FEBRUARY, 1937
INDUSTRIAL AND ENGINEEHING CHEMISTliY
It has been found that the use of Avenized cartons for whole-wheat shredded biscuits which are usually packaged without an inside paper liner is of value not only in delaying the development of rancidity but also in retarding the transfer of board odors and flavors to the food. Reichert-Wollny numbers on vacuum-packed coffee with and without Avenized liners were as follows: Vacuum Can Unlined W i t h Avenized liner
0
Days after Opening ---. 3 6 9
0.392 0.359
0.407
0.327
0,531 0,465
0 570 0.348
Enough data on the use of oat flour as an antioxidant have been given to indicate that here is a new field for investigation. More exhaustive studies may show that only with certain foods is the addition of oat flour sufficiently protective to warrant the additional expense involved. Oat flour does, however, offer possibilities of improving the quality of many products now being sold.
Literature Cited (1) Allen, “Commercial Organic Analysis,” 5th rev. ed., Vol. I X , p. 323, Philadelphia, P. Rlakiston’s Son & Co., 1932.
151
(2) Anderson, Lyle, unpublished progress report from Musher Foundation, Inc., a t U. S. Bur. Fisheries, Seattle, Wash (3) Bengis, R. O., IND.ENG.CHEM.,28, 280 (1936). (4) Bollmann, H . , U. S. P a t e n t 1,575,529 (March 2 , 1926). (5) Florence, E. B., N. Y . Coffee & Sngar Exchange, unpublished data.
(6) French, R. B., Olcott, H . S.,a n d Mattill, H . A , , ISD. ENG. CHEY.,27, 724 (1935). (7) Greenbank, G . R . , U. S. P a t e n t 1,898,363 (Feb. 21, 1933). (8) H a r t , W. J., unpublished progress report from Musher Foundation, Inc., a t U. S. Bur. Fisheries, College P a r k , M d . (9) Holm, G. E., Greenbank, G. R , a n d Deysher, E. F.. IND.ENG. CHEM.,19, 156 (1927). (10) Hopkins, F. G., Biochem. J.,14, 724 (1920). (11) H u b e r t , J . P., U. S. P a t e n t 1,680,047 (Aug. 7, 1928). (12) Musher, Sidney, Zbid., 2,026,697 ( J a n . 7, 1936). (13) Ibid., 2,029,248 ( J a n . 28, 1936). (14) Ibid., 2,038,752 (April 28, 1936). (15) I b i d . , 2,049,017 (July 28, 1936). (16) Newton, R. C., a n d Grettie, D . P., Ibid., 1,903,126 (March 28, 1933). (17) Newton, R . C., a n d Richardson, W.D., Ibid., 1,890,589 (Dee. 13, 1932). (18) Nitardy, F. R.,Ibid., 1,879,762 (Sept. 27, 1932). (19) Rogers, T. H . , Ibid., 1,805,458 ( M a y 12, 1931). (20) Steenbock, H . , Boutwell, P . W., a n d K e n t , H. E., J. Hiol. Chem., 35, 517 (1918). (21) Whipple, D. V., J. Pediatrics, 8, 734 (1936). RECEIVED September 14, 1936
Cereal Flours as Antioxidants for Fishery Products Halibut Liver and Salmon Oils LESLIE LOWEN, LYLE ANDERSON, AND ROGER W. U. S. Bureau of Fisheries, Seattle, Wash.
Various substances have been reported to be effective antioxidants. I n this investigation attention was given to the cereal flours because they are food materials of bland odor and flavor, readily available at low cost and, if effective, acceptable without question by food regulatory bodies. The antioxidant value of oat flour was tested on experimentally prepared halibut liver oils and commercia1 salmon oil. Oat flour was found to retard the initial peroxide formation, and its effectiveness in retarding rancidity increased as less accelerated conditions of exposure to air were used. The salmon oils showed a more pronounced retardation of oxidation and of off-odors and flavors than was noticeable in the halibut liver oils. There were sufficient favorable results in each case to warrant further investigation.
