Determination of biodiesel and used cooking oil in automotive diesel/green diesel fuels through high-performance liquid chromatography.

This study reports a simple and convenient analytical method for the simultaneous determination of biodiesel and vegetable oils or used cooking oils in petrodiesel and green diesel (hydrotreated vegetable oils or paraffinic diesel). The approach is based on normal-phase high-performance liquid chromatography with refractive index detection. It employed silica stationary phase, n-hexane mobile phase with isopropanol modifier to achieve optimum separation between hydrocarbons (petrodiesel or green diesel), fatty acid methyl esters (biodiesel) and triglycerides (vegetable oils and used cooking oil). In addition to determining vegetable oils or used cooking oils as adulterants in diesel, this method is also proposed as a better alternative to the standard method ASTM D7371, which is currently recommended for determining fatty acid methyl esters in petrodiesel. The method development involved screening of various stationary and mobile phases, with and without modifiers, to achieve acceptable chromatographic resolutions between analytes. Under the optimized method conditions, silica column, and n-hexane containing 0.6% isopropanol as the mobile phase provided the best results. The real-world scenario was simulated for the method validation carried out by fortifying Jatropha seed oil, soybean oil, and used cooking oil in the biodiesel blended petrodiesel and green diesel. Measurement of all analytes was accompanied by high precision, low limit of detection/quantification and linear response range of 0.05 to 50% for biodiesel, and 0.05 to 30% for vegetable oils. The proposed method is simple, fast (runtime 7 min), and does not require sample pre-treatment and backflushing.

Multidimensional gas chromatographic‒Mass spectrometric method for separation and identification of triacylglycerols in olive oil.

A 'heart-cut' multidimensional gas chromatography‒mass spectrometry (H/C MDGC‒MS) method for separation and identification of triacylglycerols (TAGs) in extra virgin olive oil was developed. A GC configuration, comprising a non-polar first dimension (1D) column (15 m length) and a mid-polarity second dimension (2D) column (9 m length), was employed. Standard TAGs were used to test and demonstrate the H/C MDGC method, for identification of TAG components and to validate the method. Various chromatographic conditions such as column flow and temperature program were evaluated. The 1D separation resulted in overlap of some standard TAG peaks. These overlapped 1D regions of the standard TAGs were H/C to 2D for further separation and resulted in clearly distinguished individual TAG component peaks. The 1D separation of olive oil TAGs displayed three major peaks and four minor peaks. The application of the H/C MDGC method to olive oil TAGs resulted in the separation of each sampled 1D region into two or more TAG peaks. TAG components in olive oil resolved on the 2D column were identified based on characteristic mass fragment ions such as [M-RCO2]+, [RCO+128]+, [RCO+74]+ and RCO+ and comparison of their mass spectra with that of the standard TAGs. Sixteen olive oil TAGs were identified by MS after 2D separation. The repeatability of the H/C method was evaluated in terms of retention time shift and area response in the 2D and found to be <0.02% and <8% RSD respectively.

miRNA/Target Gene Profile of Endothelial Cells Treated with Human Triglyceride-Rich Lipoproteins Obtained after a High-Fat Meal with Extra-Virgin Olive Oil or Sunflower Oil.

SCOPE: The effects of triglyceride-rich lipoproteins (TRLs) on the miRNA expression of endothelial cells, which are very involved in atherosclerosis, according to the type of diet are not known. METHODS AND RESULTS: The differences between the effects of TRLs isolated from blood of subjects after a high-fat meal with extra-virgin olive oil (EVOO) and sunflower oil (SO) on the microRNA-Seq profile related to atherosclerosis in human umbilical vein endothelial cells are analyzed. 28 upregulated microRNAs with EVOO-derived TRLs, which can regulate 22 genes related to atherosclerosis, are found. 21 upregulated microRNAs with SO-derived TRLs, which can regulate 20 genes related to atherosclerosis, are found. These microRNAs are mainly involved in angiogenesis, with a predominance of an anti-angiogenic effect with EVOO-derived TRLs. Other microRNAs upregulated with SO-derived TRLs are involved in cardiovascular diseases. Pathways for the target genes obtained from the upregulated microRNA with EVOO-derived TRLs are involved in lipid metabolism and inflammatory and defense response, while those with SO-derived TRLs are involved in lipid metabolic process. CONCLUSION: EVOO-derived TRLs seem to produce a more atheroprotective profile than SO-derived TRLs. This study provides alternative mechanisms on the protective role of EVOO against the atherogenic process through microRNA regulation in endothelial cells.

