Refined, unhydrogenated soybean oil and edible beef tallow were interesterified with sodium methoxide. This was done as an alternative to hydrogenation for the production of plastic fats for use as margarine oils. Using 0.5% sodium methoxide at 80 C, interesterification was complete in 30 min as determined by lipase hydrolysis. A blend of 60% soybean oil and 40% edible beef tallow was found to have physical characteristics (melting point, solid fat index) similar to those of commercial tub margarine oils. The level of polyunsaturated fatty acids was slightly lower and the level of saturated fatty acids slightly higher than the commercial margarine oils. Iodine value and trans fatty acid determinations indicated no discernible effect on the degree of unsaturation or the level of isomeric fatty acids by the interesterification process. The interesterified blend did contain 3.0% trams fatty acids which were originally present in the tallow. Oxidative stability of the interesterified oils was estimated by peroxide value determinations over several days on samples stored at 60 C. Experimental blends treated with 0.1% citric acid had poorer stability than the partially hydrogenated margarine oils; however, 0.01% BHA significantly delayed oxidation of the experimental samples.

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Interfacial tension (IFT) between fat and water was measured as a means of evaluating fats used for frying. The Du Noi.iy ring method was used with a tensiometer to obtain IFL The IFT of donut frying fats, which were diluted 1:1 with unused fat, decreased with increasing frying time from 21 mN/m in unused fat to 5 mN/m in fat at the point of discard. To determine which individual chemical components in donut frying fat are responsible for the decreased IFT, various surfactants were added. The addition of surfactants to the water phase (phosphatidylcholine, sodium oleate, and sodium chloride) or oil phase (monoacylglycerols, diacylglycerols, and fatty acids) had varying effects on the IFT of soybean oil against water at 25 + 0.1 °C. The IFT decreased with increasing concentration of monoacylglycerols, sodium oleate, phosphatidylcholine, and sodium chloride. Sodium oleate was the most effective agent in lowering IFT, reducing it almost to zero at a concentration of 0.1%. At a concentration of 0.2%, monoacylglycerols lowered IFT of fresh soybean oil by 14% (monolinolein), 22% (monoolein), and 26% (monostearin). Egg lecithin lowered the IFT by 42%. These surfactants changed the IFT of fresh soybean oil by their adsorption at the oil/water interface. Although sodium chloride is not a surfactant per se, it lowered IFT by salting out surfactants from the aqueous phase onto the interface. The addition of diacylglycerols or fatty acids had virtually no effect on IFT. JAOCS 72, 951-955 (1995).

Phospholipids of crude and degummed soybean oils were isolated and separated by column chromatography and thin layer chromatography. Standards and specific spray reagents were used to identify the phospholipids. Phospholipids identified in the crude and degummed oils were phosphatidylcholine, phosphatidylethanolamine, phosphatidylinositol, phosphatidic acid, lysophosphatidylcholine and lysophosphatidylethanolamine. Several unknown phosphorus‐containing compounds were present. Samples of crude and degummed oil were collected from four soybean oil processors over four consecutive days. Total and individual phospholipids were quantitated by determining the phosphorus content. The total phosphorus content of crude oil varied among companies, with the average ranging from 453 to 676 ppm. The average total phosphorus content of the degummed oil of the four processors ranged from 12 to 84 ppm. Processors removed an average of 86‐98% of the phosphorus present in the crude oil during the degumming process. There was also a daily variation in phosphorus removal within the individual companies. During the degumming process, the proportion of phosphatidylcholine decreased and the proportion of unknown, nonpolar phosphorus compounds increased in samples from all companies. Significantly higher proportions of phosphatidic acid and lyso compounds were found in the degummed oil of some but not all companies.

Single‐strength orange juice was exposed to 0, 0.89, 2.24, 4.23 and 8.71 kGy gamma radiation at 5C, and then stored at 23C for 6 days and 7C for 21 days. Conversion of ascorbic acid (AA) to dehydroascorbic acid (DHA), and loss of AA, total AA (TAA = AA plus DHA) and total antioxidants increased with radiation dose. Rate of TAA loss due to irradiation was much less than that of AA loss. Compared to nonirradiated juice (0 kGy), juice irradiated at 2.24 kGy or less had similar rates of AA and TAA loss during storage while juice irradiated at 4.23 and 8.71 kGy had higher rates of AA and TAA loss. Loss of total antioxidants in irradiated orange juice appeared to result from loss of AA.