T H E EFFECT OF K H E A T GERM OIL OK T H E KEEPING QUALITIES OF FATS AND FOOD RATIOYS* BY P. E. ROLLER
Considerable interest has been displayed for some time concerning the rancidity of fats and oils, both edible and inedible, and concerning methods of preventing or delaying rancidity. Moureu and Dufraisse’ have published a number of articles in which they discuss anti-oxidants. Holm, Greenbank, and Deysher2 have shown that glycerol, resorcinol, phenol, benzylic alcohol, and dihydroxystearic acid delay the rate of adsorption of oxygen by linseed oil. Some of the other investigators who have worked on anti-oxidants are: FisherJ3L ~ n d Smith , ~ and Wood,j Fiero,6 Yoshio Tanaka and Mitsuo Sakamura,’ Husa and Husa,* Mattill,g and Mattill and Crawford.’O Wheat germ oil has received considerable attention in the treatment of certain ailments and deficiency disease^^^,^^,'^,". Barnett Sure15 has done considerable work on the dietary requirements of wheat germ oil for reproduction. Mattill16 and hnderegg and Xelson” have suggested that perhaps vitamin E in food rations may be destroyed when oxidative changes take place in fats. Some facts which are presented confirm this assumption. Wheat germ oil was found to protect food rations for a certain period of time as well as to supply the necessary vitamins. Mattill found that the vitamin E content did not parallel the acetyl values of vegetable fats and oils. He also found that other vegetable fats and oils would not protect food rations in a similar manner as wheat germ oil did. The present investigation was carried out to study the effect of wheat germ oil and the different constituents of the oil on the keeping qualities of fats and oils and food rations. Laboratory Method and Apparatus The effect of wheat germ oil on the keeping quality of fats and oils was determined by a modified form of apparatus such as was used by Moureu and Dufraisse‘ and refined later by Greenbank and Holm.1a In every case, about 500 cc. of fat were melted and a definite quantity removed by a warmed pipette. This furnished a uniform portion of the joo cc. sample. T o this portion a definite amount of wheat germ oil was added. From I O cc. to 2 0 cc. samples of this mixture were pipetted into 2 5 0 cc. Erlenmeyer flasks which were connected to mercury manometers. Oxygen replaced the air in the flasks. The thermostat was maintained a t a temperature of 70°C. During the temperature adjustment, the pressures in the system were adjusted by means of two-way stopcocks inserted in the tubes
* Contribution from the Research Division of The S. M. A. Corporation, Cleveland, Ohio.
EFFECT OF WHEAT GERM OIL ON FATS AND FOOD RATIOSS
3287
connecting the manometers and the flasks. The period for temperature adjustment varied from thirty minutes to two hours or two hours and thirty minutes. I t was found that the induction period for cod liver oil was generally one of the shorter induction periods for fats. Skimmed milk powder was used as the basis for all the food rations. When the cod liver oil and skimmed milk powder were thoroughly mixed together, rancidity was easily detected by the penetrating odor, very likely acrolein. Generally 50 g. of skimmed milk powder, 8 cc. of cod liver oil, and various amounts of wheat germ oil were used. The mixtures were put in pint jars in an air atmosphere at room temperature.
Results It has been reported by Mattill16 that vegetable oils, other than wheat germ oil, sometimes afford protective action in preventing rancidity in food rations, but wheat germ oil affords almost unfailing protection. I t was of interest to find that not all samples of wheat germ oil afford protective action for fats and oils, and food rations. Typical sets of results are given for an active sample and an inactive sample of wheat germ oil. Two different flasks containing fat of the same composition were used at the same time. Manometer KO.I and Manometer No. I1 were connected to the flasks.
TABLE I Active wheat germ oil was added to cod liver oil CC wheat Induction Periods germ oil
Trial I I1 li I I1 ((
l1
li
I1 I
('
11
lL
(' 'I ((
'(
I I1 I I I1 I I1 I
hr.
IO
min.
I
0
I ( (
IO
. 2 j
I ( (
' 2 5
I
('
'5
1''
35
"
I
((
((
I I1 I
Manometer No. I
0
Manometer No. I1 I
hr.
((
35
I "
40
I ( (
35 45
lL
I i (
35
dl
I ' l
45
((
Z L L
IO
'[
IO
((
i1
40
Z i 1
IO
1.47
2 "
IO
((
Z L L
2.4 2.4
2 ' l
15
i1
2
2 ' (
IO
4.8
3 " 30 3 " 25 3 ( ( 20
4.8 7 9.1 9.1
411
min.
I5
1.47
'5
j
I i l
!(
2 ( ' "
(' lL
I5
4('
I5
I3 I3
4 " 4 "
IT
4 "
30 30 30
5 20
3 " 30 3 ( ' 25 3 1 1 45
lL
l1 ii
iL lL
411
20
"
4li
"
4 "
30 30
"
li
4 "
35
lL
li
('
3288
P. E. ROLLER
TABLE I1 Inactive wheat germ oil was added to cod liver oil % wheat Induction Periods Manometer No. I
germ oil
min.
I l l
I5
l1
I l l
IO
3.2
I ( '
20
l(
I "
IO
6.2
I ( (
11(
IO
((
I ( l
I5 I5
l(
9.1
l(
I ( '
I5
((
I ( (
I5
I (
