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Applications of sunflower oil in food manufacture
Abstract
Greater than 90 % of commercial oils and fats used for human consumption are plant-derived vegetable oils. The predominant vegetable oils in commerce can be divided into three types based on carbon chain length- lauric, palmitic and oleic oils. Oleic oils predominantly contain 18-carbon fatty acids, stearic, oleic, linoleic and linolenic acids. The soybean, cottonseed, canola, corn, peanut and sunflower oils belong in this category. Sunflower production has increased during the last 25 years mainly because of the high content of linoleic acid that is considered nutritionally positive (essential fatty acid). Commercially available sunflower varieties contain from 39 to 49% oil in the seed. Sunflower oil is generally considered a premium oil because of its light color, high level of unsaturated fatty acids and lack of linolenic acid, bland flavor and high smoke points. The primary use is as a salad and cooking oil or in margarine. In the USA, sunflower oils account for 8% or less of these markets, but in many sunflower-producing countries, sunflower is the preferred and the most commonly used oil. The fatty acid composition of sunflower oil is determined by plant variety and genetics. In a given variety the fatty acid composition changes a little, due to geography and environmental factors. The traditional sunflower oil has a fatty acid composition given in average weight percent as follows: 7 % of C16:0, 5% of C18:0, 19% of oleic, 68% of linoleic, and 1% of C18:3. Relatively recent developments in biotechnology and plant breeding make it possible to develop new genetic varieties, which yield oils with different fatty acid composition than traditional oils. Species of sunflower that possess oil rich in oleic acid exist since 1985. These types contain > 80% oleic acid. High oleic sunflower has higher oxidated stability than conventional oil. It has expanded the application of sunflower oils for frying purposes, tends to enhance shelf life of snacks, and could be used as an ingredient of infant formulas requiring stability. More recently, in 2006, new types of sunflower with such an amount of saturated fatty acids that hardening is no longer necessary or that may be fractionated to obtain a stearin fraction were developed by plant breeding. These oils contain more stearic acid in a high-oleic background, 21% stearic and 62% oleic contents, or less stearic acid, 13% stearic acid content in high-oleic background. This variety will found many applications in food products, such as spreads, sauces, ice-cream, soups, bakery products, and confectionery products.
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Oil quality in vegetable oils is a relative concept that depends on the enduse of the oil. Vegetable oils are intended for food applications (salads and cooking oils, margarines, shortenings, etc) and nonfood industrial applications (biodiesel, lubricants, surfactants, etc). Sunflower (Helianthus annuus L.) oil has been traditionally appreciated in the world oil market. However, new emerging markets are demanding changes In oil quality for both food and nonfood applications. Nutritional and functional properties determining oil quality are primarily determined by the fatty acid composition of oil and the total content and composition of natural antioxidants, especially tocopherols. During the last 30 years these components have been extensively modified in sunflower through conventional selection from naturally occurring variation and trough mutagenesis. As a result, together with the standard sunflower oil whose fatty acid profile is made up of 11% saturated fatty acids, 20% oleic acid, and 69% linoleic acid, there is currently available a vast diversity of other sunflower oil types, for example low saturated (<7%), high palmitic (>25%), high stearic (>25%), high oleic (>85%), high linoleic (>75%) as well as a number of oils with intermediate levels and combinations among them. Similarly, the standard sunflower oil with 95% of the tocopherols in the alpha-tocopherol form has been modified to produce oils with high levels of betatocopherol (>75%), gamma-tocopherol (>95%), and delta-tocopherol (>65%). The novel fatty acid and tocopherol traits are in all cases governed by a reduced number of genes, which facilitates considerably their management in plant breeding programs aimed at developing cultivars with Improved oil quality.
Lard and high-oleic sunflower oil (Trisun® Extra) were interesterified at 55°C for 24 h with SP435 lipase from Candida antarctica to produce plastic fats. As the amount of trisun increased, percentage free fatty acid, unsaturated fatty acid/saturated
fatty acid value, oxidizability, and the amount of 18:1 found at the sn-2 position of triglyceride products increased. Differential scanning calorimetry showed that the low-melting components in
the product contained more 18:1 than the high-melting components. A 60:40 (w/w) ratio of lard to trisun had the widest plastic
range (3–26°C). The scaled-up reaction to produce this blend resulted in a product that had 60.1% 18:1 at the sn-2 position compared to 44.9% for the physical blend. The solid fat content of the 60:40 interesterified mixture resembled
soft-type margarine oil.
Phospholipid composition and phosphorus content of several crude and degummed sunflower oils were measured in order to compare
theoretical and experimental factors used to convert phosphorus content to phospholipid content. Differences in phospholipid
content between sunflower oils obtained by different extraction and degumming methods were also considered. From FA and phospholipid
compositions, average theoretical conversion factors of 24.7 and 23.0 were found for crude and degummed sunflower oils, respectively.
The experimental conversion factor for degummed oils was in good agreement with the theoretical value. In contrast, fitted
experimental factors were significantly lower for crude oils. The differences could be attributed to phosphorus from sources
other than phospholipids and to the presence of minor phospholipids not quantified by chromatographic analysis. The relative
phospholipid concentrations of oils depended on the method of extraction and the type of degumming. Solvent-extracted oils
had a higher total phospholipid content, being generally more concentrated in PC and PE. The content of nonhydratable phospholipids
was relatively low; acid or enzymatic degumming removed 40 to 70% of these phospholipids.