T
HE development of rancidity in fats and fat-bearing materials is associated with certain oxidative changes in the fat. The rate and exHARRISON tent of such reactions can be influenced by the presence or absence of oxygen, exposure to light, prevailing temperatures, and the incorporation or presence of certain prooxidant or antioxidant substances. The characteristic odors and flavors developed are attributed to the formation of various aldehydes, ketones, and acids. Food industries are concerned with rancidity because the development of oft-odors and flayors, together with chemical changes associated with them, decreases the quality, market life, and sales value of the product affected. As early as 1890 Langbein and Stohlman (18) reported that rancid lard was of lower calorific value than fresh lard. More recently Whipple (39, 40) obtained evidence of the formation of toxic compounds and loss in nutritional value in rancid oils, and Powick (%), Mattill (do), and Whipple (58) reported that rancidity tends to destroy vitamin A. The fishing industry is particularly confronted by the problem of rancidity because fish oils are, in general, highly unsaturated and are therefore extremely susceptible to oxidative deterioration. This pertains to both the extracted oils and to fresh and preserved fishery products. Such preservative methods as chilling, freezing, smoking, salting, and canning were developed primarily for retarding proteolytic decomposition and do not in all cases protide suitable protection against oxidative deterioration. On this account and because of further limitations in controlling oxidation during normal storage and distribution, there is need for
INDUSTRIAL AND ENGINEERING CHEMISTRY
152
incorporating substances with fishery products which have specific powers for retarding oxidative changes in the oil. Since 1922 when Moureu and Dufraisse (94) reported the effectiveness of hydroquinone as an antioxidant, a vast number of materials has been described in the literature as possessing the property of inhibiting oxidative changes in fats and oils. Some of these are such phenolic compounds as hydroquinone (6, 3f, S6), pyrogallol (6, 36), pyrocatechol (6, 31),guaiacol (6, as), apionol (31), resorcinol (SB), and aand /3-naphthol (21, S I , 36); numerous organic nitrogen compounds including various amines (19, SS), hydrazines (19, 3 4 , amides, imides ( I @ , diphenyl guanidine (41) and
GRAMS
OF
SAMPLE
FIQTJRE 1. THE EFFECTOF SAMPLE SIZE ON PEROXIDE VALUE
cyanamide (16); several chlorinated and brominated paraffins (?); polybasic acids such as phthalic (6), aconitic (11), maleic (6, 11), and fumaric (11); and such materials as gum guaiac ( I S ) , lecithin (8, l 7 ) , cephalin (E%), various carotenoid pigments (10, 29, SO, 35), and crushed oil-bearing seeds and cereal flours (26, 26, 27, 28) and extracts therefrom (3, 9, 12, 14, 16). Colored wrappers have also been found to influence rancidity (6, 99). In spite of the great variety of antioxidant materials reported in the literature, relatively few meet all the requirements for treating food products. I n this investigation attention has been given to the cereal flours, especially oat flour, because they are food materials of bland odor and flavor, readily available a t low cost. Further, there is no question concerning their acceptance as antioxidants by food regulatory bodies.
VOL. 29, NO. 2
products. The points considered were illumination, access of air, surface exposure, and the amount and nature of the cereal flour used. The progress of the oxidation reaction, as influenced by treatment with the cereal flours, was followed by the measurement of peroxides. In some cases data were obtained to permit a correlation between peroxide formation and decrease in vitamin A potency. The technic for measuring peroxides was essentially that of Wheeler (87): One-gram samples of oil were dissolved in 30 ml. of a 60 per cent acetic acid40 per cent chloroform mixture in ground-glass-stoppered Erlenmeyer flasks, 0.5 ml. of fresh saturated potassium iodide solution was added, and the flask was rotated gently for exactly 2 minutes. After adding 100 ml. of freshly distilled water, the liberated iodine was titrated immediately with 0.01 N sodium thiosulfate solution, using 1 ml. of 1 per cent starch solution as an indicator. Peroxide values were reported as milliliters of 1 N thiosulfate per 1000 grams of oil. Because of the high pigmentation of both halibut liver and salmon oils, samples larger than one gram interfered with estimation of the end oint. In this connection it was found that larger samples of o x gave lower peroxide values (Figure 1) Vitamin A was determined by the antimony trichloride' test of Carr and Price (4) modified in this laboratory as follows: The antimony trichloride solution was prepared by making a saturated solution in U. S. P. chloroform at room temperature, chilling in a laboratory refrigerator at 3" to 4 ' C. for about 24 hours, decanting, and holding at this temperature in brown glass bottles until used. During the tests the solution was held in an ice bath. A weighed sample of oil, depending in amount upon its potency, was dissolved in anhydrous chloroform and made up into three dilutions so that 0.2 ml. of each solution in 2 ml. of the antimony trichloride solution would give readings in a Rosenheim-Schuster tintometer ranging from about 2 to 8 blue units (Lovibond). Curves were plotted from the data at each dilution (milligrams of oil os. blue units), and the weight of oil required to give five blue units was read from the curve. This value was then recomputed to blue units per gram of oil.