Effect of Heating on Compositional Characteristics and Oxidative Stability of Crude and Refined Rice Bran Oil.

The compositional characteristics and oxidative stability of rice bran oil were determined by observing the formation of oxidative products and alteration in chemical composition of oils during microwave or oven heating. The values of oxidative indicators such as free acidity, peroxide, p-anisidine, total oxidation, thiobarbituric acid and color values, increased faster in refined oils compared to crude ones during heating. In gas chromatography analysis, the percentages of total saturated, monounsaturated and polyunsaturated fatty acids in the studied oils such as lab extracted crude rice bran oil, lab extracted and refined rice bran oil, crude rice bran oil from commercial mill and refined rice bran oil from commercial mill were: 23.07 to 23.56, 41.15 to 42.38 and 34.38 to 35.88, respectively. The heating caused the reduction of polyunsaturated fatty acids content with increasing saturated fatty acids content, and these changes were greater in refined rice bran oil indicating extensive lipid oxidation occurred in refined oil. The change in triacylglycerol species content as determined by High-performance liquid chromatography, was lower in crude oil; the higher stability of these species in crude oil could have contribution to reduce oxidation. During thermal treatment, the generation of hydroperoxides, their degradation and formation of secondary oxidative products evaluated by Fourier-transform infrared spectroscopy, were lower in crude oils. However, the rate of formation of oxidative products in lab prepared samples was lower compared to that in the samples collected from commercial mill. Under extreme thermal condition, the order of oxidative stability: lab extracted crude rice bran oil > crude rice bran oil from commercial mill>lab extracted and refined rice bran oil > refined rice bran oil from commercial mill. The present results will be useful to oil seed processing mills in refining of rice bran oil for economic feasibility and better marketability.

Lipid Characteristics of Camellia Seed Oil.

Camellia oleifera, C. japonica and C. sinensis are three representative crops of the genus Camellia. In this work, we systematically investigated the lipid characteristics of these seed oils collected from different regions. The results indicated significant differences in acid value (AV), peroxide value (PV), iodine value (IV), saponification value (SV) and relative density of the above-mentioned camellia seed oils (p < 0.05). The C. japonica seed oils showed the highest AV (1.7 mg/g), and the C. sinensis seed oils showed the highest PV (17.4 meq/kg). The C. japonica seed oils showed the lowest IV (79.9 g/100 g), SV (192.7 mg/g) and refractive index (1.4633) of all the oils, while the C. sinensis seed oils showed the lowest relative density (0.911 g/cm3). The major fatty acids in the camellia seed oils were palmitic acid (16:0), oleic acid (18:1) and linoleic acid (18:2); the oleic acid in C. oleifera and C. japonica seed oils accounted for more than 80% of the total fatty acids. The oleic acid levels in the C. oleifera and C. japonica oils were higher than those in the C. sinensis seed oils, while the linoleic acid levels in the former were lower than those in the latter one. Differences also exist in the triacylglycerol (TAG) composition, although the most abundant TAG molecular species in the camellia seed oils was trioleoylglycerol (OOO). Seven sterol species, squalene and α-tocopherol were detected in the camellia seed oils, however, the contents of tocopherol and unsaponifiable molecules in the C. oleifera and C. japonica seed oils were significantly lower than those in the C. sinensis seed oil. These results demonstrated that the varieties of Camellia affected the seed oil lipid characteristics.

Physico-chemical Characterization, Profiling of Total Lipids and Triacylglycerol Molecular Species of Omega-3 Fatty Acid Rich B. arvensis Seed Oil from India.

