Evaluation of diastatic enzym e preparations ; taka-diastase, m alt diastase, and pancreatic d iast
ase. T. Ha r a d a (Ind. Eng. Chem. [Anal.], 1931, 3 ,
1—3).—The procedure described is a modification of L intner’s method, and is based on the production of a definite quantity of a reducing sugar by the action of a diastase on a known quantity of Lintner starch. To 100 c.c. of Lintner starch solution (2%) are added 10 c.c.
of the enzyme solution, and after 30 min. the action is stopped by addition of 10 c.c. of 0 • 25M-sodium hydr
oxide solution ; the cooled solution is titra te d with Fehling’s solution. By buffering the starch solution with potassium hydrogen phthalate and sodium hy d r
oxide the results obtained are more accurate than those obtained by other methods. The method of calculating the L intner values from the results is de
scribed, and tables are given of the L intner values of taka-diastase and of m alt and pancreatic diastases, together w ith the corresponding dextrose content of the solution, for a range of titratio n volumes.
H. F. Gil l b e. Im provem ent of E nglish cider. H. V. T a y l o r (J. Min. Agric., 1930, 3 7 , 1095—1100).—A review, giving the chemical characteristics of representative ciders, which stresses the question of variety.
E . Ho l m e s. Supposed proportionality betw een the p„ and the acid taste of aqueous solu tion s, esp ecially as regards w in es. P. C r is c i (Annali Chim. Appl., 1930,
2 0 , 566—583).—The acid taste of a wine, although
modified by such constituents as sugar, alcohol, glycerol, extract, salts, tannin, etc., is due maiuly to undissociated acid molecules, and depends more on the p tt th an on the total acidity, bu t varies widely with comparatively slight changes in j>a. There exists a certain degree of relationship between Gu and total acidity of wines, these increasing together. The p a alters little on dilu
tion of the wine w ith water, although the acid taste is markedly diminished. Although it determines only a slight and variable increase in the C,„ the introduction of organic acids into wines accentuates the acid taste and is to be regarded as rational practice.
T. H. Po p e. V itam in content of vinegar. J . St a st n y (Vestn.
Ceskoslov. Akad. Zem., 1930, 6, 611—619 ; Chem.
Zentr., 1930, ii, 1569).—Vinegar prepared by fermenta
tion of alcohol contains a substance (probably vitamin- D) which permits and accelerates alcoholic fermentation in vitamin-free media. The quantity is proportional to the acetic acid content. A. A. El d r id g e.
Pa t e n t s.
Manufacture of yeast. L. and E . Elion (B.P.
340,637, 10.10.29. Holl., 17.10.28).—Yeast with an improved fermentative power is obtained by suspending it in a solution of fermentable carbohydrates, nitrogen, and substances containing phosphorus, and by limiting its propagation in known ways other than by regulating the
aeration. C. Ra n k e n.
Seed production for b iochem ical p ro cesses.
D a r c o Sal es C orp. (B.P. 340,514, 20.9.29. U .S ., 27.7.29.
Addn. to B.P. 336,207; B., 1931, 40).—The micro
organisms are produced by culture methods, during the whole or part of which activated decolorising carbon is present in the culture medium. C. R a n k e n .
A eration of ferm enting liqu ids. E . Stic h (B.P.
340,644, 12.10.29).—The fermenting liquid is aerated by forcing air under pressure through the pores of diaphragm plates which consist of two layers. The pores of the layer immediately in contact with the liquid vary from 0-16—
B ritish C h em ica l A b s tr a c ts — B .
C l. X I X —Fo o d s. 3 I ö
(i ¡a. in d iam ., w h ils t th o se th ro u g h w h ich th e air first passes have a larger d ia m eter. C. Ra n k e n.
Ozonisation of ferm ented liqu ids. R . Co ffr e(B.P.
340,647, 14.10.29. Fr., 15.10.28).—Porous bodies or carriers, such as oak chips, are alternately steeped in the fermented liquid and ozonised after draining for
several hours. C. Ra n k e n.
X IX .— FOODS.
Bound w ater of w heat-flour su sp en sion s. R. Ne w
ton- and W . H. Cook(Canad. J. Res., 1930,3, 560—578).
—The bound-water method has been modified in order to determine the hydration of flour in suspensions in water and in dilute lactic acid solutions. In 15% aqueous suspensions, from which the natural electrolytes have been eliminated by washing, the bound water varies from 1-8 to 5-2% , according to the p n, there being maxima a t p a 3 and 10 ; rather higher results are ob
tained if more dilute (0 • 5M) sucrose solution is employed.
