Sunflower detection

Each plant tissue tends to have an obviously distinctive profile of flavonoids. The flavonoid content can reach about 0.5% in pollen, 10% in propolis, and about 6 mg/kg in honey. Havonoid aglycones appear to be present only in propolis and honey, while pollen contains flavanols in herosidic forms. The flavonoids in honey and propolis have been identified as flavanones and flavanones/flavanols (Campos et ah, 1990). The antimi-crobially active flavanone pinocembrine was foimd to be a major flavonoid in honey (Bogdanov, 1989). Amiot et ah (1989) studied two blossom and two honeydew Swiss honey samples and foimd that pinocembrine was the main flavonoid. Pinocembrine concentration varied between 2 and 3 mg/kg (Bogdanov, 1989). Berahia et ah (1993) analyzed sunflower honey samples and detected six flavone/flavols, four flavanone/ flavols, and pinocembrin, of which pinocembrin is the main flavonoid. The flavonoids in sunflower honey and propolis were characterized and assessed for their effects on hepatic drug-metabolizing enzymes and benzo [fl]pyrene-DNA adduct formation (Sabatier et ah, 1992 Siess et ah, 1996). 

A high content of hesperetin was detected in citrus honey samples (Ferreres et ah, 1993, 1994b,c,e). 8-Methoxy-kaempferol was the main compound in rosemary honey samples, whereas luteolin was the main compound in lavender honey samples (Ferreres et ah, 1994b, 1998). Quercetin was used as a marker for differentiating for sunflower honey... 

Activity has been detected In the Lemna bloassay with HPLC fractions of unknown allelochemlcals from sunflower using quantities as low as 5 pi of a 28 ppm w/v solution (see Saggese et al. this publication). 

After use, herbicides decompose slowly, and so affect cultivated plants for many years. In 1990, investigations in many regions of the USSR detected herbicides phytotoxic effects, especially among the si/m-triazine class, on different cultivars in many varied situations [13]. These sym-triazine herbicides, such as protrazin, simazin, atrazine, metazin, and prometrin, were used in different oblasts of the Ukraine, Kirgizia, Kazakhstan, Russia and Moldavia in previous years, especially on corn. Residual herbicide aftereffects led to the suppression and death of crops such as winter wheat, oats, barley, rye, potatoes, beets and sugar beets, linen, onions, watermelons and other melons, and sunflowers. 

Sunflower aroma detection by the honeybee study by coupling gas chromatography and electroantennography. Journal of Chemical Ecology 16 701-711. 

Fig. 29 Separation of triacylglycerols from sunflower seed oil by HPLC with a silver ion column and mass detection. For conditions see text. S = saturated fatty acid M = monounsaturated fatty acid D = di-unsaturated fatty acid.

Fig. 41 Separation of triacylglycerols on Supelcosil-LC 8 with acetone-acetonitrile (70 30, v/v) as the mobile phase and refractive index detection. Flow rate, 1.0 ml/min. (a) Olive oil, (b) soybean oil, (c) sunflower oil, (d) corn oil.

Fig. 4 HPLC separation of water-degummed and crude sunflower oil phospholipids on a 250 X 4-mm column packed with Lichrosorb Si-60 according to the AOCS method. The mobile phase consisted of hexane, 2-propanol, and acetate buffer of pH 4.2 in a volumetric ratio of 8/8/1 at 2 ml/min. Detection was accomplished by UV absorption at 206 nm. (Reproduced from Ref. 34 with permission of the American Oil Chemists Society.)...

Thiery D., Bluet J. M., Pham-Delegue M.-H., Etievant P. and Masson C. (1990) Sunflower aroma detection by the honeybee study by coupling gas chromatography and electroantennography. J. Chem. Ecol. 16, 701-711. 

It is claimed (Youk et al., 1999) that olive, sunflower and peanut oils contain mainly esterified sterols, while soyabean and sesame oils contain mainly free sterols. This does not appear to have been utilized previously, but could be useful with mixtures of the two classes. Although it is possible to de-sterolize oils, and remove characteristic sterols, this usually forms other sterols that can be detected (Biedermann and Grob, 1996 Lanuzza and Micali, 1997 Mariani and Venturini, 1997). If it is suspected that this has occurred, then the presence of other suspect components should be investigated. 

