Analyses of Vegetable Oil Triacylglycerols by Silver Ion High Performance Liquid Chromatography with Flame Ionization Detection

Lipid composition differs in diapause and nondiapause states of spotted stem borer, Chilo partellus

Spotted stem borer, Chilo partellus, undergoes larval diapause (hibernation and aestivation), and depends on the food reserve accumulated during feeding stage for its survival. Lipids are the primary source of energy during diapause, and essential for different cellular, biochemical and physiological functions. However, there is no information on lipid and lipophilic compound contents during different stages of hibernation, aestivation and nondiapause in C. partellus. Thus, we compared the concentration and composition of lipids in pre-diapause, diapause and post-diapause stages of hibernation and aestivation with nondiapause stages of C. partellus. The studies revealed significant differences in total lipids and various lipophilic compounds during different stages of diapause as compared to nondiapause C. partellus. The total lipids were significantly lower during diapause stage of aestivation and hibernation as compared to nondiapause larvae. Further, the linoleic acid, Methyl 3-methoxytetradecanoate, and l-(+)-Ascorbic acid 2,6-dihexadecanoate were significantly lower, and oleic and palmitoleic acids greater during pre-diapause and diapause stages of hibernation and aestivation as compared to nondiapause larvae. The cholesterol content was significantly greater during pre-diapause stage of hibernation, and diapause and post-diapause stages of aestivation as compared to nondiapause stages. The unsaturation ratio was significantly higher in the pre-diapause and diapause stages and lower in post-diapause stage of aestivation than the hibernation and nondiapause states. This study provides insights on differential lipid profiles during different phases of diapause, which could be useful for further understanding biochemical and physiological cross-talk, and develop target-specific technologies for the management of C. partellus.

Harnessing sponge gourd: an alternative source of oil and protein for nutritional security

Luffa cylindrica (L.) Roem. is an important cucurbit crop that assures food security and dietary diversity among the poor communities. In the present study, seeds of 42 genotypes of Luffa cylindrica were evaluated for their potential use as oil seed crop. Seed moisture, oil and protein content and fatty acids profile were estimated along with total phenol and sugar content. Significant differences were observed among the various genotypes where oil content ranged from 15.4-29.8% and protein 19.9-30.8%. Total phenol content was high 6.43-12.84 mg/100 g, which bodes well for the sponge gourd seeds' ability to act as antioxidants. Significant correlation were found between important constituents studied like protein and oil, palmitic acid, stearic acid and oleic acid. Total unsaturated fatty acids were in higher amount comparable to saturated fatty acids signifying the good quality of Luffa seed oil. Our research revealed that the NDSG-1, Pusa Sneha, DSG-95, DSG-98, DSG-108, and DSG-26 genotypes were very nutritious due to their high levels of protein, oleic acid, and oil output. Additionally, selection of traits having considerable correlation will be beneficial and help in improved varietal development for usage as an alternative oilseed crop. Our research sheds light on the nutritional value of sponge gourd seeds and suggests using them as a potential source for oil and protein, particularly in underdeveloped countries.

Characterization of Corn Oil Using Fluorescence Spectroscopy

In these studies, Fluorescence spectroscopy has been utilized for the characterization of pure and commercially available corn oil. The best excitation wavelength of 380 nm has been investigated, where maximum spectral information can be assessed. The emission spectra from pure and commercial corn oil samples disclosed that pure corn oil contained oleic acid, beta-carotenes, chlorophylls, isomers of vitamin E and traces of oxidized products which exhibit fluorescence at 406, 525, 675, 440 and 435/475 nm respectively. Whereas, commercial corn oils lack these valuable ingredients and only contain fats along with their primary and secondary oxidized products that emit a broad emission band centred at 440 nm. The study has also depicted that Fluorescence spectroscopy can even be used to select best quality corn oil among pure corn oil samples with different varieties and seed origins. In addition, the effect of temperature on the composition of pure and commercial corn oil samples have also been investigated by heating them at 100, 120,140, 160, 180 and 200 °C each sample for 30 min. This was done because corn oil is being used for cooking where it is generally heated up to 120 °C and for deep frying up to 180 °C. On heating, in pure corn oil, deterioration of Vitamin-E and beta-carotenes occurred with an increase in the oxidation products, whereas, in commercial oil samples, only the concentration of oxidation products increased. However, it was found that up to 140 °C, pure corn oil can be used safely for cooking purpose where it does not lose much of its valuable ingredients while in commercial corn oils, fat composition does not alter much up to 180 °C and after that oxidized products start to increase rapidly.

