledge on health benefits of OFSP ( P = .014). Age and sex of the household head and household size had no association with OFSP consumption ( P > .05).

CONCLUSION

A high percentage of households consumed OFSP during the harvesting season in Integrating Orange Project areas. Programs promoting OFSP consumption should thus focus on OFSP production and sensitizing households on nutritional benefits of OFSP and target households with children aged less than 5 years as entry point.

Incorporating orange-fleshed sweet potato into the food system as a strategy for improved nutrition: The context of South Africa

Orange-fleshed sweet potato (OFSP) is considered the single most successful example of biofortification of a staple crop, and presents a feasible option to address vitamin A deficiency. Though initially promoted as part of a crop-based approach focusing on production and consumption at household level, it evolved into small-scale commercial production, predominantly in Sub-Saharan Africa. This paper reviews OFSP initiatives in relation to the South African food environment and food supply systems, also identifying opportunities for scaling out OFSP in a situation where sweet potato is not eaten as a staple. Current per capita consumption of sweet potato is low; the focus is thus on increasing consumption of OFSP, rather than replacing cream-fleshed varieties. For the major OFSP variety, Bophelo, 66g consumption can be sufficient to meet the recommended daily allowance for 1-3year old children (300μRE vitamin A). Despite a national Vitamin A supplementation programme and fortified staple foods in South Africa, 43.6% of children under 5years of age were reported to be vitamin A deficient in 2012, indicating a stronger need to promote the consumption of Vitamin A-rich foods, such as OFSP. To increase availability of and access to OFSP, all aspects of the food supply system need to be considered, including agricultural production, trade, food transformation and food retail and provisioning. Currently, small-scale commercial OFSP producers in South Africa prefer to deliver their produce to local informal markets. To enter the formal market, small-scale producers often have difficulties to meet the high standards of the retailers' centralised procurement system in terms of food quality, quantity and safety. Large retailers may have the power to increase the demand of OFSP, not just by improving availability but also by developing marketing strategies to raise awareness of the health benefits of OFSP. However, currently the largest scope for scaling out is through a number of public sector programmes such as the National School Nutrition Programme, Community Nutrition and Development Centres, Small-holder Farmer programmes and Agriparks. Though the major approach is focused on unprocessed, boiled OFSP, there are unexploited opportunities for processing of OFSP. However, the nutritional quality of products should be a main consideration within the context of the co-existence of undernutrition, overnutrition and micronutrient deficiencies in the country.

A Review of Production, Post-harvest Handling and Marketing of Sweetpotatoes in Kenya and Uganda

Sweetpotato (Ipomea batatas) is a versatile crop that serves the roles of food and nutrition security, cash crop in both raw and processed forms. It is a source of livestock feed and has great potential as a raw material for industrial processing. The potential of sweetpotato has been greatly under exploited by the fact that it has been regarded as a poor man’s food and is mainly grown under marginal conditions for subsistence by most producers, who are rural small-scale farmers in developing countries, such as Kenya and Uganda. Losses in the highly perishable root crop and its leaves are exacerbated by lack of appropriate postharvest knowledge, technologies and facilities. Inadequate information on available cultivars also limits the maximum utilization of the crop and leaves. The current review examines production potential, post harvest handling practices, marketing, and physicochemical and nutritional properties of sweet potatoes.

Development and Identification of SSR Markers Associated with Starch Properties and β-Carotene Content in the Storage Root of Sweet Potato (Ipomoea batatas L.)

Sweet potato (Ipomoea batatas L.) is a nutritious food crop and, based on the high starch content of its storage root, a potential bioethanol feedstock. Enhancing the nutritional value and starch quantity of storage roots are important goals of sweet potato breeding programs aimed at developing improved varieties for direct consumption, processing, and industrial uses. However, developing improved lines of sweet potato is challenging due to the genetic complexity of this plant and the lack of genome information. Short sequence repeat (SSR) markers are powerful molecular tools for tracking important loci in crops and for molecular-based breeding strategies; however, few SSR markers and marker-trait associations have hitherto been identified in sweet potato. In this study, we identified 1824 SSRs by using a de novo assembly of publicly available ESTs and mRNAs in sweet potato, and designed 1476 primer pairs based on SSR-containing sequences. We mapped 214 pairs of primers in a natural population comprised of 239 germplasms, and identified 1278 alleles with an average of 5.972 alleles per locus and a major allele frequency of 0.7702. Population structure analysis revealed two subpopulations in this panel of germplasms, and phenotypic characterization demonstrated that this panel is suitable for association mapping of starch-related traits. We identified 32, 16, and 17 SSR markers associated with starch content, β-carotene content, and starch composition in the storage root, respectively, using association analysis and further evaluation of a subset of sweet potato genotypes with various characteristics. The SSR markers identified here can be used to select varieties with desired traits and to investigate the genetic mechanism underlying starch and carotenoid formation in the starchy roots of sweet potato.