In 15% suspensions in dilute (about 0-45%) lactic acid the flour solids are hydrated to the extent of about 40—50%, washing raising the values slightly. The hydration of wheat starch averages 30% under all con
ditions, whilst th a t of gliadin and glutenin averages 85% ; in the flour the proteins are hydrated to the extent of about 100%; which after washing rises to -00%, in accordance with the general theory of emul- soids. The similarity of the results obtained with the two proteins, although the one, gliadin, disperses com
pletely, whereas the other does not form a true colloidal solution, indicates the necessity of taking into account stmcture as well as hydration when considering the properties of gluten. The differences of hydration of strong and weak flours are regarded as being too small to be of importance as factors in baking quality.
H. P. Gil l b e. Ash content of cereals and flou r. O. Hal tm eier
(2. ges. Mühlenwesen, 1930, 7, 51—52 ; Chem. Zentr., 1930, ii, 1790).:—The ratio of the ash content of the flour to th a t of the grain is preferred to the absolute' ash content of the flour as a measure of the degree of milling. The readily determined relative conductivity is also serviceable. A. A. Eldr id g e.
Relative value of honey and su crose in bread manufacture. W . F . G e d d e s and C. A. W i n k l e r (Canad. J. Res., 1930, 3 , 543—559).—Substitution of honey for sucrose in ordinary bread-baking formulée is without influence on the loaf volume, flavour, and other characteristics, and despite the absence of the hydrolysis stege the reducing sugar content and the rate of gas Production are unchanged. Buffered yeast-honey and J’east-sucrose suspensions of equivalent sugar content ljnder conditions resembling those in fermenting bread dough and a t various p n ranges exhibit the same rates of gas production. Sucrose inversion is not a limiting factor in the rate of gas production in dough, and during the inversion of sucrose by yeast the invertase stage Proceeds more rapidly than the zymase action. The llSe of honey in the baking industry is indicated only where its flavour and greater sweetening power and hygroscopicity are advantageous. H. F. G i l l b e .
U se of honey in “ w ater-ices ” and sherberts.
H. A. S m a l l f i e l d (Sci. Agric., 1931, 1 1 , 259—264).—
Addition of honey or dextrose to “ water-ice ’’mixtures prepared with sucrose lowers their f.p. and largely pre
vents the surface crystallisation of sucrose.
A. G. Po lla rd. D iastatic activity of so m e A m erican h oneys.
R. E. L o t h r o p and H. S. P a in e (Ind. Eng. Chem., 1931,
2 3 , 71—74).—About 300 genuine American honeys,
most of them of known floral type, have been examined by Gothe’s method, and the m ajority have been found to meet the German requirement th a t 1 g. of honey should hydrolyse 17-9 c.c. of 1% starch solution. Many floral types, particularly the darker coloured ones such as sage, buckwheat, and tulip-poplar, show consistently high activities, whilst the paler and more delicately- flavoured honeys such as orange and lucerne are notably low, and th a t from clover is interm ediate in value.
Gothe’s method is satisfactory only for honeys of medium diastatic activity. Improved results are obtained when the solutions are buffered to p& 5 ‘ 3 with M/15-phosphate.
Heating honey a t a moderate tem perature or storage over a period of years causes it to lose diastatic activity and to respond to the test for hydroxymethylfurfuraldehyde.
T. McLac h l a n. V ariations in the f.p . and conductivity of m ilk . W. P l u c k e r and A. S t e i n r u c k (Z. Unters. Lebensm., 1930, 6 0 , 112—123).—Detection of added water by lowering of f.p. is not dependable since at certain periods during lactation the composition of the milk may under
go considerable change. When cows were in heat some samples had f.p. 5-7 units above the range found by Weinstein, viz., 53-7—56-0 (cf. B., 1928, 910), whilst towards the end of lactation high f.p. is also to be detected, the maximum found being 58-9. The com
bined effect of these two factors may be equivalent to 7-5% of added water. In cases of souring milk, for reduction to normal acidity the factor 0 -0006 gives more nearly accurate results th an 0 ’0008. In cases of inten
tional adulteration, the percentage of added water (calc, from f.p. or conductivity measurements) was, with one exception, less than th a t actually present. In similar physiological conditions the range of conductivity was found to be 39-3—56-3 (that given by Mayr and W urster being 37-7—41 -7), so th a t a high value is alone no indication of sickness or diseased udders.
