172 TECHNOLOGY OF CEREALS not been raised BzO2 is also used in New South flours(those nearer the tail end of the break and Wales, Queensland, the U.SA, Canada, the reduction systems) in general requiring more Netherlands, New Zealand (up to 40 mg/kg, for treatment than the patent flours(cf. p. 170). It pastry four only) and Japan(up to 300 mg/kg). is therefore customary to group the machine fours according to quality into three or four Acetone peroxide streams for treatment. a possible grouping is indicated in Table 7. I Each group would be given Acetone peroxide is a dry powder bleaching appropriate bleacher treatment: e. g. the lowest nd improving agent, marketed as'Keetox',a 20% of flour might receive treatment at ten times blend of acetone peroxides with a diluent such as the rate for the best quality 50%. The final grades dicalcium phosphate or starch. The concentration are then made up by blending two or more of the in terms of H2o2 equivalent per 100 g of additive groups in desirable proportions. plus carrier is 3-10 for maturing and bleaching or0.75 for use in doughmaking. Its use has been Flours for various purposes permitted in the U.S.A. since 1961, and also in Canada, but it is not, as yet, permitted in the Wheat flour is used for making foc U. K. It is used either alone or in combination of widely varying moisture content(see Table 7.3) with benzoyl peroxide. The usual dosage rate is 446 mg/kg on flour basis. Significant dates in TABLE 7. 3 Flour-based products and their me history of flour bleaching are summarized Table 7. 2 Moisture content Type of product Range Mean Moisture level Flour blending for bleaching treatment Because the various flour streams differ in their Puddings 1367 Medium characteristics, the optimum level of bleaching 35-40 Mediurn 、 treatment varies correspondingly, the lower grade Pastry Biscuits(cookies, crackers) 1-6 TABLE 7.2 Significant Dates in the History of Flour bleaching Data extracted from McCance and Widdowson(1967) 1901 Andrews patents flour treatment with NO,(chemical The proportions in which the various ingredients of baked products are present in the recipe 1903 Alsop patents flour treatment with NOz(electrical relative to flour(100 parts), are shown in Table 909 NO, in us 7. 4. Biscuit dough is stiff to permit rolling and 1911 Keswick Convention- unmarked flour to be flattening; bread dough is a plastic mass that can 1921 Benzoyl per be moulded and shaped wafer batter is a liquid Ispension that will flow through a pipe 1922 NCl, replaces Cl as bleacher for breadmaking flour 1923 Committee appointed to inquire into use of For comparison with products listed in Tal reservatives and colouring matter in 7. 4, a typical wholemeal wheat extruded snack 1924 Committee's activities extended to chemi formulation would contain the following amounts 1927 Committee reported that bleaching of ingredients, in relation to 100 g white four: 7 g agents were in use, and that Cl, N soya protein, 14 g wheat bran, 1.4 g oil, 0.4 emulsifier, 23 g water, 7 g sugar, 2 g salt, 2 g 1949 C1O, first used in the U. S. A dicalcium phosphate, 3.6 g milk powder(Guy U 993). the U.K 1961 Acetone peroxide permitted in the U.S.A(not in the products, as purchased or as consumed, is shown in Table 7.5172 TECHNOLOGY OF CEREALS not been raised. Bz02 is also used in New South flours (those nearer the tail end of the break and Wales, Queensland, the U. S.A, Canada, the reduction systems) in general requiring more Netherlands, New Zealand (up to 40 mg/kg, for treatment than the patent flours (cf. p. 170). It pastry flour only) and Japan (up to 300 mg/kg). is therefore customary to group the machine flours according to quality into three or four streams for treatment. A possible grouping is indicated in Table 7.1 Each group would be given Acetone peroxide Acetone peroxide is a dry powder bleaching appropriate bleacher treatment: e.g. the lowest and improving agent, marketed as ‘Keetox’, a 20% of flour might receive treatment at ten times blend of acetone peroxides with a diluent such as the rate for the best quality 50%. The final grades dicalcium phosphate or starch. The concentration are then made up by blending two or more of the in terms of H202 equivalent per 100 g of additive groups in desirable proportions. plus carrier is 3-10 for maturing and bleaching, or 0.75 for use in doughmaking. Its use has been permitted in the U.S.A. since 1961, and also in Canada, but it is not, as yet, permitted in the with benzoyl peroxide. The usual dosage rate is 446 mg/kg on flour basis. Significant dates in the history of flour bleaching are summarized in Table 7.2. Moisture content Flours for various purposes Wheat flour is used for making food products U.K. It is used either alone or in combination of widely varying moisture content (see Table 7.3). TABLE 7.3 Flour-based Products and their Moisture Contents Type of product Range Mean Moisture (Yo) (”/.I level Flour blending for bleaching treatment soup 78-80 85 High 13-67 45 Medium 3540 38 Medium characteristics, the optimum level of bleaching Cakes 5-30 17 Medium Because the various flour streams differ in their Puddings Bread treatment varies correspondingly, the lower grade Pastry 7 Low Biscuits (cookies, crackers) 1-6 5 Low Data extracted from McCance and Widdowson (1967). The proportions in which the various ingredients of baked products are present in the recipe, relative to flour (100 parts), are shown in Table 7.4. Biscuit dough is stiff to permit rolling and flattening; bread dough is a plastic mass that can be moulded and shaped; wafer batter is a liquid suspension that will flow through a pipe. For comparison with products listed in Table 7.4, a typical wholemeal wheat extruded snack formulation would contain the following amounts of ingredients, in relation to 100 g white flour: 7 g soya protein, l4 g wheat bran, ’ *4 g Oil, Oe4 g emulsifier, 23 g water, 7 g sugar, 2 g salt, 2 g dicalcium phosphate, 3.6 g milk powder (Guy, 1993). The flour content of various flour-containing products, as purchased or as consumed, is shown in Table 7.5. TABLE 7.2 Significant Dates in the History of Flour Bleaching 1901 Andrews patents flour treatment with NO2 (chemical process) 1903 Alsop patents flour treatment with NOZ (electrical treatment) 1909 NO2 in use 1911 Keswick Convention - unmarked flour to be 1921 Benzoyl peroxide first used 1921 J. C. Baker patents NC13 as flour bleacher 1922 NC13 replaces Cl as bleacher for breadmaking flour 1923 Committee appointed to inquire into use of 1924 Committee’s activities extended to chemical 1927 Committee reported that bleaching and improving 1949 NC13 use discontinued in the U.S.A. 1949 C102 first used in the U.S.A. 1955 NC13 use discontinued in the U.K. 1955 C102 first used in the U.K. 1961 Acetone peroxide permitted in the U.S.A. (not in the unbleached preservatives and colouring matter in food substances for flour treatment agents were in use, and that C1, NCI3 and Bz02 were not among those least open to objection U.K.)