In flu e n c e of h y d r o g e n - io n c o n c e n tra tio n o n d e v e lo p m e n t o f c o lo u r d u r in g w o r t b o ilin g . W.
Wi n d i s c h an d P. Ko l b a c h (Woch. Brau., 1927, 44, 53—56, 64— 67).— In experim ents w ith w orts prepared by decoction m ethods of mashing, as employed in conti
n en tal brewing, i t was found th a t ad ju stm en t of the hydrogen-ion concentration by addition of acid or alkali before boiling influenced profoundly the developm ent of colour during th e boiling process. A t p H 6-16 the increase of colour during 2 lirs.’ boiling was about 100%, w hilst a t p B 5-2 i t was only ab o u t 30% . A t an y given p K value, th e increase of colour was pro
portional to th e duration of boiling up to a period of 4 hrs. H ops contribute considerably to th e develop
m ent of colour, b u t th e b itte r acids (ether extract) have m uch less influence in this direction th a n the portions insoluble in ether. The developm ent of colour during w ort boiling is also influenced b y th e character of th e m alt an d th e hops used, and by aeration.
I t is suggested th a t in th e technical analysis of m alts the colour of th e sta n d a rd w orts should be determ ined before and after boiling. J . H . La n e.
S ig n ific a n c e o f h y d r o g e n - io n c o n c e n tra tio n in th e b r e w e r y . H . Lu e r s (Woch. Brau., 1927, 44, 97— 103).— The im portance now rightly attach ed to hydrogen-ion concentration in brewing processes should n o t lead to neglect of titra ta b le acidity. W ith th e use of several indicators showing different p u values, titra tio n affords useful inform ation regarding th e buffer action of w orts or extracts. F o r example, during th e m alting of barley th e p n value (of cold w ater extracts) rem ains alm ost co n stan t a t ab o u t 6 -0 —6-25, b u t in th e course of 4— 5 days th e titra ta b le acidity tow ards phenol- phthalein (ps 9) and th e titra ta b le alkalinity tow ards m ethyl orange (p h 4-5) bo th increase to about double th eir initial values, indicating th e form ation of soluble buffer substances (phosphates) which stabilise th e hydrogen-ion concentration. J - H . La n e.
S ta n d a r d is a tio n of m a l t a n a ly s is . F . Du c h a c e k
and V. L. Zi l a (Woch. B rau., 1926,43, 455—460, 467—
472).— Before 1903 there was fairly general uniform ity in m ethods for m alt analysis on the Continent. Owing
B r itis h S h e m ic a l A b s tr a c t s— B .
424 Cl. X IX .—F o o d s .
to th e p artial or regional adoption of modifications, recommended by a brewing convention a t Bonn in 1914 and another a t H anover in 1920, there in now considerable diversity. In m ost countries th e Balling tab le of densities of sugar solutions has been replaced by the more accurate one compiled by P lato in 1900 as the basis of e x tract determ inations. The new tab le is calculated for 15°/15° in France and Sweden, for 20°/4°
in N orth Germany, an d for 17-5°/17-5° in B avaria and Czechoslovakia. I t indicates am ounts of ex tract ab o u t 1% higher th a n those found by th e Balling table.
Several te s t samples of m alts were sent by th e authors for analysis to 11 laboratories in Germany, and th e results are now com pared an d discussed, and some suggestions are made w ith a view of ensuring more concordant results. J . II. La n e.
S i m p l i c a t i o n o f w o r k i n t h e a n a l y s i s o f m a l t a n d b e e r . D o e m e n s (Woch. Brau., 1926,43, 477— 481).
— Suggestions are made for saving tim e and work in routine analyses. The sp. gr. of w orts can be rapidly and accurately determ ined by th e float m ethod, in which distilled w ater is added to 200 c.c. of th e w ort until a bulk, of accurately standardised density, neither floats nor sinks. B y noting th e tem p eratu re of the woTt and th e volume of water added, th e sp. gr. of th e wort can be a t once ascertained from a table. The m ethod is n o t so suitable for beers. In th e pyknom etric weighing of alcoholic distillates barom etric variations m ay cause differences of as m uch as 5 mg. in th e apparent weight of a filled 50 c.c. flask. J . H . L a n e .
