Sunflower and safflower seeds and oils

Summary Chemical analyses of sunflower and safflower seeds, the hulled seed, and the hulls and oils have been made. The 28 samples of sunflower seed, representing four varieties grown at seven locations, contained an average of 29% oil which was composed chiefly (51 to 68%) of linoleic acid glycerides. The eight varieties of safflower seeds grown at Huntley, Montana, contained an average of 33% oil, with an average content of 78% linoleic glycerides. Data on the amounts of ash, nitrogen, sugar, as well as oil, are presented for the whole seeds and their fractions. Paper presented at the 19th fall meeting of the American Oil Chemists’ Society, Chicago, Nov. 7–9, 1945. This is one of the laboratories of the Bureau of Agricultural and Industrial Chemistry, Agricultural Research Administration, U. S. Department of Agriculture.     

The pigments of crude cottonseed oils. I. The inhibition of color reversion in crude cottonseed oils

Summary Treatment of freshly prepared crude cottonseed oils withp-aminobenzoic acid and subsequent removal of the di-p-carboxyanilinogossypol formed makes it possible to store the oils at a relatively high temperature (37–38°C.) and for an extended period of time (30 days) without incurring any adverse changes in the refining and bleaching properties of the oils. In addition, a considerable decrease in the refining loss of the crude oil is obtained, and the stability of the bleached oil is not affected by the treatment. Spectrophotometric studies made during all phases of the chemical treatment and during the refining and bleaching procedures show that thep-aminobenzoic acid removes almost completely the gossypol-like pigments which are present in the crude oils and yields oils having the characteristic carotenoid spectrum. One of the laboratories of the Southern Utilization Research Branch, Agricultural Research Service, U. S. Department of Agriculture.     

A quantitative evaluation of a color problem in safflower oils

The dark color occasionally found in crude solvent-extracted oils from a new high-yield brown striped safflower variety originates from colorless precursors in the kernel and precursors in the hull. The precursors from the hull and the pigments formed upon heating from hull and kernel precursors are only partially removed by refining and bleaching if they are present in substantial amounts. The pigment precursors extracted from the kernels are completely removed by precipitation with water or refining. Although substantially more hull and kernel precursors are found in oil from the brown striped safflower variety, the oil can be produced in a spectrographic quality comparable to that of commercial oil if the crude extracted oil is not heated above 100 C, and if extracted and press oils are jointly refined.     

The formation of oxo- and hydroxy-fatty acids in heated fats and oils

A fast-food fat (mostly tallow), olive oil and safflower oil were heated in air for 4 d and periodically analyzed for oxofatty acids (OFA), monohydroxy-fatty acids (HFA) and polyhydroxy-fatty acids (PHFA). After transmethylation, the OFA were estimated as 2,4-dinitrophenylhydrazones, and the HFA and PHFA were quantitated as pyruvic acid 2,6-dinitrophenylhydrazone esters. At least half of the maximum concentration attained for OFA, HFA and PHFA was generated between 16–24 h of heating of each oil. Safflower oil contained greater concentrations of HFA and PHFA than either olive oil or the fast-food fat. The fastfood fat sample contained a greater concentration of OFA than did the other oils. The sum of the concentrations of OFA, HFA and PHFA at the time of maximum formation in the oils was approximately 260 μmoles/g at 48–72 h for safflower, 200 μmoles/g at 48–72 h for olive and 170 μmoles/g at 72 h for the fast-food fat. Presented at the 79th Annual AOCS Meeting, Phoenix, Arizona, May 8–12, 1988.     

Impacts of roasting oily seeds and nuts on their extracted oils

During industrial processing of seeds and nuts to produce edible oils, roasting is often applied before oil extraction. Moreover, seeds and nuts are generally consumed as snack food after appropriate roasting. These processes affect both the seeds and their extracted oils in many ways. Beside changes in macronutrients such as protein denaturation/degradation, oil oxidation, sugar pyrolysis and Maillard reactions, minor constituents such as fatty acids, sterols, phenolic compounds and tocols are also affected by roasting. On the other hand, studies have shown that antioxidant capacity of the roasted seeds and oxidative stability of the extracted oil could be greater than that of the unroasted counterpart. These improvements are attributed to the formation of Maillard reaction products, inactivation of oil degrading enzymes and facilitation of phytochemical extraction as a result of roasting.     

