Crops that feed the world 7: Rice

Fears about global food security led to a spike in food prices in 2008, social unrest and pushed a further 100 million people into poverty. Prices remain high and volatile. In this paper we take a closer look at rice, a crop that feeds billions of people in the world, and focus in particular on Asia and Africa. On both continents, rice is grown in a wide range of climatic conditions, from river deltas to mountainous regions. Irrigated systems dominate in Asia and rainfed systems in Africa. Predicted demands for rice remain strong. An additional 116 million tons of rice will be needed by 2035 to feed growing populations. In Africa, where rice is the most rapidly growing food source, about 30 million tons more rice will be needed by 2035, representing an increase of 130% in rice consumption from 2010. About one-third of this extra rice will be needed in Nigeria alone. In Asia, per capita consumption of rice may go down in some mid- and high-income countries. Rice farming will need to produce about 8–10 million tons more paddy per year over the next decade. Without area expansion this will require an annual yield increase of about 1.2–1.5%, equivalent to an average yield increase of 0.6 t ha⁻¹ world-wide. Improving global food security will, therefore, necessitate concerted efforts to increase the productivity of rice per unit of land, water and/or labor in Asia and Africa, and the development of new land and water resources in a responsible and equitable manner to counteract losses due to urbanization and industrialization. During 2007–2011, productivity increases in Africa have been leading the way, with paddy rice production levels increasing by 9.5% per year, compared to 1.6% in Asia. Priorities for rice sector development include (i) continued and increased research efforts to close yield gaps and raise yield ceilings across rice growing environments through varietal development and improved rice production methods, and coping with climate change in both continents and (ii) strengthened and equitable public-private sector partnerships and conducive policy environments in Africa, with special emphasis on mechanization of rice farming from land preparation to harvest and rice processing practices.     

Crops that feed the world 3. Investing in lentil improvement toward a food secure world

Lentils play a major role in the food and nutritional security of millions, particularly among low-income Asian families, because of the high protein content of their seed. As is the case for many pulses, lentils play an important role as a rotation crop, enhancing soil fertility and providing other environmental services in production systems. While its production has risen globally at 8.6 kg/ha/year from 1961 to 2008, the major challenge is to increase investment in lentil improvement (both research and outreach) in countries where the crop is part of the production system. Where currently grown the major abiotic stresses are low moisture availability and high temperatures in spring, and winter cold at high elevations. Among biotic stresses, rust, and vascular wilt are key, and resistance has resulted in improvements in performance. Additional production constraints include the agronomic problems of pod loss, lodging and poor crop management. Adequate variability for most genetic constraints exists within the gene pool allowing breeding. However, several key traits, such as biomass yield, pod shed, nitrogen fixation and resistance to aphids are not currently addressable by breeding because of insufficient variation. Among lentil-producing developing countries, policies have not yet focused on lentil development needs to enhance food security and provide a remunerative rotation crop for cereals. Looking towards a future in which there is likely to be less water available to agriculture, climate change, food insecurity, rising costs for inorganic nitrogen fertilizer, and an increasingly nutrition-conscious society—collectively these give a bright future for a highly nutritious food produced by a nitrogen-fixing crop such as lentil adapted to the farming systems of marginal lands.     

Crops that feed the world 5. Sweetpotato. Sweetpotatoes for income and food security

Sweetpotato (Ipomoea batatas L. Lam) is a tuber crop of immense potential as it produces more edible energy on marginal land than any other major food crop. As well as this useful property it can withstand adverse abiotic and biotic stresses and does not require intensive care. It therefore plays an important role in the economy of poor households where it acts as a major source of subsistence and is considered to be a ‘famine relief crop’. Besides this important function, the crop has immense industrial value for extraction of starch and production of animal feed. For all these reasons sweetpotato has great possibilities for enhancing food and nutrition security in developing and underdeveloped countries where most of the farmers’ holdings belong to the small and marginal categories. Although the crop is assuming greater significance owing to the ever-increasing population its importance is still underestimated and, unlike most staples, fails to attract sufficient attention of agricultural researchers throughout the tropics and subtropics. With greater attention and more collaborative research, there could be considerable improvements in the genetics of the crop and its husbandry which, together, would allow it to fulfill a wide range of needs in these areas of the world.     