Materials The halibut liver oils were prepared in this laboratory from the livers of halibut taken in the Gulf of Alaska. The oils were not solvent extracted. One sample of salmon oil had been prepared experimentally from waste incident to the canning of Alaska red salmon. The remaining salmon oil had been prepared commercially from edible Columbia River Chinook salmon trimmings as an edible product for addition to canned Chinook salmon. The cereal flours were supplied by the Quaker Oats Company through the facilities of the Musher Foundation Inc. These were Avenex 3 (rather coarsely ground whole oats consisting of approximately 35 per cent hulls and 65 per cent oat groats), Avenex 4 (rather finely ground decorticated oats), and Rice Bran Q 10.
Procedure In order to study the effectiveness of an antioxidant with reasonable dispatch, a certain amount of acceleration in test conditions is required. However, because of the limitations in methods for following rancidity and because of the possible influence of conditions on the effectiveness of the antioxidant, the work here reported was confined to a number of mildly accelerated tests suggestive of the variety of factors which might be expected to influence the effectiveness of the cereal flours during normal storage and distribution of treated fishery
?%WE, DAYS
FIQURE2 . RELATION BETWEEN VITAMINA DETERIORATION AND PEROXIDE INCREASE IN CONTROL AND OAT-TREATED HALIBUT LIVER OIL
FEBRUARY, 1937
INDUSTRIAL AND ENGINEERING CHEMISTRY ~
AND TABLEI. DATAON TREATED
153
~~~
UNTREATED SALMON AND HALIBUT LIVEROILS EXPOSED TO AIR IN SUNLIGHT AND IN DIFFUSBLIQHT Value M1 1NNa2S20s/1O0O1G. Oil
---Peroxide
Conditions Series 1, 50-ml. samples stored in 125-ml. Erlenmeyer flasks exposed t o air a t room temp. in west winter light (sun's rays through lab. window)
Oil Salmon
Halibut liver
Time Days( 0 1 2 3 15 20 0 1
2 3 15 20
Series 2 50-ml. samples stored in 125-ml: Erlenmeyer flasks exposed to air at room temp. in diffuse winter light
Salmon (offal)
Halibut liver
0
2 5 7 11 15 25 35 0
2 5 7 11 15 25 35
Untreated 5.2 5.6 7.7 10.1 45.4 70.9
Plus 5% Avenex 3 3.4 4.2 7.2 9.7 52.2 111.0
Plus 5% Avenex 3, filtered after 1 hr. 2.8 4.7 8.7 11.7 49.6 77.4
7.0 11.2 14.4 21.2 75.1 115.0
4.8 8.0 17.8 30.5 47.6 59.7 91.5 125.0 17.0 17.9 25.0 32.5 38.3 42.3 83.0 140.0
6:s 10.2 16.1 23.9 31.5 52.7 73.3 l2:6 18.3
26.3 33.2 39.4 80.0 164.0
,
0:4 13.0 22.3 32.8 40.5 66.6 91.2 16:s 23.4 31.2 41.3 45.5 76.6 146.0
Vitamin A Value, Blue U'nits/G. Oil Plus 5% Rioe Bran Plus 5% Untreated Avenex 3 Q 10 269
... ...
195 195 200 180 160 57,000
....
...
...
23s
24;
238
...
240
240
.,..
....
238
...
240
240
....
54 000 46:OOO
51,000 48,000
56,000 47,000
4 5 000
49,000 28,000 9,000
50 000 31'000 14:OOO
27'000 9:ooo
....
....
