INDUSTRIAL A N D ENGINEERING CHEMISTRY
1128
tion and precipitation changes. Suggestions as to the possibility of gel formation in foams are presented by F’reundlich (7) and Mathews (IO). At another type of interface, the fat-protein solution boundary, a membrane or semi-coagulum is likewise formed. In fact such information was presented by Ascherson ( I ) as early as 1838 and the work was verified and extended by Ord (II),whose findings were published in 1879. The results of a preliminary investigation upon mayonnaise dressing show that the whey-protein product is an excellent emulsifying agent. Not only have such emulsions been stable over a period of several months, but it has been found that a g r a t e r percentage of oil may be incorporated in the emulsion than is possible with egg yolk. Unpublished results from these laboratories also show that the addition of whey proteins considerably improves the whipping properties of ice-cream niixes, giving both a greater overrun or incorporation of air and a shortening of the freezing time necessary to obtain the proper consistency. As previously stated, the foaming power and emulsifying properties of protein solutions appear to he dependent upon related physical characterishics a t the interface. Since whey-protein products have an excellent food value, it seems probable that in the uses which are dependent upon whipping and emulsification properties these products may, in some cases, serve as a substitute for egg white or egg yolk. Such possible uses may be found in salad dressings similar to mayonnaise, sponge candies, cake icing, ice cream, thickened soups, custards, etc. With respect to those cooked or baked products, in which the heat-coagulative property is the principal consideration and is necessary to the proper texture of the food, however, such substitution will not be possible. Of the methods developed in this investigation for increasing the whipping properties of whey-protein solutions, it is believed that the addition of small amounts of calcium
Vol. 22, No. 10
hydroxide to the concentrated whey liquor, heating of the pToduct to 55” C. for 10 minutes and subsequent neutralization of the alkali, before spray-drying, will be of most practical value for its adaptation to the previously suggested uses as a whipping compound in food products. Warming of the solution of whey-protein powder to approximately 50” C. before beating, following suitable modifications of the foaming properties of the protein solution insures a large volume of foam and a stable whip. Such heat treatment is recommended as a procedure preliminary to whipping of the solution. Literature Cited Ascherson, Muller’s Archiv, 1840, p. 44, and reprinted in “Foundations of Colloid Chemistry,” Hatschek, London, 1925. Bell. Peter, and Johnson, J . Dairy Sci., 11, 163 (19281. Clayton, “Theory of Emulsions and Their Technical Treatment,“ p. 75, London, 1928. Clayton, I n d . Chemist, 1, 489 (1925). Dahlberg and Hening, N. Y . State Agr. Expt. Sta., Tech. Bull. 113 (1025). Freundlich, “Colloid and Capillary Chemistry,” Methuen, London, 1926. Freundlich, Ibid., p. 789. Cibbs, Trans. Con#. Acad. Arts Sci., 3 , 380 (1878). Mathews, “Physiological Chemistry,” p. 143, Wood, 1925. Mathews. Ibid., p. 241. Nouy, du, Science, 60, 337 (1924). Ord, “Influence of Colloids on Crystalline Form and Cohesion,” p. 11, London, 1870. Ostwald and Sterner, Kolloid-Z., 56, 342 (1925). Plateau, Pogg. A n n . , 141, 44 (1870). Ramsden, Z . physik. Chcm., 47, 336 (1904); T r a s s . Liv. Biol. SOC., s3, 3 (1919). Rogers and Associates, “Fundamentals of Dairy Science,” Chemical Catalog, 1928. Rogers and Associates, Ibid., p. 172. Rogers and Associates, I b i d . , p. 173. Seidel and Hesse, Molkerei-Ztg. (Hildeshcirn), (1900). Stables and Wilson, Phil. Mag.. 151 16, 406 (1883). Wilson and Ries, Colloid Symposium Monograph, 1923.
