Carrots of Many Colors Provide Basic Nutrition and Bioavailable Phytochemicals Acting as a Functional Food

ABSTRACT: Hippocrates, a philosopher who lived from 460 to 359 BC is often quoted as saying, “Let your food be thy medicine and your medicine be thy food.” Having lived just shy of a century at a time when life expectancies were much less, he must have understood the importance of a healthy diet. A diet high in fruit and vegetables has been linked to optimal health in a variety of studies. One vegetable that has gained popularity is the carrot due in part to the introduction of “cut & peel” convenience packages. Although most people in the United States know carrots as an orange vegetable that can be eaten raw or in a variety of cooked dishes, original carrots were yellow and purple. These carrot varieties are currently undergoing phenotypic recurrent selection to improve the profile of compounds considered to be beneficial. This process is called biofortification, which has increased provitamin A content by >40% since 1970. The most novel carrot produced to date is an orange–purple–red variety that not only contains provitamin A activity as α‐ and β‐carotene, but also contains anthocyanins and the nonprovitamin A carotenoid lycopene, of which both are potent antioxidants. A functional food is one that provides benefit beyond basic nutrition. Biofortified carrots of many colors not only provide vitamin A, but may contribute to optimal health. Because supplements have not been shown to be overly beneficial, except for correcting deficiencies, whole food‐based approaches to enhance health by utilizing functional foods such as biofortified carrots should be considered.     

Physical properties and carotenoid content of maize kernels and its nixtamalized snacks

Vitamin A and protein deficiencies afflict hundreds of millions of people, and because maize is a staple food providing a large portion of energy and nutrients for many, its genetic fortification or biofortification could significantly contribute to alleviating malnutrition. Therefore, we measured carotenoid and tryptophan contents for grain, nixtamalized (lime-cooked) maize, and processed snacks of 13 maize genotypes including landraces, quality protein maize (QPM) and non-QPM hybrids. An average 36% loss of provitamin A and an 8% increase in tryptophan were observed following nixtamalization and subsequent snack preparation by deep-frying. The correlations for physical properties of grain and maize flour with provitamin A were calculated to investigate whether secondary traits may be useful as indicators of provitamin A content. The correlation of chroma values with provitamin A contents was significant (P < 0.05) for 15% and 25% hydrated maize flour (r = 0.57 and r = 0.51, respectively), but was not significant for whole maize kernels.Industrial relevanceYellow maize is used as food and feed. Possible methodologies for rapid carotenoid estimation for industrial purposes like corn flakes or for the poultry industry will be of importance. One of the objectives of this work was to establish correlation between physical parameters and carotenoid concentration in maize. The correlation of chroma values with provitamin A contents was significant (P < 0.05) for 15% and 25% hydrated maize flour (r = 0.57 and r = 0.51, respectively), which could be explored as a methodology for rapid and inexpensive estimation of provitamin A and total carotenoids in maize. Lime-cooking is the traditional method for maize preparation in Mexico and Central America. The estimation of carotenoid losses during this process and the bioavailability studies are important to measure the impact of biofortified maize in the populations with provitamin A deficiencies. During this work we have determined that an average 36% loss of provitamin A and an 8% increase in tryptophan were observed following nixtamalization and subsequent snack preparation by deep-frying.     

Global Concerns with B Vitamin Statuses: Biofortification,Fortification, Hidden Hunger,Interactions, and Toxicity

The prevalence of undernutrition due to insufficient energy intake has been reduced by nearly 50% since 1990. This reduction is largely attributed to improved yields of staple crops, such as wheat, rice, and maize; however, these improvements did little for micronutrient deficiencies that affect an estimated two billion people worldwide. Starchy staple crops are energy dense but are often lacking in one or more B vitamins, making resource‐constrained people who consume monotonous diets comprised predominantly of these staples at risk for developing deficiency. B vitamin deficiencies occur due to a poor overall nondiversified diet and rarely occur alone. Many B vitamins are essential cofactors involved in the metabolism of other nutrients, including other B vitamins, whereby the deficiency of one B vitamin affects the metabolism and status measurements of another. Food fortification efforts have nearly eradicated diseases of extreme B vitamin deficiency, such as beriberi from thiamin deficiency and pellagra from niacin deficiency. However, subclinical deficiency, sometimes referred to as hidden hunger, is still common especially in low‐income countries. Most dietary B vitamins, due to their water‐soluble nature, are not a concern for excessive intakes, but synthetic forms used for fortification and supplements sometimes can have adverse effects when consumed in high amounts. Biofortified crops offer a long‐term sustainable method to increase the amount of dietary B vitamins for people who rely on staple crops for most of their caloric intake. Efforts have been made to improve B vitamin content of crops, especially for thiamin, vitamin B₆, and folate, but none have undergone human feeding trials; therefore, more research is needed to provide sustainable and scalable solutions in many parts of the world.     