Buglossoides arvensis is indigenous to India and its seed oil is rich in unique and nutritionally important omega-3 fatty acid namely, stearidonic acid (SDA). It is a non-conventional oil seed plant and needs to be agronomically adapt for commercial utilization. In the present study, oil extracted from the agronomically adapted high yielding cultivar of B. arvensis seeds was analyzed for its oil content, fatty acid (FA) composition, physico-chemical characteristics, total lipids and triacylglycerol molecular species. The oil content, peroxide, acid, iodine, p-anisidine values and tocopherol content of the oil were 18.53% (w/w), 2.06 meq of active oxygen / kg of oil, 2.55 mg KOH/g oil, 217.2 g I2/100g oil, 10.7 and 774.8 mg/kg oil respectively. Oxidative stability as determined by the induction period was found to be 3.1 h. Polyunsaturated fatty acid (PUFA) content of the oil was 81.3% (of total FA), comprising of α-linolenic acid (ALA; 48.5%), SDA (18.6%), linoleic acid (LA; 10.3%) and γ-linolenic acid (GLA; 3.9%). Profiling of lipid classes showed neutral lipids (89.3%, w/w) as most abundant lipid class followed by glycolipids (7.4%, w/w) and phospholipids (3.3%, w/w). High resolution mass spectrometric analysis of triacylglycerol (TAG) molecular species showed TAGs with C54 carbons in the acyl chain as most abundant. Positional distribution analysis showed GLA and SDA predominantly at the sn-2 position of triacylglycerol. FTIR analysis revealed common characteristics molecular features similar to PUFA rich oils. Overall, the results suggest that B. arvensis seed oil is an excellent ω3-ω6-ω3 or ALA-SDA-GLA source for food and nutraceutical industries.

Oleosome Oil Storage in the Mesocarp of Two Avocado Varieties.

Studies on avocado oil have focused on the most common commercial cultivars, Hass, Fuerte, and Bacon, rather than the less common varieties, P. americana var. drymifolia and P. americana var. americana, even though the drymifolia variety has a higher oil content and the americana variety is the most common avocado grown in the tropics. The most abundant storage structures for plant oils are the oleosomes, and the aim of this study was to determine the oleosome size, oil yield, and fatty acid composition of the americana and drymifolia varieties, using the Hass cultivar as a reference. Differences were found between the three avocado types for 1) oil yield, with drymifolia having higher and americana lower oil content (p < 0.05%), 2) oleosome size, with Hass having a larger (41.53 µm) and americana a smaller (11.96 µm) size, and 3) fatty acid composition, with the americana and drymifolia varieties showing less monounsaturated fatty acids (oleic) and more polyunsaturated fatty acids (linoleic) and saturated fatty acids (palmitic); while Hass had a high level (60%) of monounsaturated fatty acids. Small but significant differences were also found between oleosome and mesocarp oils isolated from the drymifolia and Hass types.

High temperature multidimensional gas chromatographic approach for improved separation of triacylglycerols in olive oil.

Heart-cut multidimensional gas chromatographic (H/C MDGC) methods under suitable flow and high temperature (T) program conditions were developed to separate olive oil triacylglycerols (TAGs). Different column sets were selected for further evaluation, each with relatively short non-polar first dimension (1D) and mid-polar second dimension (2D) columns of high T limits (350 °C). The 1D separation displayed three major groups of peaks in an area ratio of approximately 5:33:62 (of increasing retention), using flame ionisation detection (FID). Four groups of minor peaks, with 2 of them located between the major peaks, were also detected. The H/C fractions of the minor peaks, and sub-sampled regions across the major peaks eluting from the 1D outlet, were cryotrapped at the 2D inlet. The trapped TAGs then underwent temperature programmed 2D separation. Each of the 'H/C' zones generally gave 2-5 - and in some cases more - separated peaks of TAGs on the 2D column, under suitable flow condition and phase polarity that resulted in improved separation. Six sub-sampled H/Cs from various regions of the individual peaks from the 1D column were simultaneously trapped and released to 2D, resulting in apparently more than 22 individual TAG peaks. According to their different retention times, different TAGs were revealed within each of the 3 major groups, using H/C sub-sampling. A comprehensive sampling strategy that covers most of the 1D peaks further revealed the presence of more TAGs in the olive oil sample. This tandem column strategy was able to resolve more components than that usually observed on a single column.

Precolumn Derivatization with Bromine to Improve Separation and Detection Sensitivity of Triacylglycerols in Edible Oil by Reversed-Phase High Performance Liquid Chromatography.