Pan-frying is a popular frying method at home and in many restaurants. Pan-frying stabilities of two frying oils with similar
iodine values (IV)—mid-oleic sunflower oil (NuSun oil; IV=103.9) and a commercial canola oil (IV=103.4)—were compared. Each
oil sample was heated as a thin film on a Teflon-coated frying pan at ∼180°C to a target end point of ≥20% polymer. High-performance
size-exclusion chromatography analysis of the mid-oleic sunflower and canola oil samples indicated that the heated samples
contained 20% polymer after approximately 18 and 22 min of heating, respectively. The food oil sensor values increased from
zero to 19.9 for the canola sample and from zero to 19.8 for the mid-oleic sunflower sample after 24 min of heating. The apparent
first-order degradation rate for the mid-oleic sunflower sample was 0.102±0.008 min−1, whereas the rate for the canola sample was 0.092±0.010 min−1. The acid value increased from approximately zero prior to heating to 1.3 for the canola sample and from zero to 1.0 for
the mid-oleic sunflower sample after 24 min of heating. In addition, sensory and volatile analyses of the fried hash browns
obtained from both oils indicated there were no significant differences between the two fried potato samples.
Thermoxidative stability was evaluated in triaclyglycerols (TAG) from the oils of the mutant sunflower lines CAS-3, CAS-4,
and CAS-8 (with a high percentage of stearic acid), CAS-5 (with a high percentage of palmitic acid), all from standard highlinoleic
genetic backgrounds, and the mutant sunflower line CAS-12 (with a high percentage of palmitic acid), from a high-oleic genetic
background. These oils contained unusually high contents of TAG molecular species with one or two saturated fatty acids at
the sn-1,3 positions. Purified total TAG devoid of tocopherols were subjected to controlled thermoxidative treatment at 180°C. Polymerized
TAG were determined at 2-h intervals for 10 h. After this time, total polar compounds, oxidized TAG monomers, TAG dimers,
and TAG oligomers were determined. TAG from highly saturated sunflower oils with levels of linoleic acid similar to those
found in conventional sunflower oils (40–50%) showed enhanced thermal stability. In these TAG, the amount of polar compounds
formed during the thermoxidative treatment was similar to that formed in the high oleic acid line. Excellent results were
obtained for the TAG of the CAS-12 oil, which had the highest thermal stability, producing half the amount of polar compounds
as the conventional line and less than two-thirds that of the high-oleic line.
To improve sunflower (Helianthus annuus L.) oil quality, the pattern of tocopherol and the effect of brief interval of high temperature on tocopherol accumulation during embryo development were investigated. Total tocopherol content increased linearly from 12 to 33 days after anthesis (DAA) and then remained stable until maturity. γ-Tocopherol content reached a maximum on 33 DAA and then decreased. δ-Tocopherol was not detected until 19 DAA. The effect of brief interval of high temperature (⩾35 °C for seven consecutive days) on tocopherol accumulation was studied. The accelerating effect of high temperature on tocopherol accumulation on a dry weight basis was detected, but the reduction of tocopherol yield occurred from 12 to 19 DAA because the embryo dry weight was reduced significantly. However, the embryos exposed to a temperature of 35 °C from 12 to 19 DAA significantly increased the tocopherol yield per embryo, with no effect on the dry matter weight. These results are useful for evaluating the tocopherol content in sunflower oil and may help recognizing high quality of the oil.
The loss of specific molecular species of triacylglycerols from sunflower, high-oleate sunflower and palm oils has been investigated in commercial frying operations and simulated frying experiments. The non-oxidized triacylglycerols were isolated and molecular species separated by silver ion highperformance liquid chromatography. Linoleate-containing species were lost more rapidly than those containing oleate, as expected. However, all species were liable to oxidation and those containing oleate were lost more rapidly than might have been anticipated. It is suggested that oxidation of linoleate is the probable initiation step, but then the reaction can be propagated readily to all unsaturated species.
A method is proposed to assess deterioration of frying fats by measuring polar and nonpolar components separated on a silica gel column. Means for polar components measured in duplicate samples by 19 collaborators ranged from 8.0 ± 0.34 to 25.8 ± 0.90%. Coefficients of variation ranged from 3.5 to 4.9%. The method has been adopted as official first action.
A new TLC method (3M PCT120) to measure the amount of polar compounds in deteriorated frying oil was developed and launched in Europe. In the new method, a specific dye spotted on a thin layer silica gel plate moves up in proportion to the amount of polar compounds in deteriorated frying oil which is used as a developing solvent. To assess the new method, the amounts of polar compounds in five heated oils were measured by the HPLC method, and the traveling distances of the dye were also measured by 3M PCT120. The result showed a fairly close correlation between the traveling distance of the dye and the amount of polar compounds detected by the HPLC method with a correlation coefficient larger than 0.94.
Development of cultivars of sunflower ( Helianthus annuus L.) with increased levels of saturated fatty acids could increase the utility of the oil for specific edible purposes. The primary objective of this research was to induce variability for these traits by using mutagenesis. Four sunflower mutants with altered seed fatty acid compositions have been isolated by screening single M 2 and M 3 seeds from plants obtained from mutagenized seeds utilizing ethyl methanesulfonate, sodium azide, and x‐rays. The mutant lines included CAS‐5, which has an oil with a fivefold increase (252 g kg ⁻¹ ) in palmitic acid (16:0) and the appearance of palmitoleic acid (16:1; 37 g kg ⁻¹ ); and CAS‐3, CAS‐4, and CAS‐8, which have from two to six times (99–260 g kg ⁻¹ ) the stearic acid (18:0) content normally observed in the oil of cultivated sunflower. The dramatic increase in levels of either 16:0 or 18:0 were at the expense of oleic (18:1) and linoleic (18:2) acids. The relative proportion of 18:1 to 18:2 varied with the mutants. All showed variation in fatty acid composition among the seeds of the original plant, which indicated that the fatty acid changes were controlled by the genotype of the embryo. The bimodal distribution in fatty acid composition of CAS‐3 and CAS‐5 seeds suggested that major recessive genes are involved in the control of these characters.