Crops that feed the World 1. Yams

Yam (Dioscorea sp.) is a major source of food for millions of people in tropical and sub-tropical regions, especially in West and Central Africa where at least 60 million people depend on it. It is also a major source of income and an integral part of socio-cultural life. In addition to their food uses, some Dioscorea species are exploited for pharmaceutical products. Yam cultivation is undergoing intensification in many production zones leading to challenges in the management of soil fertility and structure, increasing pressure of diseases and pests (including weeds), and requirements for new varieties better suited to the changing biophysical and socio-economic circumstances. Greater attention also needs to be paid to raising labor productivity and improving access of producers to affordable and higher quality planting materials. These challenges, and the opportunities associated with the biology of the crop, need to be addressed more systematically and earnestly through collaborative research and development, and effective dissemination of the results to relevant stakeholders. The increasing capacity for, and international collaboration in, research and development on yam augur well for the future of the crop and the millions of people who depend on it.     

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.     

Crops that feed the world 10. Past successes and future challenges to the role played by wheat in global food security

Wheat is fundamental to human civilization and has played an outstanding role in feeding a hungry world and improving global food security. The crop contributes about 20 % of the total dietary calories and proteins worldwide. Food demand in the developing regions is growing by 1 % annually and varies from 170 kg in Central Asia to 27 kg in East and South Africa. The developing regions (including China and Central Asia) account for roughly 53 % of the total harvested area and 50 % of the production. Unprecedented productivity growth from the Green Revolution (GR) since the 1960s dramatically transformed world wheat production, benefitting both producers and consumers through low production costs and low food prices. Modern wheat varieties were adopted more rapidly than any other technological innovation in the history of agriculture, recently reaching about 90 % of the area in developing regions. One of the key challenges today is to replace these varieties with new ones for better sustainability. While the GR “spared” essential ecosystems from conversion to agriculture, it also generated its own environmental problems. Also productivity increase is now slow or static. Achieving the productivity gains needed to ensure food security will therefore require more than a repeat performance of the GR of the past. Future demand will need to be achieved through sustainable intensification that combines better crop resistance to diseases and pests, adaptation to warmer climates, and reduced use of water, fertilizer, labor and fuel. Meeting these challenges will require concerted efforts in research and innovation to develop and deploy viable solutions. Substantive investment will be required to realize sustainable productivity growth through better technologies and policy and institutional innovations that facilitate farmer adoption and adaptation. The enduring lessons from the GR and the recent efforts for sustainable intensification of cereal systems in South Asia and other regions provide useful insights for the future.     

Crops that feed the world 11. Pearl Millet (<Emphasis Type="Italic">Pennisetum glaucum</Emphasis> L.): an important source of food security,nutrition and health in the arid and semi-arid tropics

Pearl millet is a major cereal in the arid and semi-arid regions of Asia and Africa. It is primarily cultivated for grain production, but its stover is also valued as dry fodder. Pearl millet is resilient to climate change due to its inherent adaptability to drought and high temperatures. It is also tolerant of saline and acid soils, and is well adapted to marginal lands with low productivity. Pearl millet germplasm exhibits large genetic variability for yield components; and various agronomic, adaptation and nutritional traits. Open pollinated varieties and hybrids are two important cultivar options, but higher productivity is realized through hybrids. Pearl millet has fewer pest and disease problems compared to other cereals and is suited to different cropping systems. It is highly responsive to improved crop management practices, as witnessed in parts of India where it is grown as an irrigated summer crop that produces higher yields and better quality grain. Pearl millet has high nutritional value in terms of high levels of energy, dietary fibre, proteins with a balanced amino acid profile, many essential minerals, some vitamins, and antioxidants. These play a significant role in prevention of important human ailments such as diabetes, cancer, cardiovascular and neurodegenerative diseases. There is great potential for harnessing these positive attributes through genetic improvement, improved crop management, and grain processing and food products technologies. These should help to develop greater global awareness of the importance of this crop for food and nutritional security.     