H e a d o n b e e r f r o m t h e p h y s i c o - c h e m i c a l p o i n t o f v i e w . C. Ge y s (Woch. Brau., 1 9 2 7 ,4 4 ,1 4 5 — 147).—
The colloidal particles in beer which contribute m ost to head-form ation and -retention are n o t th e extrem ely small ones which are electrically charged and disinclined to coagulate, b u t those of larger size, which are alm ost or quite neutral, and therefore strongly inclined to coagu
lation. The la tte r ty p e of particles te n d to accum ulate in th e surface films, on which th e y confer stability.
During the later stages of brewing, from th e cooling of th e w ort onwards, th ere is, on th e whole, a tendency for th e colloidal constituents of th e w ort to increase in size. This is advantageous for head form ation. Exces
sive coagulation m ay, however, be detrim ental as it removes from th e w ort m any of th e particles which would otherwise assist th e form ation of foam. Long contact of beer w ith yeast m ay also be detrim ental owing to the peptising action of yeast enzymes on colloids
of low dispersion. J . H . La n e.
A lu m in iu m in t h e b r e w e r y . M. v o n Sc h w a r z
(Woch. Brau., 1926, 4 3 , 523—525, 541— 545).— E ecen t experience seems to indicate th a t alum inium of 99%
p u rity gives b etter results as a m aterial for brewing vessels th a n th a t of lower p u rity or even th a t of 99-5% . A defect th a t occasionally appears a few m onths after th e m etal has been rolled is th e appearance of very small blisters on th e surface, probably due to th e presence of m inute crystals of a com pound FeAl3, form ed when the m etal is m olten and accum ulated a t th e surface in th e subsequent rolling. On contact w ith an electrolyte th is com pound undergoes corrosion, yielding alum ina and hydrogen, b u t th e in ju ry to th e m etal is usually slight.
Aluminium vessels encased in m asonry w ith a layer of pilch between have sometimes corroded owing to the presence of chlorine in th e pitch. Unencased v a ts aiid tanlcs are preferred. J . II. La n e.
E m p ir ic is m a n d s c ie n c e in b r e w in g . W . Wi n d i s c h
(Woch. Brau., 1927, 4 4 , 1— 5, 13—17, 25—29, 37— 41, 49—52, 61— 64, 73—76, 85— 92).— A personal appraise
m ent of th e contributions of science to some of the more im p o rtan t problem s of th e brewing industry.
J . H . La n e. B o tto m - a n d to p - f e r m e n ta tio n y e a s ts . E . Ra t h x e and F. Wi n d i s c h (Woch. Brau., 1926, 4 3 , 537— 541).—Mainly a description of th e results obtained by Euler (cf. A., 1926, 1176). J . H . La n e.
F e r m e n ta tio n a n d r ip e n in g of b e e r . L . Na t h a n
(Woch. Brau., 1926, 4 3 , 585—589, 599—602).—A defence of the N athan process of brewing against certain
criticisms. J . H . La n e.
S a c c h a r if ic a tio n a n d f e r m e n ta tio n of g ly c o g e n a n d s t a r c h b y m a lta s e - f r e e y e a s ts . A. Go t t s c h a l k
(Woch. B rau., 1926, 4 3 , 487— 488).—See A., 1926, 544, 759.
Pa t e n t s.
D e n a tu r is in g o f a lc o h o l. M. Ta g l i e t t i and S.
Hi r s c h (Swiss P. 115,929, 18.3.25).— As d en atu ran t, rectified oils from ichthyol-shale distillate are used.
S. S. Wo o l f. D e h y d r a tio n of a lc o h o l (F.P. 608,062).— See X X . T r e a t m e n t of w a te r s fo r b r e w in g (E.P. 261,708).—
See X X III.
XIX.—FOODS.
Q u a lity o f b r e a d f r o m w h e a ts s u p p lie d w ith n itr o g e n a t d iffe re n t s ta g e s of g r o w th . W. F.
Ge r ic ic e (Cereal Chem., 1927, 4 , 73— 86).— Six varieties of w heat received similar applications of sodium n itrate (equal to 100 lb. of nitrogen per acre) a t th e tim e of planting and a t subsequent grow th periods. I n some cases addition of nitrogen caused no change in th e tim e of ripening, in .others th e m a tu rity was delayed. W hen nitrogen was applied 45 or 75 days after planting, the grain contained th e greatest am ount of protein. The variation of th e quality of th e flours, as expressed by th e loaf volume and tex tu re of the bread, w ith th e protein content and tim e of ripening is discussed.
