Flour extraction

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Flour extraction is the common process of refining Whole Grain Flour first milled from grain or grist by running it through sifting devices, often called flour dressers.

Contents

Definition

For centuries, much of the flour milled for human consumption has been run through some kind of “bolting”, sifting or “extraction” process. [1] This flour is extracted from whole grains for one of two reasons; firstly, to decrease the tendency for rancidity. The milling systems with a lower extraction percentage discard most of the rancidity prone nutritional minerals and oils associated with the bran and germ elements, [2] of the wheat kernel. [3] Baking functionality is the other issue, with increased loaf volume accomplished by simply removing just the larger flour particles. [4] [5] Like the lower extraction white flour, higher extraction flour still creates a smoother dough more inclined to hold the gas created during fermentation. However, higher extraction flour also retains the sensory flavors and nutrition associated with the smaller bran and germ elements that are also extracted along with the endosperm.

History

“White flour”, extracted from whole grains by Roller mills that eliminates the rancidity prone bran and germ elements of the wheat kernel was introduced in the late 19th century. By first hydrating the outer wheat kernel bran and germ elements to keep them intact, this new system then employed steel rollers instead of circulating stones to repetitively fracture the remaining starchy endosperm element into fine particles. The extracted endosperm flour came to be known as “white flour” as this element of the wheat kernel is white. This system ingeniously accomplished the extraction of most of the starchy endosperm while separating out virtually all of the bran and germ elements, extracting about 72% of the whole grain kernel. Roller milling eventually came (and continues) to dominate the world’s flour production. Well over 90% of U.S. flour production in 2017 was roller milled white enriched flour.

Once roller milling made white flour affordable for almost everyone, public health issues arose. As scientists learned more about the crucial health contributions of the bran and the germ, artificial enrichment of white flour was introduced that restores a small part of the nutrition lost by eliminating all the bran and germ elements.

Benefits

There are generally two benefits from extraction:

  1. The highest extraction typically retains over 85% of the original volume by focusing on just improving functionality (increased loaf volume) without a significant sensory loss. A fine Whole Grain Flour is used to just remove the larger flour particles and is commonly referred to by Artisan bakers as High Extraction flour. It is primarily used to produce a variety of non-whole grain bread products.
  2. More aggressive sifting focuses on both functionality and reduction of the potential for rancidity by eliminating 100% of the bran and germ in the kernel. This lower extraction (typically 72% or less) is most commonly Roller Milled White Enriched flour yielding a significant selection of flour types used for a variety of baking applications, the most significant of which is white bread. [6]

Higher extraction flour

The general availability of refrigeration and even flour itself, has diminished the significance of the rancidity/shelf life/keeping quality issue of whole grain flour. Higher extraction rates just focus on the elimination of the larger flour particles to increase loaf volume while retaining the majority of the nutritional bran and germ elements along with the endosperm. This is accomplished by direct extraction of the fine whole grain flour output of impact or attrition mills. Millers have been able to match the finer particle size distribution of low extraction roller milled white flour (72% extraction) that eliminated all the bran and germ elements with a higher +88% extraction that retains most of them. [7] [8]

Related Research Articles

<span class="mw-page-title-main">Flour</span> Cereal grains ground into powder

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.

<span class="mw-page-title-main">Semolina</span> Coarse, purified milled durum wheat

Semolina is the name given to coarsely milled durum wheat mainly used in making couscous, pasta, and sweet puddings. The term semolina is also used to designate coarse millings of other varieties of wheat, and sometimes other grains as well.

<span class="mw-page-title-main">Bran</span> Hard outer layers of cereal grain

Bran, also known as miller's bran, is the hard layers of cereal grain surrounding the endosperm. It consists of the combined aleurone and pericarp. 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.

<span class="mw-page-title-main">White bread</span> Type of bread made from white wheat flour

White bread typically refers to breads made from wheat flour from which the bran and the germ layers have been removed from the whole wheatberry as part of the flour grinding or milling process, producing a light-colored flour.

Wheat flour is a powder made from the grinding of 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.

Enriched flour is flour with specific nutrients added to it. These nutrients include iron and B vitamins. Calcium may also be supplemented. The purpose of enriching flour is to replenish the nutrients in the flour to match the nutritional status of the unrefined product. This differentiates enrichment from fortification, which is the process of introducing new nutrients to a food.

<span class="mw-page-title-main">Cereal germ</span> Reproductive part of a grass seed

The germ of a cereal grain is the part that develops into a plant; it is the seed embryo. Along with bran, germ is often a by-product of the milling that produces refined grain products. Cereal grains and their components, such as wheat germ oil, rice bran oil, and maize bran, may be used as a source from which vegetable oil is extracted, or used directly as a food ingredient. The germ is retained as an integral part of whole-grain foods. Non-whole grain methods of milling are intended to isolate the endosperm, which is ground into flour, with removal of both the husk (bran) and the germ. Removal of bran is aimed at producing a flour with a white rather than a brown color, and eliminating fiber, which reduces nutrition. The germ is rich in polyunsaturated fats and so germ removal improves the storage qualities of flour.

<span class="mw-page-title-main">Whole grain</span> Cereal containing endosperm, germ, and bran

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.

<span class="mw-page-title-main">Pain de campagne</span> Type of French bread Sourdough in French is "levain"

Pain de campagne, also called "French sourdough", is typically a large round loaf ("miche") made from either natural leavening or baker's yeast. Most traditional versions of this bread are made with a combination of white flour with whole wheat flour and/or rye flour, water, leavening and salt. For centuries, French villages had communal ovens where the townsfolk would bring their dough to be baked, and the loaves weighed from 1.5 to 5.5 kilograms (3–12 lb). Such large loaves would feed a family for days or weeks, until the next baking day.

