Crops that feed the world 6. Past successes and future challenges to the role played by maize in global food security

Maize is one of the most important food crops in the world and, together with rice and wheat, provides at least 30% of the food calories to more than 4.5 billion people in 94 developing countries. In parts of Africa and Mesoamerica, maize alone contributes over 20% of food calories. Maize is also a key ingredient in animal feed and is used extensively in industrial products, including the production of biofuels. Increasing demand and production shortfalls in global maize supplies have worsened market volatility and contributed to surging global maize prices. Climatic variability and change, and the consequent rise in abiotic and biotic stresses, further confound the problem. Unless concerted and vigorous measures are taken to address these challenges and accelerate yield growth, the outcome will be hunger and food insecurity for millions of poor consumers. We review the research challenges of ensuring global food security in maize, particularly in the context of climate change. The paper summarizes the importance of maize for food, nutrition and livelihood security and details the historical productivity of maize, consumption patterns and future trends. We show how crop breeding to overcome biotic and abiotic stresses will play a key role in meeting future maize demand. Attention needs to be directed at the generation of high yielding, stress-tolerant and widely-adapted maize varieties through judicious combination of conventional and molecular breeding approaches. The use of improved germplasm per se will not, however, be enough to raise yields and enhance adaptation to climate change, and will need to be complemented by improved crop and agronomic practices. Faced with emasculated state extension provision and imperfect markets, new extension approaches and institutional innovations are required that enhance farmers’ access to information, seeds, other inputs, finance and output markets. Over the long-term, large public and private sector investment and sustained political commitment and policy support for technology generation and delivery are needed to overcome hunger, raise the incomes of smallholder farmers and meet the challenges of growing demand for maize at the global level.     

Post-harvest losses in African maize in the face of increasing food shortage

Maize is the most important food staple for resource-poor smallholders in Africa, providing food and income to millions. One of the key constraints to improving food and nutritional security in Africa is the poor post-harvest management that leads to between 14 % and 36 % loss of maize grains, thereby aggravating hunger. Post-harvest losses contribute to high food prices by removing part of the supply from the market. Reducing post-harvest losses in maize is an essential component in any strategy to make more food available without increasing the burden on the natural environment. Solving the post-harvest management problems in maize will require cooperation and effective linkage among the following: research, extension, agro-industry, marketing system and favorable policy environment. Biological and socio-economic causes of post-harvest losses in maize in Africa are discussed in relation to climate change and food security, and strategies to reduce the post-harvest losses are suggested.     

Plant breeding for nutrition-sensitive agriculture: an appraisal of developments in plant breeding

Plant breeding for nutrition-sensitive agriculture (NSA) has to address the various aspects of food and nutrition security by taking on an integrated approach. In our article, we summarize past and current developments in plant breeding that are relevant to nutrition in this broader context. We outline how plant breeding can contribute to availability of, access to and utilization of food, and give examples of how the concept of NSA is differently addressed in selected plant breeding projects. Effective targeting towards the needs of vulnerable groups seems to be a key success factor. Differences exist with regard to the underlying concept of technology diffusion, the importance given to agrobiodiversity for improving food and nutrition security, and the degree and quality of participation of target groups. We conclude that the potentials of crop and variety improvement for NSA are far from being tapped. Plant breeding for NSA requires that the inherent focus of most breeding programs on crops and varieties be broadened towards people and their needs. It is thus required to integrate complementary expertise into breeding programs, and to overcome the divide between technology-oriented and system or actor-oriented approaches. Furthermore, it should be acknowledged that commercial breeding needs to be complemented by other initiatives and institutions that focus particularly on food and nutrition security of vulnerable groups. Any efforts to further harmonize agricultural, nutrition, health, environmental, and educational policies, also with international policy frameworks and obligations, could help to create an enabling policy environment for NSA.     

Food and nutrition security in the Hindu Kush Himalayan region

The status of food and nutrition security and its underlying factors in the Hindu‐Kush Himalayan (HKH) region is investigated. In this region, one third to a half of children (<5 years of age) suffer from stunting, with the incidence of wasting and under‐weight also being very high. The prevalence of stunting, wasting and under‐weight in children is particularly high in some mountain areas such as Meghalaya state in India, the western mountains and far‐western hills of Nepal, Balochistan province in Pakistan, eastern Afghanistan, and Chin state in Myanmar. Food habits in the HKH region are changing. This has led to a deterioration in traditional mountain food systems with a decline in agrobiodiversity. Factors such as high poverty and low dietary energy intakes, a lack of hygienic environments, inadequate nutritional knowledge, and climate change and environmental degradation are also influencing food and nutrition security in the HKH region. To achieve sustainable food and nutrition security in the mountains, this study suggests a multi‐sectoral integrated approach with consideration of nutritional aspects in all development processes dealing with economic, social, agricultural and public health issues. © 2017 Society of Chemical Industry     