Recent advances in banana (musa spp.) biofortification to alleviate vitamin A deficiency

Abstract

Vitamin A deficiency (VAD) is one of the most prevalent micronutrient deficiencies that disproportionately affects low income populations in developing countries. Traditional breeding and modern biotechnology have significant potential to enhance micronutrient bioavailability in crops through biofortification. Bananas (Musa spp.) are economically important fruit crops grown throughout tropical and sub-tropical regions of the world where VAD is most prevalent. Some banana genotypes are rich in provitamin A carotenoids (pVACs), providing an opportunity to use bananas as a readily available vehicle for provitamin A delivery. This review summarizes the progress made in carotenoid research in bananas relative to banana diversity and the use of conventional breeding and transgenic approaches aimed at banana biofortification to address vitamin A deficiency. Existing reports on sampling strategies, pVAC retention and bioavailability are also evaluated as essential components for a successful banana biofortification effort. The wide variability of pVACs reported in banana cultivars coupled with recent advances in unraveling the diversity and genetic improvement of this globally important but often-neglected staple fruit crop underscores their importance in biofortification schemes.     

The effectiveness of extension strategies for increasing the adoption of biofortified crops: the case of quality protein maize in East Africa

Biofortified crops can be promoted with extension strategies based on their agronomic qualities, nutritional qualities, or both, but the effectiveness of these different strategies has so far not been studied. Since 2003, quality protein maize (QPM) has been disseminated using both approaches in East Africa. This study therefore analyzes the effectiveness of promoting biofortified crops based on their agronomic and their nutritional qualities, using the adoption of QPM cultivars in East Africa as an example. A random sample survey was conducted in Ethiopia, Kenya, Tanzania, and Uganda, with 423 households from QPM extension areas and 539 households from similar areas outside the extension zone. Propensity score matching and regression analysis were used to assess determinants of QPM adoption, including farmers’ awareness of QPM, understanding of its nutritional benefits, and evaluation of agronomic performance to evaluate the agronomic and nutritional extension strategies. Results showed high familiarity with QPM, but low understanding of nutritional benefits. Farmers evaluated QPM varieties as equal or superior to conventional maize for post-harvest traits, but not always for agronomic traits (in particular yield in Ethiopia and Tanzania). Adoption in extension areas varied from 73 % in Uganda and 25 % in Tanzania to none in Kenya. Key factors that increased adoption were farmers’ participation in extension, having heard of QPM, higher overall evaluation ratings of QPM vs. conventional maize varieties, and understanding of QPM’s nutritional benefits. Agronomic performance was found to be more important than an understanding of nutritional benefits. For biofortified crops to be adopted and have a nutritional impact on target populations, they should, first and foremost, be agronomically equal or superior to conventional varieties. If farmers are convinced of the agronomic performance of biofortified crops, additional gains in adoption can be achieved by focusing extension efforts on imparting to farmers knowledge of the benefits of biofortified crops for human nutrition.     

Progress and challenges in improving the nutritional quality of rice (Oryza sativa L.)

