352 



NATURE 



[May 11, 191 i 



!ikc 



iiuiM' jiisi iciciMU l", 111'' a\i-i';i^' 

 lincl practically all the iiifi)nnation lu 



I he 



> ^ »...,.;..... , ...,, is 



really all that can be lcf;itnnatfly demanded. 



From first to last the volume is ihoronihlv well 

 illustrated, both as regards plates in coji ■ xt 



fiLiurfs, suiiii' of 111.' I. liter, as exenif)lifirii me 



' '"6 really cMiui- 



■ihtT ih.'lll !,.iMii;i! lili- 



by cxputLs. lii.\ In. 11 lii. iiiij)! i;iian;i ul aii! liorit \ . 

 Of those ill whiili i am pi-r^i malK iinicli iiiti rcsic il 

 inenliiiri ina\ be niadc of Mi ■. ljr\ "I)(/i;-~," 



\s i)i( li Ciiiilaiiis pi •■ri-^rl\- th' : i ti )i-inat i( .11 --uit- 



, ' ' ' .1 sjK . Liii-.'-^ Ill canine matters. 



1 '>f s|Hii-i, in ihc widest sense 



(M l,;r xsi.id, |v lii,; I II I 1 1 I 111 l^ I t 1 \' W C 1 I SalisflOd With thC 



\olumr as ,1 whdlc- lie iiui^i br \ii'\ hard indeed to 

 I>lra..'. R. L. 



il///; ITS AliD FLOURS.' 



RI•:lM^:l;sl:\ 1 \ IIONS having,' been made to the 

 I :1 ( u)\'ci'nmrnt Hoanl b\ Narion^ iiicciical 

 (. .1 hiallh aiul pnbbc aiiaU^t^ un tin; i^rowth 



(il lii. praiiiic of bleaching flour, and slics-, having' 

 bci 11 laid un the prohibition of bleacliinL;- in liio L'nited 

 States of Anuiica, Dr. Haniill rtecivtd instructions 

 from the l^oatcl tc maUf iiujuiries .as tn how far the 

 pr.aclice obtains and to wliai extent, if at all, it is 

 justifiable. In this report, alnr indicating the sources 

 of supply, he describes the millinyf of wheat and grad- 

 ing of flour; then, after indicaiing what are the factors 

 determining the quality of flour, he proceeds to dis- 

 cuss bleaching processes and their elTeet. 



In roller milling the production of flour is a qradual 

 operation. The whe.at passes throu^li a series of 

 fluted, chilled, iron rollers, the product from each |:)air 

 being sifted before passing to the next ; at each stage 

 the frafrments of endosperm, as they pass tlirough, 

 are further reduced, and the flour separated out. It 

 is passible for the miller either to collect in one portion 

 tlv whole of the flour produced, the mixture oht.iined 

 beiiii; termed a "str-aii^ht run flour'"; or lu- may 

 separate it into two or more portions, the one being 

 derived from the first two or three pairs, the other 

 from the last pair, of rollers. Flour is arbitrarily 

 t^^raded into " whites " or " patents," representing the 

 product from the first few rollers, and "households," 

 represt niinu the rest of the flour; a further subdivi- 

 sion is made when required. There is a difference 

 in price of as much as 55. or 6s. per sack of 280 lb. 

 between the highest and lowest grades. 



Millers in this country have to deal with wheats 

 coming from all parts of the world, and some of 

 them acquire great skill in so blending and milling 

 the wheats at their disposal as to produce a flour 

 of absolutely uniform behaviour in the bakeliouse 

 'throughout the year; this is a matter of the very 

 g'reatest importance to the baker, who has learnt to 

 appraise the market value of flour from its baking 

 qualities and appearance. For many years past the 

 baker has had to satisfy the demand for a verv white 

 loaf, especially on the part of the operative classes. 



Dr. Hamill might with advantage have considered 



1 Reports to the Local Government Bo.ird. 



(t) On the Bl.-achinsf of Floiir and the addition of the so-called 

 •Improvers" to Flour : by Br. J. M. Hamill. 