Antioxidant activity of phytogenous industrial waste and derived extracts for the production of feed and food additives

Organic wastes as well as their ethanolic, water and heptane extracts and fermented products derived from herbs, fruit and vegetables obtained worldwide from food and pharmaceutical industries were investigated regarding their antioxidant activities using different methods [1.1‐diphenyl‐2‐picrylhydrazyl, Fe^III‐reduction method and photochemiluminescence (PCL)]. The highest antioxidative activities were exhibited by different products of grape seed wastes (350–830 mg rosmarinic acid equivalent g^?1 dried material = rae g^?1 dm) followed by ethanolic extracts of blueberry (475 mg rae g^?1 dm), larch (219 mg rae g^?1 dm), willow (193 mg rae g^?1 dm) and sunflower presscake (154 mg rae g^?1 dm). Ethanolic extracts of the residues showed comparatively higher activity than water extracts. The least antioxidative capacities were found in heptane extracts of serenoa products (0.4; 0.6 mg rae g^?1 dm) and fermented waste of carrots (1.6 mg rae g^?1 dm). Correlating different assay methods, the strongest correlation was found between Fe^III‐reduction and DPPH‐method (correlation coefficient r² = 0.99**) and the weakest between Fe^III‐reduction and PCL method (r² = 0.57**) for raw materials.     

Optimisation of asymmetric flow field-flow fractionation for the characterisation of nanoparticles in coated polydisperse TiO2 with applications in food and feed

Titanium dioxide (TiO₂) has various applications in consumer products and is also used as an additive in food and feeding stuffs. For the characterisation of this product, including the determination of nanoparticles, there is a strong need for the availability of corresponding methods of analysis. This paper presents an optimisation process for the characterisation of polydisperse-coated TiO₂ nanoparticles. As a first step, probe ultrasonication was optimised using a central composite design in which the amplitude and time were the selected variables to disperse, i.e., to break up agglomerates and/or aggregates of the material. The results showed that high amplitudes (60%) favoured a better dispersion and time was fixed in mid-values (5 min). In a next step, key factors of asymmetric flow field-flow fraction (AF4), namely cross-flow (CF), detector flow (DF), exponential decay of the cross-flow (CF_exp) and focus time (Ft), were studied through experimental design. Firstly, a full-factorial design was employed to establish the statistically significant factors (p < 0.05). Then, the information obtained from the full-factorial design was utilised by applying a central composite design to obtain the following optimum conditions of the system: CF, 1.6 ml min^–1; DF, 0.4 ml min^–1; Ft, 5 min; and CF_exp, 0.6. Once the optimum conditions were obtained, the stability of the dispersed sample was measured for 24 h by analysing 10 replicates with AF4 in order to assess the performance of the optimised dispersion protocol. Finally, the recovery of the optimised method, particle shape and particle size distribution were estimated.     

Acacia saligna as a fodder tree for desert livestock and the interaction of its tannins with fibre fractions

Acacia saligna was examined as potential fodder for sheep (27.4 kg) and goats (14.8 kg) raised in arid and semi-arid areas. This leguminous tree remains green all year and can be grown in deserts using only runoff water. Phyllodes collected in March had a crude protein content of 12.5% dry matter (DM) and high tannin content (tannins as tannic acid equivalent to 11.3% and condensed tannins as leucocyanidin equivalent to 8.3% DM). DM intake was low, amounting to 0.80% and 1.05% body mass daily for sheep and goats, respectively. Sheep lost 227 g day^?1 and goats 196 g day^?1 while on this diet. Dry matter, organic matter and energy digestibilities were low in both species but were higher for goats than for sheep, and negative digestibilities were measured for acid detergent fibre (ADF) and acid detergent lignin (ADL). Metabolisable energy intake for goats was 121.9 kJ kg^?0.75 day^?1 and for sheep was 78.6 kJ kg^?0.75 day^?1. Apparent N digestibility was 17.5% and 0.9% for goats and sheep, respectively, and both species were in negative N balance of 0.25–0.30 g kg^?0.75 day^?1. Total water intake and output were higher in sheep than in goats. Extractable tannins were virtually absent in faeces in both species, however, output of condensed tannins and protein in the ADF and ADL fractions were substantially higher. This showed the presence of tannin-protein complexes in these fractions which explained the negative digestibilities of ADF and ADL. It was concluded that Acacia saligna could not be used as a sole dietary source for small ruminants because of low intake and negative nitrogen balance. This was due mainly to the high tannin content. However, the tree might have a potential as a supplementary fodder due to its high crude protein content.     