Rice is a staple food for more than 3 billion people in more than 100 countries of the world but ironically it is deficient in many bioavailable vitamins, minerals, essential amino- and fatty-acids and phytochemicals that prevent chronic diseases like type 2 diabetes, heart disease, cancers, and obesity. To enhance the nutritional and other quality aspects of rice, a better understanding of the regulation of the processes involved in the synthesis, uptake, transport, and metabolism of macro-(starch, seed storage protein and lipid) and micronutrients (vitamins, minerals and phytochemicals) is required. With the publication of high quality genomic sequence of rice, significant progress has been made in identification, isolation, and characterization of novel genes and their regulation for the nutritional and quality enhancement of rice. During the last decade, numerous efforts have been made to refine the nutritional and other quality traits either by using the traditional breeding with high through put technologies such as marker assisted selection and breeding, or by adopting the transgenic approach. A significant improvement in vitamins (A, folate, and E), mineral (iron), essential amino acid (lysine), and flavonoids levels has been achieved in the edible part of rice, i.e., endosperm (biofortification) to meet the daily dietary allowance. However, studies on bioavailability and allergenicity on biofortified rice are still required. Despite the numerous efforts, the commercialization of biofortified rice has not yet been achieved. The present review summarizes the progress and challenges of genetic engineering and/or metabolic engineering technologies to improve rice grain quality, and presents the future prospects in developing nutrient dense rice to save the everincreasing population, that depends solely on rice as the staple food, from widespread nutritional deficiencies.     

Maize: A Paramount Staple Crop in the Context of Global Nutrition

Abstract: The maize plant (Zea mays), characterized by an erect green stalk, is one of the 3 great grain crops of the world. Its kernels, like other seeds, are storage organs that contain essential components for plant growth and reproduction. Many of these kernel constituents, including starch, protein, and some micronutrients, are also required for human health. For this reason, and others, maize has become highly integrated into global agriculture, human diet, and cultural traditions. The nutritional quality and integrity of maize kernels are influenced by many factors including genetic background, environment, and kernel processing. Cooking procedures, including nixtamalization and fermentation, can increase accessibility of micronutrients such as niacin. However, man cannot live on maize alone. For one‐third of the world's population, namely in sub‐Saharan Africa, Southeast Asia, and Latin America, humans subsist on maize as a staple food but malnutrition pervades. Strategies to further improve kernel macronutrient and micronutrient quality and quantities are under intense investigation. The 2 most common routes to enhance grain nutritional value are exogenous and endogenous fortification. Although exogenous fortification, such as addition of multivitamin premixes to maize flour, has been successful, endogenous fortification, also known as “biofortification,” may provide a more sustainable and practical solution for chronically undernourished communities. Recent accomplishments, such as low‐phytate, high‐lysine, and multivitamin maize varieties, have been created using novel genetic and agronomic approaches. Investigational studies related to biofortified maize are currently underway to determine nutrient absorption and efficacy related to human health improvement.     

The production of provitamin A‐rich vegetables in home‐gardens as a means of addressing vitamin A deficiency in rural African communities

Vitamin A deficiency remains a public health problem in the developing world. The highest prevalence of vitamin A deficiency is in Africa and Asia (>30%). Dietary modification, a long‐term strategy to address vitamin A deficiency, complements food fortification and vitamin A supplementation programmes. Provitamin A carotenoids from foods of plant origin are more affordable than preformed vitamin A from animal foods, and many resource‐poor households rely on yellow/orange‐fleshed vegetables and fruits and dark‐green leafy vegetables as their main source of vitamin A. The provitamin A carotenoid content in plant foods varies widely and differences among cultivars of the same food exist. Several factors influence the bioavailability of provitamin A carotenoids. The potential contribution of plant foods to vitamin A status depends on the retention of provitamin A carotenoids after storage, preparation and processing. Home‐gardens can provide households with direct access to provitamin A‐rich vegetables that are not readily available or within their financial reach. The components and critical issues of home‐garden projects are described. Copyright © 2006 Society of Chemical Industry     

Effect of storage period on provitamin-A carotenoids retention in biofortified maize hybrids

Vitamin A-rich maize hybrids provide sustainable solutions to malnutrition. However, significant loss of carotenoids during storage reduces its efficacy. Grains of nine sub-tropically adapted crtRB1-based biofortified hybrids along with six normal hybrids were stored under conventional storage for five months. PVAC (β-carotene and β-cryptoxanthin) among crtRB1-based hybrids degraded from initial level of 18.77 to 3.24 µg g⁻¹, while NPVAC (lutein and zeaxanthin) reduced to 10.79 µg g⁻¹ from 19.00 µg g⁻¹ during storage. Among PVAC, β-cryptoxanthin (21.8%) possessed more stability than β-carotene (16.4%). For NPVAC, lutein (61.2%) showed the highest retention than zeaxanthin (50.4%). Majority of the PVAC loss occurred within first three months of storage. Retention for PVAC among crtRB1-based hybrids varied from 14% to 23% indicating the role of favourable genetic factors. APQH1, APQH7 and APH2 were the promising hybrids with higher retention (>20%) of PVAC. This is the first report on identification of provitamin A-rich crtRB1-based biofortified maize hybrids with higher retention during sub-tropical storage.     

