Distillers grains are a cereal byproduct of the distillation process. [1] Brewer's spent grain usually refers to barley produced as a byproduct of brewing, while distillers grains are a mix of wheat, maize, rice and other grains.
There are two main sources of these grains. The traditional sources were from brewers. More recently, ethanol biofuel plants are a growing source. It is created in distilleries by drying mash, and is subsequently sold for a variety of purposes, usually as fodder for livestock (especially ruminants). Maize-based distillers grains from the ethanol industry are commonly sold as a high protein livestock feed that increases efficiency and lowers the risk of subacute acidosis in beef cattle. [2]
Recently, studies indicate that dried distillers grains with solubles (DDGS) as a food source for human consumption may have some benefit in reducing heart disease risk. [3] [ failed verification ] The mash left over from the process contains nutrients, such as protein, fiber, germ, vitamins, and minerals, and research suggests that the flour made from DDG will work well with cookies and flatbread. The texture and taste of food-grade DDG, especially maize, has been compared to breakfast cereal. [4] [5] [6]
There are two common types of distillers grains:[ citation needed ]
In beer or whiskey production, grains of corn (including wheat and maize), are put through a mashing process, where grain is ground and added to hot water. The starch in the grains undergoes saccharification by enzymes, turning the starch into sugars that are released into the water. The water is removed from the grain, and becomes wort for brewing. The remaining grain, called "spent grain" for the removal of simple sugars and starch, can then be sold as a by-product.
The conversion rate of grains to ethanol and distillers grains varies with the different types of grains and the process used. The details are outlined below:
A cereal is a grass cultivated for its edible grain. Cereals are the world's largest crops, and are therefore staple foods. They include rice, wheat, rye, oats, barley, millet, and maize. Edible grains from other plant families, such as buckwheat and quinoa, are pseudocereals. Most cereals are annuals, producing one crop from each planting, though rice is sometimes grown as a perennial. Winter varieties are hardy enough to be planted in the autumn, becoming dormant in the winter, and harvested in spring or early summer; spring varieties are planted in spring and harvested in late summer. The term cereal is derived from the name of the Roman goddess of grain crops and fertility, Ceres.
Malt is any cereal grain that has been made to germinate by soaking in water and then stopped from germinating further by drying with hot air, a process known as "malting". Malted grain is used to make beer, whisky, malted milk, malt vinegar, confections such as Maltesers and Whoppers, flavored drinks such as Horlicks, Ovaltine, and Milo, and some baked goods, such as malt loaf, bagels, and Rich Tea biscuits. Malted grain that has been ground into a coarse meal is known as "sweet meal".
Pasta is a type of food typically made from an unleavened dough of wheat flour mixed with water or eggs, and formed into sheets or other shapes, then cooked by boiling or baking. Pasta was traditionally only made with durum, although the definition has been expanded to include alternatives for a gluten-free diet, such as rice flour, or legumes such as beans or lentils. Pasta is believed to have developed independently in Italy and is a staple food of Italian cuisine, with evidence of Etruscans making pasta as early as 400 BCE in Italy.
Flour is a powder made by grinding raw grains, roots, beans, nuts, or seeds. Flours are used to make many different foods. Cereal flour, particularly wheat flour, is the main ingredient of bread, which is a staple food for many cultures. Corn flour has been important in Mesoamerican cuisine since ancient times and remains a staple in the Americas. Rye flour is a constituent of bread in both Central Europe and Northern Europe.
Porridge is a food made by heating or boiling ground, crushed or chopped starchy plants, typically grain, in milk or water. It is often cooked or served with added flavourings such as sugar, honey, fruit, or syrup to make a sweet cereal, or it can be mixed with spices, meat, or vegetables to make a savoury dish. It is usually served hot in a bowl, depending on its consistency. Oat porridge, or oatmeal, is one of the most common types of porridge. Gruel is a thinner version of porridge and congee is a savoury variation of porridge of Asian origin.
Field corn, also known as cow corn, is a North American term for maize grown for livestock fodder, ethanol, cereal, and processed food products. The principal field corn varieties are dent corn, flint corn, flour corn which includes blue corn, and waxy corn.