Pattern-Type Separation of Triacylglycerols by Silver Thiolate×Non-Aqueous Reversed Phase Comprehensive Liquid Chromatography

Triacylglycerols (TAGs), as the main components of edible oils and animal fats, are responsible for the nutritional value, organoleptic features and technological properties of foods; each lipid matrix shows a unique TAG profile which can serve as fingerprint to ensure the quality and authenticity of food products. The high complexity of many foodstuffs often makes untargeted elucidation of TAG components a challenging task; thus, more efficient separation techniques may be mandatory. In this research, the TAG profile of a borage (Borago officinalis) seed oil was obtained by two-dimensional comprehensive liquid chromatography (LC×LC), by the coupling of silver thiolate and octadecylsilica monodisperse materials. A total 94 TAG compounds were identified by ion trap-time of flight detection, using atmospheric pressure ionization, with the degree of unsaturation varying from 0 to 9, and partition values ranging from 36 to 56. The group-type separation afforded by this analytical approach may be useful to quickly fingerprint TAG components of oil samples.

Optimized synthesis of 1,3-dioleoyl-2-palmitoylglycerol-rich triacylglycerol via interesterification catalyzed by a lipase from Thermomyces lanuginosus

1,3-Dioleoyl-2-palmitoylglycerol (OPO)-rich human milk fat substitute (HMFS) was synthesized from tripalmitin-rich fraction and ethyl oleate by a lipase-catalyzed interesterification. Response surface methodology was employed to optimize its OPO content and acyl migration with reaction factors - substrate mole ratio of PPP-rich fraction to ethyl oleate (1:4, 1:5 and 1:6), reaction temperature (50, 55 and 60 degrees C) and time (3, 7.5 and 12 hours). The predictive models for OPO content and acyl migration were adequate and reproducible. The OPO content increased with substrate ratio, and decreased with reaction time and temperature, whereas acyl migration increased with temperature and time. The optimal conditions for HMFS synthesis while maximizing OPO content (31.43% OPO) and minimizing acyl migration (6.07%) were predicted at the reaction combination of 50 degrees C, three hours and 5.5 substrate ratio. HMFS was resynthesized under the same condition, and no significant difference between the observed and predicted values was found. Further, the major fatty acid of HMFS was palmitic acid (80.6%) at sn-2 position, and oleic acid (64.9%) at sn-1,3 position.

Simultaneous quantification of free fatty acids, free sterols, squalene, and acylglycerol molecular species in palm oil by high-temperature gas chromatography-flame ionization detection

This paper discusses a rapid GC-FID technique for the simultaneous quantitative analysis of FFA, MAG, DAG, TAG, sterols, and squalene in vegetable oils, with special reference to palm oil. The FFA content determined had a lower SE compared with a conventional titrimetric method. Squalene and individual sterols, consisting of beta-sitosterol, stigmasterol, campesterol, and cholesterol, were accurately quantified without any losses. This was achieved through elimination of tedious conventional sample pretreatments, such as saponification and preparative TLC. With this technique, the separation of individual MAG, consisting of 16:0, 18:0, and 18:1 FA, and the DAG species, consisting of the 1,2(2,3)- and 1,3-positions, was sufficient to enable their quantification. This technique enabled the TAG to be determined according to their carbon numbers in the range of C44 to C56. Comparisons were made with conventional methods, and the results were in good agreement with those reported in the literature.

Authentication of vegetable oils by chromatographic techniques

Food authentication has been evolving continually to situations that were basically governed by a global market trend. Analytical techniques have been developed or modified to give plausible solutions to the devious adulterations at each moment. Classical tests have largely been replaced with newer technical procedures, most of which are based on gas chromatography, with some being based on high-performance liquid chromatography. Determination of trans-fatty acid and sterolic composition, together with sterol-dehydration products, have been used most frequently used to detect contamination and adulteration. Sophisticated new adulterations, e.g., olive oil with hazelnut oil, represent a new challenge for the next millennium, although suggestive proposals for detecting these kinds of adulterations are emerging with the contribution of databases and mathematical algorithms.