The Corn (Zea mays L.) belonging to the family Gramineae Maydeae tribes. Zea Mays is the only species of the genus Zea and it is only the state cultivated.
Constitution of the kernel
embryo (12-14%)
endosperm (75-80%)
casings (8-10%)
The kernel composition
The differences of kernel in corn (color, signs, weight) are very pronounced from one variety to another. The color ranges from dark violet to white, passing through red and the classic yellow color. Also the shape is very different: rounded, flattened, pointed, as well as the kernel weight that ranges from 100 g. over 1200 g. per 1000 grains. While the most common varieties have a weight of 1000 grains of about 250-300 g.
Varieties and genetic improvement
Thanks to the great genetic variety of the plant, the studies by the genetic improvement of the same have given and continue to give great successes. The research objectives are primarily to: precocity of the growing season, the plant’s resistance to disease, cold, to rot and to a pure improvement of grain quality. Worldwide research for the varietal improvement of maize has gone, as well as for other cereals, through to genetic engineering studies, creating transgenic varieties or genetically modified. The GMO varieties while in other countries are widely used, in Italy their cultivation is not allowed.
Commercial classification of hybrid varieties of corn
The main and most used is certainly the FAO (Food and Agriculture Organization of the United Nations), which is based on the maturation of varieties cycle:[su_spoiler title=”click to see the classification” icon=”arrow”]
- Class FAO 100 (not in Italy)
- Class FAO 200 (from 86 to 95 days)
- Class FAO 300 (from 96 to 105 days)
- Class FAO 400 (from 106 to 116 days)
- Class FAO 500 (from 116 to 120 days)
- Class FAO 600 (from 121 to 131 days)
- Class FAO 700 (from 132 to 140 days)
- Class FAO 800 (not in Italy)[/su_spoiler]
Classification of Sturtevant and Kuleshov
Another classification is based on the consistence of corn and then the composition of the grains and starches sugars (classification of Sturtevant and Kuleshov) from which we can draw a different intended use of the varieties: [su_spoiler title = “click to see the classification” icon = “arrow”]
- Everta: small kernels with vitreous endosperm, translucent and very protein. Corn to make (Pop-Corn)Corn
- Indurata: roundish kernels, internal floury endosperm. Corn vitreous from human or animal alimentation (Flint Corn)
- Indented: granule with horny endosperm at the sides and the remaining floury. (Dent Corn)
- Amylacea: modified starch in the constitution. (Soft Corn)
- Saccharata: with endosperm rich in soluble carbohydrates and little starch. (Sweet Corn)
- Ceratina: “waxy” mutation that induces formation of starch, only amylopectin. Waxy corn for the starch industry (Waxy Corn)[/su_spoiler]
Intended use of the Corn
The grain can be used in various forms and for various uses. The majority of the corn used for animal feed and for human consumption is produced by dry grinding, from which is obtained the separation of the bran from the endosperm of the caryopsis integuments and flours of different grain size.
[su_spoiler title = “click to see the uses” icon = “arrow”]
- Grains
- Corn Flakes
- Pop Corn
- Broken and flours (which are obtained from grinding process):
- Hominy (to be allocated after the rolling staple, Corn Flakes, for human food and animal feed)
- Grits (for the brewing industry or animal feed)
- Flour
- Germ: for the extraction of oil.
- Starch: produced in abundance and used as such or modified by physical treatments, chemical and enzymatic.
- Corn gluten: for the integration of animal feed.
- Whole grain mash: in feed for cattle and /or pigs.
- Corn silage: for feeding cattle or for Biogas plants [/ su_spoiler]