Oil-type sunflower seed hybrids grown in North Dakota were evaluated for yield, seed characteristics and composition. The
study consisted of 74 hybrids grown at Casselton, ND, during 1981. Mean analytical values were: yield (x = 2047 kg/hectare),
seed weight (x = 9.9 g/200 seed), test weight (x = 40.3 kg/hectare), hull (x = 26.7%), embryo (x =73.7%), oil (x = 45.3%),
protein (x = 20.8%), ash (x = 3.5%), lysine (x = 4.5 g/100 g protein) and chlorogenic acid (x = 2.0%). Increasing the lysine
content of hybrid sunflower protein appears to have possibilities for further study. The mean chlorogenic acid content was
slightly lower than levels previously reported.
High oleic acid sunflower oil (HOSO) is a monounsaturated oil that is being extensively used in frying. The level of total altered fatty acids and the fatty acid pattern of a fryer oil was used to evaluate the alteration of a HOSO used 20 times to fry various frozen foods with frequent replenishment (FR) or without replenishment (NR) with fresh oil during the frying. In addition, the levels of total altered fatty acids and the fatty acid composition of the fat extracted from the fried potatoes after numerous fryings were determined and compared to those of the corresponding fryer oils. Altered fatty acids increased linearly through 20 fryings within FR and NR in the frying oil and also in the fat extracted. Although differences were not quantitatively relevant, changes tended to be higher in the extracted fat, and in the NR modality as a consequence of oil renovation and fat exchange between the frying oil and the potatoes. The decrease in the oleic acid content in the oil was more pronounced (p< 0.001) in NR than in FR method, and more (at least p< 0.01) in the oils than in the corresponding extracted fats. Nevertheless, other fatty acids remained quite stable and similar or increased during frying, by both methods. These results suggest that total fatty acid alteration measure is a useful tool for frying assessments, and that they must be related not only to the degradation of unsaturated fatty acids but also to migrations of some fatty acids from the frozen prefried foods to the fryer oil as revealed by composition of the fat extracted from the fried potatoes.
Stereospecific analysis of the triacylglycerol fraction is an important tool for the characterisation of extra-virgin olive oils. The composition in the sn-1, sn-2 and sn-3 positions of triacylglycerols of extra-virgin olive oils produced in years 1992–1994 in areas characterised by increasing environmental severity (groups 1 and 2, respectively) is considered. This analytical method is based on chromatographic techniques, coupled with enzymatic ones. Linear discriminant analysis (LDA) has been applied successively for the differentiation and classification of the two groups for each year according to the positional distribution of fatty acids (palmitic, palmitoleic, stearic, oleic and linoleic acids) in the glycerol backbone. Even though the data were not very numerous, LDA has allowed a partial or total separation of scores along the discriminant eigenvector according to the climatic groups.
High-oleic sunflower seed oils containing varying levels of oleic acid were evaluated in comparison to conventional sunflower and olive oils, under both thermoxidative and frying conditions. Analytical determinations included quantitation of triglyceride species and polar compound level and distribution. Total polar compounds were significantly lower in high-oleic sunflower oils as compared to conventional sunflower oil. This was essentially attributable to oxidized and polymeric compounds. No differences were found between high-oleic sunflower oils and olive oil, which could not be anticipated on the basis of fatty acid composition but might be otherwise related to differences in triglyceride distribution. After drying, oils and lipids extracted from fried potatoes did not differ significantly in polar compounds. Overall, results showed an excellent behavior of high-oleic sunflower oils with regard to thermoxidation and frying.
A field experiment was conducted in the North Western Group of the Gezira Scheme (longitude 32°48′ and latitude 15°14′) for four successive seasons, two winter and two summer seasons, during the years 1999–2002, to study the effect of different irrigation water quantities (300, 400, 500, 600 and 700 mm per season) on oil content and oleic acid and linoleic acid percentages in two sunflower cultivars [Rodeo, an open-pollinated variety, and Hysun33, a hybrid). The experiment was designed in a split plot design, with four replicates. The cultivars were allotted to the sub-plots while the irrigation treatments were assigned to main plots. The results showed that different irrigation water quantities had significant effects on all parameters studied and the cultivar Hysun33 gave a higher oil content (36.6%) at 700 mm whereas the open-pollinated variety Rodeo gave 34.1% oil at that level of irrigation. The overall percentages of oleic and linoleic acids were 29.7 and 58.1 in winter and 47.6 and 43.1 in summer, respectively. Copyright © 2007 Society of Chemical Industry
The fatty acid and triacylglycerol composition of a vegetable oil determine its physical, chemical and nutritional properties. The applications of a specific oil depend mainly on its fatty acid composition and the way in which fatty acids are arranged in the glycerol backbone. Minor components, e. g. tocopherols, also modify oil properties such as thermo-oxidative resistance. Sunflower seed commodity oils predominantly contain linoleic and oleic fatty acids with lower content of palmitic and stearic acids. High-oleic sunflower oil, which can be considered as a commodity oil, has oleic acid up to around 90%. Additionally, new sunflower varieties with different fatty acids and tocopherols compositions have been selected. Due to these modifications sunflower oils possess new properties and are better adapted for direct home consumption, for the food industry, and for non-food applications such as biolubricants and biodiesel production.
The behaviour was studied in cottonseed oil which had been exposed to frying under controlled conditions in a system in which only the oil, water and/or the antioxidant BHT were present. In the oils, changes which had been caused by heating were evaluated through determination of acid, hydroxyl, TBA and iodine values, extinctions at 232 nm and 460 nm, fatty acid composition, viscosity, amounts of “polymers” and non-urea-adduct-forming fatty acid methyl esters. All the changes were less pronounced when the frying was carried out in presence of either nitrogen or water. The latter protected the oil only if it was present in amounts sufficient to generate such a volume of vapours which could effectively act as an inert gas-blanket. BHT had no delaying effect on the deterioration of the oil during frying. When the oil was heated in the presence of air, the antioxidant's destruction was lessened by the presence of water in the system, but a large portion of BHT was lost through steam distillation.