(i) On the Chemical Changes produced in Flour by Bleaching : by 

 Dr. G. W. Monier-Williams. 



(3.) On the presence of Calcium Sulphate in Baking Powder and Self- 

 Raising Flour: by Dr. J, M. Hamill. 



NO. 2167, VOL. 86] 



this ]H>\' tail; the demand arises 



apf>.'ir«-n prejudice, dating^ from a 



hen cheap bread was very much adulterated 

 k in colour; it is in part based on the fact 

 in. II iiie whitest bread, as a rule, is the' lightest in 

 texture and the mo«»t digestible. Colour in bread is 



probabl\ - question of optics than due to the 



original f the flour — a yellow, strong fiour 

 will oftri, , ,. ,, whiter lo^ •'• ik, ver\' white 



j flour, 'lb'- l>aker .ttt.u h' 

 I colour, but to frerdo'M '• 



Stone millin^-^ has |,( . 



com|)lic.it( (I i,t. I I -- 



I.illf-r !" 



II. 11 1 

 II , 



not merely to 



, . ..- ..; olTal or dirt. 



-uperseded by the more 



niillln!' bcc-uise the 



removal 



i.iin. As 



IS out : — 



' th<i grf-ater, part of the 

 aortion finds its wav into 



■ inr; milling a !;■ 

 !i»st in the ofia! 

 d flour. 



oth stone and roller milling it is possible to 

 \ icM of fidiir r* DrcMiitiiiL.' anvthing between about 



nilled, according to 



>ur. As a rule, the 



greater ! uf olTal in the flour — i.e. the greater 



the perc d of flour obtained from the wheat — 



the darkii i^ un loaf which it will produce. The colour 



of the loaf, however, depends not only upon the amount 



of (iff.il wliidi tlu- flour contains, but upon the milling 



roller milling) and upon the 



i or white). For these reasons 



diilai ni lluurs containing; the same percentage (abo\-e 70 



per cent.) of the total wheat may yield loaves varying very 



considiT.ilily in roloiir." 



The cjuc-tioTi ,,f the rel.iiivo food value of different 

 \\lTat- 01 ' : li.i ilour from different parts of the 

 beiry in im w a\ enters into the consideration of its 

 market wilm-. 



The bleaching of tlour is effected commercially with 

 nitrogen peroxide; it appears to be impossible to 

 detect a bleached flour by mere inspection. Flour 

 which lias been badly dressed, containing particles of 

 ofTal, is unsuitable for bleaching, as this only makes 

 the specks more conspicuous. 



Dr. Hamill concludes that bleaching produces no 

 effect upon the baking qualities of flour. It improves 

 the colour of the whole output of the mill and repre- 

 sents a peruniary gain, since it gives the miller a 

 lar;^i r pen, ni,-^, of high-grade flour. It is of assist- 

 anee in mainiainini,'- uniformity in the appearance of 

 flour, but at the same time it enables the miller to 

 use cheaper wheats [not necessarily of lower food 

 value). There is no evidence that bleachine enables 

 good flour to be made from unsound wheat. 



Flours are classed as strong or weak, according 

 as they will produce large well-risen loaves or not. 

 '1 lus property is in some way connected with the 

 character of the protein of the flour, and it has been 

 the subject of a great deal of experimental work 

 witliin recent years. It is a well-known fact that the 

 properties of colloidal substances, to which class the 

 gluten of flour belongs, are profoundly modified by 

 small quantities of electrolytes, and it has been found 

 tiiat the treatment of weak wheat during milling with 

 small quantities of phosphates causes the flour ob- 

 tained to be " strons'er " than it would otherwise be. 

 As a consequence, it is possible to make from weak 

 British wheat a strong flour, the bread from which 

 has the rich flavour characteristic of our flours. See- 

 ing that bread of the type demanded throughout the 

 country cannot be made without a considerable pro- 

 portion of a strong flour, it would seem justifiable 

 to conclude that the new invention will enable a larger 

 proportion of British flour to be used in our bread, 

 much to the advantage of the community — incident- 

 allv it should increase the value of British flour which 



