This study was conducted to examine the relationship of p-anisidine value with headspace volatiles, sensory evaluation, and polymers. Partially hydrogenated soybean frying oil was used to fry shoestring potatoes. The oil was evaluated by p-anisidine value, headspace volatile analysis, sensory evaluation, and polymer analysis. p-Anisidine value was found to be correlated with hexanal (r = 0.81), heptanal (r = 0.66), t-2-hexenal (r = 0.81), t-2-heptenal (r = 0.71), t-2-octenal (r = 0.92), and t,t-2,4-decadienal (r = 0.86) contents. p-Anisidine value was correlated with overall odor intensity (r = 0.82) and correlated with fried food odor (r = 0.53) and burnt odor (r = 0.43). p-Anisidine value and polymers were also correlated (r = 0.84).Paper no. J9010 in JAOCS 76, 945-947 (August 1999).

The frying performance of low-linolenic acid soybean oil from genetically modified soybeans was examined. Partially hydrogenated and unhydrogenated low-linolenic acid soybean oils were compared to two partially hydrogenated soybean frying oils. Frying experiments utilizing shoestring potatoes and fish nuggets were conducted. Frying oil performance was evaluated by measuring free fatty acid content, p-anisidine value, polar compound content, soap value, maximal foam height, polymeric material content, and Lovibond red color. The hydrogenated low-linolenic soybean oil (Hyd-LoLn) consistently had greater (P < 0.05) free fatty acid content and lower p-anisidine values and polymeric material content than did the other oils. Hyd-LoLn generally was not significantly different from the traditional oils for polar content, maximal foam height, and Lovibond red color. The low-linolenic acid soybean oil (LoLn) tended to have lower soap values and Lovibond red color scores than did the other oils. LoLn had consistently higher (P < 0.05) p-anisidine values and polymeric material content than did the other oils, and LoLn generally was not different (P < 0.05) from the traditional oils for polar content, maximal foam height, and free fatty acid.Deep-fat frying is a popular and convenient food preparation method. The high temperature, as well as the incorporation of oxygen and water, during deep-fat frying necessitate the use of a stable frying oil. Traditionally, partially hydrogenated oils have been used for frying purposes because hydrogenation increases an oil's resistance to thermal and atmospheric oxidation. However, a side effect of hydrogenation is the formation of positional and geometrical fatty acid isomers. Some studies have indicated that there may be adverse health effects due to dietary trans fatty acid consumption (1-3).A recent alternative or complement to hydrogenation is the use of oils with genetically modified fatty acid composition. High-oleic canola, safflower, and sunflower oils, as well as low-linolenic canola and soybean oils, have been developed (4). Several studies have examined the frying performance of modified oils (5-13). Warner and Mounts (8) compared frying stability of genetically modified, low-linolenic, nonhydrogenated and hydrogenated soybean and canola oils to nonhydrogenated, traditional soybean and canola oils. The modified oils had less room odor intensity; lower free fatty acid contents, polar compounds, and foam heights; fewer undesirable odors; and better food quality than the traditional oils after 5 h of frying. Mounts et al. (9) compared three lines of lowlinolenic acid soybean oil (LoLn) and traditional unhydrogenated soybean oil. However, most soybean oils used for frying purposes were partially hydrogenated. Lowering the linoleic acid content of soybean oil by breeding was beneficial for improved oil quality during cooking and frying. The flavor quality of fried food was enhanced with these oils. LoLn soybean oils were compared to traditionally unhydrogenated and partially hydrog...