Improved production systems for traditional food crops: the case of finger millet in western Kenya

Increasing agricultural productivity through the dissemination of improved cropping practices remains one of the biggest challenges of this century. A considerable amount of literature is dedicated to the adoption of improved cropping practices among smallholder farmers in developing countries. While most studies focus on cash crops or main staple crops, traditional food grains like finger millet have received little attention in the past decades. Traditional food grains have however an important potential to improve food security, reduce micronutrient deficiencies, and enhance smallholder adaptation to climate change. The present study aims to assess the factors that influence adoption decisions among finger millet farmers in western Kenya. Based on cross-sectional household data from 270 farmers, we estimated a multivariate probit model to compare the adoption decisions in finger millet and maize production. While improved practices such as the use of a modern variety or chemical fertilizer are relatively well adopted in maize production, they are less common in finger millet production. Social networks as well as access to extension services play crucial roles in the adoption of improved finger millet practices, while the same variables are of minor importance for the adoption of improved maize practices. A Cobb-Douglas production function shows a positive effect of modern varieties and chemical fertilizer on finger millet yields.     

Fortifying food in the field to boost nutrition: case studies from Afghanistan, Angola, and Zambia

Deficiencies in micronutrients such as iron, vitamin A, and iodine affect billions of people worldwide, causing death, disease, and disability. The UN World Food Programme (WFP) has long been recognised for its ability to deliver food to some of the most remote locations, under the toughest conditions: refugees in border camps, populations cut off by conflict, extremely poor and marginalised people like ethnic minorities, orphans, and widows. Relatively little, however, is known about its efforts to ensure that the food it delivers not only provides enough calories for immediate survival but also provides the vitamins and minerals needed for healthy growth and development. Much of the food delivered by WFP is fortified with iron, vitamin A, and other micronutrients before being shipped. But there are several reasons to mill and fortify food as close to the beneficiaries as possible. For instance, milling and fortifying food locally helps to overcome the problems of the short shelf-life of whole fortified maizemeal. It also enhances the nutritional value of locally procured cereals. And it can foster demand for fortified foods among local consumers beyond WFP beneficiaries, thus nurturing an industry with potentially significant benefits for the health of entire communities. This paper outlines three approaches by WFP to fortifying cereals in Afghanistan, Angola, and Zambia. It examines the challenges faced and the outcomes achieved in an effort to share this knowledge with others dedicated to improving the nutritional status of poor and food-insecure people. In Afghanistan, attempts to mill and fortify wheat flour using small-scale chakki mills were successful but much larger-scale efforts would be needed to promote demand and reach the level of consumption required to address serious iron deficiencies across the country. In Angola, maize has been fortified to combat the persistent occurrence of pellagra, a micronutrient deficiency disease found among people whose diets are dominated by maize. By providing fortification equipment to a commercial mill at the port of Lobito and using a vitamin and mineral pre-mix provided by UNICEF, this project has overcome many of the difficulties common in countries emerging from conflict to provide monthly fortified maize rations to some 115,000 beneficiaries. In Zambia, iron deficiency anaemia was a serious problem among camp-restricted refugees. WFP and its partners imported, installed, and trained workers in the use of two containerized milling and fortification units (MFUs), halved iron-deficiency anaemia, and reduced vitamin A deficiency among camp residents. In addition, WFP dramatically reduced waiting times for refugees who used to have their whole grain maize rations milled at small local facilities with insufficient milling capacity. The context and scale of each of the three case-studies described in this paper was different, but the lessons learned are comparable. All projects were succesful in their own right, but also required a considerable amount of staff time and supervision as well as external technical expertise, limiting the potential for scaling up within the WFP operational context. In order to expand and sustain the provision of fortified cereal flour to WFP beneficiaries and beyond, getting the private milling sector as well as governments on board would be crucial. Where this is not possible, such as in very isolated, difficult to reach locations, strong, specialized partners are a prerequisite, but these are few in number. Alternatively, in such contexts or in situations where the need is urgent and cannot be met through local flour fortification in the short term, or through local purchases of fresh foods, other approaches to improve the diet, such as the use of multimicronutrient formulations, packed for individual or household use, may be more appropriate.     