H. J. Do w d e n. Detection of heated m ilk and a new m ethod of testin g for pasteurisation b y the “ holding ” pro
cess. S. R o t h e n f u s s e r (Z. Unters. Lebensm., 1930,
6 0 , 94—109).—The degree of heating to which milk
has been subjected m ay be followed by the peroxidase or diastase present in the lead acetate serum. The reagent (“ yj-tetrosulphite ”) is prepared by dissolving 1 g. of
^-phenylenediamine hydrochloride in 12 c.c. of water and adding 4 g. of guaiacol dissolved in 100 c.c. of 96%
alcohol, the mixture being then diluted with alcohol to 150 c.c. Freshly-prepared sodium bisulphite solution (20%) is added in the proportion of 20 drops per 100 c.c.
of mixture (40 drops — 2-9 c.c.). To 10 c.c. of milk or lead acetate serum are added 3—4 drops of hydrogen peroxide (3%), and, after shaking, 10 drops of the reagent.
B r itis h C h em ica l A b s tr a c ts —B.
3 1 6 Ol. X IX .—Fo o d s.
Raw milk gives immediately a violet coloration, and highly .heated or boiled milk shows no change, whilst with moderately heated milk the colour develops more or less slowly according to the degree of heating which has been applied. W ith acid (or soured) and alkalised milks slight modifications are necessary. Pasteurisation by the “ holding ” process ( i hr. a t 63°) is revealed by the diastase activity. A small volume (1 c.c.) of a specially prepared, stable solution of starch, containing sodium chloride as co-enzyme, is mixed with 10 c.c. of lead acetate serum and kept for 10—16 hrs. a t room tem pera
ture (or less if warmed). The product is mixed w ith a small volume of 0-002A7-iodine solution and the result
ing colour indicates the earlier heat treatm ent. An immediate violet coloration denotes highly heated milk and a pale yellow fresh milk, whilst the intermediate brown-violet or red-violet shades are associated with definite temperatures. Slow development of the violet colour indicates milk pasteurised by the “ holding ” process, and an immediate blue colour boiled milk.
H . J. Do w d e n. Determ ination of m ilk -protein s. I. C hem istry of the separation of casein. G. M. M oir (Analyst, 1931, 56, 2—9).—Maximum casein values for milk are obtained when the f n is adjusted to 4-5—4-7 by the addition, to 10 c.c. of milk diluted to 50 c.c., of 1 ’5 c.c.
of 10% acetic acid followed by 4-5 c.c. of 0 • 25lV-sodium acetate. Slight souring of the milk has no effect on the results obtained. A. R. Po w ell
-Determ ination of copper in dairy products.
H. T. Geb h a r d t and H. H. Sommer (Ind. Eng. Chem.
[Anal.], 1931, 3, 24—26).—The Elvehjem-Lindow method (A., 1929, 614) yields low results when applied to the determination of copper in milk ; much of the loss occurs as the result of too long a time and too high a temperature of ignition. The maximum ashing tem pera
ture should be 565° and the operation should be com
pleted within 3—4 hrs. After dissolution of the ash in dilute hydrochloric acid and precipitation of the copper as sulphide the solution is cooled to 10° and shaken with about one half its volume of chloroform;
on settling, the copper sulphide is retained by the chloro
form layer, which after washing once is evaporated to dryness. The residue is dissolved in dilute nitric acid and after neutralisation of the solution the copper is determined colorimetrically in the usual manner, care being taken to remove all nitric acid and to prevent decomposition of the phenolphthalein indicator by either acid or alkali. This modified procedure is more rapid than the original, and the danger of losses is
minimised. H . E. Gil l b e.
C om m ercially prepared infant foods. G. J. and A. M. Hucker(New York Agric. Exp. Sta., Tech. Bull., 1930, No. 584, 13 pp.).—A general description.
M altol and its colorim etric determ ination in m alt-coffee. T. Me r l (Z. Unters. Lebensm., 1930, 60 , 216—227).—The maltol content has been found to be a convenient means of ascertaining whether the product conforms to the statutory requirements, and a method has been worked out for its determination.
Maltol is present as a pyrogenic decomposition product of amylase, and may be detected in the product and in
the roasting-chamber fumes by virtue of its phenolic reactions with uranyl nitrate and phosphomolybdic acid.