Experimental Results interest because rancidity is ordinarily reported to develop coincident with the end of the induction period, as deterExperience here has shown that fish and fish liver oils: mined by oxygen absorption ($), although Aage (1) found immediately upon being prepared from absolutely fresh raw that some rancid oils might have long induction periods, materials, have practically no odor or flavor. However, the and Coe and LeClerc (6) showed that corn oil and cottoncharacteristic fishy odor and flavor soon develops. This seed oil can become rancid without a break in the peroxide increases gradually in intensity until a slight bitterness becurve. comes detectable and then an acrid odor can he recognized. It is possible that the so-called characteristic odor and flavor No similar correlation was obaerved between peroxide value mask the bitter flavor and acrid odor in their early stages. and odor and flavor when samples were not exposed to the From a practicable viewpoint the first detectable characterair. Barnicoat (8) also reported that, a t the time rancid istic fishy odor and flavor cannot be caUed evidence of taste is first apparent, fats in sunlight have lower peroxides rancidity. On the other hand, the intensity of the fishy odor than fats stored in the dark. For these reasons the writers and flavor makes the oil disagreeable before an acrid odor is appreciate the limitations in using any arbitrary peroxide evident. For this reason, estimation of rancidity in fish value as indicative of rancidity. However, their observations and fish liver oils by organoleptic test is exceedingly difficult. were consistent to the extent that in all series of tests the treated s a m p l e s of In the ouinion of the lower peroxide value writers, Although this had less pronounced may be expected to TABLE11. DATAON TREATED AND UNTREATED HALIBUT LIVEROILS IN flavors and odors than differ with other obOPEN STORAGE EXPOSED TO DIFFUSELIQHT the untreated or conservers, the fishy odor Peroxide Value MI 1 N Vitamin A Value trol samples. and flavor of oils exBlue Units/G. Oii Na~SnOs/IOOb G.'Oil Time Plus 570 Plus 5% I n series 1 (Table posed to air was sufConditions of Series 3 Day: Untreated Avenex 3 Untreated Avenex 3 I) where salmon oil ficiently strong to be A, 30-ml. samples of freshly pre0 9.1 .... 9.0 was exposed to air in suspected of rancidity 52,000 pared halibut liver oil stored 1 ... ... 57,000 21.2 61,000 55,000 in 50-ml. Erlenmeyer flasks 3 16.9 winter sunlight transwhen t h e peroxide 29.5 59,000 59,000 23.6 exposed to air a t room temp. 5 38.1 53,000 57,000 32.0 in diffuse spring light 7 mitted through glass, value, as determined i- n 52.4 .... 43.4 _ .... the addition of 5 per in this investigation, 14 54,000 68.5 57.0 54,000 53,000 80.5 67.4 17 59,000 cent Avenex 3 caused was between 20 and 115.0 .... .... 81.8 19 21 135.0 31,000 115.0 32,000 an initial drop in per30. As will be seen 24 194.0 11,000 152.0 13,000 oxide value but did in the data, this value 263.0 6,300 26 204.0 9,000 381.0 1,900 31 293.0 3,200 not r e t a r d peroxide is reached considera.... 42 600.0 .... 469.0 .... 55 584.0 ... .... formation. The effecbly before evidence of tiveness of the flour pronounced autocata31.1 57,000 E . Oil exposed 7 days (60 ml. in 0 .... 46.4 3 ii:3 125-ml. fl.aak) before being .... in this test was conlytic p e r o x i d e f o r treated as in A .... 