Corn: Structure and Properties

The Structure and Properties of Corn
The physical properties of corn are important in the design of handling equipment and storage facilities. These properties of course, are affected somewhat by moisture content.

Compared to other grains, corn has a unique shape and low specific gravity, but many other properties are similar to other cereals.

Corn kernels are the largest cereal seed, weighing 250 – 300 mg each. They are flat seeds due to pressure during growth from adjacent on the cob.

The corn kernel has a blunt crown and pointed conical tip cap. The corn kernel is botanically classified as a caryopsis (dry, indehiscent, single seeded fruit) and is attached to the cob by the pedicle.

The kernel contains a complete embryo and all the structural nutritional and enzymatic functions required for growth and development into a plant.

The kernel is composed of four anatomical parts; the tip cap, which provides the point of attachment to the cob; the bran, which is the protective outer covering; the germ or embryo, which becomes the new plant; and the endosperm, which is the reservoir of nutrients to support germination.

Each anatomical part of the corn kernel has a different composition.

The largest fraction of the kernel is the endosperm which is largely composed of starch, the reserve energy supply for a germinating embryo.

Endosperm cells are packed with starch granules embedded in a combination matrix of amorphous protein.

Also embedded in this matrix are protein bodies composed almost entirely of the storage protein zein.

Corn is often harvested as soon as the moisture content drops below 28%. Unless quickly dried, high moisture corn is subject to raid deterioration, especially by mold infestation.

However, high temperature drying, which is occasionally used during the busy harvest period to speed drying operations, can adversely affect wet milling properties and air inlet temperature exceeding 50 degree C should be avoided.

Any hygroscopic material material like corn losses (desorbs) or gains (adsorbs) moisture depending on whether its water vapor pressure (water activity) is greater or less than that of its environment.

Equilibrium moisture content for corn is complicated by the hysteresis effect, in which the equilibrium moisture content depends on whether the grain is desorbing or adsorbing.

Also each component has a different affinity for moisture, so it is not surprise that different corn fractions have different equilibrium moisture isotherms.

Because different types of corn have slightly different composition, their moisture sorption isotherms may vary accordingly.

The critical moisture content for “safe” storage of corn is generally to be 15%, but lower moisture contents are required for corn to be stored for long periods at warm temperatures as occur in the tropics.
Corn: Structure and Properties

The Need for Sustainable Agriculture

The green revolution was a period of extreme innovation that occurred in agriculture predominantly in the 1960's and 1970's, although commenced in the 1940's. During this period huge amounts of research and development were undertaken that increased agricultural productivity significantly, the benefits of which we continue to enjoy today. Initiatives included the development of higher yielding crop varieties, the introduction of synthetic fertilisers and pesticides as well as improving and modernising farm management.

It was these innovations that enabled more food security in the developed world than previously possible. Huge yields were achieved from relatively small areas of land, making food easy to come by in the developed world for most people. As modern farming practices developed, the need for sustainable agriculture was broadened from economic and food sustainability to environmental and social sustainability. While the level of investment in agricultural research and development has been substantially reduced since the green revolution, the knowledge within the sector has greatly increased and agricultural businesses have adjusted their practices to deliver agriculture sustainability.

Sustainable agriculture program
Today all agricultural industries including grains, horticulture, fisheries, sugar and meat are concerned with sustainable agriculture. Agriculture land is not as plentiful as it was during the green revolution and to ensure the sustainability of the industries and importantly the global food supply, sustainable agriculture practices have to be at the forefront of everything the food industry does. In Australia research and development corporations, that represent farmers, invest in research and development to improve the sustainable agricultural practices. Often this is jointly funded with the federal government.

There are also plenty of agriculture schools, primary and secondary as well as sustainable agriculture courses that equip people for careers agriculture. Agricultural jobs are a lot more varied than often thought, with fields in science, engineering, exporting, international relations and e-commerce.

Sustainable agriculture is not just a buzz phrase in countries like Australia, but rather is essential business. With limited arable land, limited water and increasing climatic variability and extreme weather events improving sustainable agricultural practices is fundamental to the future success of the industry and to the worlds food supply.

Without an increase in investment in research and development the advances of the green revolution might not be enough to ensure that people continue to enjoy food security.

