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Summary Amino‐hexose‐reductones were evaluated as antioxidants in soybean, cottonseed, and corn oils and were shown to be highly effective by all oxidative and chemical tests. The activity of the eight different reductones was approximately the same in any one substrate. Slightly higher activities were given by reductones of lower molecular weight. Activity was demonstrated at concentrations as low as 0.001% and was shown to be a linear function of the concentration up to 0.02%, the approximate limit of solubility. Out‐standing features of the reductone‐treated oils were long induction periods, slow absorption of oxygen, and low rates of peroxide development. Reductones are believed not to react directly with peroxides but to prevent peroxide formation by reacting with some precursor. The combination of reductones with other antioxidants showed synergistic effects in only one sample of corn oil. The activity of combinations in soybean and cottonseed oils was for the most part strictly additive. In soybean oil, citric acid‐reductone combinations with each at the 0.01% level gave a slight improvement over the expected activity. Oils stabilized with multiple‐component, antioxidant mixtures in which an amino reductone replaced propyl gallate showed less peroxide development and were equally acceptable according to organoleptic scores. Aged oils did not show the organoleptic improvement that would be expected from the marked improvement observed in the oxidative stability. Significant improvements in flavor stability could be observed with reductones only when they were used in combination with an‐other antioxidant. Reductone‐treated soybean and cottonseed oils did not show an appreciable improvement in flavor stability. Only the di‐n‐butylamino‐and diallylamino‐reductones contributed foreign flavors to the oil. Atypical flavors are believed associated with the amine moiety of the reductone. At high temperatures and at higher concentrations of reductones a brown melanoid color develops in the oil. The anhydro derivatives developed more color than the normal reductone. The reductones do not withstand oil deodorization conditions.

Commercially prepared and packaged soybean and cottonseed salad oils from several different processors were evaluated periodically during storage for 12 months. Partially hydrogenated and winterized soybean oils, as well as unhydrogenated soybean salad oils, were stored in bottles and cans at 78 and 100 F. Control samples of all oils were held at 0 F during the entire test. Some lots in bottles and cans were packaged under nitrogen to improve storage stability. Agreement was good between organoleptic and oxidative evaluation of aged oils. After 26 weeks of storage at 100 F, the flavor of partially hydrogenated‐winterized oils packaged under nitrogen showed a minimum loss. These same oils did not exhibit much, if any, reduction in their oxidative stability as indicated by storage peroxide values (active oxygen method). Soybean oil not protected with nitrogen demonstrated progressive flavor deterioration at 100 F. After 10 weeks of storage, the deterioration became marked and the flavor score was below 5. From limited observations, bottled oils appear to have a better stability than oils packaged in screw‐cap tin cans. Hydrogenated oils packaged under nitrogen in cans had good oxidative stability, but some lowering of the flavor score was observed. Nonhydrogenated soybean oils packaged in tin cans not under nitrogen exhibited the most rapid flavor deterioration of all lots of oil investigated.

The odor threshold was determined for a series of unsaturated ketones, secondary alcohols, hydrocarbons and substituted furans added to bland edible oil. Odor thresholds were taken as the point where 50% of a 15-to 18-member taste panel could detect an odor difference from the control oil. These additives are oxidative products of fats, but the concentrations investigated were far below any level associated with an identifying odor or taste of the additive per se. Odor, rather than flavor, was selected as the starting basis because of greater acuity and ease of handling a large number of samples with less taster fatigue. Oil samples containing additive concentrations near the odor threshold levels were evaluated by flavor score and flavor descriptions. Taste panel members were experienced oil tasters and were allowed free choice in selecting terms to describe the flavor quality of the oil samples. The propyl and butyl members of the homologous series of vinyl ketones had the lowest odor thresholds, whereas the difference in odor threshold was small between homologs in the unsaturated alcohols and in the 2 substituted furans. Vinyl propyl ketone, vinyl propyl carbinol (1-hexen-3-ol) and 2-propyl furan had odor thresholds of 0.005, 0.5 and 6 ppm, respectively. Odor thresholds of the unsaturated hydrocarbons are markedly lower than those of the saturated isologs. The odor of nonane can be detected at 650 ppm. However, at 1000 ppm it cannot be tasted and oils containing it were scored equal to the control oil. 1-Nonene, 1-nonyne and other tested C-9 unsaturated hydrocarbons, including a number of dienes, have odor thresholds of about 10 ppm. The hydrocarbons 1-hexyne, 1-nonyne and 1-decyne had odor thresholds of 0.2, 5 and 4 ppm, respectively. INTRODUCTI ONWhen it comes to taste and odor sensations, we are all distinct individualists. Only through experience with food and our environment do we gain and acquire a knowledge of taste and smell. The classification of flavor is strictly a descriptive terminology based on an individual's perception and memory. Most individuals have acute odor perception, as well as the ability to identify different aromas. Offflavors in bland foods, for example, are often described in terms of distinctive odors rather than distinctive tastes. Descriptive terminology characterizing off-flavored fats as cardboardy, trainy, painty, skunky and rubbery illustrates the reliance on odor memory. Although odor perception has generally been regarded as being more sensitive than taste, we and others (1,2) found that when simple odorous compounds are added to fats, the taste threshold is equal to or greater than the individual's odor perception.The contribution of saturated and unsaturated aldehydes to off-flavor characteristics of fats has been well established by many investigators (3-6). Badings (7) in his review in 1960 states that ketones are unimportant in their contribution to oxidation off-flavors. Later, Evans (8), discussing autoxidation of fats, indicated that many volatile corn-1presented ...