Effectiveness of hand sorting,flotation/washing,dehulling and combinations thereof on the decontamination of mycotoxin-contaminated white maize

Maize is one of the major staple foods of Sub-Saharan Africa and is consumed as whole or dehulled grain. In this region, where the environmental conditions favour fungal growth and mycotoxin production, the majority of the population are subsistence consumers who, unfortunately, have little or no access to mycotoxin testing of their food. In an attempt to develop feasible reduction strategies in dietary mycotoxin exposure of the population, a three-factorial design experiment was conducted to examine and compare the efficacy of hand sorting, flotation, dehulling and combinations thereof in removing naturally occurring aflatoxins, fumonisins, nivalenol, deoxynivalenol and alternariol in shelled white maize. Regression analysis was used to determine the significant (p < 0.05) process variables on the removal of mycotoxins from the maize. Results from this experiment indicated that hand sorting had the greatest effect on mycotoxin removal, while flotation yielded the least effect. In particular hand sorting left < 6% of aflatoxin B1 and < 5% of fumonisin B1. Based on these results, hand sorting of maize grains is being recommended as a last line of defence against mycotoxin exposure among subsistence consumers.     

Nutritional deterioration of stored Zea mays L. along supply chain in southwestern Ethiopia: Implication for unseen dietary hunger

Maize plays a key role in household food security in southwestern Ethiopia, but its benefits have been negated by high post-harvest losses. Previous loss assessment and management studies have focused mainly on quantity losses. This study was therefore designed to assess nutritional quality losses of stored maize along the supply chain in Jimma Zone, southwestern Ethiopia. Three districts representing potential maize producers and different agro-ecological regimes for maize production were selected for analyses. Sample collection started at harvest and continued for six months at two-month intervals from 21 selected actors along the supply chain. The experiment was conducted for two seasons, and a total of 72 samples were collected during each season. Both nutritional and anti-nutritional analyses were carried out following the international standards of the Association of Official Analytical Chemists. Data were analysed using SAS software (version 9.2) using a general linear model (GLM). The result revealed that moisture content significantly decreases (P < 0.05) as storage duration increases under different actors and agro-ecological conditions. But, showed increment during the final months under farmers' storage conditions. In addition, moisture content at the loading stage was not optimal for safe storage. Crude protein, crude fat, carbohydrate, and calorific value content significantly decreased (P < 0.05) as the storage duration increased, but fibre, ash, and major mineral (Ca, Zn, and Fe) content increased significantly over the storage period. Phytate and tannin content varied with storage duration and agro-ecological setting. Storing maize under traditional conditions along the supply chain resulted in substantial quality losses. This has great implications for nutrition insecurity and unrecognized undernourishment in the society. Additionally, substantial increases in fibre content above the optimum have important effects on nutrient absorption. There is thus a need to develop and disseminate appropriate storage technologies that minimize quality loss in maize stores.     

Opportunities for product innovation using authorised European Union health claims

For authorisation of a health claim in Europe, applicants must follow the procedures in the legislation and in the guidelines for submission of a dossier, as well as the guidance in the European Food Safety Authority's opinions on the scientific requirements for health claims. In addition to the authorised functional benefits of the vitamins and minerals, certain foods and food constituents offer beneficial physiological effects that extend beyond traditionally accepted nutritional effects. The elucidation of these effects is becoming more important, as reflected by the increasing amount of nutrition research and number of product innovations. Provided that they are scientifically substantiated, health claims linked to food and food supplement products can help consumers make well‐informed food choices. The present review focuses on scientific substantiation and consumer understanding of health claims, and it aims to help those involved in academic research, food product development and consumer education about food and health.     

Sorghum Grain: From Genotype,Nutrition, and Phenolic Profile to Its Health Benefits and Food Applications

Globally, sorghum is one of the most important but least utilized staple crops. Sorghum grain is a rich source of nutrients and health‐beneficial phenolic compounds. The phenolic profile of sorghum is exceptionally unique and more abundant and diverse than other common cereal grains. The phenolic compounds in sorghum are mainly composed of phenolic acids, 3‐deoxyanthocyanidins, and condensed tannins. Studies have shown that sorghum phenolic compounds have potent antioxidant activity in vitro, and consumption of sorghum whole grain may improve gut health and reduce the risks of chronic diseases. Recently, sorghum grain has been used to develop functional foods and beverages, and as an ingredient incorporated into other foods. Moreover, the phenolic compounds, 3‐deoxyanthocyanidins, and condensed tannins can be isolated and used as promising natural multifunctional additives in broad food applications. The objective of this review is to provide a comprehensive understanding of nutrition and phenolic compounds derived from sorghum and their related health effects, and demonstrate the potential for incorporation of sorghum in food systems as a functional component and food additive to improve food quality, safety, and health functions.     