Orange-Fleshed Sweet Potato: Successes and Remaining Challenges of the Introduction of a Nutritionally Superior Staple Crop in Mozambique

BACKGROUND

Chronic vitamin A deficiency affects both women and children in Mozambique and populations worldwide and cannot be addressed through supplementation alone. Food-based approaches encouraging the consumption of vitamin A-rich foods, such as the orange-fleshed sweet potato (OFSP), have the potential to positively affect vitamin A status. A range of OFSP varieties have been introduced in sub-Saharan Africa in rural and urban environments and emergency and nonemergency contexts.

OBJECTIVE

To highlight the successes to date and remaining challenges of the introduction of OFSP to increase vitamin A consumption in Mozambique, collating a time line of key events.

METHODS

A systematic review of literature using The Preferred Reporting Items for Systematic Reviews and Meta-Analyses.

RESULTS

The systematic search resulted in 20 studies that met inclusion criteria. Data extracted include author and year, study location and duration, project partners, project title, sample size and characteristics, objectives, methods and measures, and outcomes.

CONCLUSIONS

Orange-fleshed sweet potatoes are widely accepted by Mozambican farmers and consumers, and various studies show a positive impact on vitamin A status due to the introduction of this nutritionally superior staple crop. Remaining challenges include vine preservation, pest and disease management, market development, and storage and processing.

Comparison of content and in vitro bioaccessibility of provitamin A carotenoids in home cooked and commercially processed orange fleshed sweet potato (Ipomea batatas Lam)

Vitamin A deficiency (VAD) remains a public health problem in some regions of Brazil. Increased use of orange-fleshed sweet potato (OFSP) as a source of pro-vitamin A represents a potential strategy for prevention of VAD. We compared the pro-vitamin A content, vitamin A equivalency and bioaccessibility of β-carotene (βC) of two varieties of home cooked OFSP and two commercial sources of processed OFSP. Pro-vitamin A carotenoid content in home cooked, Beauregard variety of OFSP exceeded that in Amelia variety and commercial products for babies. All-trans-βC was the most abundant carotenoid in raw, cooked and commercial OFSP. Boiling and frying OFSP generally decreased total βC. A serving of 100 g FW Beauregard variety of cooked OFSP contained greater than 100% of the estimated average requirement (EAR) for children and women, and up to 92% EAR for lactating women. Although the efficiency of micellarization of all-trans-βC during simulated digestion of OFSP was relatively low (4-8%) and significantly less than for cis-isomers, the quantities of trans-βC incorporated into micelles from boiled Beauregard and fried Amelia varieties exceeded that in micelles generated by digesting commercial OFSP. The bioaccessibility of pro-vitamin A carotenoids in the micelle fraction of digested OFSP was confirmed with differentiated cultures of Caco-2 human intestinal cells. Continued development of OFSP such as the Amelia and Beauregard varieties that are rich in trans-βC and dissemination of best practices for home cooking are encouraged to increase consumption of this food to decrease the risk of vitamin A deficiency in Brazil.