Sustainable farm
A sustainable farm has to be able to produce food without depleting the natural resources required to grow more produce in the future. As practices have evolved and knowledge about sustainable farming practices have expanded farmers have become aware that they are responsible for much more than their crops and animals. Where once farmers grazed animals, today sustainable livestock farmers think about themselves as managing three living ecosystems: their animals; the grass and groundcover that animals need to eat to survive and the soils which ultimately is the most important element to manage. Without good soil health sustainable farming can not exist. If soil health is depleted the grass or crops won't grow as well. Environmental degradation on the farm and in the surrounding areas is also a reality if soil health is not a focus of sustainable farming. Without good soil health the structure of the soil can be compromised leading to dust storms and also run off of top soil in heavy rains into waterways.

Agriculture irrigation
Some sectors of agriculture rely heavily on irrigation, such as rice and cotton. Other industries like soy, horticulture, grains and cattle grazing also use some irrigation. Modern irrigation spread widely with the green revolution as a way to produce food in areas that didn't have natural or adequate rain flow to support crops, although irrigation can be traced back to early Egyptian times.

Irrigation is somewhat of a polarising subject, particularly in areas of water scarcity. There are concerns that water is being diverted from its natural course, which has environmental impacts downstream. However others argue that without irrigation in some parts of the world that sustainable agriculture would not be possible. The debate is slowly moving towards finding a point where both objectives can be met to deliver sustainable agriculture and sustainable river and water systems downstream from where the agriculture irrigation is occurring.
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Cereal crop of millet

Millets are native to Africa or Asia and have been cultivated for more than 6000 years.

Millets consists several grass, it does refer to a single grain. Millet is the collective name for a number of cereal species of importance as food crops in tropical and subtropical countries or as forage crops in more northern climates.

Millets grows well in arid regions with poor soils and are valued for their relatively high protein content among the cereals.

Important millet species include: Eleusine coracana (finger millet), Setaria italica (foxtail millet), Echinochloa crus-galli (Japanese barnyard millet), Pennisetum glaucum (pearl millet), and Panicum miliaceum (proso millet).

Finger millet was domesticated in north eastern tropical Africa. It is now a staple in the eastern and central parts of the continents.

Millet forms only 1.5% of the total global cereal crop and is primarily grown for food.

In some parts of Africa and India, where millet has for centuries been an important cereal crop, the grain had multiple applications.

It may be boiled and pounded into a porridge or mush, or it can be ground into flour, formed into thin disks with water, then cooked on a hot surface to make one form of the Indian flatbread called chapatis.
Cereal crop of millet

Wheat Structure

Wheat Structure
Wheat structure is a single seeded fruit, 4 to 10 mm long, consisting of a germ and endosperm enclosed by an epidermis and a seed coat.

The fruit coat or pericaprs (45 to 50 um thick) surrounds the seed and adhere closely to the seed coat.

The wheat color, depending on the species and other factors is red a to white and is due to material present in the seed coat.

Wheat also is classified based on physical characterizes such as red, white soft, hard spring or winter.

The outer pericaprs is consist of the epidermis and hypodermis. The epidermis consists of a single layer of cells that from the outer surface of the kernel.

On the outer walls of the epidermal cells is the water impervious cuticle. Some epidermal cells at the apex of the kernel are modified to form hairs.

The hypodermis is composed of one to two layers of cells. The inner pericaprs is composed of intermediate cells and cross –cells inward from hypodermis.

Long and cylindrical tube cells constitute the inner epidermis of the pericaprs. In the crease, the seed coat joins the pigment strand, and together they form a complete coat about the endosperm and germ.

Three layers can be distinguished in the seed coat: a thick outer cuticle, a “color layer” that contains pigment, and a very thin inner cuticle.

The bran comprises all outer structures of the kernel inward to, and including the aleurone layer.

This layer is the outer layer of the endosperm, but is considered as part of the bran by millers.

The aleurone layer is usually one cell thick and almost completely surrounds the kernel over the starchy endosperm and germ.

The endosperm is composed of peripheral, prismatic and central cells that are different in shape, size and position within the kernel.