The challenges for global harmonisation of food safety norms and regulations: issues for India

Safe and adequate food is a human right, safety being a prime quality attribute without which food is unfit for consumption. Food safety regulations are framed to exercise control over all types of food produced, processed and sold so that the customer is assured that the food consumed will not cause any harm. From the Indian perspective, global harmonisation of food regulations is needed to improve food and nutrition security, the food trade and delivery of safe ready‐to‐eat (RTE) foods at all places and at all times. The Millennium Development Goals (MDGs) put forward to transform developing societies incorporate many food safety issues. The success of the MDGs, including that of poverty reduction, will in part depend on an effective reduction of food‐borne diseases, particularly among the vulnerable group, which includes women and children. Food‐ and water‐borne illnesses can be a serious health hazard, being responsible for high incidences of morbidity and mortality across all age groups of people. Global harmonisation of food regulations would assist in facilitating food trade within and outside India through better compliance, ensuring the safety of RTE catered foods, as well as addressing issues related to the environment. At the same time, regulations need to be optimum, as overregulation may have undue negative effects on the food trade. © 2013 Society of Chemical Industry     

Impact of improved maize adoption on household food security of maize producing smallholder farmers in Ethiopia

In recent years, maize has gained prominence as an important staple crop in Ethiopia second only to teff in terms of acreage. Most of this is grown by semi-subsistence farm households whose livelihoods are tied to crop production and some livestock keeping. Therefore, an important policy question concerns the impact that the reported maize revolution has had on household food security. This paper answers that question by examining the empirical regularities that explain the adoption of improved maize varieties (IMVs) and how this has impacted household food security in a sample of 2327 maize producing households in 39 districts of Ethiopia. An endogenous switching regression model supported by the dose-response continuous treatment effect method was used to empirically assess the impact of IMV adoption on per capita food consumption expenditure and perceived household food security status. Results show that IMV adoption has a robust and positive impact on per capita food consumption and also significantly increases the probability of a smallholder being in food surplus. The advances in the adoption of improved maize has thus contributed significantly to the food security of maize producing smallholders, confirming the role of crop improvement in contributing to food security of agrarian households.     

Prospects for using marker‐assisted breeding to improve maize production in Africa

Maize (Zea mays L.) production in sub‐Saharan Africa has historically been constrained by a number of biotic and abiotic factors, including drought, insects, disease, and weeds. New agricultural research involving genomics and molecular markers may assist plant breeders in developing new varieties that will benefit producers and consumers in this region. Over the past few decades, plant breeders have used molecular markers to identify numerous genomic regions affecting maize production and nutritional value. Marker‐assisted selection (MAS) presents the potential to improve the efficiency of plant breeding by allowing for the transfer of these specific genomic regions of interest and accelerating the recovery of the elite parent background. However, to this point, few examples of successful MAS in breeding programs, particularly those with benefits in Africa, have been noted. This review discusses the use of molecular markers in the identification of quantitative trait loci (QTL) affecting the production and nutritional quality of maize, as well as the potential to use the results from the vast number of QTL studies that have been performed in MAS breeding programs. Copyright © 2008 Society of Chemical Industry     

Diversity among maize populations from Spain and the United States for dough rheology and gluten‐free breadmaking performance

Maize is used for bakery and for gluten‐free food for coeliac patients. Our objective was assessing diversity for dough rheology and breadmaking in maize with different origins, grain types and growth cycles. Endosperm type affected bread crumb colour having dent maize higher L* and a* and instant recovery speed. Population origin affected flotation index, onset pasting temperature, bread crumb colour, hardness and instant recovery speed. Finally, growth cycle affected flotation index, crumb colour L* and a* and cohesiveness. Water‐binding capacity, crumb colour and hardness were the most discriminative parameters for maize. The maize population Andaluz/Daxa was the less distant from wheat parameters, and Tremesino was the most different.     