The role of dietary fats and oils in human nutrition is currently one of the key issues related to diet and health. Nutritional fats and oils contain both saturated and unsaturated fatty acids, mostly of cis-configuration. Physiological functions of trans fatty acids in foods, especially their possible role in atherosclerosis, the level of blood cholesterol, and coronary heart disease is of concern, but still subject to controversy. Furthermore, the cancer prevention properties of conjugated linoleic acid isomers, present in small quantities in typical diets, remain to be confirmed. An overview on the occurrence and physiological considerations of trans fatty acids is given.
The fatty acid (FA) composition of oil crops is of some importance under technological as well as under nutritional aspects. The influence of temperature on this parameter in rapeseed, soybeans and sunflowers was investigated under practical agricultural conditions, whereby varietal variations were taken into account. The analysed plant material originated from variety testing trials located in different climatic zones of Austria. As a measure of the climatic conditions of a location, the mean temperature of the last 30 days before harvest was calculated. Despite the low temperature differences between the various locations, moderate but significant negative correlations between temperature and the share of linolenic (18 : 3), respectively, linoleic (18 : 2) acid on the whole quantity of FAs in rapeseed (R² = 0.18–0.42), soybeans (R² = 0.11–0.13) and sunflowers (R² = 0.15) were found. Furthermore, there was a good negative correlation in the case of sunflower seeds between temperature and oil level (R² = 0.45). The environmental influence on the share of polyunsaturated FAs differed between the different species. The results show that quality of vegetable oils is as well a question of environment as of variety.
There are dozens of tests an oil chemist has at his disposal for evaluating fresh and used frying oils. These include chemical tests, instrumental methods, physical methods and rapid tests. Not all are applicable to use when evaluating oils used for deep-fat frying. Rather than run the gamut of all the tests available to the oil chemist or quality control technician, this presentation will focus on the different rapid tests that have been developed for the marketplace. These include physical tests, tests that measure physical parameters of the oil, and chemical tests. Tests may be quite simple or complex. The presenter will provide an overview on the different rapid test methods, but will emphasize that it is up to the researcher or the processor to evaluate for themselves whether the technology is something that they can use in their own operations.
High-oleic high-palmitic sunflower oil (HOHPSO) has been obtained from field-grown mutant sunflower seeds CAS-12. The fatty acid and triacylglycerol compositions, the thermo-oxidative stability and the physical properties of the HOHPSO were determined and compared with those of the conventional and high oleic sunflower oils and those of a liquid fraction of palm oil (olein). The major fatty acids of the HOHPSO were monoenes (57.7% oleic, 7.3% palmitoleic) and palmitic (27, 8%), while the content of linoleic acid was low (2.3%). The saturated fatty acids were almost absent from the sn-2 position and, thus, the major triacylglycerol (TAG) molecular species were those with one or two saturated fatty acids at the sn-1, 3 positions and oleic acid at the sn-2 position (mainly POO and POP). Total polar compounds and their distribution in oxidised TAG monomers and TAG polymers were determined after 10 h at 180 °C. The HOHPSO showed enhanced thermal stability, producing half the amount of total polar compounds, and much less TAG polymers, as the palm olein. The stability index (Rancimat) of the HOHPSO was unusually high (19 h at 120 °C). The thermal properties of the HOHPSO (determined from the differential scanning calorimetry thermograms) were different from those of the palm olein. The HOHPSO presents lower solid fat con-tents than the palm olein above 15 °C and hence remains liquid at common working temperatures.
High-oleic, high-palmitic sunflower oil (HOHPSO) is a seed oil from a new mutant sunflower line characterized by increased
levels of both oleic acid (>50%) and palmitic acid (>25%) and a high oxidative stability. In this study, its performance at
frying temperature was compared with that of palm olein in thermoxidative assays (4 h, 180°C). Also, industrial discontinuous
frying of almonds, peanuts, and sunflower seeds (200 kg of each product) was carried out to define both the performance of
HOHPSO and the main changes undergone by the foods. The evaluation of polar compounds and their distribution in the main groups,
i.e., polymers, oxidized monomers, and DAG, as well as changes in tocopherols and oxidative stability, demonstrated the excellent
behavior of HOHPSO during thermoxidation and frying. The increase in polar compounds and the loss of tocopherols and stability
were much lower for HOHPSO than for palm olein under identical heating conditions. Only 1.3% polar compounds were formed during
industrial discontiuous frying for 4 h and the oil stability increased, probably due to the formation of antioxidant compounds.
As for the foods, the FA composition of the surface oil was clearly different from that corresponding to the internal oil,
the former denoting the presence of HOHPSO in high concentration, particularly in fried sunflower seeds. Changes in oil stability
of the foods attributable to the frying process clearly demonstrate the interest in using a highly stable oil such as HOHPSO
to protect the surface against oxidation during food storage.
The contents of total and individual tocopherols of sunflower oils at different stages of industrial chemical and physical refining processes were determined by high-performance liquid chromatography (HPLC). According to the results, total and individual tocopherol contents gradually decreased until the end of the refining processes. The average losses of total tocopherol content during the chemical and physical refining processes were found to be 30.2% and 35.5%, respectively. The steam distillation stage of the physical refining process caused greatest overall reduction (average 24.6%) in total tocopherol content. In contrast to the physical refining process, the degumming-neutralizing stage in the chemical refining process caused greatest overall reduction (average 14.7%) in total tocopherol content. An additional average loss of 11.0% occurred during deodorizing in the chemical refining process. In both chemical and physical refining, the bleaching stage caused similar effects. The physical refining process caused higher loss in the total and individual tocopherol contents when compared with the chemical refining process. The conditions of the refining processes should be carefully evaluated to reduce the loss of tocopherols.