The complexity of triacylglycerols (TAGs) in edible oils is largely due to the many similar unsaturated TAG compounds, which makes profiling TAGs difficult. In this study, precolumn derivatization with bromine (Br2) was used to improve the separation and detection sensitivity of TAGs in edible oils by RP-HPLC. Oil samples dissolved in n-hexane and TAGs were derived by reaction with a Br2-CCl4 (1:1, v/v) solution for 3 h at room temperature. The derivate product solution was stable and was best separated and detected by RP-HPLC using a C18 column, with a mobile phase of methanol-n-hexane (91.5:8.5, v/v) at 25°C. A detection wavelength of 230 nm was used. The results showed that the approach enabled the separation and detection of more similar TAGs by RP-HPLC. The method was applied to profile 20 types of edible oil, and the results presented the differences in the TAG profiles of various edible oils, which may be useful in the identification of edible oils.

Influence of indigenous minor components on fat crystal network of fully hydrogenated palm kernel oil and fully hydrogenated coconut oil.

Purification of triglycerides from fully hydrogenated palm kernel oil (FHPKO) and fully hydrogenated coconut oil (FHCNO) was performed by a chromatographic method. Lipid composition, thermal properties, polymorphism, isothermal crystallization behaviour, nanostructure and microstructure of FHPKO, FHPKO-triacylglycerol (TAG), FHCNO and FHCNO-TAG were evaluated. Removal of minor components had no effect on triglycerides composition. However, the presence of the minor components did increase the slip melting point and promote onset of crystallization. Furthermore, the thickness of the nanoscale crystals increased, and polymorphic transformation from ß' to ß occurred in FHPKO after the removal of minor components, and from α to ß' in FHCNO. Sharp changes in the values of the Avrami constant K and exponent n suggested that the presence of minor components changed the crystal growth mechanism. The PLM results indicated that a coarser crystal structure with lower fractal dimension appeared after the removal of minor components from both FHPKO and FHCNO.

Modulatory Effect of an Isolated Triglyceride from Fenugreek Seed Oil on of α-Amylase, Lipase and ACE Activities, Liver-Kidney Functions and Metabolic Disorders of Diabetic Rats.

This study was designed to examine physicochemical characteristics, chemical compositions and biological activities of fenugreek seed oil (FSO) and its pure triglyceride (TG). One fenugreek TG was purified using a bioassay-guided fractionation and administrated to surviving diabetic rats. The free fatty acids percentage as well as, the peroxide, the saponification and the iodine values were 2%, 12 mequiv. O2/kg of oil, 189 (mg KOH/g) and 110 (g/100 g of oil), respectively. Linolenic acid (C18:3 26.14%), Linoleic acid (C18:2 41.13%) and Oleic acid (C18:1 17.07%) were the dominant fatty acids in the FSO. ß-sitosterol was the major sterol (85.3%) in the FSO. LnLnO (17.1%), LLL (16.6%), OLL and OOLn (8.4%), were the abundant triglycerides. The hexane extract of fenugreek seed (exhibiting the powerful inhibitory activity against alpha-amylase) was purified using a bioassay-guided fractionation affording one fenugreek TG: (11Z)-11- eicosenoic acid 2, 3- bis[((9Z, 12Z, 15Z)-1-oxo-9, 12, 15-octadecatrien-1-yl)oxy] propyl ester. In diabetic rats, the administration of the fenugreek TG inhibited α-amylase activity in small intestine by 36% as compared to untreated diabetic rats. Moreover, fenugreek TG increased insulin sensibility which leads to decrease in blood glucose level by 43%. In addition, this study demonstrated that administration of pure fenugreek TG to diabetic rats ameliorated the glycogen rate in liver and muscle. In addition, the administration of fenugreek TG reverted back the activity of angiotensin converting enzyme respectively in kidney and plasma by 33 and 29%. Interestingly, the fenugreek TG inhibited lipase activity in small intestine by 33% which leads to the regulation of lipid profile. Moreover, the fenugreek TG protected liver-kidney function evidenced by histological study. In conclusion, our finding demonstrates that the administration of fenugreek TG to diabetic rats can make it a potential candidate for industrial application as a pharmacological agent for the treatment of hyperglycemia.