A determination is possible through its reaction with iodine and caustic soda to form iodoform, which is then converted into silver iodide, but the method is not so convenient as the following colorimetric method. The sample of coffee (50 g.), mixed with sand, a few c.c. of water, and animal charcoal, is extracted for 4—5 hrs.
with carbon tetrachloride, the extract being afterwards I shaken with 100 c.c. of ferric chloride solution (contain
ing 3 drops of 10% fcrric chloride solution and 2 c.c. of iV-hydrochloric acid). A violet coloration is imparted to the carbon tetrachloride layer, which is separated, j filtered, and compared in a colorimeter against the colour of a standard salicylic acid solution containing ferric chloride. A formula for the evaluation is given.
The method has been satisfactorily applied to a number of roasted barley products which had undergone | various degrees of germination, and from the results it ; is concluded th a t normal malt-coffee should contain not less than 0-06% of maltol. By its action as an anti-oxidant, maltol prevents the oils and fats from j becoming rancid and thus improves the keeping qualities j of the coffee. H. J. D o w d e n .
Iodine content of lam b thyroids. B. W. Simpson
(New Zealand J. Agric., 1930,41, 302—306).—A definite parallellism exists between the thyxoid-iodine content of lambs born and reared in a particular area and the amount of iodine available in th a t area. Systemic advisory work on iodine-feeding could be based on such analytical data. A. G. Po lla rd.
D eterm ination of purine com pounds in meat extracts. A Escudero and G. Wa ism a n (Semana med., 1930, II, 1436—1438).—The proteins are removed from a 10% solution by Folin and W u’s method, the purine compounds being determined by Krueger and Smid’s method by means of copper sulphate, and sodium hydrogen sulphite. Chem ical Ab s t r a c t s.
M icrochem ical detection of benzoic and salicylic acids and of p -h ydroxybenzoic esters in foods and dru gs. R. Eisc h er and F. St a u d e r (Mikrochem..
1930, 8, 330—336).—The free acid or ester is isolated by extraction of 1—2 g. of the material with ether after acidification with hydrochloric acid and evaporation of the extract a t 50°. F a tty substances should first be digested with warm sodium bicarbonate solution. The residue is heated for 15 min. a t 55—60°, when benzoic acid, if present, sublimes and may be recognised by the growth of mercuric benzoate crystals when mercuric acetate is added to the aqueous solution. On raising the tem perature to 65—70° -p-hydroxybenzoic esters sublime and may bo recognised by the, red coloration formed with Millon’s reagent and differentiated by the m .p .: methyl (Nipasol) 97°, ethyl 116°. propyl (Nipagin) 109—112° (lit. 126°). Salicylic acid sublimes a t 70—-85 • The sublimation tube should be 10—11 mm. deep, in order to prevent contamination of the sublimate with
ether. H. F. Gill be.
C om position of fruits as used for jam manufac
ture in Great B ritain. T. Ma c ar a (Analyst, 1931.
56, 35—43).—Tables are given showing the extreme
B ritish C h em ica l A b s t r a c t s —B .
C l. X IX .—Fo o d s. 3 1 7
and average co m p o sitio n o f fru its u se d for m a k in g jam and th e ran ge o f v a lu e s for th e c o n te n t o f in solu b le .solids, acids, an d p e c tin in va rio u s fru its, to g e th e r w ith notes on th e a n a ly sis o f fru its a n d th e m eth o d of u sin g the data ta b u la te d in in terp retin g th e resu lts o f jam
analyses. A. R . Po w ell.
Composition of tom atoes and tom ato conserves and the determ ination of w ater content. A. L e o n
h a r d (Z. Unters. Lebensm., 1930, 6 0 , 185—195).—
Tie sample (10 g. if thick and 5 g. if thin) is distilled with 150 c.c. of xylene in a specially constructed apparatus, the distillation being arranged to last for 20 min. The formation of emulsions and the adherence of droplets to the receiver are obviated by distilling briskly towards the end of the operation and by shaking the distillate with 1 c.c. of potassium hydroxide solution (50%). The distillate is free from volatile constituents, is almost neutral, and leaves no perceptible residue on evaporation. Repeat experiments were in good agreement, and the results for Italian and German commercial products, tom ato preserve of various degrees of thickness (puree, marc, extract), and for fresh tom ato marc are recorded. H. J. Do w h e n .
Storage of potatoes. N . D. V y a s (Agric. J. India, 1930, 2 5 , 408— 416).—The most successful but the costliest method of storing potatoes in India is by cold storage. Storage in coarse dry sand leads to losses between 40 and 90% or more, which can be reduced to 28—31% (by wt.) by the use of cinders or charcoal.
