The superior efficiency of capillary columns is desirable for the gas chromatographic analysis of complex mixtures of fatty acids, but there have been some reservations regarding quantitation and reproducibility. This paper discusses the use of wall‐coated glass capillary columns in a semiautomated system for the determination of food fatty acids. Glass columns coated with SP2340 were used for extended periods at temperatures up to 200 C without appreciable deterioration. Up to 1900 samples were analyzed on a single column over an 11‐month period, with only minor changes in retention ratios, response factors and column efficiency. Quantitative precision of results, calculated either as normalized weight percentage or as absolute amounts, based on the use of an internal standard, were typically within 2% relative deviation. Difficulties encountered in obtaining acceptable chromatograms and reproducible data are discussed, and typical analyses of the fatty acids from foods presented.

A number of mono-, di-, and trisaccharides have been separated, identified, and quantitatively determined by a gas chromatographic method applicable to foods and applied specifically to wheat and wheat products. The sugars were extracted by conventional means, then reacted with hydroxylamine hydrochloride to convert reducing sugars to their oximes. The mixture of nonreducing sugars and reducing sugar oximes was silylated to form TMS ethers which were quantitatively determined by gas chromatography on SE-30. A combination of isothermal and programmed oven temperatures was used to separate arabinose, ribose, fructose, galactose, glucose, sucrose, lactose, maltose, and raffinose in a single chromatogram. Evaluations of linearity of response and recovery of standards added to bread were made, and responses to the internal standard inositol determined. The use of the oxime decreased the number of tautomers of some sugars; the procedure used gave a mixture whose tautomeric equilibria were consistent and stable. Data on the sugar content of wheat, wheat flour, bread, and wheat flakes cereal are given.growing awareness of the differences in the nutritional effects of different sugars has created a need for in-

The lipid composition of margarines from stores in selected locations in the U.S. is reported. The lipids determined include the fatty acids, tocopherols and major plant sterols. Data are included for isomeric octadecenoic fatty acids (14 isomers or groups of isomers) and four isomeric octadecadienoic fatty acids common in partially hydrogenated vegetable fats, insofar as these are separable by capillary gas chromatography. Amounts of individual lipids found in vegetable oil margarines, spreads, imitation and diet margarines were: palmitate, 8.49 to 13.17% (normalized weight percent, calculated as triglyceride); stearate, 4.78 to 9.53%; linoleate, 6.06 to 46.39%; linolenate, 0.18 to 3.57%; α‐tocopherol, 0.3 to 24.3 mg/100g; γ‐tocopherol, 3.0 to 55.0 mg/100g; δ‐tocopherol, 0.5 to 18.9 mg/100g; campesterol, 10.6 to 106.3 mg/100g; stigmasterol, 13.1 to 60.9 mg/100g; sitosterol, 42.3 to 412.9 mg/100g. Amounts oftrans‐unsaturated octadecenoic fatty acids in these margarines varied from 10.74 to 30.06%. Small amounts of thetrans,trans, trans,cis andcis,trans isomers of linoleate also are reported.

A method is described for simultaneously determining tocopherols and sterols in fats and oils by quantitative capillary gas chromatography. Samples containing ca. 100 mg of lipid were saponified in capped tubes with aqueous KOH by heating for 8 min at 80 C; the unsaponifiable fraction was extracted with cyclohexane, freed of solvent, derivatized to form the trimethylsilyl ethers of both tocopherols and sterols, and ehromatographed on a 50 m X 0.25 mm glass capillary column coated with Dexsil 400. Most of the individual tocopherols and common sterols were well separated, although interfering peaks were seen in some samples, which for better specificity should ~be subjected to an initial purification. For most samples, however, the simplified sample preparation, without preliminary purification, was adequate when combined with capillary gas chromatography. Recovery, method and gas liquid chromatographic precision, and applications are discussed.

Methods are now available for the determination of all the specific tocopherol forms found in nature. Although the greatest interest centers on alpha‐tocopherol, much information has been gathered on the amounts of individual tocopherols in foods and fats contributing to the human diet. This paper summarizes and discusses the recent literature on the tocopherols in natural, processed and prepared foods. Alpha‐tocopherol, although the most widely distributed, is in many instances not the predominant form. In a number of important tocopherol sources, e.g., soybean oil, much larger amounts of gamma‐tocopherol are found. The levels of tocopherols are variable, but the evidence suggests that the identities of the specific forms are characteristic of the source. In cereal grains the further observation may be made that the related tocol‐tocotrienol pairs tend to be found together. Processing and preparation almost invariably reduce the tocopherol content, sometimes to insignificant levels.

The nutrient composition of fresh pork was studied in samples from 71 carcasses. On separable lean, nutrient composition was determined for 7 raw retail cuts from one side of each of 11 carcasses, and nutrient retention was determined on the 7 matching cuts from the other side that had been cooked by common household methods. Loins from 60 additional carcasses were analyzed to determine whether USDA grades 1,2, and 3 and region of production affected nutrient composition. The data indicated that variation in nutrient composition of pork is more dependent on the retail cut within the carcass than either the grade or the region of production of the carcass. Cooking method significantly affected retention of most of the nutrients analyzed.

A method is described for the analysis of foods for the forms of vitamin E. Detailed procedures are given for extraction, saponification and partial purification by thin layer chromatography. The individual tocopherols (both tocols and tocotrienols) are identified and estimated as their trimethylsilyl ethers by gas liquid chromatography on SE‐30 or Apiezon L at 235 C. Retention ratios are also given for separations on OV‐17. Response factors relative to didecyl pimelate as an internal standard and overall recoveries were determined for α‐tocopherol, β‐tocopherol, γ‐tocopherol, δ‐tocopherol, β‐tocotrienol and α‐tocotrienol. Sample sizes depended on tocopherol content and were usually chosen to contain 3–50 µg of the individual tocopherols. Data for a number of seeds and oils are given. The greatest variety of forms was found in barley, which contains all the forms listed above, plus γ‐tocotrienol.

Results of analytical studies on the composition of l0 selected margarines representative of consumeravailable hard and soft types are presented. Paired hard and soft products from the same manufacturer were chosen where possible. All of the margarines were compared on the basis of total fatty acid composition, polyunsaturated to saturated fatty acid ratios, total trans and the trans content of the monoene and diene fractions, location of the double bond in the monoene isomers, per cent conjugation, distribution of the fatty acids at the 2 position of the triglycerides, tocopherol content, and the ratios of c~-tocopherol to polyunsaturated fatty acids. As expected the soft margarines contained more polyunsaturated fatty acids than their companion hard types, but all soft margarines did not contain more polyunsaturated fatty acids than all of the hard margarines. The one margarine containing safflower oil had the highest polyunsaturated to saturated ratio. Eight of the ten margarines contained more than 15% trans monoene and nine contained less than 5% trans diene. Positional isomers in the monoene fraction were A6 to A12 with the cis A9 isomer predominating. All of the margarines contained less than 1.9% conjugation. The percentage of trans monoene at the 2 position was greater for some margarines than that in the total fatty acid. This was attributed to the preferential placement of polyunsaturated fatty acids at the 2 position in the original vegetable oils. The forms of tocopherol found were characteristic of the original vegetable oils. Ratios of a-tocopherol to PUFA varied from 0.1 to 0.5 mg/g. Determination of the relationship of the amount of tocopherol content to either source or hardness is not possible on the basis of our data.