Fatty acid composition of oils extracted from Canadian weed seeds

The fatty acid composition of the diethyl ether extract from nine varieties of Canadian weed seeds is reported. Fatty acid compositions forRumex pseudonatronatus L. Borbus,Setaria viridis L. Beauv., andChenopodium album L. have not been previously reported. Contribution no. 358, Grain Research Laboratory, Canadian Grain Commission.     

FTIR estimation of free fatty acid content in crude oils extracted from damaged soybeans

A user-interactive computer-assisted Fourier transform infrared (FTIR) method has been developed for estimation of free fatty acids (FFA) in vegetable oil samples by deconvolution of the infrared (IR) absorbances corresponding to the triglyceride ester and FFA carbonyl bonds. Peak areas were used to determine FFA as a percentage of the total carbonyl areas in weighed standards of refined, bleached, deodorized soybean oil containing from 0 to 5% added oleic acid. These data for percent FFA by FTIR were compared to corresponding FFA data obtained by two titration methods-the AOCS Official Method Ca 5a-40 and the Official Method with a slight modification. Correlation coefficients were 0.999 for the Ca 5a-40, 0.999 for the modified and 0.989 for the FTIR methods. FFA in samples of crude soybean oils extracted from damaged beans (0.5 to 2.1% FFA) were measured by FTIR and compared to data obtained by titration of the same samples (correlation coefficient, 0.869). To whom correspondence should be addressed at National Center for Agricultural Utilization Research, Agriculture Research Service, U.S. Department of Agriculture, 1815 North University Street, Peoria, IL 61604. ¹The mention of firm names or trade products does not imply that they are endorsed or recommended by the U.S. Department of Agriculture over other firms or similar products not mentioned.     

Polymerization of safflower and rapeseed oils

Rates of polymerization of oils from 2 safflower and 2 rapeseed varieties were measured in the air and under vacuum. Thermal polymerization rates showed a stronger dependence on the degree of unsaturation than on oxidative polymerization. Molecular weight distributions of polymerized oils were determined by size exclusion chromatography, and the relationship between viscosity and weight-average molecular weight was determined.     

On the mechanisms of cyclic and bicyclic fatty acid monomer formation in heated edible oils

Using recent literature data reporting definite chemical structures for cyclic fatty acid monomers (CFAM), we present new insights into cyclization and rearrangement mechanisms that may be involved in the formation of CFAM and their further transformation into bicyclic fatty acid monomers (BFAM) during the frying process. The existence of structural similarities between CFAM and the unsaturated fatty acids from which they were formed, and between structurally related BFAM and CFAM, led us to examine various possible concerted reactions and thermal rearrangements. These structural similarities as well as the limited number of isomers formed provide evidence for concerted routes that are concordant with all identified structures formed from oleic, linoleic and linolenic acids. The proposed reaction pathways account for the presence of BFAM as well as their most probable structures.     

The effect of oxygen concentration on oxidative deterioration in heated high-oleic safflower oil

High-oleic safflower oil was heated at 180°C in atmospheres with four levels of oxygen concentration (2, 4, 10, and 20%) modified with nitrogen gas, to assess the effects of atmospheric oxygen concentration on the oxidative deterioration of deep-frying oils. Acid value, carbonyl value, polar materials, linoleic acid, tocopherol contents, and oxidative stability were measured to evaluate the quality of heated oils. These values were found to be correlated with both heating time and oxygen concentration. Acid and carbonyl values and polar material content of oils heated at oxygen concentrations of 2 and 4% were lower than those at 10 or 20%. On the other hand, linoleic acid and tocopherols were hardly reduced in oils after heating for 30 h at 2% O₂, whereas they were decomposed according to the oxygen concentration and heating time. Oxidative stability was well maintained in oils heated at 2 and 4% O₂. These results suggest that the oxidative deterioration of heated higholeic safflower oil depends on oxygen concentration.     

Oxidative stability of high oleic sunflower and safflower oils

High oleic sunflower seed progenies derived from normal seed by chemical mutagenesis were extracted and their oils refined by standard laboratory procedures. Oxidative stability was related directly to linoleic acid content with an AOM value of 100 hr obtained at 1% linoleate. Data is presented comparing linoleate concentration and oxidative stability of oils obtained from normal sunflower seed and high linoleic (normal) and high oleic (naturally induced mutations) varieties of safflower seed.     

