Nutritional and natural toxicology of African Crops
Maize ( Zea mays L))
Maize is a plant commonly grown in the humid tropics for its seeds that enter into many foods or
animal feeds.In West Africa, maize is consumed roasted or as porridge, pancakes, couscous and
mainly as starch paste. Maize is also used in major producing countries such as USA to produce
edible oil, starches and sugar.
The main macronutrients encountered in maize seeds are carbohydrates but proteins are present at
a low level (OECD, 2002). The major amino acid and major fatty acid of maize seeds are leucine and
linoleic acid respectively. Maize grains are poor in lysine (an essential amino acid).The major
minerals and vitamins are magnesium, phosphorus and potassium, and vitamin C (OECD, 2002;
USDA, 2001; Souci et al., 2000; NRC, 1994, 1998, 2000 and 2001).
Maize is not known to contain substances toxic to humans but may contain antinutrients such as
phytates, raffinose and a low level of trypsin inhibitor. The phytates can diminish the bioavailability
of phosphorus in maize for non-ruminant animals (Newsmonger et al., 1990) and raffinose can
cause flatulence (OECD, 2002).
Maize also contains an indigestible lipid transfer protein (9kDA) that survives cooking and has been
reported to be allergenic to humans (Pastorello et al., 2000).The allergic reaction can cause skin
rash, swelling or itching of mucous membranes, diarrhea, vomiting, asthma and, in severe cases,
anaphylaxis. It is unclear how common this allergy is in the general population (OECD, 2002) but the
frequency to which allergic disease could be attributed to maize is low (Zavala et al., 2006).
According to OECD consensus document (2002), the nutritional and compositional analysis of maize
grains should be focused on proximate analysis (protein, fat, total dietary fibre, ash and
carbohydrates), minerals, vitamins, amino acids, fatty acids, phytic acid, raffinose, furfural, ferulic
acid and p-coumaric acid. For the summary, see Table below.
Table: Summary for maize
Key considerations
Food characteristic
1. What is the most important species of maize
used as food?
Zea mays9
2. What are the edible parts?
Seeds 9
3. What are foods derived from maize?
Maize starch, oil, alcoholic beverages, pancakes and
snacks9.
4. What is the major macronutrient?
Carbohydrates 9,10 ,11
5. What is the major amino acid?
Leucine4,6,7,8,10,11,14,17
6. What is the major fatty acid?
Linoleic acid9, 10 ,11
7. What is the major vitamin?
Vitamin C9, 10,11
8. What are the major minerals?
Magnesium, phosphorus and potassium9,10,11
9. What are the main toxic substances?
No known toxic substances but anti-nutrients9,17
10. What are the main anti-nutrients?
Phytic acid , raffinose9 and low levels of trypsin inhibitors17
11. What are their main adverse effects?
Phytates reduce the bioavailability of phosphorus in maize
for non-ruminant animals and raffinose causes flatulence9
12. What is the route of exposure?
Oral9,17
13. Is food derived from maize known to be
allergenic?
Possible allergenicity to two allergens; a lipid transfer
protein and a trypsin inhibitor3, but low frequency 19
References
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the age and plant organ in maize. Phytochemistry; 53: 223-229.
3 Pastorello E A, Farioli L, Pravettoni V, Ispano M, Scibola E, Trambaioli C, Giuffrida MG, Ansaloni R, GodovacZimmermann J, Conti A, Fortunato D, Ortolani C., 2000. The maize major allergen, which is responsible for foodinduced allergic reactions, is a lipid transfer protein. J Allergy Clin. Immunol; 106(4): 744-51.
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Academy Press, Washington D.C., USA.
9 Organization for Economic Co-operation and Development (OECD), 2002. Consensus Document on
Compositional Considerations for new varieties of maize (Zea Mays): Key food and feed nutrients, anti-nutrients
and secondary plant metabolites. Series on the Safety of Novel Foods and Feeds No.6.
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Publishers - CRC press, Stuttgart, Germany, 2000.
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Standard Reference, Release 14.
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14 Watson SA, 1982. Corn, amazing maize, general properties. pp 3-29. In: Wolff IA (Ed.) CRC Handbook of
processing and utilization in agriculture, Vol. II, Part I, Plant Products. CRC Press, Inc, Florida.
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and Technology, Amer. Soc. Cereal Chem. Inc. St Paul, Minnesota.
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composition and nutritive values. Cereal Foods World; 40 (10): 756-762.
18 Xie Y, Arnason JT, Philogene BJR, Olechowski HT, Hamilton RI, 1992. Variation in hydroxamic acid content in
maize roots in relation to geographic origin of maize germplasm and resistance to Western corn rootworm
(Coleoptera: Chrysomelidae). Journal of Economic Entomology; 85: 2478-2485.
19 Zavala VMP, Vega Robledo GB, Sánchez Olivas MA, Duarte Diaz RJ, Oviedo CL., 2006. Maize (Zea mays): allergen
or toleragen? Participation of the cereal in allergic disease and positivity incidence in cutaneous tests. Rev. Allerg.
Mex; 53(6): 207-11
Lassina Ouattara
2013