Ochratoxin A concentrations in food and feed from a region with Balkan Endemic Nephropathy.

Balkan Endemic Nephropathy (BEN), a chronic renal disease of unknown aetiology, is found in geographically close areas of Bulgaria, Romania, Serbia, Croatia, Bosnia and Herzegovina, Slovenia, and the former Yugoslav Republic of Macedonia. Ochratoxin A (OTA), a secondary metabolite of Aspergillus and Penicillium species and a natural contaminant of food and feed, is a putative cause of BEN. Some studies have found a geographic covariation between OTA content in food/feed and BEN manifestation; others have not. In May 2000, using a competitive direct ELISA assay for OTA (detection limit 1 microg kg(-1)), we investigated OTA contamination in 165 samples of home-produced food (beans, potatoes, corn, wheat, flour) and feed from households in villages from the BEN region (Vratza district) of north-western Bulgaria. Samples were collected from: (a) BEN villages (n = 8), and therein from BEN households (20), and BEN-free households (16) (within-village controls, WVC households); and (b) BEN-free villages (7) and therein BEN-free households (22) (between-village controls, BVC). BEN households consistently had a higher proportion of OTA-positive samples than WVC households, but similar (for some foods) or lower (for other foods) proportions to BVC households. The proportion of OTA-positive samples was also higher in BVC than in WVC households. Furthermore, BEN households had a similar proportion of OTA-positive samples to the pooled, WVC and BVC, group of households. OTA-exposure estimates, derived from our OTA-concentration findings and the reported average per capita monthly consumption of basic foods in rural Bulgaria, showed the highest OTA intake in BEN households (1.21 microg day(-1)), versus 1.03 microg day(-1) in BVC and 0.71 microg day(-1) in WVC households. These OTA intakes are higher than those in the EU, and are close to the upper limits acceptable to several food-safety organizations. The results indicate that OTA may not alone cause BEN; only synergistically with other environmental toxicants and/or predisposing genotypes may do so.     

Whole-herd optimization with the Cornell Net Carbohydrate and Protein System. I. Predicting feed biological values for diet optimization with linear programming

We developed a diet optimizer for least-cost diet formulation with the Cornell Net Carbohydrate and Protein System (CNCPS) using linear programming. The CNCPS model is intrinsically nonlinear, and feed biological values vary with animal and feed characteristics. To allow linear diet optimization, we first used the CNCPS model to generate biological values to characterize the energy and protein content of each feed for the specific group for which the diet was being formulated. The biological values used were metabolizable energy (Mcal/kg), metabolizable protein [(% dry matter (DM)], passage rate (%/h), bacteria yield efficiencies (g/g), and degradation rate of the carbohydrate B2 fraction (%/h). In addition, the ruminal balances for nitrogen and peptides were included in the optimizer to optimize ruminal degradation of fiber. The objective function was to minimize diet cost subject to animal requirement and feed availability constraints. The animal constraints were set by requirements for DM intake (kg/d), metabolizable energy (Mcal/kg), metabolizable protein (%DM), and effective neutral detergent fiber (%DM) for a given level of production. Data from a dairy farm were used to evaluate this linear diet optimizer. Across all classes of dairy cattle, the CNCPS 4.0 model typically obtained a solution in less than six iterations that met the requirements with nearly 100% accuracy. We conclude this linear optimizer can be used to accurately formulate least-cost diets with the CNCPS model.     