56.3 7 50.3 .... 69.3 10 .... 54.8 sidered negative. mation and likewise b?,000 80.2 12 48,000 70.1 I n the case of the comes well within any 56,000 92.8 14 .... 81.6 22,000 137.0 110.0 31,000 17 halibut liver oil under s 0-c a lle d induction 19,000 158.0 19 138.0 19,000 24 247.0 4,900 225.0 5,000 similar conditions, the period as indicated by .... 475.0 35 468.0 .... flour caused definite peroxide formation 525.0 .... 48 450.0 .... r e t a r d a t i o n in perThis behavior was of I
INDUSTRIAL AND ENGINEERING CHEMISTRY
154
VOL. 29, NO. 2
TABLE111. DATAON TREATED AND UNTREATED HALIBUT LIVER OIL IN CLOSEDSTORAQE EXPOSEDTO DIFFUSELIQHT
Conditions Series 4. Extd. from fresh. landed livers' oil stored a t room temp. in diffuse lighi in 4-oz. stoppered, clear glass bottles with 1-05. air space; bottles opened and oil removed for eriodio test. Yield of oil: untreated h e r s , 26.8%; livers 1%Avenex 3, 17.5%
Time in Days 0
20 50 90 120 155 215 250
+
Series 5. Oil from same lot of livers as series 4 after livers had been in frozen stora e for 80 days: oil storage as in 4. Y i e d of oil: untreated livers, 12.2%; livers 1% Avenex 3, 8.5%
+
+ 0 + 30 + + 60 120 170
80 80 80 80 80 f
Seriaa 6. Extd. from fresh landed livers; oil stored in 5-m& stoppered, clear glass vials with 1-ml. airs aoe; eaoh vial represented an individuaftest sam le. Yield of oil: untreated livers, 1 2 . 7 2 livers 1% Avenex 3, 9.7%
Peroxide Value M1 1 N Na&Os/ l O O b G.'Oil Plus 5% From Avenex 3, livers Plus 5% filtered 1% Untreated Avenex 3 after 1 hr. Avenex 3 4.1 5.3 4.2 4.2 i:7 9:s 4.3 4.5 6.8 10.9 5.0 13.0 6.3 7.0 5.3 4.7 16.7 10.8 8.4 6.7 22.2 15.2 2.5 1.5 3.5 0.3 12:o 10:o
+
+
.... .... .... .... .... .... .... 47,000
....
18.8
12.7 15.6
18.7 16.2 18.6 13.0 15.0
.. .. .. *. ..
14.0 13.7 10.6 6.7 8.8
30,000 22000 22'000 21:OOO 20,000
24,000 23000 24'000 23:OOO
5.1 3.0 4.1 5.8 4.3 7.7 6.2 6.4
3:4 4.2 5.8 4.2 6.0 4.8 6.4
5:2 4.6 5.9 5.0
..
4.3 3.2 5.5 6.1 4.4 6.4
52,000 51,000 48000 45:OOO 47,000
51,000 55000 49:OOO 41,000
52000 48'000 44:OOO
46,000 47,000 48,000 45 000 43:OOO
0:4
7:2
41,000 32,000
42,000 40,000
39,000
42,000
18.4 20.7
0 30 65 85 120 150 195 245
+
Vitamin A Value, Blue Units/G. Oil Plus 5% Avenex 3, From Plus 5% filtered livers 1% Untreated Avenex 3 after 1 hr. Avenex 3 18,000 19.000 ii.060 15,000 17 000 is;ooo 14:OOO 15 000 15,000 15:OOO 14,000 12,000 12,000 13,000
....
....
....
.... ....
....
27,000 22,000 23,000 21,000 19,000
.... ....
,
1
TABLEIV. PEROXIDE VALUESOF TREATED AND UNTREATED SALMON OILS EXPOSED TO AIR IX M1. 1 N Sodium Thiosulfate per 1000 Grams Oil Salmon oil of low initial eroxide value Plus Plus 10% Avenex 3 Avenex 3
Time, Days
58
Untreated 1.7 5.9 9.8
0
3
6
19.3
... 24.2
i:6
14: 0
ii:g
6.8 7.3
..
6.5 6.6
12.4
13.5
12.7
20: 6
16:s
15: 2
16:3
40.6 45.9 49.5
si14 24.2 28.3
21.0 25.3
59.1
... ...
5i:6
..
.. .. 19:s .. .,
76:s
31.2
27.4
23.2
24.7
39:O
36: 5
....* .
...
*.
..
.. 34:4 .. ..
..
..
b
Plus 5% Avenex 3 53.1
.. .. 2i:6 .. ..
*...
Plus 5% Avenex 4 60.1 71.2
43.1 45.7
12:o
18:5
oil of high initial peroxide valuePlus Avenex 10% 4 Untreated
3:0
14.8
b
---Salmon
Avenex 4
33:4
...
Avenex 5%3 62.3 71.4
9:s
..
i:s
5.1
Plus 10%'
27.7
...
33 35 38 41 45 47
5: 3
5.8
...
9 12 14 15
i:1
Plus 5% Avenex 4
DARK(SERIES7")
THE
.. .. ..
.. 35:5 .. ..
52.3
Plus 50/0 Avenex 4 48.3
29.6 30.1
..
