Introduction 

A cereal is any cultivated grass grown for the edible components of its grain.  The word cereal is derived from Ceres, the Roman goddess of harvest and agriculture.  The term can also refer to the resulting grain itself, which can more specifically be called the cereal grain.  The edible components of a cereal grain are composed of the endosperm, germ, and bran.  Cereal grain crops are grown in greater quantities and provide more food energy worldwide than any other type of crop.  Maize is the most highly produced cereal worldwide with over one billion metric tons grown annually.  Wheat is second with nearly eight hundred million metric tons per year, followed by rice at nearly five hundred million metric tons, barley at just over one hundred and fifty million metric tons, and sorghum at around sixty million metric tons annually.  Other cereals with significant worldwide production include millet and quinoa.  Some cereals like maize are grown in many different areas in the world as there are species and varieties that have adapted to climate and growing conditions while others are more specific to certain parts of the world.  In their natural and unprocessed form, cereal grains are a rich source of vitamins, minerals, carbohydrates, fats, oils, and protein.  When the bran and germ are removed, the endosperm is mostly carbohydrate.  In some developing countries, cereals are the primary food for daily sustenance and impoverished countries often depend on cereal shipments from other parts of the world.  The long shelf life, high caloric content, and nutritional composition of cereal grains makes them ideal for such purposes.  In developed countries, cereal consumption is more moderate and products can vary, but is still substantial in many countries.  One important processed product of cereal grains and another use of the word “cereal” is breakfast cereals, which are often simply referred to as cereal in many Western societies where consumption is substantial.  Hot cereals require a brief cooking period but are less popular than cold cereals, which are made ready to eat and are almost always eaten with milk. 

History and Market Analysis 

Cereals have played a substantial role in the development of human civilization.  There is evidence of cultivation of cereals in Syria around nine thousand years ago.  Wheat, barley, rye, oats, and flaxseeds were all domesticated in the Fertile Crescent region in ancient times.  The name Fertile Crescent at least partially came from the development of agriculture in this region, along with irrigation and technological developments.  Around the same time, farmers in China began to grow rice and millet.  Farmers began to use irrigation, human-made floods, fires, and soil amendments to improve the growth of food crops.  Around eight thousand years ago, cereal grains were domesticated in multiple parts of the world, including wheat and barley in multiple regions, millets and rice in East Asia, and sorghum and millets in sub-Saharan West Africa.  Wheat, barley and oats were cultivated in Greece as early as 7000 B.C. and by 6000 B.C., farmers were starting to mill grains by hammering them with stones and were toasting grains as well.  Egyptians cultivated wheat and barley and fermented them to make beer.  The first hand mills for grinding grain appeared around 1200 B.C. and continued to be used for thousands of years. As civilization developed more, cereal became a foundation for determining frontiers.  Both the Great Wall of China and Roman limes demarcated the northern limit of cereal cultivation.  The Silk Road, a stretch of trade routes connecting the east and west that was central to cultural, economic, political and religious development for many centuries, was built along the cereal belt of Eurasia.  Cereals played an integral role in how long an army could be mobilized and how large it could be.  Many ancient Chinese, Jewish, and Christian writings make references linking cereals with war.  In more modern times, wheat was a staple of the European diet in the colonial era.  The first European colonists in America imported wheat but had problems storing it and the cool climate made it difficult for crops to survive.  Over time, colonists learned to grow oats, maize, and a hardy dry land rice as until the nineteenth century, rice was grown on dry land and not in paddles as it is today.  Cornbread made out of maize became a staple of the American diet in the colonies.  In 1769, the steamroller mill was introduced, making it possible to process wheat before it decayed.  In 1834, a mechanical revolution began in farming with the introduction of the mechanical reaper as the capacity for growing cereal grains had far exceeded the ability to harvest it.  Combine harvesters were introduced about fifty years later and by the early 1900s, a single farm could harvest almost twenty times as much land as could have been harvested one hundred years due to the mechanical revolution.  Today, advances continue in cereals but mostly on the product itself, such as vitamin fortification, making products with increased health and nutritional benefits, and genetic engineering. Cereals and cereal-based products will continue to be a major part of the food chain around the world. 

