21 CFR § 137.105 - Flour.
(a) Flour, white flour, wheat flour, plain flour, is the food prepared by grinding and bolting cleaned wheat, other than durum wheat and red durum wheat. To compensate for any natural deficiency of enzymes, malted wheat, malted wheat flour, malted barley flour, or any combination of two or more of these, may be used; but the quantity of malted barley flour so used is not more than 0.75 percent. Harmless preparations of α-amylase obtained from Aspergillus oryzae, alone or in a safe and suitable carrier, may be used. When tested for granulation as prescribed in paragraph (c)(4) of this section, not less than 98 percent of the flour passes through a cloth having openings not larger than those of woven wire cloth designated “212 µm (No. 70)” complying with the specifications for such cloth set forth in “Official Methods of Analysis of the Association of Official Analytical Chemists” (AOAC), 13th Ed. (1980), Table 1, “Nominal Dimensions of Standard Test Sieves (U.S.A. Standard Series),” under the heading “Definitions of Terms and Explanatory Notes,” which is incorporated by reference. Copies may be obtained from the AOAC INTERNATIONAL, 481 North Frederick Ave., suite 500, Gaithersburg, MD 20877, or may be examined at the National Archives and Records Administration (NARA). For information on the availability of this material at NARA, call 202-741-6030, or go to: http://www.archives.gov/federal_register/code_of_federal_regulations/ibr_locations.html. The flour is freed from bran coat, or bran coat and germ, to such extent that the percent of ash therein, calculated to a moisture-free basis, is not more than the sum of 1/20 of the percent of protein therein, calculated to a moisture-free basis, plus 0.35. Its moisture content is not more than 15 percent. It may contain ascorbic acid in a quantity not to exceed 200 parts per million as a dough conditioner. Unless such addition conceals damage or inferiority or makes the flour appear to be better or of greater value than it is, one or any combination of two or more of the following optional bleaching ingredients may be added in a quantity not more than sufficient for bleaching or, in case such ingredient has an artificial aging effect, in a quantity not more than sufficient for bleaching and such artificial aging effect:
(1) Oxides of nitrogen.
(3) Nitrosyl chloride.
(4) Chlorine dioxide.
(5) One part by weight of benzoyl peroxide mixed with not more than six parts by weight of one or any mixture of two or more of the following: potassium alum, calcium sulfate, magnesium carbonate, sodium aluminum sulfate, dicalcium phosphate, tricalcium phosphate, starch, calcium carbonate.
(6) Acetone peroxides complying with the provisions of § 172.802 of this chapter.
(7) Azodicarbonamide (complying with the requirements of § 172.806 of this chapter, including the quantitative limit of not more than 45 parts per million).
(2) When ascorbic acid is added, the label shall bear the statement “Ascorbic acid added as a dough conditioner”. When the optional ingredient α-amylase obtained from Aspergillus oryzae” is used, it may alternatively be declared in the list of ingredients as “Fungal alpha-amylase,” “Fungal α-amylase”, “Enzyme”, or “Enzyme added for improved baking”. When any optional bleaching ingredient is used, the label shall bear the word “Bleached”. Wherever the name of the food appears on the label so conspicuously as to be easily seen under customary conditions of purchase, the word “Bleached” shall immediately and conspicuously precede or follow such name, without intervening written, printed, or graphic matter; except that where such name is a part of a trademark or brand, other written, printed, or graphic matter, which is also a part of such trademark or brand, may so intervene if the word “Bleached” is in such juxtaposition with such trademark or brand as to be conspicuoulsy related to such name.
(c) For the purposes of this section:
(1) Ash is determined by the method prescribed in the AOAC, 13th Ed. (1980), section 14.006, “Direct Method - Official Final Action,” under the heading “Ash (5),” which is incorporated by reference. The availability of this incorporation by reference is given in paragraph (a) of this section. Ash is calculated to a moisture-free basis by subtracting the percent of moisture in the flour from 100, dividing the remainder into the percent of ash, and multiplying the quotient by 100.
(2) Protein is 5.7 times the nitrogen as determined by the method prescribed in section 2.057, “Improved Kjeldahl Methods for Nitrate-Free Samples (20) - Official Final Action,” AOAC, 13th Ed. (1980), which is incorporated by reference. The availability of this incorporation by reference is given in paragraph (a) of this section. Protein is calculated to a moisture-free basis by subtracting the percent of moisture in the flour from 100, dividing the remainder into the percent of protein, and multiplying the quotient by 100.
(3) Moisture is determined by the method prescribed in the AOAC, 13th Ed. (1980), sections 14.002 and 14.003, “Vacuum Oven Method (2) - Official Final Action,” under the heading “Total Solids Moisture, Indirect Method,” which is incorporated by reference. The availability of this incorporation by reference is given in paragraph (a) of this section.
(4) Granulation is determined as follows: Use No. 70 sieve complying with the specifications for “Nominal Dimensions of Standard Test Sieves (U.S.A. Standard Series)” prescribed in paragraph (a) of this section. Attach bottom pan to sieve in Ro-Tap sifter (or an equivalent sifter). Place half of a rubber ball or other sieving aid in the sieve. Pour 100 grams of the sample in the sieve and turn on the sifter with knocker. Sift exactly 5 minutes. Weigh the residue on the No. 70 sieve and convert to percentage.