<span class="mw-page-title-main">Brown bread</span> Whole grain bread

Brown bread is bread made with significant amounts of whole grain flours, usually wheat sometimes with corn and or rye flours. Brown breads often get their characteristic dark color from ingredients such as molasses or coffee. In Canada, Ireland and South Africa, it is whole wheat bread; in New England and the Maritimes, it is bread sweatend with molasses. In some regions of the US, brown bread is called wheat bread to complement white bread.

Wheat middlings are the product of the wheat milling process that is not flour. A good source of protein, fiber, phosphorus, and other nutrients, they are a useful fodder for livestock and pets. They are also being researched for use as a biofuel.

<span class="mw-page-title-main">Wheat berry</span> Whole wheat kernel without the husk

A wheat berry, or wheatberry, is a whole wheat kernel, composed of the bran, germ, and endosperm, without the husk. Botanically, it is a type of fruit called a caryopsis. Wheat berries have a tan to reddish-brown color and are available as either a hard or soft processed grain They are often added to salads or baked into bread to add a chewy texture. If wheat berries are milled, whole-wheat flour is produced. Wheatberries are similar to barley, with a somewhat nuttier taste.

<span class="mw-page-title-main">Sprouted bread</span> Type of bread

Sprouted bread is a type of bread made from whole grains that have been allowed to sprout. There are a few different types of sprouted grain bread. Some are made with additional added flour; some are made with added gluten; and some, such as Essene bread and Ezekiel bread are made with very few additional ingredients.

Maize miller is the processing of maize (corn) for safe and palatable consumption as food. Processing can be by machine-milling in either large- or small-scale mills, or by hand-milling in domestic or community settings.

<span class="mw-page-title-main">Whole wheat bread</span> Bread made of flour milled from wheat grains

Whole wheat bread or wholemeal bread is a type of bread made using flour that is partly or entirely milled from whole or almost-whole wheat grains, see whole-wheat flour and whole grain. It is one kind of brown bread. Synonyms or near-synonyms for whole-wheat bread outside the United States are whole grain bread or wholemeal bread. Some regions of the US simply called the bread wheat bread, a comparison to white bread. Some varieties of whole-wheat bread are traditionally coated with whole or cracked grains of wheat, though this is mostly decorative compared to the nutritional value of a good quality loaf itself.

A Unifine mill is a single one-pass impact milling system which produces ultrafine-milled whole-grain wheat flour that requires no grain pre-treatment and no screening of the flour. Like the grist or stone mills that had dominated the flour industry for centuries, the bran, germ, and endosperm elements of grain are processed into a nutritious whole wheat flour in one step. Consumers had accepted whole wheat products produced by grist or stone mills. The flour produced by these mills was quite coarse as they included the bran and the germ elements of the grain.

<span class="mw-page-title-main">Whole-wheat flour</span> Basic food ingredient, derived by grinding or mashing the whole grain of wheat

Whole-wheat flour or wholemeal flour is a powdery substance, a basic food ingredient, derived by grinding or mashing the whole grain of wheat, also known as the wheatberry. Whole-wheat flour is used in baking of breads and other baked goods, and also typically mixed with lighter "white" unbleached or bleached flours to restore nutrients, texture, and body to the white flours that can be lost in milling and other processing to the finished baked goods or other food(s).

Graham flour is a type of coarse-ground flour of whole wheat named after Sylvester Graham. It is similar to conventional whole-wheat flour in that both are made from the whole grain, but graham flour is ground more coarsely. It is not sifted ("bolted") with a flour dresser after milling. A report from 1913 claimed that bread made from graham flour had a protein content of 12.1% – only slightly less than white wheat flour and essentially the same as whole wheat flour.

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.

The Roller Mill was created by Hungarian bakers in the late 1860s and its popularity spread worldwide throughout the 1900s. Roller mills now produce almost all non-whole grain flour. Enriched flour is flour that meets an FDA standard in the United States. Roller milled white enriched flour makes up over 90% of the flour that comes out of the United States.

References

  1. ↑ Hazen, Theodore. "Flour Bolting (Sifting) and Bolting Cloth". Mill Builder. Retrieved 1 June 2018.
  2. ↑ "What is Wheat Germ". Kretschmer Wheat Germ. Kretschmer. Retrieved 1 June 2018.
  3. ↑ "Wheat Kernel" . Retrieved 1 June 2018.
  4. ↑ Sakhare, Suresh; Ubandar, Aashitosh; Indrani, Soumya; Rao, G. Venkateswara (December 2014). "Effect of flour particle size on microstructural, rheological and physico-sensory characteristics of bread and south Indian parotta". Journal of Food Science and Technology. 51 (12): 4108–4113. doi:10.1007/s13197-013-0939-5. PMC   4252461 . PMID   25477689.
  5. ↑ Wang, Naifu; Hou, Gary; Dubat, Arnaud (1 December 2016). "Effects of flour particle size on the quality attributes of reconstituted whole-wheat flour and Chinese southern-type steamed bread". LWT - Food Science and Technology. 82: 147–153. doi:10.1016/j.lwt.2017.04.025.
  6. ↑ Edgerton, David, Britain's War Machine: Weapons, Resources, and Experts in the Second World War, p. 179, Oxford University Press, 2011 ISBN   9780199832675
  7. ↑ Mangold, Scott. "Extraction Flour Bench Test Results". Unifine Flour Mill. Unifine Mill. Retrieved 1 June 2018.
  8. ↑ "Addendum to the Scott Mangold May 2015 Extraction Flour Baking Bench Test Comparative Flour Lab Analysis". Unifine Flour Mill. Unifine Mill. Retrieved 1 June 2018.
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