Wheat flour is perhaps the most ubiquitous ingredient in the foods of many societies, where it forms the basis of not only the staple diet but also of many value-added baked goods. In 2002-03, the Food and Agriculture Organization (FAO) of the United Nations estimated world wheat consumption had reached over 600 million tonnes, with most of it being milled for human consumption.
Flour is considered the best carrier for supplements or fortification that are needed to replace deficiencies in diets. Consideration is also now being given to similar fortification of maize and rice products in regions where these products are the staple foods. The process of adding the naturally occurring nutrients back to the flour is called enrichment. Fortification is the addition of nutrients at higher levels than naturally occur, or the addition of nutrients that are not typically present in natural form.
Fortification, as practiced today with all its benefits, is in marked contrast to the treatment of foods prior to 1875, when the British Sale of Food & Drugs Act was passed. Until that Act, there was widespread dilution of flour and other staple foods with additives that were often adulterants and potentially harmful rather than beneficial to the consumer.
The Micronutrient Initiative (MI)and UNICEF released a report in 2004 which concluded that vitamin and mineral deficiency was one of the most pressing public health problems of our time. As a result, several international organizations are cooperating in various active initiatives to encourage the fortification of white flours in support of individual national efforts to reduce malnutrition in this generation.
Fortification of flour was introduced into several countries, including the United States (U.S.) and the United Kingdom (U.K.), during World War II, when there was concern about the nutrition of a population lacking many of the wholesome foods available in peacetime.
It was in 1963 that the Codex Alimentarius Commission, established by the FAO and the World Health Organization (WHO), began the harmonization of international standards for foods. However, the emphasis in the Codex Alimentarias, as it applies to flour and baked goods, is on additives and processing aids rather than on nutrition.
WHEAT AND MILLING
The wheat kernel is rich in minerals and potentially beneficial trace ingredients, some of which are inevitably lost during the milling process. Most of those vitamins, minerals and phytates are concentrated in the outer layers, particularly the aleurone layer, which are removed in conventional milling in the quest to produce flour for palatable white bread.
The phytates inhibit the body’s ability to absorb iron. However, since phytates and iron are lost in roughly equal proportions during milling, the refined flour has less iron but fewer phytates so that added iron will be readily absorbed.
Bran contamination has long been known to adversely affect the perceived quality and appearance of baked bread. For this reason the so-called “ash test,” which gave a measure of the bran contamination in conventional milling processes, was established as one of the principal means to measure flour
quality. However, ash merely indicates the amount of inert mineral matter in the flour. These minerals are nutritionally beneficial and have little or no effect on baking. It is thus a perverse but unintended consequence of this most commonly used measure of flour quality that retention of these minerals is militated against by the ash test.
Recent milling processes such as debranning and peeling are able to remove the bran contamination while retaining more of the colorless aleurone layer, together with its mineral components, in the flour, thus rendering the ash test inappropriate for continued use.
Fortunately, more recent analytical techniques, such as those based on image analysis or near infrared (NIR) technology, provide better correlation with the rheology of the flour (and thus its suitability for baking) than ash determination.
ENRICHMENT OR FORTIFICATION
During World War II, the authorities in the U.S. and Great Britain, as part of programs of public health, mandated the addition of Vitamins B1 (thiamine),
B2 (riboflavin), iron and niacin to white bread flour. The British authorities additionally required the addition of calcium carbonate because of concern regarding the effects resulting from production of the high extraction flours.
The Food and Drug Administration (FDA) of the U.S. has attempted to strike a balance in its regulations so that bread is not seen as a “vitamin pill delivery system.” In addition to the well-established fortification of flour and breakfast cereals with the iron and vitamins from 1998, enriched flours are required to contain 0.7 milligrams (mg) per pound (about 0.15 mg per 100 g) of folic acid.
The U.K., in the Bread and Flour Regulations 1998, which superseded those of 1984, mandate the following addition rates to bread flour: between 235 and 390 mg per 100 g of calcium carbonate; more than 1.65 mg per 100 g of iron; more than 0.24 mg per 100 g of thiamin; and more than 1.60 mg per 100 g of niacin.
Through the efforts of the Flour Fortification Initiative and the MI, great progress has been made toward the goal of fortifying 70% of wheat flour worldwide with at least iron and hopefully folic acid by the end of 2008.