E. Ho lm es. Effect of pure culture inoculation on th e quality and chem ical com position of sauerkraut. C. S.
Pkderson (N.Y. State, Agric. E x p ., Sta. Tech. Bull., 1930, No. 169, 29 pp.).—Inoculation of k raut with pure cultures of Leuconostoc mesenterioides, Lactobacillus penloacelicus, and non-gas-forming bacilli results in some changes of flavour and variations in the amount of total, volatile, and non-volatile acids produced. Generally speaking, the product is inferior. A. G. Polla iid.
Calorific value of sila g e. M. Y. Ak se n o v a (Trudi
\ ologod. Molochno-Choz. Inst. Bull., 1929, No. 81, 63—67).—The following calorific values (kg.-cal. per kg.
of dry substance) are recorded: clover hay 4610-2, clover silage 4678, oat straw 4451-3, beet pulp 4518-8, wheat middlings 4770, linseed meal 5242-9, sunflower- seed meal 5312-5. During a feeding period without milage two cows voided, respectively, 19,393-3 and 20,757-9 kg.-cal. as manure in 24 hrs. ; corresponding figures with silage were 22,009-1 and 22,110-3, respec- tively. Coefficients of digestibility and starch equivalent values have been calculated. The physiologically useful energy of clover silage is 2426-6 kg.-cal. per kg.
Chem ical Ab str a c t s. Nutritive value and d ig estib ility of sila g e from clover. V. A. Skvortzov (Trudi Vologod. Molochno- Choz. Inst. Bull., 1929, No. 81, 29—51).—Addition of clover silage to the fodder of cows increased the digesti
bility of cellulose and nitrogen-free extractive substances, but decreased th a t of proteins and fat.
Chem ical Ab s t r a c t s. Exchange products in feeding clover sila g e.
^ • Aksenova (Trudi Vologod. Molochno-Choz. Inst.
Bull., 1929, No. 81, 55—60).—Addition of silage to a dairy ration decreased the coefficient of digestibility of nitrogenous substances, apparently owing to stimulation of the splitting off of metabolic exchange products since the digestibility of the crude protein is unaltered by addition of silage. Ch em ical Ab s t r a c t s.
T he antiscorbutic vitam in . J. T il lm a n s (Z.
Unters. Lebensm., 1930, 6 0 , 34— 44).—E or the differen
tiation of natural and artificial foodstuffs by measure
ment of their reduction potentials, 2 : 6-dichlorophenol- indophenol has been found extremely sensitive (cf. B., 1929, 301), and the presence of these reducing substances has been correlated with th a t of vitamin-O. By titration with a solution of the dye i t was found th a t the reducing material in lemon juice possesses a sensitivity towards heat, hydrogen, and alkalis which is exactly parallel to th a t of the vitamin, whilst the titration values of a large number of other foodstuffs agree closely with the recorded content of vitamin-C'. An attem pt has been made to isolate the reducing substance from fresh lemon juice in an atmosphere of nitrogen, but, after removal of 97% of the solids, only an aqueous solution, charac
terised by strong reducing properties, could be obtained.
No crystalline substance could be isolated. When tested on animals the aqueous solution exhibited high anti
scorbutic activity. The inference th a t the reducing substance and the vitam in are identical has not been confirmed (cf. Zilva, A., 1928, 801). H, J. D o w d e n .
Silver for chem ical plant. McDo n a l d.— S ee X.
Saponification values of edible fats. Gr o ssf e l d.—
See X II. V itam in-D in vinegar. St a s n y.—See X V IIL D eterm ination of w ater in sp ices etc.
Pr itzk ee and Ju n g k u n z.—See XX.
Pa t e n t s.
T reatm ent of grain. W. vo n Gel in c k a n d W.
Fa iir en h o r st (B.P. 341,616, 14.11.29. G er., 23.11.28).
— A n a p p a ra tu s for p ro d u cin g d ou gh from an u n m illed , so fte n e d grain , w h ic h is fe d by m ea n s of tw o w orm s to c u ttin g d iscs u n d er a pressure in su fficien t to cru sh th e
grain. E. B. Hu g h e s.
T reatm ent of edible m illin g products. H. C. J. H.
Ge l is s e n and F. V. Hooft, Assrs. to No v ad el-Agene
Ge l is s e n and F. V. Hooft, Assrs. to No v ad el-Agene