维生素A摄取过剩和不足对人体的影响

译自:《日本食品添加物新闻》2006年第26卷第5号。1关于维生素A1.1维生素A的物性维生素A是脂溶性维生素的一种,表示维生素A的生物作用的所有物质总称的通用名。维生素A对维持人体的视觉、听觉、生殖器官等的机能,促进生长,保持皮肤、黏膜等上皮组织的正常分化机构,通过发现遗传因子抑制癌细胞增殖,参与蛋白质合成等方面起着重要的作用。维生素A中含有视黄醇(维生素A1),3-脱氢视黄醇(维生素A2)及其诱导体。化学性质非常不稳定,遇酸、空气、光、热而异化、分解、聚合。此外,在体内被转换成维生素A的前维生素(维生素A的前驱体)属于类胡萝卜…     

Valorization of the major agrifood industrial by-products and waste from Central Macedonia (Greece) for the recovery of compounds for food applications

Food by-products and waste valorisation practices have gained much attention lately as a means of a sustainable management, which can concomitantly increase the profit for local economies. So far, these materials constitute an underexploited source for the recovery/production of compounds for food applications and other needs of the food chain (energy production, feeds). To highlight new trends and show the potential for regional economies the present contribution focuses on Central Macedonia, the largest Greek region with significant agro-industrial activities, such as olive oil, wine and rice production, that generate different types and quantities of by-products and waste. Proposals for the exploitation of selective streams using chemical and biotechnological tools for the recovery/production of compounds of high interest for the food industry are critically discussed. Know-how developed by academia and research institutions in the Central Macedonia should be examined by the respective stakeholders in order to contribute to the zero-waste society target set by European Union till 2025.     

Validation and application of a robust yeast estrogen bioassay for the screening of estrogenic activity in animal feed.

Previously we described the construction and properties of a rapid yeast bioassay stably expressing human estrogen receptor alpha (hERalpha) and yeast enhanced green fluorescent protein (yEGFP), the latter in response to estrogens. In the present study this yeast estrogen assay was validated as a qualitative screening method for the determination of estrogenic activity in animal feed. This validation was performed according to EC Decision 2002/657. Twenty blank animal feed samples, including milk replacers and wet and dry feed samples, were spiked with 17beta-estradiol (E2beta) at 5 ng g(-1), 17alpha-ethynylestradiol (EE2) at 5 ng g(-1), diethylstilbestrol (DES) at 10 ng g(-1), zearalenone at 1.25 microg g(-1) or equal at 200 microg g(-1). All of these blank and low estrogen spiked feed samples fulfilled the CCalpha and CCbeta criterions, meaning that all 20 blank feed samples gave a signal below the determined decision limit CCalpha and were thus classified as compliant, and at least 19 out of the 20 spiked samples gave a signal above this CCalpha (beta = 5%) and were thus classified as suspect. The method was specific and estrogens in feed were stable for up to 98 days. In this study we also present long-term performance data and several examples of estrogens found in the routine screening of animal feed. This is the first successful example of a developed, validated and applied bioassay for the screening of hormonal substances in feed.     

Oral administration of the probiotic combination Lactobacillus rhamnosus GR-1 and L. fermentum RC-14 for human intestinal applications

Lactobacillus rhamnosus GR-1 and L. fermentum RC-14, previously characterized as urogenital probiotics were evaluated for human intestinal applications. RC-14 and GR-1 were tolerant to 0.3 and 0.5% (w/v) bile, respectively. Both strains were suspended in skim milk, stored as a frozen concentrate and administered in combination to five healthy women twice daily for 14 days. Faecal samples were analyzed and the Lactobacillus flora assessed by Randomly Amplified Polymorphic DNA (RAPD). Both strains were recovered from all subjects during the 14-day administration period and GR-1 was detected for at least 7 days post-administration in some individuals. No notable increases in serum IgG, IgA or IgM were observed and IL-2 and IL-4 were undetectable. Although IL-6 and IFN-γ levels increased slightly in some individuals, concentrations remained within normal ranges. Thus, L. rhamnosus GR-1 and L. fermentum RC-14 are bile tolerant and survive gastrointestinal transit without induction of systemic immune or inflammatory responses. These data together with the previously demonstrated probiotic properties of GR-1 and RC-14 make this strain combination potentially useful for human intestinal applications.