The global market for cereal and grain seeds is projected to reach $73.6 billion within the next five years while growing at a CAGR of 9.2%.  The Asia-Pacific market is currently the largest market for cereal seeds and is expected to remain so in coming years, accounting for more than 30% of global demand.  Driving factors in market growth include increasing demand from the food and especially animal feed industries, shrinking farmland, and increased biofuel demand.  Global usage of maize in the animal feed industry increased over 2% from 2020 to 2021, with an estimated worldwide usage of 613 million metric tons.  Maize is the major crop seed traded worldwide, accounting for over 35% of the global cereals and grain seed market share, followed by soybean and wheat.  More than half of global maize production is in the United States and China, with the European Union and Brazil also holding significant market share.  Growing population in Asian countries, especially China and India, is increasing demand in Asia while North America is projected to have comparable growth due to rising demand for biofuel. 

The global breakfast cereals market is expected to grow from $44.5 billion in 2020 to $63.3 billion in 2028 at a CAGR of 4.8% during the forecast period.  Projected growth is primarily attributed to the rising awareness of consumers regarding healthy foods and a balanced diet as well as a growing demand for ready-to-eat meals and advancements and innovations in food production.  The market is dominated by cereals that can be consumed as is (usually with milk) and consist of wheat, corn, mixed grains, and other supplements.  Breakfast cereals that are not fortified with sugar are considered very healthy as they are high in vitamins and minerals.  They considered to have a perfect balance of time-saving, convenience, high energy, and good nutritional content in a food product.  Globalization and rapid urbanization in developing countries has helped increase demand for these types of foods in many economies and global demand for cereal and cereal-based products will continue to increase in coming years. 

Barley Composition, Growing, Harvesting, and Processing 

Barley ranks fifth among all crops in dry matter production in the world.  It has been cultivated for centuries because of its versatility, adaptability to unfavorable and changing climate and soil conditions, and superior properties for malting and brewing.  It is generally more tolerant to drought and saline soils than other cereal grains.  The top five barley producers are Russia, France, Germany, Ukraine and Canada.  Approximately 65% of barley produced in the world is used for animal feed, 30% for malting and brewing, and around 3% for human consumption.  The primary use of barley as animal feed is for cattle.  The nutritional content of barley is comparable to corn, oats, wheat, and sorghum.  The energy content is slightly lower than most other grains due to higher fiber content, but the crude protein content of barley is higher than corn and similar to wheat and oats. Malted barley is the preferred grain that brewers use for making beer.  The most basic form of malted barley is barley that has been allowed to germinate by soaking the grain in water, which prepares the starches to be converted to fermentable sugars.  Barley is not a staple food for human consumption in most developed societies with the exception of Scandinavia and parts of Eastern Europe, but it is a staple food in many developing countries.  In rural Tibet, barley provides approximately 80% of calories for native diets.  However, there is increased interest in barley as a human food ingredient due to studies showing it to be an excellent source of dietary fiber, especially β-glucan.  Barley kernels contain complex carbohydrates, are low in fat, are well-balanced in terms of protein to meet amino acid requirements, and are rich in some minerals, vitamins (especially Vitamin E), and antioxidant polyphenols.  As is the case with all cereal grains, barley does not contain calcium and for this reason, supplemental calcium is used in diets for beef cattle.  It can be used as whole-grain, pearled, raw-grain flour, whole-roasted grains flour, and roasted-grain flour.  Roasted-grain flour particularly is used in many products, such as breakfast cereals, stews, soups, pastas, noodles, sauces, and baked products.   

Barley varieties have many different types of classifications.  The most important classification is two-row barley or six-row barley, a distinction in the physical morphology of the plant.  The difference is caused by a single gene out of approximately thirty thousand.  Both types have alternating sets of three spikelets along the barley head but in two-row barley, only the central spikelets are fertile and they develop seed creating a flat-shaped head.  Six-row barley has a rounded head appearance with all six kernels developing.  Two-row varieties are generally higher in starch and six-row varieties are higher in protein, but otherwise the nutritional composition is very similar.  Two-row barley is usually more adaptable to dry growing conditions. Studies comparing the two types for animal feed have not shown any clear advantage between them.  For brewing, two-row barley is desirable in some ways because germination is more uniform, seeds need a shorter steeping time, and have lower protein as high protein can make beer cloudy.  However, six-row barley is used by many large brewers in North America as the higher protein favors higher potential for enzymatic activity which helps for conversion of mashes that are heavy in adjuncts like rice and corn.  Other important classifications include malting vs. feeding, covered vs. hull-less, and floury starch vs. waxy starch.  Hull-less barley is a form of domesticated barley with an easier to remove hull.  It has lower fiber and higher protein and energy levels than covered barley.   