Composition of European and California Almonds’ C. V. Hart FRUITPRODCCTS LABORATORY, UNIWRSITY OF CALIFORNIA, BERKELEY, CALIF. NOTE: The investigation reported in this paper was conducted by
C. V. Hart and was part of a more extensive study planned by him. Realization of his plans was frustrated by hi, untimely death. His data have been prepared for publication for the information of those interested in the composition of fonds and food products. Doctor Hart received his Ph D. degree with Doctor Franklin, of Stanford University. The work reported in this paper was the first undertaken by him after receiving his degree. Hemicellulose determinations were contemplated but not made before Doctor Hart’s death; these are reported by G . A. Pitman elsewhere in this issue.-W. V. CRUESS
LMONDS used industrially in confectionery, ice cream, and bakery products and those used on the table come principally from the Mediterranean countries, particularly Spain and Italy, and from California. It has been deemed of interest and value to food chemists to ascertain by careful analysis the chemical composition of samples of the more important commercial varieties of imported and domestic almonds. Through the cooperation of the California Almond Growers Exchange and several importers of almonds, authentic samples of 5 to 25 pounds of each of the leading varieties were obtained. The official methods of the A. 0. A. C., in so far as they applied, were followed in conducting the analyses;
A
1 Received
July 21,1930.
CON-
SiOn FesOs CaO
E8: Na?O
KzO SOs
COa
DOhlI3STIC
FOREIGN
I 0123 %
% 0.12 0.54 0.30 6 . 7 3 11.01 1 4 . 8 4 13 6 4 38.99 40.28 3.23 2.12 26.98 24.73 3.29 2.24 4.40 5.22
% I 0%. 1 4
0.16 0 39 11 35 14.91 38 9 3 2 36 26 59 2.36 3 01
0.32 14.28 14.75 36.76 3.98 24.13 3.85 4.15
9 9 . 0 8 100.06
102 36
- -- - 99.81
% 1.15 0.27 14.61 13.63 34.88 2.59 23.87 3.46 3.86
__
% 0.22
0 31
12.17 13 61 39.75 1.45 27.71 2.62 4.11
--
% 0.23 0.37 11.92 13 8 2 33.21 1.83 25 30 2.62 Notdetd.
9 8 . 3 2 101 9 5
There is apparently very little difference in the composition of imported and California grown almonds. Unfortunately,
INDUSTRIAL, A N D ENGINEERING CHEMISTRY
October, 1930
Table I-Composition
of Almonds: Organic C o n s t i t u e n t s a n d Total Ash UNIDENTI-
SUCROSE
FAT
SAMPLE
ALCOHOL EXTRACT
.. . . . .
SUCROSE
IN HOL
IN
PENTOSANS
ASH
PENTOSANS
NITROGEN
........ .. .. .. .. ..
7.32 10.2 6.80 (1) 5.65- 0.15 8.34 (1) 7.291 0.08
64.19 70.03 57.90
........ ... .. Jordan.. . . . . . . . 1.X.L. . . . . . . . . .
,55.32&0.13 ,55.41*0.10 57.00* 0.16 58.75 1 0.26 55.93t0.02
7.76*0.23 7 04 (1) 7.30 (1) 6.67 (1) 8.29 (1)
60.02
65:89
E:zyT;f,
PROTEINS
FREE _ _ SAMPLR) ------ --, ~
~
%
%
%
4.65 4.78 3.24 4.48 4.80
2.67 2.02 2.41 3.86 2.49
3.00 3.09 2.91 3.41 3.07
3.28 3.43 3.40
3.32dz0.03 3.83t0.05 3.91t0.03 3.22t0.01 3.87t0.02
20.75 23.93 24.43 20.12 24.18
9.92 9.88 9.70
4.57 4.68 4.42 4.73 4.36
3.19 2.36 2.88 1.94 3.93
3.38 3.36 3.46 3.42 3.33
3.43 3.84
3.704~0.03 4.07*0.00 3.61 * O 02 3.58t0.03 3.55r0.03
23.12 25.43 22..56 22.37 22.18
9.50 9.91 10.20 10.32 11.80
%
.59.65* 0.08 68.45*0.02 ;9.30*0.04 ,37.00* 0.03 ,59.05*0.03
Valencia., Jordan Marcona. Aetna.. . , Alicante ...