5i:3
34:4
93:o 107.0
.. .. ..
es:5
48:s
.. .. .. ..
.. ..
.. ..
103:o 1ii:o 99.0 112.0 138.0 102.0 5s: 4 49:3 .. a 200-ml. s a m les.of edible salmon oil stored in 600-ml. beakers exposed t? air in the dark a t room temperature. b Sample divixed into three portiona. Same surfaoe volume ratio maintained.
TABLE V.
..
.. .. ..
..
PEROXIDE VALUEOF TREATED AND UNTREATED SALMON OIL EXPOSED TO AIR IN VARIOUS LIGHTS(SERIES8")
--
M1. of 1N Sodium Thiosulfate per 1000 Grams of Oil7 Oil exposed in the dark -Oil exposed in diffuse lightexposed in sunlightPlus 5% Plus 5% Plus 5% Day: Untreated Avenex 3 Untreated Untreated Avenex 3 Avenex 3 4.2 4.2 2.3 4.2 2.3 4.2 2.3 4.2 2.3 4.2 0 2.3 6.b 16.7 6.8 6.9 1 19.7 11.1 33.6 10.3 10.0 2 42.8 67.0 14.4 14.8 11.2 3 75.7 95.0 ,.. 18.1 20.6 13.2 4 101* 0 135.0 23.4 . . . 26.3 16.2 6 138.0 1i:2 15i:0 167.0 lira: 0 27.0 31.3 32.4 32.8 17.9 1s:o 6 170.0 21.6 .. 209.0 33.1 41.0 7 216.0 253.0 40.5 49.5 23.1 8 257.0 283.0 50.2 76.0 30.8 9 274.0 343.0 67.0 105.0 37.3 311.0 364.0 128.0 195.0 43.6 12 lo 371.0 45 .'S 2%: 0 386.0 30910 211.0 12i:o 252.0 13i:o 49.3 47 :s 13 416.0 40-ml. samples of oil stored in 600-ml. beakers exposed to air a t room temperature in sunlight, diffuse light, and the dark.
Time
-Oil
... ... ... ...
... ... ...
... ...
... ... ...
.. .... ..
... ... ... ...
... ... ... ...
... ... ...
... ...
.. .. ..
oxide formation since the control reached the range of suspected rancidity in 60 per cent of the time required for the sample treated with Avenex 3. With both oils, removal of the flour by filtration decreased the protective effect. I n series 2, where Avenex 3 and Rice Bran Q 10 were added to salmon and halibut liver oils exposed to air in deuse winter light, the rice bran was least efTeo€ive in retarding peroxide
... ...
...
... ...
... ...
..
.. *.
formation. Neither material, however, had any pronounced effect in preserving vitamin A, as indicated by the antimony trichloride test. I n the case of the salmon oils, the treated samples maintained rather constant blue unit values in contrast to a decrease in the control, but the color test is not sufficiently accurate in this low range to permit a definite statement to that effect. In this series 5 per cent Avenex 3 retarded peroxide forms-
FEBRUARY, 1937
INDUSTRIAL AND ENGINEERING CHEMISTRY
155
tion in the salmon oil but, in the case of the halibut liver oils, I I I I I I I I peroxides increased a t approximately the same rate after an initial drop. The poorer results with the halibut liver oil in series 2 raised a question as to the possible relation of initial peroxide value to the effectiveness of the flour. Series 3 involves halibut liver oil with an initial peroxide value of 9 and the same oil after reaching a value of 31, when treated with 5 per cent Avenex 3, The results given in Table I1 and Figure 2 show a definite retardation in peroxide formation in both series of samples, and again no significant protection of vitamin A. The ratio of the time required for the treated sample to the time required for the control to approach suspected rancidity was practically the same as that for series 1. Perhaps the most significant point with respect to the data of series 3 is the correlation between autocatalytic peroxide formation and decrease in vitamin A, and the fact that the oils gave no definite indication of loss of vitamin A until well past the point where odor and flavor were disagreeable. Series 4, 5 , and 6 (Table 111)show no definite or consistent changes in peroxide formation in oils stored in stoppered bottles exposed to diffuse light. However, during the period of test the several samples developed a more pronounced fishy odor and flavor than were originally present or would be expected of a freshly prepared oil of similar peroxide value. The odor and flavor of the treated samples were less pronounced than the controls. As mentioned previously, these data suggest the danger of indiscriminate use of the FIGURE 3. PEROXIDE FORMATION IN OAT-TREATEDAND UNperoxide test as a quantitative indication of rancidity. TREATED SALMON OIL I N OPEN STORAGE IN THE DARK As in series 2 and 3, no significant vitamin A protection could be attributed to treatment with Avenex 3, although improvement in odor or flavor could be detected as an imthe treated samples maintained