Assessment of genetic diversity of sweet potato in Puerto Rico

Sweet potato (Ipomoea batatas L.) is the seventh most important food crop due to its distinct advantages, such as adaptability to different environmental conditions and high nutritional value. Assessing the genetic diversity of this important crop is necessary due to the constant increase of demand for food and the need for conservation of agricultural and genetic resources. In Puerto Rico (PR), the genetic diversity of sweet potato has been poorly understood, although it has been part of the diet since Pre-Columbus time. Thus, 137 landraces from different localities around PR were collected and subjected to a genetic diversity analysis using 23 SSR-markers. In addition, 8 accessions from a collection grown in Gurabo, PR at the Agricultural Experimental Station (GAES), 10 US commercial cultivars and 12 Puerto Rican accessions from the USDA repository collection were included in this assessment. The results of the analysis of the 23 loci showed 255 alleles in the 167 samples. Observed heterozygosity was high across populations (0.71) while measurements of total heterozygosity revealed a large genetic diversity throughout the population and within populations. UPGMA clustering method revealed two main clusters. Cluster 1 contained 12 PR accessions from the USDA repository collection, while cluster 2 consisted of PR landraces, US commercial cultivars and the PR accessions from GAES. Population structure analysis grouped PR landraces in five groups including four US commercial cultivars. Our study shows the presence of a high level of genetic diversity of sweet potato across PR which can be related to the genetic makeup of sweet potato, human intervention and out-crossing nature of the plant. The history of domestication and dispersal of sweet potato in the Caribbean and the high levels of genetic diversity found through this study makes sweet potato an invaluable resource that needs to be protected and further studied.

Insect pests of sweetpotato in Uganda: farmers' perceptions of their importance and control practices

Insect pests are among the most important constraints limiting sweetpotato (Ipomoea batatas) production in Africa. However, there is inadequate information about farmers' knowledge, perceptions and practices in the management of key insect pests. This has hindered development of effective pest management approaches for smallholder farmers. A standard questionnaire was used to interview individual sweetpotato farmers (n = 192) about their perception and management practices regarding insect pests in six major sweetpotato producing districts of Uganda. The majority (93%) of farmers perceived insect pests to be a very serious problem. With the exception of Masindi and Wakiso districts where the sweetpotato butterfly (Acraea acerata) was the number one constraint, sweetpotato weevils (Cylas puncticollis and C. brunneus) were ranked as the most important insect pests. Insecticide use in sweetpotato fields was very low being highest (28-38% of households) in districts where A. acerata infestation is the biggest problem. On average, 65% and 87% of the farmers took no action to control A. acerata and Cylas spp., respectively. Farmers were more conversant with the presence of and damage by A. acerata than of Cylas spp. as they thought that Cylas spp. root damage was brought about by a prolonged dry season. Different levels of field resistance (ability of a variety to tolerate damage) of sweetpotato landraces to A. acerata (eight landraces) and Cylas spp. (six landraces) were reported by farmers in all the six districts. This perceived level of resistance to insect damage by landraces needs to be investigated. To improve farmers' capabilities for sweetpotato insect pest management, it is crucial to train them in the basic knowledge of insect pest biology and control.

Orange-fleshed sweet potato-based infant food is a better source of dietary vitamin A than a maize-legume blend as complementary food

BACKGROUND

White maize, which is widely used for complementary feeding and is seldom fortified at the household level, may be associated with the high prevalence of vitamin A deficiency among infants in low-income countries.

OBJECTIVE

The nutrient composition of complementary foods based on orange-fleshed sweet potato (OFSP) and cream-fleshed sweet potato (CFSP), maize-soybean-groundnut (Weanimix), and a proprietary wheat-based infant cereal (Nestlé Cerelac) were assessed using the Codex Standard (CODEX STAN 074-1981, Rev. 1-2006) specification as a reference. Additionally, the costs of OFSP complementary food, CFSP complementary food, and Weanimix production at the household level were estimated. Phytate and polyphenols, which limit the bioavailability of micronutrients, were assessed.

METHODS

Energy, macronutrients, and micronutrients listed as essential composition in the Codex Standard were determined and expressed as energy or nutrient density.

RESULTS

All the formulations met the stipulated energy and nutrient densities as specified in the Codex Standard. The beta-carotene content of OFSP complementary food exceeded the vitamin A specification (60 to 180 microg retinol activity equivalents/100 kcal). All the formulations except Weanimix contained measurable amounts of ascorbic acid (> or = 32.0 mg/100 g). The level of phytate in Weanimix was highest, about twice that of OFSP complementary food. The sweet potato-based foods contained about twice as much total polyphenols as the cereal-based products. The estimated production cost of OFSP complementary food was slightly higher (1.5 times) than that of Weanimix.

CONCLUSIONS

OFSP complementary food is a good source of beta-carotene and would therefore contribute to the vitamin A requirements of infants. Both OFSP complementary food and Weanimix may inhibit iron absorption because of their high levels of polyphenols and phytate, respectively, compared with those of Nestlé Cerelac.