F . R . En n o s. W h e a t a n d f lo u r s tu d ie s . X . F a c to r s in flu e n c in g th e v is c o s ity o f f lo u r - w a te r s u s p e n s io n s . I . E ffects of t e m p e r a tu r e , d e g r e e of h y d r a tio n , a n d m e th o d o f m a n ip u la tio n . A. H . Jo h n s o n (Cereal Chem., 1927, 4 , 87— 128).— The viscosity of flour-w ater suspensions depends on th e q u a n tity of electrolytes present and th e degree of h y dration of th e flour con
stituents. The viscosity is greater th e higher the tem perature of th e w ater used in th e prelim inary ex trac
tion, since the degree of hydration and th e am ount of electrolyte rem oved are increased. Lengthening the period of extraction a t lower tem peratures and shaking more vigorously have a sim ilar effect. The increase in viscosity is accompanied b y a dim inution in th e resis
tiv ity of th e wash water, b u t there is no relationship betw een th e tw o, owing to th e effect of hydration of th e
B r itis h C hem ical A b stra o te—B .
Cl. XIX .—F o o d s . 425
flour, especially a t higher tem peratures, on the viscosity of th e suspensions. Although th e electrolyte contained in flour probably consists m ainly of dipotassium hydrogen phosphate, sufficient of other electrolytes is present to prevent th e calculation of th e ash content, by comparison of th e resistivities of the decantates with those of th is salt. A t 50° a change begins to take place in th e properties of th e flour-w ater suspensions, as is shown by a sharp increase in th e viscosity. By viscosity m easurem ents made after removal of the proteins b y pepsin, i t is shown th a t th e increase is due m ainly to hydration of th e proteins, and to a much less e x te n t of th e starch. The employm ent of the viscosi- m etric m ethod for determ ining th e ra te of proteolytic activ ity in a flour suspension is only possible if the degree of hydration of th e flour and the quantity of electrolytes present can be made constant. The method of extraction recom m ended is to wash w ith several litres of distilled w ater a t 40° until a m axim um viscosity is
obtained. F. R . Ennos.
D e te r m in a tio n of m ilk s o lid s in food p r o d u c ts . I . D ir e c t m e th o d f o r m ilk p r o te in s in c a c a o p ro d u c ts.
H . G. Wa t e r m a n and H . A. De p p e r (Ind. Eng. Chem., 1927, 19, 501— 506).—A m ethod is described, directly applicable to m ilk chocolate, for th e separation of casein, lactalbum in, and lactoglobulin as a group from the cacao protein group. Prelim inary experim ents showed the necessity of rem oving (a) fats by extraction with ether and (b) cacao proteins by first extracting w ith acidified alcohol (85% b y vol. of anhydrous ethyl alcohol and 1%
by vol. of glacial acetic acid), and then w ith a weakly acid aqueous m edium (5 g. of anhydrous sodium sulphate in 1 litre of 0 -015iV-hydrochloric acid, equivalent to pH 2-0). The residue is th e n dehydrated with alcohol followed by ether. E x tractio n of th e milk proteins is performed a t p ^ 11-6— 11*8 b y means of a m ixture of borate and caustic soda, th e borate exerting a buffer action, so th a t the fall in p s during th e extraction is not more th a n 0-4—0-6 unit. A fter centrifuging and filtering, to ta l nitrogen in th e ex tract is determined by th e K jeldahl m ethod. Milk proteins are then determined by selective precipitation w ith 0 ■ liV-sulphuric acid at about p n 4-5, which p oint is determ ined by titration w ith m ethyl red as indicator. A fter removal of the precipitate, non-m ilk protein nitrogen is determined in th e filtrate b y th e K jeldahl m ethod. The difference between th e tw o nitrogen figures represents th a t due to casein, lactalbum in, and lactoglobulin, th e conversion factor 6-38 being used. H . J . Do w d e n.
