Antioxidant Activity Evaluation of Tocored through Chemical Assays,Evaluation in Stripped Corn Oil,and CAA Assay

γ‐Tocopherol‐5,6‐quinone (tocored) is a crucial oxidized product of γ‐tocopherol (γ‐T) found in edible oil. Previously published studies on antioxidant activity (AOA) of tocored are not consistent. This study aims to monitor its AOA comprehensively through chemical assays (1,1‐diphenyl‐2‐picrylhydrazyl [DPPH] and ferric reducing antioxidant power [FRAP]), antioxidant evaluation in a food model system (stripped corn oil), and cellular antioxidant activity (CAA) assay, which would reasonably widen the knowledge of the AOA of γ‐T and tocored. In both DPPH and FRAP assays, tocored shows less AOA than γ‐T. Results of chemical properties in the Schaal oven test show that tocored possesses better AOA than γ‐T. Correlation coefficients of γ‐T and tocored between peroxide and K₂₃₄ or p‐AnV are 0.8784–0.9875 and 0.8716–0.9879, respectively. The CAA assay also shows that tocored possesses better cellar AOA than γ‐T, with an EC₅₀ at 21.55 µg mL^?1. Drawing conclusions from the results from chemical assays, evaluation in stripped corn oil, and CAA assay, tocored is verified as a potent antioxidant in edible vegetable oils compared to γ‐T. Practical Applications: The present work widens the knowledge of antioxidant activity of tocored and gamma‐tocopherol, and contributes to the understanding of existing antioxidant activity when gamma tocopherol is depleted when edible oils are in storage and processing processes.     

Synergistic antidiabetic activity of ZnO nanoparticles encompassed by Urtica dioica extract

The present study aimed at producing ZnO nanoparticles using the leaf extract of nettle (Urtica dioica) as a medicinally valuable plant to maximize the antidiabetic property of ZnO while excluding the chemical pollution from the synthesis process. The properties of the ZnO-extract sample were uncovered by various techniques and compared to that produced without the extract (ZnO). The results of the surface, optical, and thermal studies disclosed the presence of the extract biomolecules over the ZnO-extract sample and was further confirmed by GC–MS analysis. The ZnO-extract was intraperitoneally injected to alloxan-induced diabetic rats and the effects on the serum levels of fasting blood glucose, insulin, high-density lipoprotein cholesterol, total cholesterol, and total triglyceride were assessed. The obtained results were then compared with the effects of ZnO, nettle leaf extract, and insulin on the same factors. Among all the examined treatments, the best antidiabetic performance was obtained in the rats treated by ZnO-U. dioica extract mainly owing to the great synergistic interaction between its constituents.     

Medium chain triglycerides (MCT): State-of-the-art on chemistry,synthesis, health benefits and applications in food industry

Medium chain triglycerides (MCT) are esters of fatty acids with 6 to 12 carbon atom chains. Naturally, they occur in various sources; their composition and bioactivity are source and extraction process-linked. The molecular size of MCT oil permits unique metabolic pathways and energy production rates, making MCT oil a high-value functional food. This review details the common sources of MCT oil, presenting critical information on the various approaches for MCT oil extraction or synthesis. Apart from conventional techniques, non-thermal processing methods that show promising prospects are analyzed. The biological effects of MCT oil are summarized, and the range of need-driven modification approaches are elaborated. A section is devoted to highlighting the recent trends in the application of MCT oil for food, nutraceuticals, and allied applications. While much is debated about the role of MCT oil in human health and wellness, there is limited information on daily requirements, impact on specific population groups, and effects of long-term consumption. Nonetheless, several studies have been conducted and continue to identify the most effective methods for MCT oil extraction, processing, handling, and storage. A knowledge gap exists and future research must focus on technology packages for scalability and sustainability.     

Seasonal and regional variation in triglyceride composition of French butterfat

In the present study, high-performance liquid chromatography analysis of butterfat allowed separation of 46 peaks at 32°C. Knowing the theoretical carbon number value of each triglyceride (TG), 32 peaks of the butterfat chromatogram were identified. These TGs were determined by extrapolation of their capacity factor values, and their identifications were confirmed with some standard TGs. Analysis of winter and summer butterfat from five different French areas showed significant seasonal and regional variation in the TG composition. However, the most important contribution to this variation was provided by TG groups represented by only four peaks. To approximately select the predominant TGs in these four peaks, a random distribution hypothesis was used to predict the amount of each TG. This hypothesis allowed the prediction of the TG components that seem to provide the most important contribution to both seasonal and regional variation.     

Determination of the country of origin of pistachio nuts by DSC and HPLC

The laboratories of the U.S. Customs Service frequently encounter the major analytical problem of determining the country of origin of imported commodities. This is particularly challenging with natural products. This paper will describe the process for one such commodity —pistachio nuts. Two approaches were taken, high performance liquid chromatography (HPLC) and Differential Scanning Calorimetry (DSC). It was found that the results of these two techniques were complimentary and confirmatory. The HPLC data was obtained on the petroleum ether soluble fraction of the pistachio nuts while the DSC runs evaluated both this fraction and the whole nut. The HPLC results were further investigated by collecting fractions from the eluting peaks, derivatizing them to form the methyl ester of the fatty acids, and profiling by gas chromatography to confirm the triglycerides originally present. The U.S. Customs Service is currently using DSC area ratios to screen imported pistachio nuts for country of origin.     

