Amino acid profiles and protein quality of cooked cassava leaves or ‘saka‐saka’

Cassava (Manihot esculenta Crantz) leaves form the main source of protein in a diet consisting of processed cassava roots as sole staple food in konzo‐affected areas of the Democratic Republic of Congo. Pounded cassava leaves were hydrolysed and analysed by HPLC before and after cooking to assess amino acid profiles and protein quality. An average of about 58% loss of total protein content was observed in five different cooked samples. The protein content in cassava leaves was high, an average of 285.9 g kg^?1 dry weight in the raw and 119.2 g kg^?1 dry weight in the cooked samples, but of poor quality, with sulphur amino acids as the most limiting amino acids. Lysine and leucine were also limiting amino acids in some of the raw samples. Lysine, histidine, leucine and isoleucine were limiting amino acids in the cooked samples besides the sulphur amino acids. The consumption of cassava leaves does not compensate the dietary deficiency of sulphur amino acids in the roots that are the staple food in konzo‐affected areas. Sulphur amino acids are essential for detoxification of the residual cyanogens remaining in insufficiently processed cassava roots. Cereals and legumes, as sources of sulphur amino acids and lysine respectively, should be promoted as part of the diet in those areas to prevent the paralytic neuro‐toxico‐nutritional disease konzo among the poor population. Copyright © 2003 Society of Chemical Industry     

Industrial Demand for Cassava Starch in India

Cassava (Manihot esculenta crantz) is a staple food crop cultivated in several developing countries. Cassava is consumed either directly as cooked tubers or as the products prepared from cassava. Cassava in India is used mainly in the human consumption, industrial and animal feed sectors. In India nearly 60% of cassava is used industrially in the production of sago, starch and dry chips. The presented study has clearly indicated that the future of cassava in India lies in its diversified uses in the industrial sector. The projected demand is predominantly in the adhesive sector, especially in the corrugation gums and paper conversion industry, and in the paper industry. The projected demand‐supply gap in the industrial sector is expected to be 1.5×10⁶ t of cassava tubers requiring another 750 000 ha to be brought under cassava cultivation. New and potential areas in the non‐traditional cassava‐growing states are to be considered for area expansion.     

Processing Techniques to Reduce Toxicity and Antinutrients of Cassava for Use as a Staple Food

ABSTRACT: Cassava is a valuable source of food for developing countries, but it contains highly toxic cyanogen compounds and antinutrients. Cyanogens are found in 3 forms in cassava: cyanogenic glucoside (95% linamarin and 5% lotaustratin), cyanohydrins, and free cyanide. Different processing techniques exist to remove cyanogens and their effectiveness depends on the processing steps and the sequence utilized, and it often is time‐dependent. Pounding or crushing is the most effective for cyanogenic glucoside removal because it ruptures cell compartments, thus allowing direct contact between linamarin and the enzyme linamarase that catalyzes the hydrolytic breakdown. Crushing and sun‐drying cassava roots made into flour removes 96% to 99% of total cyanogens, whereas soaking and sun‐drying into lafun or fufu, or soaking and fermenting and roasting into gari or farina, removes about 98% of cyanogens. For cassava leaves, which have 10 times more cyanogens than roots, pounding and boiling in water is an efficient process to remove about 99% of cyanogens. Other strategies to reduce toxicity include development of low‐cyanogen cassava varieties and cassava transgenic lines with accelerated cyanogenesis during processing. Although phytate and polyphenols have antioxidant properties, they interfere with digestion and uptake of nutrients. Fermentation and oven‐drying are efficient processing methods to remove phytate (85.6%) and polyphenols (52%), respectively, from cassava roots. Sun‐drying the leaves, with or without prior steaming or shredding, removes about 60% phytate. Cassava is a nutritionally strategic famine crop for developing countries and, therefore, reducing its toxicity and improving its nutritional value is crucial.     