slightly higher values. At the end of 8-month storage the percentage decrease in mediate effect of the flour treatment, as nearly as could be vitamin A in the control samples was approximately the same judged by organoleptic test the treated sample maintained an for each series. This behavior was interesting since slightly increasingly better relative condition in subsequent storage. different storage conditions, different oils, different initial perWhen the controls of this series were divided a t still higher oxide values, and different initial vitamin A potencies were peroxide values, and portions of each having the original involved. I n this case there was no relation between vitamin surface-volume ratio were treated with 5 per cent Avenex A decrease and peroxide formation as was noted in series 3. 3 and 4, respectively, a similar but less pronounced decrease Oat flour retarded peroxide formation in livers during in peroxide formation was obtained. The results of the entire storage but detracted from oil vield. The flour had some series are shown to larger scale in the lower part of Figure 3. nullifYyingeffect on the treatmentlused for liberatThe data from series 7 (Figure 3) show that: ing the oil. Unless overcome, this effect would (a) I n the case of the two controls, one very fresh prove to be a greater disadvantage than any and the other suspected of being rancid, evidence benefit in retarding oxidative changes. I n spite of autocatalytic peroxide formation began a t apof the higher potency of oil from the same livers proximately the same value; (b) in the range kept in frozen storage, the lower oil yield resulted preceding autocatalytic oxidation, the rates of in approximately 25 per cent less total vitamin A peroxide formation in the fresh and rancid conrecovery. trols were practically identical; ( c ) in the same When larger samples of salmon oil with lower range the similarly treated fresh and rancid samsurface-volume ratios were stored exposed to air in ples had practically the same rate of peroxide forthe dark, the cereal flours were much more effecmation; ( d ) beyond the range of uniform peroxide tive (Table IV and Figure 3). Oil treated with 5 formation the oat flours were progressively less per cent Avenex 3 maintained a peroxide value of effective; and (e) under similar conditions of stor50 to 60 per cent that of the control in the range age the oat flour did not prolong appreciably the preceding suspected rancidity, whereas the oil period preceding autocatalytic peroxide formation treated with 5 per cent Avenex 4 maintained a but instead seemed to exert a retarding effect peroxide value of 35 to 45 per cent of the conthroughout the storage period. This was of pertrol. Although not shown in Figure 3, 10 per cent haps most significant practical value because the Avenex 3 had a greater retarding effect than 5 per oils became undesirable before reaching the point cent Avenex 3, but was not as effective as 5 per of autocatalytic peroxide formation. cent Avenex 4. On the other hand, 10 per cent I n the tests 5 per cent Avenex 3 prolonged the Avenex 4 gave practically no improvement over estimated fresh l i e of the sample approximately 5 per cent of the same material. 80 per cent whereas 5 per cent Avenex 4 prolonged The addition of 10 per cent Avenex 4 to an oil the fresh life approximately 125 per cent. The just above the point of suspected rancidity caused times required for the control, oil plus 5 per cent F I Q U R ~ 4. EFFECT a drop in peroxide value and a retardation in perAvenex 3, and oil plus 5 per cent Avenex 4 t o OF ILLUMINATION ON oxide formation sufficient to require 12 days before PEROXIDEFORMA- reach the arbitrary value of 20 were 12, 22, and reaching its original value. Although no definite TION 27 days, respectively.
156
INDUSTRIAL AND ENGINEERING CHEMISTRY
Table V and Figure 4 demonstrate definitely the catalytic effect of light on peroxide formation. The data show also that the cereal flours like other antioxidants become less effective as conditions for oxidation are accelerated. It waa of interest also that the peroxide values of the treated oils eventually exceeded those of the controls under highly accelerated oxidation, but in the range preceding suspected rancidity the cera1 flours gave appreciable protection.
