flour(redirected from All-purpose flour)
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a food product obtained by grinding the grain of various crops. Most often flour is made from wheat, but it may also be made from rye, barley, corn, oats, sorghum, buckwheat, soybeans, and peas. Flour is used for making bread and other baked goods, pastry, pasta products, and mixed feeds. In addition, it is mixed with other feeds and given to livestock.
The chemical composition, the nutritional value, and the technical qualities of flour depend on the type and quality of the grain, the particular type of milling, the yield (the percentage of flour in the total grain weight), and the grade of flour (see Table 1).
|Table 1. Chemical composition of wheat flour (in percentage of dry weight)|
|Patent flour ..........||14||73.6||10.8||0.2||0.9||0.5|
|First Clear ...........||14||72.9||11.0||0.3||1.1||0.7|
Whole wheat and low-grade flour contain vitamins B1, B2, PP, and E, while patent flour and first clear have virtually no vitamins. Flour also contains various enzymes (proteinase, beta-amylase, alpha-amylase, catalase, lipase), which greatly affect the process of bread-making and the quality of the bread. Rye flour is most often produced as a one-grade, or straight-grade, flour. Also produced are a straight-grade 96 percent wheat-rye flour (70 percent wheat and 30 percent rye) and a straight-grade 95 percent rye-wheat flour (60 percent rye and 40 percent wheat). The yield and the grade determine the flour’s color, particle size, and ash content; in wheat flour, they also determine the quality and quantity of the crude gluten. Good-quality flour has a slight floury aroma and a fresh taste.
When flour is stored, its quality can alter. During the first storage period (up to one month) and under conditions of increased temperature (20°-30°C), maturing occurs (an improvement in baking properties) as a result of fat hydrolysis and oxidation processes. With protracted storage, the quality of the flour deteriorates. The moisture content of flour should be no higher than 15 percent. Flour with higher moisture content turns sour, becomes moldy, and may self-heat; flour with lower moisture content (9–13 percent) rapidly turns bitter.
Flour must not be contaminated with granary pests. It should contain no more than 3 percent sprouted seed and 0.05 percent harmful impurities. Metal impurities (up to 3 mg/kg of flour) are permitted only in the form of round dustlike particles. The color, ash content, and particle size of the flour are also control indicators for the production process and for the correct extraction of the various grain parts. To obtain high-quality products, wheat flour, depending on its grade and yield, should contan at least 20–30 percent crude gluten of the first or second group. To determine the technical qualities of wheat flour, the elasticity of the dough during kneading and rising is recorded. The qualities of rye flour are determined on an amylograph, which indicates the viscosity of the flour paste and, thereby, the amylolytic activity of the flour and the degree of starch hydrolysis. The baking properties of a particular flour may be determined from experimental bakes using the same recipe. (See.)
L. A. TRISVIATSKII