The industrial applications of cassava: current status,opportunities and prospects

Cassava (Manihot esculenta Crantz) is a drought‐tolerant, staple food crop that is grown in tropical and subtropical areas. As an important raw material, cassava is a valuable food source in developing countries and is also extensively employed for producing starch, bioethanol and other bio‐based products (e.g. feed, medicine, cosmetics and biopolymers). These cassava‐based industries also generate large quantities of wastes/residues rich in organic matter and suspended solids, providing great potential for conversion into value‐added products through biorefinery. However, the community of cassava researchers is relatively small and there is very limited information on cassava. Therefore this review summarizes current knowledge on the system biology, economic value, nutritional quality and industrial applications of cassava and its wastes in an attempt to accelerate understanding of the basic biology of cassava. The review also discusses future perspectives with respect to integrating and utilizing cassava information resources for increasing the economic and environmental sustainability of cassava industries. © 2017 Society of Chemical Industry     

Cyanide detoxification in cassava for food and feed uses

Cassava (Manihot esculenta Crantz) is an important tropical root crop providing energy to about 500 million people. The presence of the two cyanogenic glycosides, linamarin and lotaustralin, in cassava is a major factor limiting its use as food or feed. Traditional processing techniques practiced in cassava production are known to reduce cyanide in tubers and leaves. Drying is the most ubiquitous processing operation in many tropical countries. Sun drying eliminates more cyanide than oven drying because of the prolonged contact time between linamarase and the glucosides in sun drying. Soaking followed by boiling is better than soaking or boiling alone in removing cyanide. Traditional African food products such as gari and fufu are made by a series of operations such as grating, dewatering, fermenting, and roasting. During the various stages of gari manufacture, 80 to 95% cyanide loss occurs. The best processing method for the use of cassava leaves as human food is pounding the leaves and cooking the mash in water. Fermentation, boiling, and ensiling are efficient techniques for removing cyanide from cassava peels.     

Cassava (Manihot esculenta Crantz) and Yam (Dioscorea spp.) Crops and Their Derived Foodstuffs: Safety,Security and Nutritional Value

Cassava (Manihot esculenta Crantz) and yam (Dioscorea spp.) are tropical crops consumed by ca. 2 billion people and represent the main source of carbohydrate and energy for the approximately 700 million people living in the tropical and sub-tropical areas. They are a guarantee of food security for developing countries. The production of these crops and the transformation into food-derived commodities is increasing, it represents a profitable business and farmers generate substantial income from their market. However, there are some important concerns related to the food safety and food security. The high post-harvest losses, mainly for yam, the contamination by endogenous toxic compounds, mainly for cassava, and the contamination by external agents (such as micotoxins, pesticides, and heavy metal) represent a depletion of economic value and income. The loss in the raw crops or the impossibility to market the derived foodstuffs, due to incompliance with food regulations, can seriously limit all yam tubers and the cassava roots processors, from farmers to household, from small-medium to large enterprises. One of the greatest challenges to overcome those concerns is the transformation of traditional or indigenous processing methods into modern industrial operations, from the crop storage to the adequate package of each derived foodstuff.     

Cassava leaves as animal feed: Potential and limitations

The nutrient composition and potential productivity of cassava (Manihot esculenta Crantz) leaves are examined, and their usefulness as a protein supplement in animal nutrition in the tropics is reviewed. On average, meal prepared from cassava leaves contains (on a dry matter basis) 210 g kg^?1 crude protein, 250 g kg^?1 acid detergent fibre, 85 g kg^?1 ash, 14.5 g kg^?1 calcium and 4.5 g kg^?1 phosphorus. Cassava leaf protein is well balanced, except for a deficiency of sulphur-containing amino acids. The presence of hydrocyanic acid and tannins is considered, but a leaf meal with low levels of these anti-nutritional factors may be prepared using simple processing techniques. The most immediate prospects for the use of cassava leaf products are in the following areas: (i) low level inclusion of leaf meal in feed formulations for monogastric animals, and (ii) fresh forage as a protein supplement to low-quality roughages in ruminant feeding. Relevant future research needs are also identified.     

Condensed tannins: A factor limiting the use of cassava forage

Cassava (Manihot esculenta, Crantz), an important tropical root crop, is considered to have a good potential for use as a forage because leaf blades generally contain <20% crude protein (CP). However, neutral-detergent fibre (NDF) obtained from cassava leaf blades contains condensed tannins (CTs) and high levels of CP. The amount of CP in the NDF that is insoluble when treated with pepsin or protease is highly correlated with the amount of CTs in the NDF. CTs in the NDF are rich in prodelphinidin. CTs may be an important factor limiting the nutritive value of cassava forage.     