Evaluation of green solvents: Oil extraction from oleaginous yeast Lipomyces starkeyi using cyclopentyl methyl ether (CPME).

Cyclopentyl methyl ether (CPME) was evaluated for extracting oil or triacylglycerol (TAG) from wet cells of the oleaginous yeast Lipomyces starkeyi. CPME is a greener alternative to chloroform as a potential solvent for oil recovery. A monophasic system of CPME and biphasic system of CPME:water (1:0.7) performed poorly having the lowest TAG extraction efficiency and TAG selectivity compared to other monophasic systems of hexane and chloroform and the biphasic Bligh and Dyer method (chloroform:methanol:water). Biphasic systems of CPME:water:alcohol (methanol/ethanol/1-propanol) were tested and methanol achieved the best oil extraction efficiency compared to ethanol and 1-propanol. Different biphasic systems of CPME:methanol:water were tested, the best TAG extraction efficiency and TAG selectivity achieved was 9.9 mg/mL and 64.6%, respectively, using a starting ratio of 1:1.7:0.6 and a final ratio of 1:1:0.8 (CPME:methanol:water). Similar results were achieved for the Bligh and Dyer method (TAG extraction efficiency of 10.2 mg/mL and TAG selectivity of 66.0%) indicating that the biphasic CPME system was comparable. The fatty acid profile remained constant across all the solvent systems tested indicating that choice of solvent was not specific for any certain fatty acid. This study was able to demonstrate that CPME could be used as an alternative solvent for the extraction of oil from the wet biomass of oleaginous yeast. © 2017 American Institute of Chemical Engineers Biotechnol. Prog., 33:1096-1103, 2017.

Chemical composition of Lycium europaeum fruit oil obtained by supercritical CO2 extraction and evaluation of its antioxidant activity, cytotoxicity and cell absorption.

We studied the total phenols and flavonoids, liposoluble antioxidants, fatty acid and triacylglycerol profiles, and oxidative status of oil obtained from Lycium europaeum fruits following supercritical CO2 extraction (at 30MPa and 40°C). Linoleic (52%), palmitic (18%), oleic (13%), and α-linolenic (6%) were the main oil fatty acids, while trilinolein and palmitodilinolein/oleodilinolein represented the main triacylglycerols. The oil was characterized by high levels of all-trans-zeaxanthin and all-trans-ß-carotene (755 and 332µg/g of oil, respectively), α-tocopherol (308µg/g of oil), total phenols (13.6mg gallic acid equivalents/g of oil), and total flavonoids (6.8mg quercetin equivalents/g of oil). The oil showed radical scavenging activities (ABTS and DPPH assays) and inhibited Caco-2 cell growth. Moreover, the incubation of differentiated Caco-2 cells with a non-toxic oil concentration (100µg/mL) induced a significant intracellular accumulation of essential fatty acids. The results qualify L. europaeum oil as a potential source for food/pharmaceutical applications.

Fat-Modified Breast Milk Resolves Chylous Pleural Effusion in Infants With Postsurgical Chylothorax but Is Associated With Slow Growth.

BACKGROUND: Chylothorax occurs in ~3%-5% of infants undergoing cardiac surgery. Standard treatment requires discontinuation of breast milk feeding, due to the abundance of long-chain triglycerides and transition to a medium-chain triglyceride (MCT)-based formula. OBJECTIVE: To determine the effectiveness of fat-modified breast milk (MBM) for the treatment of chylothorax compared with MCT formula. MATERIALS AND METHODS: Infants diagnosed with chylothorax following surgery for congenital heart disease between January 2008 and December 2009 at The Hospital for Sick Children were eligible for this nonrandomized open-label study. Treatment infants (n = 8) received mother's own milk that had been modified by removing the fat layer via centrifugation and adding MCT, nutrients, and essential fatty acids to provide an estimated 74 kcal/100 mL and 1.4 g/100 mL protein (MBM group). Control infants (n = 8) received an MCT formula (MCT group). The feeding intervention was a minimum of 6 weeks after chest tube removal per The Hospital for Sick Children standard chylothorax treatment protocol. RESULTS: Daily volume and duration of chest tube drainage were not different between the MBM and MCT groups. While there was no statistically significant difference in rates of weight gain (g/d) between feeding groups, infants in the MBM group, who tended to be younger, experienced a decline in mean weight (P = .04) and length (P = .01) for age z scores. CONCLUSION: Fat-modified breast milk resolved chylothorax; however, strategies to address poor growth need to be developed and evaluated in larger trials prior to widespread clinical adoption of this novel treatment.