Fat content and fatty acid composition of oils extracted from selected wild-gathered tropical plant seeds from Nigeria

As the search for alternative sources of food to alleviate hunger continues, this study was undertaken to determine the fat content and the fatty acid composition of 15 lesser-known wild tropical seeds gathered in Nigeria. Results were contrasted with five tropical soybean varieties (Glycine max). The fat content varies from less than 1% (Pterocarpus santalinoides, Daniellia ogea) to 59% (Entandrophragma angolense). The fatty acid composition of most of the wild and mostly leguminous seeds differed considerably, compared to the composition of tropical soybeans. The oil of Adansonia digitata, Prosopis africana, Afzelia lebbeck, Enterolobium cyclocarpium, and Sesbania pachycarpa contained high proportions of linoleic and oleic acid as well as palmitic and linolenic acid. Seeds of Milletia thonningii, Lonchocarpus sericeus, and S. pachycarpa were much higher in linolenic acid and relatively poor in linoleic acid, compared to soybeans. The content of saturated fatty acids was higher than that of soybeans, resulting in lower polyunsaturated/saturated (P/S) ratios (0.83–2.12) than observed in soybeans (P/S=3.4), with the exception of the composition of S. pachycarpa (P/S=3.15). Some of these less familiar wild seeds could be used as sources for industrial or edible oils, provided that possible toxic constituents could be removed.     

The color and spectral transmittance of vegetable oils

A SPECTROPHOTOMETRIC analysis of 125 vegetable oils, 111 of which are from the cotton seed, has been made as a rational physical basis for the discussion and development of improved methods for the color grading of oils. The lightness and chromaticity of all the oils, and their spectral transmittance from 440 to 720 mμ, are indicated in tabular form. Consideration is given to some difficulties inherent in the color grading problem, arising chiefly from the independent variation of the concentrations of several different pigments present in the oils. Color grading in terms of the Lovibond glass standards is discussed along with other abridged methods of colorimetry suggested by the data. A Paper Presented at the 26th Annual Meeting of the American Oil Chemists’ Society, at Memphis, May 23–24, 1935     

Determination of monoglycerides in crude oils and fats

The periodate oxidation method was adapted for the determination of small amounts of monolycerides present in natural oils and fats. The modification consisted in enriching the monoglycerides by extraction with 90% acetic acid saturated with boric acid in order to eliminate interfering substances prior to the reaction with periodate. A multifold concentration of monoglycerides originally present was achieved. This reduced the error of the standard periodate method to a minimum. Crude oils, such as soybean, rice bran, coconut, and palm, analyzed by the modified method showed monoglyceride contents considerably lower than those obtained by direct reaction of periodate with these oils.     

Production of free fatty acids in safflower seeds by fungi

In 1975, free fatty acids (FFA) reached 0.50% in hand-sampled seeds (achenes) from the Sacramento Valley but never exceeded 0.10% in samples from the San Joaquin Valley. High levels of FFA in safflower seeds from the Sacramento Valley were attributed to seed-borne fungi, especiallyAlternaria sp., having a lipolytic action on safflower oil. Greenhouse inoculations on representative safflower cultivars reduced yields and oil content while increasing FFA. In vitro experiments using safflower oil-potato dextrose agar medium showed that theAlternaria species and four other fungi isolated from safflower had lipolytic activity. TheAlternaria sp. produced 3.90% FFA after 20 days of growth on this medium. Separation of the FFA by thin layer chromatography and characterization by gas liquid chromatography indicated that fatty acids are released by all five fungi in proportions similar to those in safflower oil. Presented in part at the AOCS Meeting, New York, May 1977.     

Phosphatides isolated from seeds of commercial and experimental safflower varieties

Studies on phosphatides from several safflower varieties show the following five major results. The total phosphatide contents of the various safflower seeds are quite similar (0.48% for a commercial and 0.58% for a brown-striped variety). The same three major and one minor phosphatides were present in all varieties: phosphatidyl choline (PC), phosphatidyl ethanolamine (PE), phosphatidyl inositol (PI) and phosphatidyl serine (PS). The amounts of these lipids present in the crude phosphatide mixture were quite similar in all varieties tested (}36% for PC, }15% for PE, }23% for PI, and less than 2% for PS). The fatty acid composition of the phosphatides of UC-1 high oleic safflower is very different from that of the other varieties, but it reflects the composition of the corresponding oil triglycerides as far as the major acid is concerned. All other safflower seed phosphatides investigated have linoleic acid as the major fatty acid constituent. A simple and very sensitive color test has been found which can differentiate phosphatides of the high linoleic from the high oleic type. W. Utiliz. Res. Dev. Div., ARS, USDA.