Cassava as a food

This review has attempted to examine information pertaining to the role of cassava (Manihot esculenta) as a major food source for a large part of the world population, particularly the countries of South America, Africa, and Asia, where it is primarily a major source of energy for 300 to 500 million people. Its cultivation, usually on small farms with little technology, is estimated to cover on an annual basis about 11 million hectares providing about 105 million tons, more than half of which is consumed by humans. The importance of cassava as an energy source can be seen by its growing demand in the European economic community countries where it forms up to 60% of the balanced diets for swine. Cassava is one of the crops that converts the greatest amount of solar energy into soluble carbohydrates per unit of area, thus 1 kg of moisture-free cassava meal may yield up to about 3750 kcal which would mean that a yearly production of 15 tons of cassava meal per hectare would yield some 56 million kcal. The major limitations of cassava as food appear to be its poor protein content and quality and the rapid post harvest deterioration of its roots which usually prevents their storage in the fresh state for more than a few days. However, in addition to its use for culinary purposes, cassava finds application in industrial products such as an adhesive for laundry purposes, for manufacturing paper, alcohol, butanol, dextrin, adhesive tape, textile sizing, and glue.     

Composition of some tropical tuberous foods

Four tropical root tubers were evaluated for their chemical compositions and amino acid patterns. These were winged bean (Psophocarpus tetragonolobus (L.)DC., yam, sweet potato and cassava (Manihot utillisima, Pohl.). Winged bean tubers had protein contents ten times higher than those of cassava and sweet potato and five times higher than yam and contained a high level of carbohydrates. The minerals analysed were about the same in concentration but winged bean tubers had about three times more iron than other root tubers.Although cassava roots have the highest content of S-containing amino acids, winged bean roots have the highest values for lysine, tyrosine, tryptophan and threonine. The total content of essential amino acids is much greater in winged bean tubers than in the other tuberous roots.     

Rising African cassava production,diseases due to high cyanide intake and control measures

Cassava is the staple food of tropical Africa and its production, averaged over 24 countries, has increased more than threefold from 1980 to 2005, and the population has more than doubled over that time compared with a 1.5 times increase worldwide. Agriculturally, cassava performs very well but the roots and leaves contain cyanogenic glucosides that are dangerous to human health. These cyanogens sometimes produce acute intoxication leading to death, they exacerbate goitre and cretinism in iodine‐deficient regions, cause konzo and are implicated in the occurrence of tropical ataxic neuropathy and stunting of children. Konzo is an irreversible paralysis of the legs with many thousands of cases, mainly amongst children, in Mozambique, Tanzania, Democratic Republic of Congo, Cameroon, Central African Republic and probably other tropical African countries. Attempts to alleviate cassava cyanide toxicity have included the development of an information network and distribution in developing countries of picrate kits, which measure total cyanide in cassava and urinary thiocyanate. A simple wetting method that reduces total cyanide in cassava flour three‐ to sixfold has been successfully field tested and is being introduced in Mozambique. Transgenic technology shows promise in increasing the rate of loss of cyanide from roots during processing. World health and agricultural bodies should pay more attention to emerging health problems associated with toxicity of cyanogens in cassava. Copyright © 2008 Society of Chemical Industry     

Utilization Potentials of Cassava in Nigeria: The Domestic and Industrial Products

Cassava (Manihot esculenta) is an important food crop in the tropics—a major carbohydrate staple consumed in various forms by humans. Furthermore, its usage as a source of ethanol for fuel, energy in animal feed, and starch for industry is increasing. Given that cassava represents a valuable subsistence and cash crop in many countries, its domestic and industrial potential needs to be fully exploited. Processing of cassava reduces the moisture content and converts it into a more durable and stable product. Women traditionally process cassava, although it could be processed at the small, medium, or industrial scale. This article discusses the major Nigerian domestic products as well as the potential industrial products of cassava that are yet to be produced locally and the machines used in their production. Although improved technology is one of the keys to increasing the productivity of micro-enterprises and generating broad-based, sustainable economic growth, the extent to which a given technology is acceptable to a given culture may depend on a number of considerations beyond the mechanical efficiency of the device. These topics are discussed and recommendations are suggested to encourage the establishment of more cassava based industries.     