E x a m in a tio n of r a w m ilk b y th e s m a ll p late m e th o d . A. M. v a n d e n B u r g h (Pharm . Weekblad, 1927, 6 4 , 417-—423).—Comparative figures on the deter
m ination of bacteria in m ilk by th e m ethod devised by F ro st in 1915 and modified by Clarenburg in 1925 are given, and th e m ethod is strongly recommended for the exam ination of raw milk. W ith pasteurised milk low results are obtained. S. I . Le v y.
B a c te r ia c a u s in g s p o ila g e of e v a p o ra te d m ilk . C. D . Ke l l y (Trans. Roy. Soc. Canada, 1 9 2 6 , [iii], 2 0 , V, 3 8 7 — 3 9 4 ).—Three types of spoilage are classified, the bacteria responsible for th e changes described being
typical forms of Bacillus cereus, Franklaud, Bacillus simplex, Gottheil, and Bacillus megatherium, De Bary.
A. Wo r m a l l. C ritic a l s o lu tio n t e m p e r a t u r e s a n d b u t t e r a n a ly s is . J . Wa u t e r s (Bull. Soc. chim. Belg., 1927, 36, 271—276).—A lthough a norm al Crismer value (critical solution tem perature in absolute or nearly absolute alcohol) alone is n o t a proof of absence of adulterants in butter, th e sum of th e Crismer value and th e R eichert - Meissl value is less th a n th e norm al 83— 84 when cacao b u tter, n eutral lard, or oleomargarine is present. A further confirm ation of adulteration is obtained by a determ ination of insoluble volatile acids (W auters and Reychler m ethod), which gives higher figures with adulterated th a n w ith pure b u tter. P riority as against Polenske is claimed. C. Ho l l i n s.
P r o d u c tio n of a “ c a r a m e l ” o d o u r a n d fla v o u r in d a ir y p r o d u c ts b y S tr e p to c o c c u s la c tis , L is te r . W. Sa d l e r (Trans. Roy. Soc. Canada, 1926, [iii], 2 0 , V, 395— 409).— Organisms, classified as typical Streptococcus lactis, Lister, strains, proved to be responsible for the specific an d undesirable flavour of a sample of b u tter.
Remedial and preventive m ethods, based m ainly on sterilisation of th e apparatus, are outlined.
A. Wo r m a l l. G a s s to r a g e of f r u i t . F . Ki d d, C. We s t, and M. N.
Ki d d (Dept. Sci. Ind. Res., Food Investigation Special Rep., 1927, No. 30. 87 pp.).— In an a tte m p t to prolong the storage life of fru it by storing in an atm osphere rich in carbon dioxide, w ith or w ithout tem perature control, apples alone being studied, th e fruit w’as stored in closed chambers, restricted ventilation being controlled by opening and closing air ports. The respiratory processes of the apples result in a rise of tem perature and an increase in the carbon dioxide content of the atmosphere w ith a corresponding dim inution in th a t of oxygen. The principal difficulties encountered in storing under restricted ventilation were an increase in hum idity to 90— 98% and an accum ulation of various volatile organic products in th e stagnant atm osphere. A high hum idity as such has n o t been proved to be deleterious, b u t th e actual deposition of w ater on the fruit encourages growth of fungi. The use of oiled-paper wrappers for the apples, or em bedding in saw dust or oiled sawdust, removes th e ill-effects of th e stag n an t atmosphere, which otherwise encourages superficial scald. An atmosphere of approxim ately 10% of carbon dioxide and 11% of oxygen was found to be the m ost su ita b le ; higher concentrations of carbon dioxide led to a danger of wastage due to brown heart. W ith this atmosphere, increases in storage life of 50— 100% were recorded.
Rise in tem perature due to self-heating was an im portant factor, and some form of tem perature control was found to be desirable. A tem perature of about 10° is believed to be th e m ost suitable. A t this tem perature an increase in storage life of 100% on a semi-commercial scale has been recorded, b u t a t higher or lower tem peratures the efficiency of th e m ethod falls off. This is ascribed to variations in the concentration of oxygen and of carbon dioxide in solution in the tissue fluids. A t too low tem peratures th e carbon dioxide concentration in the tissue fluids becomes too high and m ay lead to brown
B ritish C hem ical A b s tr a c ts —B.
420 _ Cl. X X .— O r g a n i c P r o d u c t s ; M e d i c i n a l S u b s t a n c e s ; E s s e n t i a l O i l s .
h e a r t ; a t too high tem peratures th e oxygen content is insufficient to support respiration. The preservation of th e colour, firmness, and juiciness of th e apples is associated w ith th e prolongation of th e storage life.