The contribution of β-carotene to vitamin A supply of humans

Populations that administer highly restrictive diets using a strong dietary regime, excluding certain types of food, might be at risk of vitamin A insufficiency, even in developed countries. Thus, provitamin A carotenoids from plants represent an additional major dietary source of vitamin A for most of the world's population. Our aim was to estimate the contribution of β-carotene to vitamin A supply in industrialized countries using available data from the literature. A total of 11 studies from 8 countries were used, representing data of 121,256 participants. Intakes of total vitamin A, provitamin A carotenoids, including β-carotene were retrieved and used to calculate the retinol activity equivalents (RAE) utilizing current conversion factors. Mean total daily dietary intake of RAE was 1083±175. The mean β-carotene intake was 3.9 mg/day. Preformed vitamin A accounts for nearly 65% of total vitamin A intake, carotenoids make up 35%. No statistical differences between men and women in total intake of retinol were observed. We conclude that a safe vitamin A intake in general cannot be reached by consuming only one component (vitamin A or β-carotene) alone, even in Western countries where animal products are commonly available.     

Genetic variability in Musa fruit provitamin A carotenoids,lutein and mineral micronutrient contents

Bananas and plantains (Musa spp.) are a staple food for millions of impoverished people and as such are an important source of vitamins and micronutrients. To evaluate the potential of Musa spp. to meet dietary micronutrients requirements, we have screened 171 different genotypes for fruit provitamin A carotenoids (pVACs) contents, and a subset of 47 genotypes for macro- and micro-mineral (iron and zinc) contents using standardised sampling and analytical protocols. The results indicate that there is substantial variability in mean fruit pulp pVACs contents between cultivars, and that cultivars with a high fruit pVACs content are widely distributed across the different genome groups but only at a low frequency. The introduction of such high pVACs cultivars has much potential for improving the vitamin A nutritional status of Musa-dependent populations at modest and realistic fruit-consumption levels. In contrast, fruit pulp mineral micronutrient contents (iron and zinc), were low and showed limited inter-cultivar variability, even for genotypes grown under widely-differing environments and soil types. Results are discussed within the framework of the development of strategies to improve the nutritional health and alleviation of micronutrient deficiencies within Musa-consuming population groups.     

Combining experimental auctions with a modified home-use test to assess rural consumers’ acceptance of quality protein maize,a biofortified crop

Biofortification, or breeding food crops for improved nutritional content, is a cost effective way to improve nutritional status. The process can, however, alter the sensory characteristics of the crop, and consumer acceptance is essential for their adoption. The oldest biofortified crop is quality protein maize (QPM), biofortified with essential amino acids, a trait now incorporated in many recently-released varieties in East Africa. To estimate rural consumers’ acceptance and willingness to pay (WTP) for QPM in the dispersed population of Northern Tanzania, a novel method, combining a modified home-use test with a Becker–DeGroot–Marschak experiment, was developed. The results showed that rural consumers in Tanzania could distinguish stiff porridge made from QPM and from conventional maize (CM). They generally preferred the former, as expressed by higher scores during affective tests for texture, taste, and overall qualities. Further, rural consumers who were not provided with information about the nutritional benefits of QPM were willing to pay a premium of 16% over CM, and those who were given information, 39%. The scores on the affective test and the information on QPM’s nutritional benefits were the main factors determining WTP in the experiment, while no personal characteristics of the participants were found to be significant. We conclude that QPM is, at least, as well accepted as conventional maize, and preferred for its sensory characteristics. Information on nutritional benefits increases rural consumers’ willingness to pay for it, so information campaigns may be effective in increasing demand for QPM varieties. However, these varieties need to be competitive for other characteristics that rural households value, in particular, field and storage qualities.     