The fatty acid composition and tocopherol content of sunflower seeds from experimental plantings in Japan were determined.
Lipid content of sunflower seed was almost the same irrespective of the variety and the average lipid content was 38.8%. The
saturated fatty acids were low and the combined percentage of linoleic acid and oleic acid was ca. 90%. The ratio of oleic
acid to linoleic acid largely varied with the planting location and date. There was a strong correlation between the percentage
of linoleic acid or oleic acid and the temperature during maturation of seed. The sunflower seed contained predominantly α-tocopherol
and small amounts ofβ-,γ- and δ-tocopherol. There was no correlation between a-tocopherol content and the percentage of linoleic acid.
The quality of oil extracted from ecologically cultivated olives of the Picual variety was compared with oil extracted from
Picual olives cultivated using conventional methods. Olive trees were grown in a two-section plot. Fruits from each plot were
harvested at various stages of ripeness, and acidity value, peroxide index, ultraviolet absorption at 232 and 270 nm, stability
to oxidation, sensory analysis, fatty composition, and contents of tocopherols, phenolic compounds, and sterols were determined
on oil extracted from each treatment. The results showed that the organic virgin olive oil was of a superior quality to the
conventional virgin olive oil in all the quality parameters analyzed.
The seed lipids from five sunflower mutants, two with high palmitic acid contents, one of them in high oleic background, and
three with high stearic acid contents, have been characterized. All lipid classes of these mutant seeds have increased saturated
fatty acid content although triacylglycerols had the highest levels. The increase in saturated fatty acids was mainly at the
expense of oleic acid while linoleic acid levels remained unchanged. No difference between mutants and standard sunflower
lines used as controls was found in minor fatty acids: linolenic, arachidic, and behenic. In the high-palmitic mutants palmitoleic
acid (16∶1n−7) and some palmitolinoleic acid (16∶2n−7, 16∶2n−4) also appeared. Phosphatidylinositol, the lipid with the highest
palmitic acid content in controls, also had the highest content of palmitic or stearic acids, depending on the mutant type,
suggesting that saturated fatty acids are needed for its physiological function. Positional analysis showed that mutant oils
have very low content of saturated fatty acids in the sn-2 position of triacylglycerols, between the content of olive oil and cocoa butter.
The validity of measurements of polar compounds in used frying oils was investigated. Compared were the reference method, the food oil sensor (FOS), and a newly developed HPLC method. It was shown that the HPLC values correlate better with the reference method than the FOS measurements. The standard deviation of the results obtained by the reference method was three times higher than those of the FOS and the HPLC methods. Because of the better precision and the higher speed, the HPLC approach is considered to be an attractive alternative to the reference method.
A new sunflower mutant, CAS-12, was obtained, which has both high palmitic (≈30%) and high oleic acid contents, and also a
substantial amount of palmitoleic acid (≈7%). The mutant was selected after X-ray irradiation of dry seeds of the inbred line
BSD-2-423, which had normal palmitic (≈3%) and high oleic (≈88%) acid levels. The increase of palmitic and palmitoleic acids
occurred at the expense of the oleic acid content, which decreased to around 55% in respect to the original line. Linoleic
acid content is always under 5%. Palmitic and palmitoleic acid levels were similar to those of the high palmitic mutant CAS-5
obtained in a previous programme from a low oleic line isogenic to BSD-2-423 using a similar mutagenic treatment. In that
previous programme we also selected three high stearic acid mutants using chemical mutagenic treatment on the same sunflower
line (RDF-1-532). We attempted to obtain mutants in other lines but were unsuccessful. The isolation of similar mutants in
isogenic parental lines illustrates the importance of the genetic background in the development of specific mutants with an
altered seed oil fatty acid composition. The oil of this mutant will increase the range of potential uses of sunflower oil.
A method for the stereospecific analysis of triacyl-sn-glycerols by high-performance liquid chromatography (HPLC) on a chiral column is described. Triacyl-sn-glycerols were partially degraded with ethyl magnesium bromide, and the monoacylglycerols produced were separated as 1- and
2-monoacylglycerol fractions by thin-layer chromatography on boric acid-impregnated silica gel plates. The 1-monoacylglycerols
were resolved intosn-1 andsn-3 monoacylglycerol fractions by HPLC on a chiral column (Sumichiral OA-4100) after derivatization with 3,5-dinitrophenyl
isocyanate. Fatty acid methyl esters obtained from the original triacyl-sn-glycerols, 1- and 2-monoacylglycerol fractions, andsn-1 andsn-3 monoacylglycerol fractions were analyzed by gas chromatography on open-tubular columns. Stereospecific acyl distributions
in triacyl-sn-glycerols were calculated from the data. The acyl distributions of several oils were obtained. The method is rapid, simple
and gave reproducible results.
Plantings of sunflower,Heliantbus annuus L., were made 5 times between Feb. 2 and Nov. 15 in Florida so that the effect of planting date on the fatty acid composition
of sunflower oil might be assessed. Eleven popular hybrids were planted at Gainesville, FL, on Feb. 2 and 28, April 2, and
Aug. 14, and 15 hybrids were planted at Lake Worth, FL, on Nov. 15. Sunflower planted on Nov. 15 would be subjected to freezing
temperatures if grown in Gainesville. Yields of sunflower achenes for the four planting dates at Gainesville declined with
lateness of planting date. Oleic acid content of the oil (17.6–58.4%) was intermediate for the February plantings, highest
for the April planting, and lowest for the late plantings. The linoleic acid content (32.5–71.0%) varied inversely with the
oleic acid content. Because sunflower oil is needed for different purposes, such as for salad oil, for deep frying and for
making margarines, oil low in linoleic acid (high in oleic acid) as well as oil high in linoleic acid (low in oleic acid)
are needed. In Florida, adjusting the planting dates should result in the production of oil of the desired fatty acid composition.