VOL. 29, NO.2
Literature Cited Aage, L., Tida. K j e m i Bergvesen, 5, 102 (1925). Barnicoat, C. R.,J. SOC.Chem. Ind., 50,361-51’ (1931). Bradway, E. M., a n d Mattill, H. A., J. Am. Chem. SOC.,56,
2405 (1934). Carr, F. H., a n d Price, E. A.,Biochem. J.,31,497 (1926). Coe, M.R.,a n d LeClerc, J. A., IND. ENQ. C H ~ M 26, . , 245 (1934). Coe, M. R.,a n d LeClerc, J. A., Oil & Soap, 12,231-3 (1935). Davidsohn, I., a n d Strauss, R., German P a t e n t 619,928(Oct. 9,
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Conclusions In open storage exposed to air, increase in peroxide value correlated with increase in off-odors and flavors and decrease in vitamin A potency. I n tests where oil was held in stoppered bottles exposed to diffuse light, no correlation was obtained. The peroxide test is therefore of limited usefulness in studying oil deterioration. Oat flour retarded peroxide formation initially and increased in effectiveness in retarding rancidity as less accelerated conditions of exposure to air were used. However, because of the greater susceptibility of fish oils towards oxidation, the cereal flours were less effective than when used with lard and vegetable oils (25, 26). Holmes, Corbett, and Hartzler (16) reported protection to vitamin A in halibut liver oils using hydroquinone and lecithin as antioxidants. I n the experiments reported here, the cereal flours did not give sufficient protection to vitamin A to be considered significant. However, the halibut liver oils used here exhibited a pronounced initial resistance to vitamin A change, whereas their data indicated a more or less uniform decrease during the test period. The possible significance of this difference as related to the effectiveness of the cereal flours is being investigated further. These data would indicate that halibut liver oil is quite stable with regard to vitamin A; because of the high peroxide values of some of the freshly prepared oils of these experiments, it appears that an oil in some cases will no doubt reach a condition where “repeating” will occur before any significant vitamin destruction takes place. Oat flour retarded oxidation of oil in the liver but interfered with the method of extraction used. The pronounced retardation of oxidation and of off-odors and flavors in the salmon oils exposed to air in the dark were considered to be of sufficient significance to warrant further investigation of the cereal flours for maintaining the quality of fresh, frozen, smoked, salted, and canned fatty fishery products. These experiments are in process and will be reported later.
E v a n s , E . I., IND. ENQ.CHEM.,27, 329 (1935). French, R. B., Olcott, H. S., a n d Mattill, H. A., Ibid., 27, 724
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(1922). Musher, S., Food Industries, 7, 167-8 (April, 1935). [bid., 7, 329-30 (July, 1935). Musher, S., U. 5.P a t e n t 1,816,338(July 28, 1931). Ibid., 1,841,842(Jan. 19, 1932). Newton, R.,Oil & Soap, 9, 247 (1932). Newton, R.,a n d Richardson, W. M . , Canadian P a t e n t 323,764 (June 28, 1932). Olcott, H . S., J. Am. Chem. Soc., 56, 2492 (1934). Olcott, H.S., a n d Mattill, H . A., Oil & Soap, 13,98 (1936). Powick, W. C., J. Agr. Research, 31,1017 (1925). Stephan, K.,Chem.-Ztg., 59, 416 (1935). Swift a n d Company, French P a t e n t 713,967(March 27, 1931). Wagner, A.,a n d Brier, J . , IND. ENQ.C H E M . ,23, 662 (1931). Wheeler, D. H., Oil & Soap, 9,89 (1932). Whipple, D., J. Pediatrics, 8,734 (June, 1936). Whipple, D., Oil & Soap, 10,228 (1933). Whipple, D . , Progress Med. Sci., June, 1934,864. Yamaguchi, B., Rept. Aeronautical Research Inst. Tokyo I m p .
Univ., 5,287 (1930). RECEIVEDSeptember 23, 1936. Presented before the Division of Agricultural and Food Chemistry at the 92nd Meeting of the American Chemical Society, Pittsburgh, Pa., September 7 t o 11, 1936. This paper gives resulta of a codperative study between the U. S. Bureau of Fisheries and the Musher Foundation Inc. Leslie Lowen and Lyle Anderson are fellows of the Musher Foundation.