''ED *LCOHOL
EXTRACT SAMPLEEXTRACT
%
%
% FOREIGN:
1129
%
3:i6
%
%
...
9.40
DOMESTIC:
Nonpareil Drake.. . .
Ne P l u s . . . . . . . .
...
7O:Ql 52.55
most of the European varieties are not grown in California; however, samples of imported (Spanish) and of California Jordan variety almonds. were available for comparison; the analyses will be found in Table 11. It will bt? seen that the domestic sample had 58.75 per cent oil, the imported 58.45 per cent oil; alcohol extracts 5.5 and 6.8 per cent; pentosans 3.56 and 3.43 per cent; and protein 22.37 and 23.93 per cent. No difference in behavior on cooking or in quality of the two samples after cooking could be observed. It is believed that such small differences in composition as
... 3.56 ..
were observed were due rather to the effect of variety than of locality. The domestic almonds were slightly higher in total protein, an average of 23.13 per cent compared with 22.68 per cent and slightly lower in oil content, a n average of 56.5 per cent compared with 58.68 per cent. The ash of all samples was high in P20s, as would be expect,ed for seeds such as the almond, and high in KzO and MgO. From the analyses it can be seen that almonds, as food, are a good source of protein, fat, phosphorus, and potassium.
Further Comparison of California and Imported Almonds' Gilbert Pitman FRUITPRODUCTS
r
LABORATORY. UNIVERSITY OF CALIFORNIA.
HE work herein reported was undertaken to complete some of the unfinished work of the late (2. V. Hart, of this laboratory.* Shearing Stress
The apparatus consisted. of two pieces of brass strip, by 1 inch (5 by 25 mm.), one used as a support, the other as a knife. The knife was inserted vertically through a hole in the support in such manner that a section of a nut could be placed horizontally through a hole in the knife and thus made to support the weight of the knife and any added weight. The edges of the holes were square and sharp to minimize crushing before shearing. The bottom of the knife was provided with a receptacle into which shot was poured until the knife sheared the specimen. The shot was then removed and its weight recorded. The sections of the nuts that were tested were cut by hand and calipered to "16 by 3/le inch (5 by 5 mm.). They were then placed in the apparatus with the division between the cotyledons in the vertical plane, as varying the position of this plane affected the shearing stress. It was found that an average of twentyfive determinations gave practically the same result as a n average of one hundred determinations. The weights given in Table I are for imported Aetna variety almonds and are typical of the shearing stresses as determined in the above manner. The average shearing stresses found by this method on the uncooked nuts are given in Table 11. "1s
1 2
Received July 21, 1930. The work of Doctor Hart is reported on page 1128 of this issue.
Kg. 3.48 3.87 3.92 4.00 4.05
BERKELEY, CALIF. Table I-Shearing Stress Data KR. Kg. KR.
3.19 3.39 3.65 3.95 3.54
4.00 3.60 4.00 3.25 4.55 Average, 3.50kg.
Table 11-Shearing DOMESTIC Nonpareil I. x. L. Drake
Kg. 6.28 5.50 3.93
3.92 3.87 4.05 4.05 3.95
K& 3.47 3.75 4.02 4.02 3.54
Stresses of Uncooked Nuts IMPORTED KR.
Jordan Alicante Marcona Valencia Aetna
2.78 3.82 3 49 2.95 3.80
The above figures show a somewhat greater shearing stress for the domestic than for the imported varieties and a considerably higher stress for the Nonpareil than for the Drake. Hemicellulose Content
PROCEDURE-The
method used was that proposed by
W. H. Dore (unpublished), of the Division of Plant Nutrition, University of California. About 5 grams of the ground and mixed sample were extracted for 16 hours with alcohol in a Soxhlet extraction flask and aliquots equivalent to 1 gram of the original sample were treated as follows: The analysis of the alcohol-insoluble material as proposed by Dore includes a determination of starch which precedes the hemicellulose determination, as starch will respond to the hemicellulose test. By testing with iodine the filtrate of the alcohol-insoluble portion after digestion by boiling the samples was found to be starch-free, so the starch determination was omitted. The aliquot of alcohol-insoluble