Biedermann, M. and Grab, K. (1996) Detection of desterolized sunflower oil in olive oil through isomerized A7-sterols. Z. Lebensm. Unters. Forsch., 202, 199-204. 

Most oils contain low levels of saturated and unsaturated hydrocarbons. In olive oil, the unsaturated hydrocarbon squalene can constitute up to 40% of the unsaponifiable fraction (Boskou, 1996). Other hydrocarbons commonly present in olive oil are straight chain alkanes and alkenes with 13 to 35 carbon atoms, along with very low amounts of branched chain hydrocarbons. Variations are found between different olive varieties but the main hydrocarbons are those with 23, 25, 27 and 29 carbon atoms (Guinda et al., 1996). Olive oil can clearly be differentiated from other vegetable oils on the basis of hydrocarbon components, and levels of 2.6% crude rapeseed oil or crude sunflower oil can be detected by hydrocarbon analysis (Webster et al., 1999). Terpenes have been identified in the volatile fraction of crude sunflower oil (Bocci and Frega, 1996). 

The induced inhibition of longitudinal growth by tetcyclacis results both from inhibited cell elongation and from reduced cell division. The relative proportions to which cell elongation and cell division contribute to the shortening effect varied in trials with maize, sunflowers, and soybeans, i.e., the influence effected via cell division increased with an increase in concentration of the PBR. The inhibitory effect on cell division detected in intact plants has been confirmed in cell suspension cultures of the same plant species (11). 

Flaxseed oils contain much lower amounts of tocopherols, half of the amount present in sunflower and canola oils and one-third of that present in soybean oil (Table 2). A lower content of these antioxidants makes these oils even more susceptible to oxidation. Gamma-tocopherol was found as the main tocopherol in flax oils, with a contribution of about 80% to the total amount. This makes flax oil comparable with soybean oil. Among unique antioxidants detected in flax oils was plasto-chromanol-8. This compound is a derivative of gamma tocotrienol with twice as long unsaturated side chain. Plastochromanol-8 was found to be a more efficient antioxidant than any tocopherols isomer (15). A low content of tocopherols in flaxseed did not make them more susceptible to oxidation experiments showed that milled flaxseed could be stored for 28 months at ambient temperatures without measurable changes in oxidation products. This can be attributed to the presence of antioxidants other than tocopherols in the seeds (16). 

Composition and content of tocopherols in camelina oil was similar to perilla oil, where more than 80% of all tocopherols were gamma isomer (Table 4). Alpha and delta tocopherols were detected as minor antioxidants (77). The total content of tocopherols was comparable with perilla oil, and higher than that in flax oil (Tables 4 and 2). The total content of tocopherols in camelina oil is higher than canola, flax, soybean, and sunflower. 

In regular sunflower oil, the main component is p-sitosterol, followed by A-7-stigmasterol. The latter may be used as a tracer for detection of adulterations in sunflower oil, as most vegetable oils (except safflower oil) have fairly low amounts of A-7-stigmasterol (less than 7%). 

Several studies have been aimed at the detection of a fraudulent addition of vegetable oils to olive oil. In particular, different analytical methods can be applied to determine blends of regular and high-oleic sunflower oil with olive oil. The minimum sunflower oil detection level depends on the analytical method used. For example, a minimum detectable level of 0.7% of regular or high-oleic sunflower oil may be achieved through methods of sterol analysis, and analysis of the fatty acids will not enable detection of additions below 20% (45). 

Results show that regular sunflower oil rarely reaches a critical value of 25% of polar compounds in continuous frying processes with frequent turnover, indicating the suitability of sunflower oil for this use. However, use of this oil is recommended only for frying of crisp-type foods with short commercialization periods, ensuring their consumption before detectable levels of deterioration of the absorbed oil are reached (109). 

Diterpenic, phytyl, and geranylgeranyl esters were reported in olive and sunflower oils, but benzyl esters were only detected in olive oils (78). The wax esters of sunflower oil were found to have carbon atom numbers between 36 and 48, with a high concentration in the C-40-C-42 fraction (79). Waxes in dewaxed and refined sunflower oils mainly contained <42 carbon atoms indicating selective retention after refining. 

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