Cyanogenic,carotenoids and protein composition in leaves and roots across seven diverse population found in the world cassava germplasm collection at CIAT,Colombia

The objective of this study was to characterise the nutritional potential of leaves and identify a diversity centre with low cyanide and high nutrient content among 178 Latin American cassava genotypes. This field-based collection represents the seven diversity centres, held at The International Center for Tropical Agriculture (CIAT Palmira, Colombia) by the Cassava Program. The cyanide, all-trans-β-carotene and lutein concentrations in cassava leaves ranged from 346 to 7484 ppm dry basis (db), from 174–547 μg g⁻¹ db and 15–181 μg g⁻¹ db, respectively. Cassava leaves also showed significant levels of essential amino acids leucine, lysine, phenylalanine, valine and threonine, and average total protein content of 26.24 g 100 g⁻¹ db. Among seven diversity centres, South American rainforest group showed low cyanide and high carotene content in leaves. In addition, VEN77 and PAN51 genotypes stood out for having low cyanide in leaves and roots and high carotene in leaves. This genetic diversity can be used to select high potential progenitors for breeding purposes.     

Chronic poisoning by hydrogen cyanide in cassava and its prevention in Africa and Latin America

Africa produces more than 30 million tons of cassava on about 5 million hectares (6 tons per hectare). Approximately 80% of the root production and 70% of the harvested area are from Western Africa. Recent reports suggest that the ingestion of poorly processed cassava roots is associated with the incidence of an ataxic neuropathy (konzo) in African countries. When cassava-based diets are not supplemented with good sources of protein and iodine, goiter and rickets are also prevalent. In certain countries of Africa where the rate of ataxic neuropathy is high, the incidence of thyroid disorders is also high. Persons consuming poorly processed cassava in large quantities are susceptible to neuropathologies caused by cyanide. Cyanide detoxification in the body is impaired by protein deficiency. When properly processed, the root of cassava is safe and cheap as a major dietary energy source for humans and domestic animals; however, a cassava-based diet will lack sufficient protein and will be particularly deficient for the growth and development of children unless it is supplemented by protein from animal, including fish, or legume sources. Cassava leaves, if they are appropriately cooked, can be a useful source of some nutrients.     

Flour,starch and composite breadmaking quality of various cassava clones

Bread was made using a straight-dough baking process from a local soft wheat flour partially substituted at four levels with flour from nine different cassava (Manihot esculenta, Crantz) clones. The physicochemical properties of the blended flouts, including starch quality, were determined and related to dough rheology, bread volume and crumb characteristics. Breadmaking quality at substitution levels of 100 and 200 g kg^?1 of mixed flour was reliably predicted from the cassava flour diastatic activity only. Flours with relatively high diastatic activities, ie above ～ 145 mg of maltose, had deleterious breadmaking effects. Baking absorption effects were more critical at substitution levels of 300 and 400 g kg^?1. Cassava flour diastatic activity was highly dependent on the moisture contents of the respective tuberous roots, and affected the extent of starch gelatinisation in the breadcrumbs.     

Processing factors affecting the level of residual cyanohydrins in gari

Intake of cyanogens in gari, a food processed from cassava roots, is implicated in the causation of tropical ataxic neuropathy (TAN). This neurological syndrome is endemic in some communities in south‐western Nigeria. Studies have shown that methods of processing cassava roots determine the quantity of cyanogens in gari. This study was conducted to investigate the effects of the method of dewatering and the duration of fermentation on cyanogens in gari. Cassava roots (400 kg) were peeled, washed, grated and divided into 14 woven polyethylene sacks. The mash in seven of the sacks was dewatered continuously during fermentation, while the mash in the remaining seven sacks was fermented without dewatering, but dewatered at the end of fermentation. Cassava mash from each treatment was roasted into gari at 24 h intervals up to 168 h. Mean cyanohydrin content in gari roasted from cassava mash dewatered continuously during fermentation was 10.8 mg HCN eq kg^?1 dw (CI 9.7–11.9), while mean cyanohydrin content in gari roasted from cassava mash dewatered after fermentation was 6.3 mg HCN eq kg^?1 dw (CI 5.3–7.4). Mean linamarin content was 4.0 mg HCN eq kg^?1 dw (CI 3.1–4.9) and mean HCN content was 1.6 mg kg^?1 dw (CI 1.3–1.9) in gari roasted from cassava mash dewatered continuously, while mean linamarin content was 3.2 mg HCN eq kg^?1 dw (CI 2.3–4.0) and mean HCN content was 1.2 mg kg^?1 dw (CI 0.9–1.5) in gari roasted from cassava mash dewatered after fermentation. The method of dewatering cassava mash and the duration of fermentation were significantly associated with the level of cyanohydrin in gari (p < 0.001). This study shows that dewatering of cassava mash continuously during fermentation contributes to the dietary cyanide load in TAN‐affected communities. © 2002 Society of Chemical Industry     