Barley is easily planted in prepared seedbeds and can also be successfully no-tilled.  It prefers adequate but not excessive moisture and will not grow well in waterlogged soils.  Barley grows well in well-drained loams or light, clay soils in areas with dry and mild winters.  It tolerates alkaline soils better than other cereal crops.  There are numerous varieties and it is important to select a variety adapted to the region. Many varieties of barley are well-adapted to high altitudes and short, cold growing seasons.  Pest and weed management are also particular to given regions.  Harvesting is crucial in determining grain yield and quality of barley.  The simplest and most common method is direct heading when the grain has ripened and dried to a moisture content of less than 12%.  A thresher is used and is it important to set it up correctly to prevent the skinning and cracking of grain.  If there are long periods of high relative humidity, the harvesting can be delayed and this increases the risk of head loss or discoloring of the grain.  Grain can be direct harvested at a moisture above 12% but after harvesting, the grains must be placed under aeration or passed through a grain dryer to get the moisture to a proper level for storage.  Drying at a temperature greater than 43°C can greatly reduce grain quality.  If the moisture falls below 10% before harvesting, the barley grain becomes susceptible to skinning from over-threshing.  If the barley is covered, the first step in processing is to remove the hull by blocking.  Processing is especially important for barley used as animal feed as digestibility in processed barley is much higher than that of whole barley.  The most common processing method is known as dry rolling.  Barley should be crushed or cracked so that each kernel is broken into two or three pieces.  This is usually done with a single-stage roller mill with ten to twelve grooves per inch.  This method is effective and increases digestibility in animals, but shattered kernels that produce fine particles reduce the effectiveness of the feed.  Variation in kernel size can make precise processing difficult.  Steam rolled barley is subjected to high moisture steam for a period of one to eight minutes and is then rolled to produce a flat flake.  Temper rolled barley requires the addition of water to increase the moisture to 18% to 20% before rolling and also results in a flaked product.  Advantages of these two methods include fewer fine particles and improved ration acceptability.  Steam flaking uses moisture, heat, and pressure to gelatinize starch granules.  There have been numerous studies on different methods of processing barley as well as different varieties and their benefits and drawbacks.  Ultimately, growing conditions and proper harvesting and processing have proven to be the most crucial factors in determining barley quality as a common quality parameter for variations in physical, chemical, and biochemical properties in processed barley grain has yet to be determined.   

Breakfast Cereal History, Production and Processing 

Breakfast cereal is a processed food made of grain and is usually intended to be eaten with milk during the morning meal.  Cold breakfast cereals come ready to eat while hot breakfast cereals require a brief cooking period.  Hot cereal has existed for centuries, beginning with the grinding of whole grains and cooking them in water to create gruels or porridge.  The first types of cold cereal were invented in the late nineteenth century and in 1906, the Kellogg brothers formed the Kellogg Company after developing the first precooked and flaked cereal.  By 1909, the company had sold over one million cases of cereal and cold breakfast cereal has far eclipsed hot cereal in popularity.  Soon after, Charles Post founded what is now known as the General Foods Corporation.  Today, competition among companies is strong for the breakfast cereal market which is at an all-time high, especially in the United States.  It is a highly penetrated market in the United States and Europe but there is room for growth in many other parts of the world.  In the United States, companies are looking to boost consumption by repositioning breakfast cereal as a snack or dessert, introducing new and eye-catching flavors, and playing to the increasing awareness of health and nutritional benefits of foods, especially breakfast foods.   