The endosperm cells are packed with starch granules, which lie embedded in a matrix that is largely protein.
Wheat Structure

Sorghum

Sorghum
The genus of Sorghum is found in warm, dry climates, especially in Africa, India, Pakistan, China and the Southern USA where its members are grown as important grain or forage crops. Because sorghums have been in cultivation for a long time and because interspecific hybrids are easily formed, the taxonomy of the genus is somewhat confused. Until recently the cultivated types were loosely grouped together in the species Sorghum vulgare, but a thorough revision of taxonomic relationships suggests that Sorghum bicolor is the species to which the grain crops should belong.

The seed of grain sorghum or dura as it is often called, contains no gluten, and hence is by itself not suitable for bread making. Normally for human consumption the grain is group into flour, mixed with water or fat and cooked to form a porridge or batter. Alternatively, the grain is fed to pigs or poultry, its starch may be used for a variety of purposes such as an adhesive or for sizing or it may be fermented to produce alcohol. Sorghum are also grown as forage crops and may produce high yields of the order of 30,000 kg/ha from several cuts throughout the year.

Best resulted are obtained from special forage types such as sorgo, sweet or sugar sorghum which is variously described as a variety of sorghum or as a separate species (Sorghum saccharatum). Sudan grass (S. Sudanese), a tall and tufted tropical grass, is often used top produce hybrids with sorghum, as for example the production forage plants Sudax or Sordan.

One possible problem with these forages is that contained in the leaves there may be a cyanogenic glycoside, dhurrin, which when eaten by animals hydrolyses to form poisonous hydrogen cyanide. In ruminants, hydrogen cyanide is rapidly detoxified in the rumen and liver by reaction with sulphide or cystine, but the danger of toxicity remains of glycoside levels are high or sulphur intake is low. The problem can be avoided by the choice of safe cultivars by not allowing stock to graze very immature growth, or by feeding as hay or silage.
Sorghum

Peaches Fruit

Peaches Fruit
Peaches are grown commercially in about 35 states in United States, California producing by far the largest amount. There are a number of varieties classified as clingstone or freestone varieties. The flesh of clingstone varieties, use primarily for canning, adheres tightly to the pit. In freestone varieties used both as fresh and for canning, the flesh is easily separated from the pit.

Peach trees not long lived, are set out form nursery stock and produce significant quantities of fruit for 7 – 16 years. Yearly pruning and thinning of peach trees is practiced. Peaches are harvested or picked when in the firm, ripe condition, but before they come soft. The fruit is picked into buckets or bags that are emptied into lug boxes for transportation to processing plants.

At the processing plant, peaches to be handled as fresh are washed in dilute cid or alkaline solutions to remove spray residues, then rinsed in water and allowed to drain and dry. Decayed specimens are removed as the fruit passes over an inspection belt, and the unblemished fruit is packed in boxes. The fruit is air-cooled to 31 degree to 32 degree F, and should be held at this temperature until sold to the consumer. Handled in this manner, the fresh fruit has a storage life of 2 – 4 weeks.
Peaches Fruit

Canadian Oats

Canadian Oats
Only about 50 percent of Canadian oat production is commercially traded. Based on 98/99 estimates, about 40% of Canadian oats are exported, primarily to the US performance and milling oat markets. Canada supplies the USA with 70% of its oats imports, with Finland and Sweden supplying the rest. In the Canadian domestic market, about four per cent of the oats are used for human consumption market, and another four per cent for seed.

The majority of Canadian oats are still used in the Canadian feed market. A large amount of the feed oats are produced and fed on farm, with a small amount moved to the Canadian racehorse market. Although oats are being used in more quality specific markets, in years of ample supply, the North American feed market is still a significant factor in determining overall oat prices.

Typically, the best oats produced are fed to horses! Performance oats, referred to by many as "pony oats", are high quality oats sold to premium horse feed markets. These oats normally are bought according to buyer specifications, but usually fit within the No. 1 grade specified by the Canadian Grain Commission. Buyer specifications require oats that are consistently plump, bright-colored and of heavy test weight.

Performance oats are normally shipped in raw bulk or bagged form. Bagged product usually undergoes a process of double re-cleaning and clipping to increase bushel weight before being bagged. This produces quite a bit of by-product - screenings of weed seeds, dust, small oats, etc. - which grain companies also market.
Canadian Oats