The preserving action of th e atm osphere used is found to be proportional to the reduced respiratory activ ity of th e fruit. Discussing overseas tra n sp o rt of fruit, the authors ascribe th e varying success of tra n sp o rt in unventilated holds to variations in the ex ten t of accidental
ventilation. F . H . Ge a k e.
E d ib le v is c e r a . A. M. Wr i g h t a n d J . C. Fo r s y t h
(J.S.C .I., 1927, 4 6 , 36—38 t).— Edible viscera an d blood represent 21% of th e dressed weight of th e sheep, 20% of th e lam b, an d 14% of th e steer. R esults collected from th e work of various other investigators show th a t v itam in s-/! and - B are widely distributed am ongst th e edible viscera, occurring chiefly in the kidney, liver, and brain, w hilst v itam in -0 also occurs in notable q u a n tity in th e kidney an d th e liver. The results of chemical analyses of th e edible viscera from sheep and oxen are tab u lated . A canned m ixture of heart* an d diaphragm s m arketed as “ hearts and skirts ” has a very high food value. Blood is a valuable source
of album in. F . H . Ge a k e.
S te r ilis a tio n o f g r e e n fo d d e r b y a liq u id m e d iu m . I . C. B rahm , G. A n d re se n , an d R. P r i l l w i t z (Biochem.
Z., 1927, 1 8 1 , 96— 104).— If green fodder be k ep t in 0 -1 % —or, better, in 0 -2 % —hydrochloric acid, th e butyric acid ferm entation is largely suppressed. Acetic acid ferm entation, however, is little affected.
C. R. Ha r i n g t o n. F o o d d y e . Jo h n s o na n d St a u b.— S e e IV.
Pa t e n t s.
T r e a t m e n t o f c o n d e n s e d o r e v a p o r a te d m ilk . A. E . Vi d a l. F rom An d e r s o n- Ba r n g r o v e r Ma n u f. Co.
( E .P . 268,138, 6.4.26).— 1Tlie herm etically-sealed tin s of' condensed m ilk are passed through a steam -heated cham ber w ith a num ber of divisions, each of which has a higher tem perature th a n th e preceding one, th e tem p eratu re of th e last being below th a t required for sterilisation. A fter autom atic rem oval of th e leaky tins, th e rem ainder are heated in a second cham ber a t th e sterilising tem perature (115°), cooled in a th ird cham ber a t a pressure above atm ospheric, an d again passed through a leak detector. F . R. En n o s.
M a n u f a c tu r e of a n in v a lid fo o d f r o m m i l k . K.
Ho e f e l i i a y r (E .P. 265,910, 23.4.26. Conv., 12.2.26).—
Condensed milk, m ilk powder, or curdled m ilk is sub
jected to th e action of ultra-violet light for some tim e.
The product has antirachitic properties. [Reference is directed, in pursuance of Sect. 7, Sub-sect. 4, of th e P a te n ts an d Designs Acts, 1907 and 1919, to E .P . 236,197 ; B., 1925, 735.] H . Ro y a l- Da w s o n.
P r o c e s s f o r o b ta in in g c o n c e n tr a te d v ita m in p r e p a r a t i o n s . L. A. A gopian (E .P. 268,655, 24.9.26;
cf. E .P . 168,903 ; B ., 1923, 470 a).—F resh vegetables or fru it are crushed, and th e m ixture of juice an d pulped residue is tre a te d w ith a solution of lead acetate (80 pts.) and copper acetate (1 p t.). The precipitate, after separa
tion by th e filter press, is washed w ith w ater, dried, and powdered, th e vitam in A being ex tracted w ith cold light
petroleum . The e x tract is concentrated in vacuo, and th e vitam in either diluted w ith a suitable vegetable oil or fu rth er concentrated b y ex traction w ith 99% m ethyl
alcohol. F . R . En n o s.
O b ta in in g e x tr a c tiv e s f r o m coffee [ g r o u n d s ] . K .
v o n Vi e t i n g h o f f ( E . P . 268,241, 20.10.26).— Cofiee grounds are heated w ith w ater under a pressure of 8— 12 atm . a t 160— 200°, and th e resulting solution, which contains a fu rth er 12— 18% of arom atic extract, is evaporated if desired. F . R . En n o s.