Carotenoid-rich bananas: a potential food source for alleviating vitamin A deficiency

This review article points out that bananas are an important food for many people in the world. Thus, banana cultivars rich in provitamin A carotenoids may offer a potential food source for alleviating vitamin A deficiency, particularly in developing countries. Many factors are associated with the presently known food sources of vitamin A that limit their effectiveness in improving vitamin A status. Acceptable carotenoid-rich banana cultivars have been identified in Micronesia, and some carotenoid-rich bananas have been identified elsewhere. Bananas are an ideal food for young children and families for many regions of the world, because of their sweetness, texture, portion size, familiarity, availability, convenience, versatility, and cost. Foods containing high levels of carotenoids have been shown to protect against chronic disease, including certain cancers, cardiovascular disease, and diabetes. Because the coloration of the edible flesh of the banana appears to be a good indicator of likely carotenoid content, it may be possible to develop a simple method for selecting carotenoid-rich banana cultivars in the community. Research is needed on the identification of carotenoid-rich cultivars, targeting those areas of the world where bananas are a major staple food; investigating factors affecting production, consumption, and acceptability; and determining the impact that carotenoid-rich bananas may have on improving vitamin A status. Based on these results, interventions should be undertaken for initiating or increasing homestead and commercial production.     

Determination of carotenoids in foods by high-performance liquid chromatography

The mean values of alpha and beta-carotene of 10 fruits and vegetables from supermarkets in Cairo and Alexandria have been determined using HPLC method, and the average vitamin A activities (in retinol equivalents) calculated. Carrots, spinach and sweet potatoes were the best sources of provitamin A activity. Beta-carotene was the more prevalent carotenoid compared with alpha-carotene. An analysis of variance including all foods investigated demonstrated that there were no significant differences among either locations or times of analysis. There was no difference between the analysed values of vitamin A activity and the USDA Handbook No. 8 values.     

Determination of carotenoids in foods by high-performance liquid chromatography.

The mean values of alpha and beta-carotene of 10 fruits and vegetables from supermarkets in Cairo and Alexandria have been determined using HPLC method, and the average vitamin A activities (in retinol equivalents) calculated. Carrots, spinach and sweet potatoes were the best sources of provitamin A activity. Beta-carotene was the more prevalent carotenoid compared with alpha-carotene. An analysis of variance including all foods investigated demonstrated that there were no significant differences among either locations or times of analysis. There was no difference between the analysed values of vitamin A activity and the USDA Handbook No. 8 values.     

Vitamin D and provitamin D in fish

A highly-sensitive high-performance liquid chromatographic method for measuring vitamin D₃ and provitamin D₃ in the edible part of fish was developed. The sample preparation procedure consisted of cold saponification and liquid/liquid extraction of the unsaponifiable matter using a disposable kieselguhr cartridge. For the purification of the sample extracts a semipreparative stage using normal-phase HPLC with UV-detection was applied. A vitamin D and a provitamin D fraction was collected and subsequently quantified by analytical reversed-phase HPLC with electrochemical detection. Internal standardization was used for quantitation. The accuracy of this method was evaluated by recovery experiments. The investigated fish included most of the important fish species consumed in Germany.     

Retention of Provitamin A Carotenoids in Staple Crops Targeted for Biofortification in Africa: Cassava,Maize and Sweet Potato

HarvestPlus, part of the Consultative Group on Internation Agriculture research (CGIAR) Program on Agriculture for Nutrition and Health (A4NH) uses conventional plant breeding techniques to develop staple food crops that are rich in micronutrients, a food-based approach to reduce micronutrient malnutrition known as biofortification. The nutritional breeding targets are established based on the food intake of target populations, nutrient losses during storage and processing and bioavailability. This review collates the evidence on the retention of provitamin A carotenoid (pVAC) after processing, cooking, and storing of the staple crops targeted for pVAC biofortification: cassava, maize, and sweet potato. Sun drying was more detrimental to the pVAC levels (27–56% retention) in cassava than shade (59%) or oven (55–91%) drying, while the pVAC retention levels (66–96%) in sweet potato were not significantly different among the various drying methods. Overall, boiling and steaming had higher pVAC retention (80–98%) compared to baking (30–70%) and frying (18–54%). Gari, the most frequently consumed form of cassava in West Africa had the lowest pVAC retention (10–30%). The pVAC retention of maize grain and cassava and sweet potato flour reached levels as low as 20% after 1–4 months of storage and was highly dependent on genotype. Therefore, we recommend that an evaluation of the pVAC degradation rate among different genotypes be performed before a high pVAC crop is promoted.