The main raw ingredient in breakfast cereal is grain and many types are used, such as corn, wheat, oats, rice, rye, and barley.  Some types of hot and cold cereals, such as plain oatmeal and shredded wheat, are consumed with the addition of no other ingredients but most types of breakfast cereal include many additional ingredients depending on the recipe and processing method.  Some of these ingredients include salt, sweeteners, yeast, coloring and flavoring agents, preservatives, vitamins, minerals, seeds, nuts, cinnamon, chocolate, marshmallows, and dried fruits.  While some natural cereals are sweetened with concentrated fruit juice, most breakfast cereals use white or brown sugar, corn syrup, or malt.  Any added vitamins or minerals need to be added after cooking as most of them will greatly lose nutritional value when exposed to high heat.   

Breakfast cereal manufacturing requires several stages and there are different types of processes depending on the final product, but all processes begin with the preparation of the grain.  When grain arrives at the cereal factory, it is inspected and cleaned.  Some cereals use whole grain while others require crushing between metal rollers to remove the outer layer of bran and grind the grain into a fine flour.  Whole and partial grains are mixed with other ingredients in a pressure cooker.  Speed of rotation, time, and temperature are subject to the type of grain used.  After cooking, the grain is passed to a drying oven but a certain amount of moisture must be left so it can be shaped as needed.  If flour is used, the flour is mixed with other ingredients and cooked in an extruder.  A long screw mixes the flour with other ingredients while moving the mix through the extruder.  At the other end, the cooked dough is expelled and cut into pellets by a rotating knife.   

Types of breakfast cereal include flaked cereal, puffed cereal, shredded cereal, and granola.  Flaked cereal can be made from whole grains or extruded pellets which are allowed to temper for several hours, allowing the moisture to stabilize.  After tempering, the grains or pellets are flattened by rollers and sent to an oven for toasting and removal of excess moisture.  Unmodified corn starch is often added to help the flakes withstand processing.  Moisture control is crucial during this process.  Moisture should be between 28% and 32% after tempering and between 1% and 3% in the finished product to obtain the correct crunchy texture and toughness.  Puffed cereal is usually made of rice or wheat.  It uses a piece of equipment called a gun after tempering and partial flattening between rollers (known as bumping).  A gun is a high temperature and pressure oven that swells the grains and suddenly releases the pressure, causing them to puff up in size. A gun needs to operate between 400°C and 500°C and around 200 psi to be effective.  Puffed grains have a moisture content between 5% and 7% which needs to be dropped to between 1% and 3%.  These grains absorb moisture very easily, requiring a final layer of coating and proper packing to maintain crispiness and prevent spoilage.  Wheat is usually used for shredded cereal.  It is boiled in water to allow full moisture penetration.  After boiling, the grain is tempered for up to twenty-four hours and passed through two metal rollers.  While similar to the process for flaked cereal, shredded cereal uses one smooth roller and one grooved roller while both rollers are smooth for flaked cereal.  A metal comb against the grooved roller shreds the grain into a continuous ribbon as it passes through, which is then cut and baked until the right color and dryness are obtained.  Granola is made by mixing grain and other ingredients which are cooked as a mix. Common ingredients in granola include nuts, dried fruits, seeds, honey, and malt extract.  Oil is added to the mix to allow the ingredients to stick together.  The mixture is cooked between 300°F and 425°F until lightly brown with a moisture content of around 3%.  Certain types of carbohydrates can be added to help with binding.  Some cereals may be sprayed with a layer of coating after processing that can include sweeteners, flavors, food coloring, preservatives, vitamins, and mineral.  Coatings can add sweetness, provide a layer between the cereal and milk to prolong crispiness, and improve storage stability.  Proper packaging is essential in airtight and waterproof bags to prevent spoilage.  High density polyethylene (HDPE) is typically used but manufacturers are exploring alternatives such as plant-based packaging and also looking to improve convenience for the consumer by using resealable, flexible, stand-up, and single-serve packages.  The cereal bag is then usually put into a cardboard box for further protection.  As the breakfast cereal market continues to grow, proper monitoring and quality control methods will evolve to meet new challenges presented by innovative products and manufacturing processes.  