玉米、花生发酵营养酸奶的研制

以玉米、花生、鲜牛乳为原料 ,以乳酸菌和双岐杆菌为发酵菌 ,发酵研制了一种营养丰富、具有玉米风味和花生香味的发酵酸奶     

Carotenoid diversity in tropical-adapted yellow maize inbred lines

Maize is a staple food for millions of people in sub-Saharan Africa where a significant number of people suffer from vitamin A deficiency. Yellow maize contains both pro-vitamin A and nonprovitamin A carotenoids with potential health benefits to humans. An improvement in the concentration of these compounds can have a positive impact on dietary intakes in areas where yellow maize is consumed. An essential first step in breeding yellow maize for enhanced carotenoid concentrations involves an assessment of the carotenoid diversity of adapted maize inbred lines. Trials were thus conducted (i) to explore the genetic variation in carotenoid concentrations among tropical-adapted yellow maize inbred lines, (ii) to assess the potential for concurrent improvement of different carotenoids and (iii) to determine the consistency of carotenoid concentrations in different locations. Seed samples of a large set of lines harvested from four trials grown in one location and a fifth trial grown in two locations were analyzed for carotenoid concentrations using HPLC. The analyses of variance revealed that carotenoid concentrations were not strongly affected by the differences in replications or locations. There were large differences among the tropical-adapted yellow maize inbred lines in lutein, zeaxanthin, β-carotene, β-cryptoxanthin, α-carotene and total pro-vitamin A contents. As significant correlations were observed among carotenoids sharing a single branch of the carotenoid biosynthetic pathway, it should be feasible to increase the levels of multiple carotenoids simultaneously. Principal component analysis on the carotenoid composition of the yellow inbred lines identified some lines with higher levels of all carotenoids formed across both major branches of the carotenoid biosynthetic pathway, and other lines having higher levels of those carotenoids formed under a single major branch of the carotenoid biosynthetic pathway. These indicate that the selection of parental lines with diverse carotenoid profiles may possibly be exploited for genetic improvement of carotenoids in tropical maize.     

Food safety regulations in Australia and New Zealand Food Standards

Citizens of Australia and New Zealand recognise that food security is a major global issue. Food security also affects Australia and New Zealand's status as premier food exporting nations and the health and wellbeing of the Australasian population. Australia is uniquely positioned to help build a resilient food value chain and support programs aimed at addressing existing and emerging food security challenges. The Australian food governance system is fragmented and less transparent, being largely in the hands of government and semi‐governmental regulatory authorities. The high level of consumer trust in Australian food governance suggests that this may be habitual and taken for granted, arising from a lack of negative experiences of food safety. In New Zealand the Ministry of Primary Industries regulates food safety issues. To improve trade and food safety, New Zealand and Australia work together through Food Standards Australia New Zealand (FSANZ) and other co‐operative agreements. Although the potential risks to the food supply are dynamic and constantly changing, the demand, requirement and supply for providing safe food remains firm. The Australasian food industry will need to continually develop its system that supports the food safety program with the help of scientific investigations that underpin the assurance of what is and is not safe. The incorporation of a comprehensive and validated food safety program is one of the total quality management systems that will ensure that all areas of potential problems are being addressed by industry. © 2014 Society of Chemical Industry     

Polyphenol oxidase activity in white tan‐plant‐type sorghums: An important determinant of the relatively dark colour of their porridges

The relatively dark colour of food products from white tan‐plant (food‐grade) sorghums can compromise their acceptability. The relationship between white tan‐plant sorghum polyphenol oxidase activity (PPO) and porridge colour was investigated, primarily using lines grown in the same locality over two seasons. Sorghum was intermediate in PPO between wheat and maize. White tan‐plant sorghum and white maize whole grain flours were similar in colour. However, with white tan‐plant sorghum, the transition from flour to porridge caused a much larger reduction in L* value. Further, the correlation between white tan‐plant sorghum PPO activity and porridge L* values was highly significantly negative (P < 0.001), the relationship accounting for 40–50% of variation. PPO in white tan‐plant‐type sorghums is therefore an important determinant of the relatively dark colour of porridges. Breeding to reduce PPO activity could improve consumer appeal. Cultivar Sima (IS 23520) that had low PPO activity and produced light‐coloured porridge could be useful for breeding.     

