White flour

Roll mills are employed in a wide variety of applications for medium-coarse down to fine size reduction. By far the most prevalent use is in flour milling where banks of roU mills, beginning with coarse profiles and ending with smooth roUs, are used in series with sifting machines to extract the white flour from the associated bran. 

White flour and whole wheat flour are mixed together in a ratio of 5 parts white flour to 1 part whole wheat flour. How many pounds of white flour are in 48 pounds of this mixture ... 

After the milling process, any gaseous treatments are applied, any powder treatments, e.g. ascorbic acid, are added, as well as any fortifying ingredients such as calcium sulfate. Different countries have various policies on fortifying flour. In the UK, white flour is fortified with calcium to make up for the calcium lost by not making a wholemeal flour. In the USA, bread is fortified with folic acid. It is possible for an untreated flour to be mixed with a flour improver containing the powder treatments. 

All of the above flours are white flours of ordinary whiteness. If the extraction rate is reduced still further, whiter flour known as patent flour is obtained. A patent flour can be produced from the grist of baker s grade or higher flours. The resulting flour will not only be whiter it will have a lower protein content. The quality of the protein will be higher. 

Bakers tend not to like wholemeal bread flour because it is less reliable in performance than white flour. One reason for this is the restrictive legal position on flour improvers, which makes the dough less tolerant. In addition, when a wholemeal flour is made in a roller mill, all the flour components that the mill has separated have to be recombined at the bottom of the mill. If a spout blocks temporarily one component will be held back. If this sort of problem leads to an excess of white flour then the flour will bake well, if a local excess of bran occurs then baking performance will suffer. 

Although the 100% extraction rate ensures a bigger yield, wholemeal is not particularly popular with millers as a stronger grist is needed. In addition, its shelf life is only three months (cf. a year for white flour). The reduction in shelf life is supposed to be caused by oxidation of the lipid fraction that is absent from white flour. Furthermore, wholemeal flour must be kept apart from white flour less that is contaminated. 

Long ago it was noticed that the baking quality of white flour improved with storage for 1-2 months. This effect occurred more rapidly if the flour was exposed to the air. During storage, initially the level of free fatty acids increases, presumably owing to lipolytic activity. Lipoxygenase activity then produces oxidised fatty acids as the proportion of linoleic and linolenic acids falls while the number of -S-S- bonds decreases. 

Wholemeal and brown flours create problems for both millers and bakers since both sorts of flour have a limited shelf life (about three months) compared with the twelve month shelf life of white flour. Steps have to be taken to prevent brown or wholemeal flour contaminating white flour. 

The flour is made by adding at least 10% of heat-treated wheat germ to a white flour. The purpose of the heat treatment is to stabilise the... 

Wholemeal bread flour behaves in a slightly different way to white flour so this variation is to work with wholemeal bread flour. In particular, wholemeal flour has a higher water absorption than white flour but no flour treatment is used. 

The three levels of water addition used in variation 8, i.e. 800 mL, 900 mL and 1 L, should be tried. As a result of this experiment it should be apparent which is the optimum level for this batch of flour. Experimenters are warned that wholemeal flour develops more slowly and will never rise as much as white flour. 

MW Trucksess, DWR Ready, MK Pender, CA Ligmond, GE Wood, SW Page. Determination and survey of deoxynivalenol in white flour, whole wheat flour, and bran. J AOAC Int 79 883 - 887,1996. 

In many of my recipes, I try to include some whole wheat pastry flour, which is finely ground whole wheat with a lower gluten content than standard whole wheat flour, so it can be used in delicate recipes. Because the outer bran of the wheat is included, the flour contains more fiber, nutrients, and vitamins. However, in some recipes, you must use white flour or else the cake will be gummy and... 

Table 12-2 Comparison of Flour Enrichment Requirements in Canada and the United States Canada (Flour, White Flour, Enriched Flour, or United States Enriched White Flour) (Enriched Flour) ...

Table I lists the zinc content of some cereal-based food products (, ). Substantial zinc loss occurs during refinement of cereal grains, e.g., milling of wheat to produce white flour. Therefore, products which are less refined or which contain the bran...

A number of studies have shown that zinc, as compared to other minerals, is poorly utilized from phytate-contalning foods. The relative BV of zinc in a number of phytate-contalning foods was recently examined by Franz et al ( ). Each product was prepared as for human consumption and Incorporated into a semi-purifled diet fed to rats. Whole corn and brown rice had a low relative BV (0.58 or less compared to 1.00 for zinc in zinc sulfate) while wholewheat flour and unleavened wholewheat bread had medium values (0.63-0.74). Refined cereal products such as white flour, leavened and unleavened white bread and white rice (all low in phytate) had high relative BV (0.89-1.08) as did leavened wholewheat bread... 

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