Bran, also known as miller's bran, is the component of a cereal grain consisting of the hard layers - the combined aleurone and pericarp - surrounding the endosperm. Corn (maize) bran also includes the pedicel. Along with the germ, it is an integral part of whole grains, and is often produced as a byproduct of milling in the production of refined grains. Bran is highly nutritious, but is difficult to digest due to its high fiber content; its high fat content also reduces its shelf life as the oils/fats are prone to becoming rancid. As such, it is typically removed from whole grain during the refining process - e.g. in processing wheat grain into white flour, or refining brown rice into white rice.
Wheat flour is a powder made from the grinding of common wheat used for human consumption. Wheat varieties are called "soft" or "weak" if gluten content is low, and are called "hard" or "strong" if they have high gluten content. Hard flour, or bread flour, is high in gluten, with 12% to 14% gluten content, and its dough has elastic toughness that holds its shape well once baked. Soft flour is comparatively low in gluten and thus results in a loaf with a finer, crumbly texture. Soft flour is usually divided into cake flour, which is the lowest in gluten, and pastry flour, which has slightly more gluten than cake flour.
Ethanol fermentation, also called alcoholic fermentation, is a biological process which converts sugars such as glucose, fructose, and sucrose into cellular energy, producing ethanol and carbon dioxide as by-products. Because yeasts perform this conversion in the absence of oxygen, alcoholic fermentation is considered an anaerobic process. It also takes place in some species of fish where it provides energy when oxygen is scarce.
A whole grain is a grain of any cereal and pseudocereal that contains the endosperm, germ, and bran, in contrast to refined grains, which retain only the endosperm.
In West Africa, garri is the flour of the fresh starchy cassava root.
Corn kernels are the fruits of corn. Maize is a grain, and the kernels are used in cooking as a vegetable or a source of starch. The kernel comprise endosperm, germ, pericarp, and tip cap.
Mash ingredients, mash bill, mashbill, or grain bill are the materials that brewers use to produce the wort that they then ferment into alcohol. Mashing is the act of creating and extracting fermentable and non-fermentable sugars and flavor components from grain by steeping it in hot water, and then letting it rest at specific temperature ranges to activate naturally occurring enzymes in the grain that convert starches to sugars. The sugars separate from the mash ingredients, and then yeast in the brewing process converts them to alcohol and other fermentation products.
Corn ethanol is ethanol produced from corn biomass and is the main source of ethanol fuel in the United States, mandated to be blended with gasoline in the Renewable Fuel Standard. Corn ethanol is produced by ethanol fermentation and distillation. It is debatable whether the production and use of corn ethanol results in lower greenhouse gas emissions than gasoline. Approximately 45% of U.S. corn croplands are used for ethanol production.
Starch production is an isolation of starch from plant sources. It takes place in starch plants. Starch industry is a part of food processing which is using starch as a starting material for production of starch derivatives, hydrolysates, dextrins.
Extrusion in food processing consists of forcing soft mixed ingredients through an opening in a perforated plate or die designed to produce the required shape. The extruded food is then cut to a specific size by blades. The machine which forces the mix through the die is an extruder, and the mix is known as the extrudate. The extruder is typically a large, rotating screw tightly fitting within a stationary barrel, at the end of which is the die.
In agriculture, grain quality depends on the use of the grain. In ethanol production, the chemical composition of grain such as starch content is important, in food and feed manufacturing, properties such as protein, oil and sugar are significant, in the milling industry, soundness is the most important factor to consider when it comes to the quality of grain. For grain farmers, high germination percentage and seed dormancy are the main features to consider. For consumers, properties such as color and flavor are most important.
Corn wet-milling is a process of breaking corn kernels into their component parts: corn oil, protein, corn starch, and fiber. It uses water and a series of steps to separate the parts to be used for various products.
Feed manufacturing refers to the process of producing animal feed from raw agricultural products. Fodder produced by manufacturing is formulated to meet specific animal nutrition requirements for different species of animals at different life stages. According to the American Feed Industry Association (AFIA), there are four basic steps:
Dry milling of grain is mainly utilized to manufacture feedstock into consumer and industrial based products. This process is widely associated with the development of new bio-based associated by-products. The milling process separates the grain into four distinct physical components: the germ, flour, fine grits, and coarse grits. The separated materials are then reduced into food products utilized for human and animal consumption.