The retail market for fresh cassava root tubers in the European Union (EU): the case of Copenhagen,Denmark — a chemical food safety issue?

BACKGROUND: A number of retail shops in Copenhagen sell fresh cassava roots. Cassava roots contain the toxic cyanogenic glucoside linamarin. A survey was made of the shop characteristics, origin of the roots, buyers, shop owner's knowledge of toxicity levels, and actual toxicity levels. RESULTS: Shops selling fresh cassava were shown mostly to be owned by persons originating in the Middle East or Afghanistan, buyers were found to predominantly be of African origin, and sellers' knowledge concerning the potential toxicity was found to be very restricted. Seventy‐six per cent of the roots purchased had a total cyanogenic potentials (CNp) above the 50 mg HCN equivalents kg^?1 dry weight (d.w.) proposed as acceptable by an EU working group. Two of 25 roots purchased had CNp higher than 340 mg HCN eq. kg^?1 d.w. CONCLUSION: The EU has previously made risk assessments concerning cassava and cyanogenic compounds. In the light of the conclusions drawn, the EU needs to make decisions about how to deal with the regulation and control of fresh cassava roots imported to the European food market. Also cassava root products and cassava leaves should be considered. Copyright © 2009 Society of Chemical Industry     

木薯——生物乙醇生产的新原料

从全球范围来看,生物乙醇的生产导致了对农作物需求的持续增长。过去大部分农作物主要用于食品和饲料,种植规模受到限制;现在随着生物乙醇生产对原料的需求,使农作物得到了新的应用,而种植规模的扩大将给农民带来更多的收入。木薯,在热带和亚热带,特别是在土地相对贫瘠,其他农作物产量相对较低的地区广泛种植,过去常常被当作食品和饲料。文中的经济分析和新技术的介绍表明,木薯是一种非常有竞争力的生物乙醇生产原料。     

Cassava (Manihot Esculenta Crantz.) Improvement through Gamma Irradiation

Cassava (Manihot esculenta Crantz., Euphorbiaceae) is an important dietary carbohydrate source for approximately 800 million people in the tropics. Cassava breeding through conventional approaches are hampered with some limitations which resulted in a low number of superior varieties. The objective of this research was to generate several mutant lines with higher yield and starch content. According to field studies it was found that several cassava mutant lines have higher yield (root fresh weight >10-20 kg plant^-1). Two mutant lines has a high starch content (>39%). However, diversity on some variables are still found in M1V2 generation of cassava.     

Nutritional assessment of transgenic lysine‐rich maize compared with conventional quality protein maize

BACKGROUND: The gene sb401 encoding a lysine‐rich protein has been successfully integrated into the genome of maize (Zea mays), its expression showing as increased levels of lysine and total protein in maize seeds. As part of a nutritional assessment of transgenic maize, nutritional composition, especially unintended changes in key nutrients such as proximates, amino acids, minerals and vitamins as well as in antinutrient (phytate phosphorus), and protein nutritional quality were compared between transgenic maize (inbred line 642 and hybrid line Y642) and conventional quality protein maize (QPM) Nongda 108. RESULTS: The contents of total protein, lysine, some other amino acids, several minerals and vitamin B₂ in transgenic inbred line 642 and hybrid line Y642 were significantly higher than those in conventional QPM. Water‐soluble protein and G2‐glutelin were significantly promoted in transgenic maize Y642. CONCLUSION: Insertion of the lysine‐rich sb401 gene increased the total protein and lysine content of transgenic maize varieties, leading to an improved amino acid score and therefore an improvement in the nutritive value of maize. © 2013 Society of Chemical Industry