The compositions of positionssn-1,sn-2 andsn-3 of triacylglycerols from “extra-virgin” olive oil (Olea europaea) were determined. The procedure involved preparation of diacyl-rac-glycerols by partial hydrolysis with ethyl magnesium bromide; 1,3-, 1,2- and 2,3-diacyl-sn-glycerols as (S)-(+)-1-(1-naphthyl)ethyl urethanes were isolated by highperformance liquid chromatography (HPLC) on silica, and their fatty
acid compositions were determined. The same procedure was also carried out on the five main triacylglycerol fractions of olive
oil after separation according to the degree of unsaturation by HPLC in the silver ion mode. Although stereospecific analysis
of the intact triacyl-sn-glycerols indicated that the compositions of positionssn-1 andsn-3 were similar, the analyses of the molecular species demonstrated marked asymmetry. The data indicate that the “1-random,
2-random, 3-random” distribution theory is not always applicable to vegetable oils.
Changes in composition were examined in oils extracted from genetically modified sunflower and soybean seeds. Improvements
were made to the analytical methods to accomplish these analyses successfully. Triacylglycerols (TAG) were separated on two
300 mm × 3.9 mm 4µ Novapak C18 high-performance liquid chromatography (HPLC) columns and detected with a Varex MKIII evaporative
light-scattering detector. Peaks were identified by coelution with known standards or by determining fatty acid composition
of eluted TAG by capillary gas chromatography (GC). Stereospecific analysis (fatty acid position) was accomplished by partially
hydrolyzing TAG with ethyl magnesium bromide and immediately derivatizing the resulting diacylglycerols (DAG) with (S)-(+)-1-(1-naphthyl)ethyl isocyanate. The derivatized sn-1,2-DAG were completely resolved from the sn-2,3-DAG on two 25 mm × 4.6 mm 3 µ silica HPLC columns. The columns were chilled to −20°C to obtain baseline resolution of
collected peaks. The distribution of fatty acids on each position of the glycerol backbone was derived from the fatty acid
compositions of the two DAG groups and the unhydrolyzed oil. Results for the sn-2 position were verified by hydrolyzing oils with porcine pancreatic lipase, isolating the resulting sn-2 monoacylglycerols by TLC, and determining the fatty acid compositions by GC. Results demonstrated that alterations in the
total fatty acid composition of these seed oils are determined by the concentration of TAG species that contain at least one
of the modified acyl groups. As expected, no differences were found in TAG with fatty acid quantities unaffected by the specific
mutation. In lieu of direct metabolic or enzymatic assay evidence, the authors’ positional data are nevertheless consistent
with TAG biosynthesis in these lines being driven by the mass action of available acyl groups and not by altered specificity
of the acyltransferases, the compounds responsible for incorporating fatty acids into TAG.
The aim of the present study was to highlight the main differences between seed oils produced from conventionally cultivated
crops and organically cultivated ones and processed using mild extraction procedures. The composition and the nutritional
and health aspects of both types of sunflower seed oils were compared and were analytically tested to determine the macroscopic
differences in proximate composition, the main differences in the minor components, the main quality parameters, the in vitro antioxidant activity, and the presence of trans-ethylene steroisomers in FA. No significant trends were found in the oil samples for TAG and FA composition, but remarkable
differences were found in the composition of minor components and in the main chemical and analytical quality properties.
The organically grown samples had a higher total antioxidant activity compared with the conventional samples. Trans FA were found only in the conventional oils.
Tocopherols are natural antioxidants that increase the stability of fat-containing foods and perform important biological
activities. Significant variations (389 to 1873 μg g oil−1) in the total tocopherol concentration of sunflower seed oil have been reported. The main objectives of this work were to
determine the influence of intercepted photosynthetically active radiation on tocopherol concentration during seed filling
and to establish and validate relationships between tocopherol concentration in oil and other quality variables of the seed.
Seven sunflower hybrids were grown under good water and nutritional conditions in two similar experiments carried out in two
contrasting environments. Treatments were applied to modify the amount of radiation intercepted per plant during seed filling
in order to obtain a range in oil yield per plant and its components. Greater per plant intercepted radiation decreased the
tocopherol concentration in oil. Tocopherol concentration decreased when oil weight per seed increased. Tocopherol concentration
stabilized for oil weight per seed higher than 23 mg oil seed−1. This exponential relationship accounted for 73% of the variability in tocopherol concentration (507 to 1203 μg g oil−1) despite differences in hull type, locations, hybrids, and radiation treatments. The proposed relationship acceptably predicted
independent results. Crop management techniques could lead to seeds with greater concentrations of tocopherols.
A sunflower mutant, CAS-3, with about 25% stearic acid (C18:0) in the seed oil was recently isolated after a chemical-mutagen treatment of RDF-1-532 seeds (8% C18:0). To study the inheritance of the high C18:0 content, CAS-3 was reciprocally crossed to RDF-1-532 and HA-89 (5% C18:0). Significant reciprocal-cross differences were found in one of the two crosses, indicating possible maternal effects. In the CAS-3 and RDF-1-532 crosses, the segregation patterns of the F(1), BC(1), and F(2) populations fitted a one-locus (designated Es1) model with two alleles (Es1, es1) and with partial dominance of low over high C18:0 content. Segregation patterns in the CAS-3 and HA-89 crosses indicated the presence of a second independent locus (designated Es2) with two alleles (Es2, es2), also with partial dominance of low over high C18:0 content. From these results, the proposed genotypes (C18:0 content) of each parent were as follows: CAS-3 (25.0% C18:0) =es1es1es2es2; RDF-1-532 (8.0% C18:0) =Es1Es1es2es2; and HA-89 (4.6% C18:0) =Es1Es1Es2Es2. The relationship between the proposed genotypes and their C18:0 content indicates that the Es1 locus has a greater effect on the C18:0 content than the Es2 locus. Apparently, the mutagenic treatment caused a mutation of Es1 to es1 in RDF-1-532.