Semi-volatile and volatile compounds formed by degradation of triglycerides in a pressurized reactor

The products formed during precombustion reactions of several saturated and unsaturated triglycerides upon their injection into a reactor, simulating conditions that exist in a diesel engine, were collected. Two traps were employed in order to distinguish between volatile and semi-volatile components. The resulting samples were analyzed with gas chromatography-mass spectrometry techniques. Various aliphatic and aromatic hydrocarbons were detected as major degradation products. Oxygenated degradation products were found in smaller numbers. Differences observed in the samples compared to previous work are attributed to the higher temperature used in the present study (450°Cvs. 400°C). The environment (air or nitrogen) had considerable influence on product formation. The number of components was less for samples of tripalmitin, tristearin and triolein reacted under nitrogen than under air; but more components were formed from trilinolein and trilinolenin under nitrogen atmosphere than under air. Presented in part at the 82nd AOCS Annual Meeting, Chicago, IL, May 1991.     

Effect of lipids and surfactants on extracellular lipase production by Yarrowia lipolytica

The production of extracellular lipase in submerged cultures of Yarrowia lipolytica CECT 1240 has been investigated. Several compounds have been added to the culture medium, in order to assess their efficiency as inducers of lipase production. First, the effect of triglycerides (olive oil, sunflower oil, tributyrin) and fatty acids (oleic acid) has been studied. The highest activity level was obtained with sunflower oil (58 U cm^?3), followed by olive oil (49 U cm^?3). The cultures with tributyrin and oleic acid attained similar activities (33 U cm^?3). Then, several surfactants (Tween 80, Triton X‐100, gum arabic, polyethylene glycol 200) were added to the cultures with sunflower oil, in an attempt to increase the levels of extracellular lipase activity. The obtained activities were slightly lower than those achieved without surfactants. The assay of a wide range of surfactant concentrations in the case of PEG‐200 (with which the highest activity levels had been attained) did not improve the results. This strain secreted lipase concentrations two‐fold higher and showed significantly different behaviour towards the presence of surfactants in the culture medium, compared with other wild‐type Yarrowia lipolytica strains. Copyright © 2003 Society of Chemical Industry     

Oligopolymer,diglyceride and oxidized triglyceride contents as measures of olive oil quality

The objective of this study was to test the qualities of olive oils of different commercial grades by quantifying oligopolymer compounds by high-performance size-exclusion chromatography (HPSEC). The method required no sample manipulation and was accurate and rapid. The mean level of oligopolymers in refined olive oils was 0.70% and was more than twice as high in refined olive pomace oils. Conversely, edible virgin olive oils had no oligopolymer compounds. HPSEC analyses of polar compounds by silica gel column chromatography also allowed determination of oxidized triglycerides and partial glycerides, which help define levels of oxidative degradation and hydrolysis. Research supported by National Research Council of Italy, Special Project RAISA, Sub-project 4, Paper No. 321.     

Wetting of fat crystals by triglyceride oil and water. 1. The effect of additives

Wetting of fat crystals has been extensively examined in this work by contact angle (θ) measurements of fat crystal, oil, and water in three-phase contact. Contact angle was measured in oil. The crystals were nonpolar and wetted by oil for a contact angle equal to 0°, and polar and wetted by water for an angle equal to 180°. Fat crystals are expected to contribute to the stability of margarine emulsions if they are preferentially wetted by the oil phase (0°<θ<90°), but result in instability if they are preferentially wetted by the water phase (90°<θ<180°). In the absence of oil and water additives, fat crystals in α and β' polymorphs were introduced to the oil/water interface from the oil side (contact angle θ ∼ 30°). β Polymorphs were completely wetted by oil (θ ≈ 0°). The contact angle for β' crystals decreased with increasing temperature and was slightly lower in butter oil than in soybean oil. Emulsifiers in the oil phase (lecithins, monoglycerides and their esters, ethoxylated emulsifiers) and surface-active proteins in the water phase (milk proteins) made the crystals more polar (higher θ). Nonsurface-active proteins, sugar, and citric acid had no significant effect, although concentrations of salt lowered θ. Contact angle increased with temperature for emulsifiers of limited solubility in the oil, e.g., saturated monoglyceride.     

Supercritical fluid chromatographic analysis of new crop seed oils and their reactions

Supercritical fluid chromatography (SFC) with an open tubular column of nonpolar stationary phase separated triglycerides from crambe, meadowfoam,Euphorbia lagascae, and vernonia oils based on their molecular weight. The triglyceride compositions were consistent with the literature. SFC proved also to be a valuable tool in analyzing lipase-catalyzed transesterification reactions where lesquerella oil and estolides were among the substrates employed. Analyte molecular weights could be estimated from a retention time- (or elution density-) molecular eeight calibration curve. An increase in isothermal column temperature during SFC pressure or density programming improved the resolution of high-molecular-weight (>600 Da) analytes but yielded poorer resolution for analytes of molecular weight <200. A simultaneous pressure and temperature ramping program proved superior in enhancing resolution in several instances. Presented at the AOCS Annual Meeting & Expo, May 1995, San Antonio, Texas. Retired