Cereals and Barley and NIR Spectroscopy  

NIR spectroscopy has emerged as a tool for rapid, non-invasive, and cost-effective analysis of parameters of interest in cereals and barley that could potentially replace traditional reference methods.  There are a number of quality parameters in cereals and barley that have been studied and predicted with NIR spectroscopy with results suitable for process control purposes. Other parameters have shown results good enough for screening purposes and more study and calibration work could improve the prediction results.  One review paper examined the use of NIR spectroscopy for determining essential parameters in the field and at harvest for cereal crops.  These parameters include dry matter, nitrogen, water content, starch, sugars, and various plant diseases, although the monitoring of mycotoxins must be carefully validated as the actual concentration of these is usually far below the threshold of detection for NIR spectroscopy.  Another review paper specifically examined various components related to starch in cereal grains and associated biophysical and chemical properties, such as amylose, amylopectin, pasting, gelatinization, and viscosity.  Malt barley is essential for beer manufacturing and a practical application used NIR spectroscopy to evaluate yield and quality traits in different varieties of malt barley by examining kernel protein and starch content to determine high yield varieties.  Superoxide dismutase (SOD) is a protective enzyme in barley and NIR spectroscopy was examined for determining the activity of SOD in barley leaves, showing acceptable results.  Herbicides can have a detrimental effect on barley growth and amino acid content is considered an important physiological parameter for measuring the effect of herbicides.  NIR spectroscopy was used to determine amino acid content to evaluate the effect of herbicides on barley leaves.  Barley milk production as a replacement for cow milk is steadily increasing and NIR spectroscopy was examined for measuring parameters in barley milk by determining particle size and total dissolved solid to optimize blending time. Sorghum is the next highest produced cereal grain after barley and one study examined determining various quality traits in sorghum using NIR spectroscopy, including amylose, protein, lipids, endosperm texture, and hardness.  Sugar content is an essential component in breakfast cereal and one study examined using NIR spectroscopy to determine total sugars as well as sucrose, fructose, and glucose in breakfast cereals, showing excellent results.  Rising demand for snack foods has increased the production of cereal bars of various types and NIR spectroscopy was used to classify three different sample types of cereal bars (Conventional, Diet, and Light). All these parameters and measurements have been studied using NIR spectroscopy with results showing the potential to replace traditional reference methods. 

References 

Cereal Grains 

https://www.encyclopedia.com/history/dictionaries-thesauruses-pictures-and-press-releases/cereal-grains 

 Cereals & Grains 

http://www.fao.org/in-action/inpho/crop-compendium/cereals-grains/en/ 

 Grain Seed Market – Growth, Trends, COVID-19 Impact, and Forecasts (2021-2026) 

http://www.fao.org/in-action/inpho/crop-compendium/cereals-grains/en/ 

 Global Cereals and Grains Seed Market Share 2021 with Top Countries Data And Covid-19 Analysis: Industry Overview by Size, Share, Future Growth, Development, Revenue, Top Key Players Analysis and Growth Factors 

https://www.marketwatch.com/press-release/global-cereals-and-grains-seed-market-share-2021-with-top-countries-data-and-covid-19-analysis-industry-overview-by-size-share-future-growth-development-revenue-top-key-players-analysis-and-growth-factors-2021-04-21 

 Breakfast Cereal Market Size, Share & Trends Analysis Report By Product (RTE, Hot Cereal), By Distribution Channel (Supermarket, E-Commerce, Convenience Store), By Region, Vendor Landscape, And Segment Forecasts, 2018 – 2025 

https://www.grandviewresearch.com/industry-analysis/breakfast-cereals-market 

 Barley 

https://www.sciencedirect.com/topics/agricultural-and-biological-sciences/barley 

 Barley Production – Harvest and Grain Quality 

https://www.agric.wa.gov.au/barley/barley-production-harvest-and-grain-quality 

 2-Row vs. 6-Row 

https://www.montana.edu/barleybreeding/learning-center/maltster-resources/articles-posters/2r-v-6r.html 

 Effects of Barley Grain Processing on Productivity of Cattle 

https://www.sciencedirect.com/science/article/abs/pii/S0377840106005335 

 A Guide on the Production and Processing of Breakfast Cereals 

https://cablevey.com/a-guide-on-the-production-and-processing-of-breakfast-cereals/