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Three oil lettuce seed samples (lactuca Sativa LS10, LS20, LS30) were cultivated under three irrigation conditions (well, normal and water deficient conditions, after 10, 20 and 30 days respectively) to evaluate their oils and to see to what extent the oil lettuce plant resists draught conditions. The oils extracted from the three seed samples were evaluated by determining eight lipid profiles using HPLC in conjunction with capillary GLC. Lettuce seed oils are characterized by high contents of linoleic and oleic acids. Of the triacyl glycerols determined, those containing linoleyl and oleyl acyles are the major ones. The whole sterol profiles include β-sitosterol (as major component) followed by 7-stigmasterol, campesterol and 5-stigmasterol, which were found in all the lettuce seed oil samples but with slight differences. Furthermore, sterol patterns of the free and acylated sterols, free and acylated sterylglycosides were determined. It was found that LS30 oil has the highest tocopherol content and α-tocopherol is the only constituent in all the lettuce seed oil samples. On the other hand, the 2-position in the lettuce seed oil samples is mainly acylated by unsaturated fatty acids (98.6%) namely, oleic and linoleic acids. According to these results, it can be concluded that irrigation conditions do not affect the lipid constituents of the oil and the oil lettuce plant resists draught and its lipid profiles are in agreement with those of conventional vegetable oils.

Eight lipid patterns of Silybum marianum (L.) Gaertn seed oil, not hitherto reported, (20%) have been elucidated in this laboratory using capillary GLC and HPLC as main tools of analysis. The oil is rich in linoleic acid (53.3%) and oleic acid (21.3%). Five major triacylglycerols containing linoleic acyls namely LLL, LLO, LLP, LOO and LOP were detected by HPLC using FID detector, these triacylglycerols are also predominating in both cottonseed and sunflower oils but in different proportions. The total tocopherols content (260 ppm) was determined directly in the oil by HPLC. It was found that the oil contains alpha -tocopherol as a major constituent (84.5%) resembling sunflower oil. The whole sterols pattern, as determined as their trimethylsilyl derivatives by GLC, includes campesterol, 5-stigmasterol, beta-sitosterol, 7-stigmasterol, avenasterol and spinasterol. The four sterols lipid clases of free and acylated sterols and sterylglycosides have been determined as their 9- and 1- anthroylnitrile derivatives by fluorescence and UV- HPLC respectively.

The effect of microwave heating on three vegetable oils having different lipid compositions was studied. Sunflower, soybean and peanut oils in comparison with oil admixture of soybean and peanut oil (1:1, w/w), were selected for this study. Each oil was heated for 2, 4, 6, 8, 10, 12, 15 and 18 minutes in microwave oven. Peroxide value, free acidity and colour absorbance (at 420 nm) were proportionally increasing with the increase of heating period. Colour absorption threw light on the formation of browning products arising from phospholipids during microwave heating. Total tocopherol contents were determined by preparative thin layer chromatography, whereas the fatty acid compositions and formed epoxy acid were analyzed by capillary gas liquid chromatography. The formed conjugated dienes and trienes were determined by UV spectrophotometry. It was found that the total tocopherols of the microwave heated oils, decreased depending on the type of the predominating tocopherols. Also a relation of peroxide formation, during microwave heating, with changes in total tocopherol composition was discussed. It was found that polyunsaturated fatty acids generally decreased by increasing the heating period. The results obtained from the heated oil admixture helped interpret the results obtained from other heated individual oils.

Changes in lipids of three newly developed varieties of rapeseed during seed maturation were studied. Triacylglycerol molecular species, fatty acid composition, whole sterol, and four sterol lipids as well as tocopherol were determined at different maturation stages. It was found that marked variations in some lipids were observed in one variety than the other. Efficient methods of analysis employed in this investigation and the individual lipid components, even in very minor quantities, were accurately detected. Marked varietal changes in lipids compositions during seed maturation manifest themselves, to some extent, in three new rapeseed varieties. Changes in lipids of maturing seeds were interpreted in the frame of probable conversion-interconversion reactions that may occur during seed maturation.

HPLC analysis of triacylglycerols and minor components, such as free and acylated sterols, and sterylglycosides, tocopherols and ¡soprenoid alcohols, have been employed for establishing oil authenticity. GLC analysis of the whole sterols as their TMS - derivatives has been also conducted. Genuine oils, namely, rapeseed, sunflower and corn oil as well as corn oil admixtures with the two oils were analyzed. Triacylglycerols and tocopherols were directly determined in the oils whereas the four sterol in lipids (free and acylated sterols and sterylglycosides) and isoprenoid alcohols were isolated and derivatized into their anthroyi nitrile derivatives. It was concluded that the analysis of minor components in combination with triacylglycerols is more advantageous for authentication of corn oil. However, ¡soprenoid alcohols are more decisive in this respect. Natural variability of the components in the oils from different origins can modify the detection limits.

Mixtures of cocoa butter with different replacers, added at different levels, were prepared. From their properties, and particularly solid fat index, helped much in selecting the more suitable mixture for local chocolate production. It was found that cocoa butter-Illexao mixtures, at levels 10% and 15% replacer, gave more satisfactory results with respect to mouthfeel, hardness and brittleness.

The variation of lipid constituents in maturing sunflower oil seeds has been investigated with the aim of determination of the proper harvesting time as well as the oil quality. Marked variations in fatty acid, sterol and tocopherol constituents of the oil were observed. Capillary gas chromatography and high performance liquid chromatography were used in the analysis which enabled the determination of major as well as minor constituents in the oil. In addition, gas chromatography coupled to mass spectrometry was used to confirm the structure of cycloartenol sterol. Postulations on the key compounds of fatty acids, sterols, and tocopherols were proposed in the frame of the main biosynthetic pathways. The proper harvesting time was found to be 118 days after plantation since the oil content was high and the constituents of the oil were balanced.

Eight lipid patterns of Salicornia seed oil have been elucidated using HPLC as the main tool of analysis in conjunction with capillary GLC. The whole oil is rich in linoleic (66.5%) with lower amount of linolenic acid (1.4%). Of the 22 triglycerides (TG) determined, three major TG containing 3 and 2 linoleic acyls were detected by HPLC. The total tocopherols content (720 ppm) was determined directly in the oil by HPLC and it was found that alpha-T (49.1%) and gamma-T (48.2%) are predominating. The whole sterol profile, as determined by GLC, includes cholesterol (1.0%), brassicasterol (1.4%), campesterol (2.4%), 5-stigmasterol (8.7%), beta-sitosterol (23.0%), spinasterol (17.0%), isofucosterol (0.8%), 7-stigmastenol (42.0%) and 7-avenasterol (3.7%). Furthermore, sterols patterns of the free (nonacylated) sterols (FS), acylated sterols (AS), free sterylglycosides (FSG) and acylated sterylglycosides (ASG) were determined by HPLC as their anthroylnitriles. FS and AS were determined as their steryl-9-anthroylnitriles (S-9-AN) whereas FSG and ASG were analysed as their sterylglycosidyl-1-anthroylnitriles (SG-1-AN) at nanogram level. Comparing Salicornia SOS-7 oil with traditional freshwater seed oils, Salicornia exhibits mostly a unique lipids constitution.