Assessment for fungal,mycotoxin and insect spoilage in maize stored for human consumption in Zambia

BACKGROUND: Maize constitutes the main staple food and most important crop grown in Zambia. However, maize incurs considerable losses both in field and storage due to pathogens and insects. Some of the pathogens and resultant mycotoxins reduce the nutritional quality of the product. Mycotoxins are toxigenic fungal compounds that can cause cancer and suppress growth. In spite of this health hazard, there has been very little research to document their occurrence. Maize grains stored for human consumption were sampled from different agro‐ecosystems (forest, valley and plateau areas) of three agroecological zones (high, mid and low altitude). RESULTS: Several fungal genera were recovered among which Aspergillus flavus, A. niger, Fusarium verticillioides, F. solani, Rhizopus stolonifer and Penicillium spp. were prevalent. The weevil Sitophilus zeamais and the larger grain borer Prostephanus truncatus were the most damaging. Enzyme‐linked immunosorbent assay (ELISA) tests yielded fumonisins and aflatoxins ranging between 0.02 and 21.44 ppm, and 0.7 and 108.39 ppb in 96.4% and 21.4% of samples, respectively. Fumonisin was more pronounced in villages in forest areas whereas aflatoxin was highest in valley and forest areas in Zone II. CONCLUSION: Strategic interventions to curtail fungal, mycotoxin and insect contamination should be directed towards improved agronomic and post‐harvest practices of maize from fields to consumers. Copyright © 2009 Society of Chemical Industry     

Effects of light environment on maize in hillside agroforestry systems of Nepal

Maize (Zea mays L.) is the most important staple food in the mid-hills region of Nepal. The mid-hills are characterized by steeply sloping land and complex farming systems where crops, livestock and trees are inseparable components, and maize has to compete with trees grown for fodder, fuel wood, building materials and other purposes in a landscape severely constrained for agricultural purposes. This paper reports the effects of the presence of trees growing on crop terrace risers on bari (upper-slope, rainfed) land on growth and yield of maize grown on terrace benches. Maize performance was compared with and without tree and artificial shade to determine its responses above and below ground to such limiting factors. Mean photosynthetic photon flux density (PPFD) incident on maize in farm conditions was lower than 700 μmol m^-2 s^-1, well below the light saturation point for maize (1,500 μmol m⁻² s⁻¹). Grain yield was reduced by 33% under tree shade and by 43% under artificial shade compared with natural (unshaded) conditions. As the light environment is sub-optimal for maize, the crop rarely achieved maximum rates of photosynthesis. Farmers claim that local landraces are better adapted to shade than station-bred genotypes, but there was no evidence of varietal effects upon rates of photosynthesis. However, there was some evidence that there were varietal adaptations to shade for other factors such as greater numbers of leaves and more competitive rooting patterns. Maize varieties with deeper root systems and adapted to low light conditions are required if productivity in these complex systems is to be improved. The findings of this study should be useful to breeders in developing maize genotypes suitable for the complex hillside systems of Nepal, thereby improving food security.     

东北褐变玉米品质变化及影响褐变的因素研究

2013年到2016年东北地区高水分玉米收获烘干时发生了严重的褐变现象,颜色呈褐色,部分地区超出国家标准对热损伤粒最低限量要求。本研究对比了同一地区褐变玉米及非褐变玉米的理化指标和部分营养指标,对褐变玉米的食用品质和使用品质做出了评价,并对研究了影响褐变的因素。褐变玉米的理化指标和部分营养指标均未按照褐变程度表现出一致的规律性变化。食用品质严重裂变,制作的窝头味道发苦发涩,已不适宜食用。玉米淀粉出粉率及品质变化较小。褐变玉米的猪有效能值及鸡表观代谢能均与正常玉米平均水平相当。烘干温度,成熟度及寒冷环境下多次冻融都会影响玉米的褐变。     

Perceived relevance and foods with health-related claims

Although consumer perception of the health claims and nutrition information has been studied widely there is relatively little understanding about the motivational factors underpinning claim perception. The objective of this study is to investigate how levels of perceived relevance influence consumers’ responses to health claims that either promise to reduce a targeted disease risk or improve well-being in comparison to other types of health-related messages, and how attitudes towards nutritionally healthy eating, functional food and previous experience relating to products with health claims affect the consumers’ perceptions of nutrition and health claims. The data (N = 2385) were collected by paper and pencil surveys in Finland, the UK, Germany and Italy on a target group of consumers over 35 year old, solely or jointly responsible for the family’s food shopping. The results showed that relevance has a strong influence on perceptions of personal benefit and willingness to buy products with health claims. However the impact of relevance is much stronger when the health risks are relevant to self than when it is relevant to those close to oneself, especially when the claim promises a targeted risk reduction with detailed information about function and health outcome. Previous experience with products with health claims and interest in nutritionally healthy eating promoted the utility of all claims, regardless of whether they were health or nutrition claims. However, to be influenced by health claims consumers also need to have a positive attitude towards functional food products.