The relationships between crude and refined oils are examined by quantitation of minor glyceridic compounds, namely, oxidized triglyceride monomers, dimers and diglycerides, associated with oil quality. Particularly, two groups of compounds, i.e. oxidized triglyceride monomers and diglycerides, are of especial interest as they are indicative of oxidative and hydrolytic alterations, respectively. Olive, sunflower and soybean oils differing in initial quality, as evaluated by classical indices and levels of undesirable minor compounds, were subjected to physical and alkali refining in a laboratory system. In all assays, results indicated that amounts of oxidized triglyceride monomers and diglycerides in refined oils remained close to those found in the starting crude oils. Triglyceride dimers were the only group of compounds showing a significant increase, which was dependent on fatty acid composition and initial quality of crude oils. The main conclusion is that quantitation of minor glyceridic compounds in refined oils not only offers a new possibility for quality evalution but also allows the crude oils to be characterised by the presence of markers of oxidative and hydrolytic alterations.
Lipase-catalyzed interesterification of high oleic sunflower oil (HO) and fully hydrogenated soybean oil (FHSBO) at different weight ratios (55:45, 60:40, 65:35 and 70:30, HO:FHSBO) was carried out in both a batch-type reactor (BA) and a packed-bed reactor (PBR) to produce zero trans shortening. Interesterified products in both PBR and BA consisted of 34–46 g/100 g saturated fatty acids (SFA) (mainly stearic acid) and 54–66 g/100 g unsaturated fatty acid (USFA) (mainly oleic acid). After interesterification the physical characteristics such as melting point and solid fat content (SFC) were changed in each product. The differential scanning calorimetry (DSC) result showed that SFC content in PBR was higher than that in BA at each measured temperature. Decrease in tocopherols was also observed, however, the PBR product contained much higher amounts of tocopherols than BA product.
The oxidative and thermal stabilities of genetically modified high oleic sunflower oil (87% oleic acid) were compared with those of regular sunflower (17% oleic acid), soybean, corn, and peanut oils during storage at 55 °C and simulated deep fat frying at 185 °C. Oxidative stability was evaluated by measuring the oxygen content and volatile compounds in the sample bottle headspace and peroxide value. The coefficient variations (CVs) for volatile compound, headspace oxygen, and peroxide value analyses were 2.02%, 1.41%, and 3.18%, respectively. The oxidative stability of high oleic sunflower oil was greater than those of regular sunflower and soybean oil (P < 0.05) and as good as those of corn and peanut oils (P > 0.05). The thermal stabilities of oils during deep fat frying were evaluated by measuring the infrared absorption at 2.9 μm and conjugated diene content. The CV of conjugated diene content was 1.07%. Infrared and conjugated diene results showed that the high oleic sunflower oil had greater thermal stability than had regular sunflower, soybean, corn, and peanut oils (P < 0.05). The genetically modified high oleic sunflower oil, with 5.5% linoleic acid, had better oxidative and thermal stabilities than had the regular sunflower oil with 71.6% linoleic acid.
The objective of this study is to compare the fatty acid composition of commercially available edible oils derived from certified organic and conventional agricultural methods. A total of 59 certified organic and 53 conventional oils were purchased from retail markets in Sydney, Australia. Organic and conventional products were matched for comparison according to the description of production methods, labelled total fat content, brand name (wherever possible), and country of origin. Total fat was extracted and the fatty acid composition of the oils was determined by gas chromatography. No consistent overall trend of difference in the fatty acid composition was observed between organic and conventional oils. Saturated (SFA), monounsaturated (MUFA) and polyunsaturated (PUFA) fatty acids were all significantly different between types of oil (P < 0.001 in all three), and each had significant interaction between type and production method (P = 0.002, P < 0.001 and P < 0.001, respectively) indicating that organic and conventional oils differed in these components in an inconsistent fashion. Despite this, there were large differences particularly between MUFA and PUFA components in specific pairs of oils, especially in sunflower and mustard seed oils. The absence of an overall difference in the fatty acid composition of organic and conventional oils does not support the tenet that organic foods are of a higher nutritional quality than their conventional counterparts.
A zero-trans fat shortening was prepared by chemical interesterification (CI) of high oleic sunflower oil, fully hydrogenated canola oil, and fully hydrogenated soybean oil (FHSO) in a weight ratio of 70:17:13. The product was crystallized in a votator and tested by baking chewy brownie cookies. The CI process produced a fat with comparable plasticity, solid fat content profile, melting point and morphology as the commercial shortening, and was appropriate for use as a high stability shortening. Interestingly, the CI material was predominantly in the β polymorph, and did not seem to be influenced by the mechanical and cooling treatment. Moreover, small crystallites in the range of <5 μm were observed. Cookies containing 30% FHCO showed the same hardness, but a higher spread ratio than cookies made using a commercial shortening. The results of sensory analysis showed the same acceptability for the two types of cookies.
A study is made of the evolution of the composition of sunflower oil kept over prolonged periods of time at high temperature (190 degrees C) in a domestic fryer. The technique used is (1)H NMR spectroscopy. The degradation rate of linoleic acyl groups is determined in this process, as well as the proportions of monounsaturated, of saturated plus modified acyl groups and the iodine values. Intermediate oxidation compounds having hydroperoxide groups and conjugated dienic systems were not detected; however, some secondary oxidation compounds such as aldehydes are generated very early, among them, the genotoxic and cytotoxic 4-hydroxy-trans-2-alkenals. Both concentrations of each kind of aldehyde at different heating times and changes in their concentration were also determined. Simultaneously, the level of oil degradation corresponding to a content of 25% of polar compounds measured by Viscofrit test was analyzed in function of the (1)H NMR spectra derived data.