According to FFI, flour fortification is mandatory in North America, South America, Australia and most of the Middle East as well as some countries in Africa. Fortification is starting to take place on a voluntary basis in countries such as China, India, Turkey, Poland and Ukraine. FFI lists Russia as being in the planning stages for flour fortification.
In some developing countries, there remains a suspicion among the general public concerning any perceived “tampering” with their staple foods by authorities whom they do not necessarily trust. This trust needs to be gained for the initiatives to be fully successful.
The fortification of flour with folic acid is the most topical of additives at the present time.
Folate is a water soluble B9 vitamin which occurs naturally in food. It was first extracted from spinach leaves in 1941. Folic acid is the synthetic form now more commonly used as an additive in human foods.
Since 1996, the Food and Drug Administration (FDA) in the U.S. has specified the level of folic acid to be added to cereal foods, including wheat flour, and the regulation was implemented in 1998.
Although adequate folate intake provides a number of health benefits, the principal objective of this program has been to protect pregnant women against congenital malformations in their babies by preventing anaemia in the expecting mother.
Since 1998, other countries such as Australia and Chile have followed suit and require bread flour, in particular, to be fortified with folic acid. By 2004, almost 40 countries were fortifying with folic acid.
Currently, proposals to introduce this fortification into the regime in Britain are under discussion with the Food Standards Agency.
Due to the high value of the additives and the potentially harmful effect of excessive consumption of some of them, it is desirable that fortification is introduced by accurate and reliable equipment. This need not, however, be expensive. At the simplest level, the additive comprising a master mix containing the nutrients can be introduced on a continuous basis by a calibrated volumetric feeder directly into a flour stream in the production process.
Loss-in-Weight feeder systems are gaining in popularity with flour millers, as they have the ability to meter premixes in proportion with the flour production rate.
In facilities that are equipped with a batch blending plant, the additives can be easily introduced as individual ingredients or a master mix in the batch recipe. Batch blending with micro-computer control for recipes containing as many as 50 ingredients is a well proven and exceedingly accurate means of producing flours to a specification and on demand. Typically, batch blending comprises three parallel metering and weighing systems rated to best suit the amounts being handled. The first would handle the major ingredients, being the flour components. The second would meter the minor ingredients of up to 5% of batch weight. These ingredients include gluten, calcium carbonate and raising agents, such as acid calcium phosphate and bicarbonate of soda, for self-raising flours. The third would be dedicated to the micro-ingredients, down to only a few grams individually up to about 0.5% percent of the batch.
The cost of fortifying flour varies but is claimed to be as low as 0.5% of the cost of the processed flour. For example, a premix of iron and folic acid costs around 25¢ per tonne of wheat being milled. The cost of suitable dosing equipment is typically between $1,000 and $5,000. This must be weighed against the productivity losses due to iron deficiency. In South Asia alone, that cost is estimated at about $5 billion annually.
SUPPLEMENTS AND IMPROVERS
Nutritional supplements taken in pill or capsule form are not to be confused with fortification. They are generally supplied in a much higher concentration and may even be harmful unless taken under medical supervision. Generally, these additional vitamins and minerals are better consumed as components of a balanced diet, unless the individual concerned is suffering from a specific diagnosed deficiency.
Many improvers are commonly used as process aids for the baking or cooking that follows. However, health concerns have led to the phasing out of some of these, even though they may have no proven deleterious effect on the consumer.
Potassium bromate, once an almost universally used bakery improver, although still permitted in the U.S., has all but disappeared from use elsewhere. In many cases, this is due to circumstantially-based allegations that have proved too costly to challenge.
Similarly, chlorine treatment, although it leaves no residue and is an effective means to modify the gluten strength and control Ph levels so that the processed flour makes cakes with a light, friable texture, has now been discontinued in many countries. Heat treatment processes have been developed to replicate much of the effect of chlorine, and these have gained wide acceptance since they are deemed intrinsically safe.
As more trace minerals and other nutrients are found to be important to human well-being, there will be a case for considering additions to the established list for fortification of wheat flour.
The essential trace mineral, selenium, as a component of seleno proteins, is now known to be of fundamental importance to human health and its deficiency can result in a number of serious health effects. Selenium enters the food chain through plants including wheat. Wheat from some regions is much richer in selenium due to the higher levels in the soil in which it is grown.
Bryan McGee, a milling industry consultant, may be contacted at firstname.lastname@example.org? .