R e m o v in g th e b i t t e r c o n s titu e n ts f r o m lu p in s . Ge s. f u r Lu p i n e n- In d. h.b.H . (G.P. 437,355, 4.5.22.
A ddn. to G.P. 335,646; B ., 1921, 599 a).—Loss of protein is diminished by using solutions containing n itrates, sulphates, or phosphates, instead of sa lt solution as described previously. L . A. Co l e s.
S te r ilis in g m ilk a n d o th e r p r o d u c ts in g la s s b o ttle s o r o th e r c o n ta in e r s . F . Hu m b e e c k (E .P . 268,603, 23.6.26).
X X.-0RGANIC PRODUCTS; MEDICINAL SUBSTANCES; ESSENTIAL OILS.
P r e p a r a t i o n o f f o r m a ld e h y d e b y c a ta ly tic d e h y d r o g e n a tio n o f m e t h y l a lc o h o l. I . J . C. Gh o s ii
and J . B . Ba k s i (J. In d ian Chem. Soc., 1926, 3 , 415—
430).— The effects of physical aggregation, tem perature, and th e presence of various prom oters on th e copper cataly st in th e p rep aratio n of form aldehyde b y th e catalytic dehydrogenation of m ethyl alcohol have been studied. A pure copper cataly st retains its activ ity for a longer period when th e oxide (precipitated from copper acetate, n o t sulphate) is reduced in th e form of small, loose pills or granules (between 10- an d 20-mesh) th a n when it is used in th e form of powder. Silver is useless as a prom oter, w hilst nickel increases th e initial activ ity of th e catalyst, which, however, rapidly loses its activity. The best prom oters are thorium and cerium oxides. A cataly st prepared from copper acetate containing 0 -1 % of thorium n itra te a t 205°
had a space velocity of 900, and yielded approxim ately 15 g. of form aldehyde per hr. from 16-8 g. of m ethyl alcohol, and retained its a c tiv ity unim paired for an alm ost indefinite period. W ith increase in th e percentage of thorium or rise of tem p eratu re th e percentage decom
position of th e form aldehyde into carbon monoxide and hydrogen increases. The m ost efficient cataly st is prepared from copper acetate containing 0 -1 % of cerous n itrate, which a t a reaction tem p eratu re of 200° h ad a space velocity of 1774, an d gave an alm ost q u an titativ e yield of form aldehyde. This cataly st is ab o u t tw ice as efficient as th e 0 -1 % th o ria preparation.
J . W . Ba k e r. S ta n d a r d s f o r r e c tif ie d e th y l a lc o h o l. A. V . Ra k o v s k i (Trans. In st. P u re Chem. R eagents, Moscow, 1927, 26—30).— S tandards are suggested for th e physical properties and for th e permissible im purities in ordinary rectified, double rectified, and p u rest (prim a prim a) alcohol, an d results of analysis are given for a num ber of
samples received. T. H . Po p e.
P r e p a r a t i o n o f c a m p h o r f r o m p in e n e . H . M.
Mu l a n y and E . R . Wa t s o n (J. In d ian Chem. Soc., 1926,
B r itis h C hem ical A b stra c ts—B.
Cl. X X .—O k g a n i o P r o d u c t s ; M e d i c i n a l S u b s t a n c e s ; E s s e n t i a l O i l s . 427
3, 253— 254).— The preparation of camphor from Indian tu rp en tin e m ay be effected by heating th e pinenewith 2 pts. of salicylic acid a t 110° for 17 hrs. and then gradually raising th e tem p eratu re to 150° in 11 hrs., a 7 0-8% yield of bornyl salicylate being obtained. This, on hydrolysis w ith 5 p ts. of 20% alcoholic potassium hydroxide solution for 8—10 hrs., gives borneol in 44%
3, 253— 254).— The preparation of camphor from Indian tu rp en tin e m ay be effected by heating th e pinenewith 2 pts. of salicylic acid a t 110° for 17 hrs. and then gradually raising th e tem p eratu re to 150° in 11 hrs., a 7 0-8% yield of bornyl salicylate being obtained. This, on hydrolysis w ith 5 p ts. of 20% alcoholic potassium hydroxide solution for 8—10 hrs., gives borneol in 44%