Bioavailability of iron, zinc, and provitamin A carotenoids in biofortified staple crops

International research efforts, including those funded by HarvestPlus, a Challenge Program of the Consultative Group on International Agricultural Research (CGIAR), are focusing on conventional plant breeding to biofortify staple crops such as maize, rice, cassava, beans, wheat, sweet potatoes, and pearl millet to increase the concentrations of micronutrients that are commonly deficient in specific population groups of developing countries. The bioavailability of micronutrients in unfortified staple crops in developing regions is typically low, which raises questions about the efficacy of these crops to improve population micronutrient status. This review of recent studies of biofortified crops aims to assess the micronutrient bioavailability of biofortified staple crops in order to derive lessons that may help direct plant breeding and to infer the potential efficacy of food-based nutrition interventions. Although reducing the amounts of antinutrients and the conduction of food processing generally increases the bioavailability of micronutrients, antinutrients still possess important benefits, and food processing results in micronutrient loss. In general, biofortified foods with relatively higher micronutrient density have higher total absorption rates than nonbiofortified varieties. Thus, evidence supports the focus on efforts to breed plants with increased micronutrient concentrations in order to decrease the influence of inhibitors and to offset losses from processing.

Nutritional Analysis of Vitamin A Enriched Bread from Orange Flesh Sweet Potato and Locally Available Wheat Flours at Samre Woreda, Northern Ethiopia

Vitamin A deficiency (VAD) is a public health problem in Ethiopia. Periodic supplementation of vitamin A (VA) capsules has developed as a short-term life saving intervention. However, it is important to shift from a subsidized periodic capsule distribution to a more sustainable food-based intervention, which could supply VA in the diet of low income rural communities. Orange flesh sweet potato (OFSP) was selected in this study as a potential raw material that used in food-based intervention, because of its high β-carotene content (naturally biofortified food). Therefore, this study aimed to analyze nutritional compostion of the VA enriched breads for pre-school children from OFSP and locally available Wheat flours of the study area. Blending of OFSP flour with whole Wheat flour (WWF) was conducted at laboratory by employing Complete Randomized Design (CRD). i.e. four bread blends of OFSP flour:WWF (0:100, 10:90, 20:80 and 30%:70%) were prepared and subjected to nutritional analysis at Ethiopian Health and Nutrition Research Institute (EHNRI). For proximate and β-carotene analysis AOAC (2000) standard method and manual column chromatography were used, respectively. The data were analyzed using SPSS, versions 16. Bread enriched with 30% OFSP flour can contribute 83.3 and 74.2% of VA to 3 and 4-6 years old children’s daily requirement, respectively. Therefore, WWF can be substituted by 30% OFSP flour for pre-school children’s bread making. A general trend of nutrient analysis showed that moisture, ash, fiber, β-carotene increased significantly (p < 0.05) as proportion of OFSP flour increased; while protein, fat, carbohydrate and energy content decreased. Therefore, OFSP flour enriched breads have added advantages nutritionally, especially in β-carotene. This will give responsible individuals, policymakers and donors more confidence to invest and work in OFSP for alleviation of VAD.

The use of sensory attributes, sugar content, instrumental data and consumer acceptability in selection of sweet potato varieties

BACKGROUND

As eating quality is important for adoption of new varieties, nine orange-fleshed and three cream-fleshed sweet potato varieties were assessed for sensory characteristics, dry mass and free sugar content, instrumental texture and colour and consumer acceptability (n =  216) in a peri-urban South African setting.

RESULTS

Cream-fleshed varieties were higher in yellow-green colour and sweet potato-like flavour and lower in graininess. Orange-fleshed varieties were higher in pumpkin-like flavour, orange colour, discolouration and sucrose content. Partial least squares regression analysis showed that the most accepted varieties (Impilo, Excel, Resisto, 2001_5_2, Serolane, W-119 and Monate) were associated with sweet flavour, dry mass and maltose content, while the least accepted varieties (Beauregard, Khano and 1999_1_7) were associated with wateriness. Pearson correlation analysis highlighted correlations of sensory attributes yellow and orange with instrumental colour measurements (colour a* and colour b*), instrumental firmness with sensory firmness, dry mass with sensory wateriness, and maltose content with sensory sweet and sweet potato-like flavour. The varieties were clustered into three groups. Consumer acceptability for eating quality correlated with maltose content, dry mass and sweet flavour.

CONCLUSION

Chemical and instrumental measurements were identified to evaluate key attributes and will be useful in the intermediate phases of sweet potato varietal development.