Triacylglycerol oxidation of thermally stressed (6 h at 180 degrees C, simulating deep-frying conditions) edible vegetable oil (sunflower and olive) was studied using matrix-assisted laser desorption ionization-time-of-flight mass spectrometry (MALDI-TOF MS). Chromatographic separation of the nonpolar and polar components from the heated oil performed on silica gel prior to MS analysis significantly enhanced the detection of oxidized components. The spectra contained signals that were assigned to triacylglycerols (TAG), diacylglycerols (DAG), triacylglycerol oxidative dimers, oxidized TAG, and TAG fragments arising from the homolytic beta-scission of linoleyl, peroxy, and alkoxy radicals. Enrichment of the polar compounds prevented mass spectrometric ion suppression, thus allowing the detection of minor species originating from thermal oxidation. In addition, this allowed the monitoring of polar compounds in vegetable oils undergoing mild thermal treatment. As such, chromatographic separation coupled with MALDI-TOF MS analysis provided a rapid, sensitive, and specific tool to assess the thermal oxidation of vegetable oils.
The 1,3-random-2-random theory was proposed several years ago to explain the fatty acid distribution in vegetable oil triacylglycerols. However, by demonstrating an asymmetry between positions sn-1 and sn-3 in olive oil, cocoa butter, sunflower oil, etc., a number of studies have shown that this theory does not hold true for some oils and fatty acids. Accordingly, the distribution of fatty acids in sunflower triacylglycerols has been studied, calculating the alpha coefficient of asymmetry in several combinations of standard linoleic, high-oleic, and high-stearic sunflower oils. The results obtained from the oils of these lines and from single seed oil samples indicate that the asymmetry for saturated fatty acids is greater in high-oleic than in standard linoleic backgrounds. Hence, the distribution of the fatty acids within the triacylglycerol molecule appears to depend not only on the fatty acid under study but also on the other fatty acids in the oil. Thus, it is demonstrated for the first time that certain fatty acids can influence the distribution of other fatty acids within triacylglycerols.
A compilation has been made of the individual tocopherols in foods based on available literature reports for the period 1965 to 1975. Tocopherol content depends on stage of life cycle, agronomic and genetic factors, season, weather, harvesting methods, processing procedures, storage environment, and time periods of storage. Tocopherols are sensitive to oxygen and oxidative reactions, especially in the presence of catalysts, heat, alkali, and certain radiation. α‐Tocopherol has the highest vitamin E activity for man and animals and is usually the predominant tocopherol in their tissues. Its content varies in plant tissues. A technology currently exists for the addition of the mote stable ester α‐tocopheryl acetate to foods as a nutrient where it has merit and α‐ or γ‐tocopherol as an antioxidant to foods where natural‐type antioxidants are desired.
Deep-fat frying is one of the most commonly used procedures for the preparation and manufacture of foods in the world. During
deep-fat frying, oxidative and thermal decompositions may take place with the formation of volatile and nonvolatile decomposition
products, some of which in excessive amounts are harmful to human health. A limited survey of frying fats used in commercial
operations indicated that some were maintained at good quality and others were overused or abused. The volatile decomposition
products produced by corn oil, hydrogenated cotton-seed oil, trilinolein, and triolein, under simulated commercial frying
conditions, were collected, fractionated, and identified. A total of 211 compounds were identified. The nonvolatile decomposition
products produced by trilinolein, triolein, and tristearin under simulated commercial frying conditions were collected and
characterized. After being treated under deep-fat frying conditions at 185 C for 74 hr, trilinolein yielded 26.3% non-urea-adduct-forming
esters, triolein yielded 10.8%, and tristearin also yielded 4.2%.
Polyunsaturated fatty acids are thought to lower the serum cholesterol level more effectively than monounsaturated fatty acids. It is unclear whether the difference--if any--is due to a lowering of the level of high-density lipoprotein (HDL) or low-density lipoprotein (LDL) cholesterol. We therefore placed 31 women and 27 men on a mixed natural diet rich in saturated fat (19.3 percent of their daily energy intake from saturated fat, 11.5 percent from monounsaturated fat, and 4.6 percent from polyunsaturated fat) for 17 days. For the next 36 days, they received a mixed diet with the same total fat content, but enriched with olive oil and sunflower oil ("monounsaturated-fat diet": 12.9 percent saturated fat, 15.1 percent monounsaturated fat, and 7.9 percent polyunsaturated fat) or with sunflower oil alone ("polyunsaturated-fat diet": 12.6 percent saturated fat, 10.8 percent monounsaturated fat, and 12.7 percent polyunsaturated fat). The serum LDL cholesterol level decreased by 17.9 percent in those on the monounsaturated-fat diet and by 12.9 percent in those on the polyunsaturated-fat diet (95 percent confidence interval for the difference between the effects of the two unsaturated-fat diets, -9.9 percent to 0.0 percent). In men, the HDL cholesterol level fell slightly but not significantly with both diets. In women, the HDL cholesterol level did not change with either. We conclude that a mixed diet rich in monounsaturated fat was as effective as a diet rich in (n-6)polyunsaturated fat in lowering LDL cholesterol. Both diets lowered the level of HDL cholesterol slightly in men but not in women.
Conjugated dienoic linoleate (CLA), a linoleic acid derivative, has received considerable attention as a chemoprotective agent in the past few years because it has been shown experimentally to inhibit rat mammary tumorigenesis, mouse forestomach neoplasia, and mouse skin carcinogenesis. CLA has several unique structural and functional properties resulting in chemical and physiological effects that are different from those of all-cis, nonconjugated polyunsaturated fatty acids. In turn, these unique qualities appear to modulate cellular processes involved in carcinogenesis. This review will introduce the chemical background of conjugated dienoic linoleate, examine findings describing its chemoprotective qualities, present possible mechanisms of chemoprotection, and correlate the possible significance of dietary CLA modulation to carcinogenesis to humans.