Characterization of Shrimp Oil from Pandalus borealis by High Performance Liquid Chromatography and High Resolution Mass Spectrometry.

Northern shrimp (Pandalus borealis) oil, which is rich in omega-3 fatty acids, was recovered from the cooking water of shrimp processing facilities. The oil contains significant amounts of omega-3 fatty acids in triglyceride form, along with substantial long-chain monounsaturated fatty acids (MUFAs). It also features natural isomeric forms of astaxanthin, a nutritional carotenoid, which gives the oil a brilliant red color. As part of our efforts in developing value added products from waste streams of the seafood processing industry, we present in this paper a comprehensive characterization of the triacylglycerols (TAGs) and astaxanthin esters that predominate in the shrimp oil by using HPLC-HRMS and MS/MS, as well as 13C-NMR. This approach, in combination with FAME analysis, offers direct characterization of fatty acid molecules in their intact forms, including the distribution of regioisomers in TAGs. The information is important for the standardization and quality control, as well as for differentiation of composition features of shrimp oil, which could be sold as an ingredient in health supplements and functional foods.

Suppressive effects of coixol, glyceryl trilinoleate and natural products derived from Coix Lachryma-Jobi var. ma-yuen on gene expression, production and secretion of airway MUC5AC mucin.

In this study, we investigated whether natural products including coixol derived from Coix Lachryma-Jobi var. ma-yuen affect MUC5AC mucin gene expression, production and secretion from airway epithelial cells. Confluent NCI-H292 cells were pretreated with oleic acid, linoleic acid, glyceryl trilinoleate, beta-stigmasterol or coixol for 30 min and then stimulated with PMA (phorbol 12-myristate 13-acetate), EGF (epidermal growth factor) or TNF-α (tumor necrosis factor-α) for 24 h. The MUC5AC mucin gene expression, mucin protein production and secretion were measured by RT-PCR and ELISA. The results were as follows: (1) Oleic acid, linoleic acid, glyceryl trilinoleate, beta-stigmasterol and coixol inhibited the expression of MUC5AC mucin gene induced by PMA from NCI-H292 cells; (2) Oleic acid, linoleic acid, glyceryl trilinoleate, beta-stigmasterol and coixol also inhibited the production of MUC5AC mucin protein induced by the same inducers from NCI-H292 cells; (3) Coixol inhibited the expression of MUC5AC mucin gene and production of MUC5AC mucin protein, induced by EGF or TNF-α from NCI-H292 cells; (4) Coixol decreased PMA-induced MUC5AC mucin secretion from NCI-H292 cells. This result suggests that coixol, the characteristic component among the examined five natural products derived from C. Lachryma-Jobi var. ma-yuen, can regulate gene expression, production and secretion of mucin, by directly acting on airway epithelial cells.

Anti-inflammatory effects of trilinolein from Panax notoginseng through the suppression of NF-κB and MAPK expression and proinflammatory cytokine expression.

In this study, we have investigated the anti-inflammatory effects of trilinolein (TL) using a lipopolysaccharide (LPS)-stimulated mouse macrophage (RAW264.7) and carrageenan (Carr)-induced mouse paw edema model. When RAW264.7 macrophages were treated with different concentrations of TL together with LPS, a significant concentration-dependent inhibition of nitric oxide (NO), tumor necrosis factor (TNF-α), interleukin-1 (IL-1ß), and IL-6 production was detected. Western blotting revealed that TL blocked the protein expression of inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), nuclear factor-κB (NF-κB), IκBα, and mitogen-activated protein kinases (MAPKs). In the anti-inflammatory test, TL decreased the paw edema at the 5th h after λ-Carr administration in paw edema. We also demonstrated TL significantly attenuated the malondialdehyde (MDA) level in the edema paw at the 5th h after Carr injection. TL decreased the NO and TNF-α levels on the serum level at the 5th h after Carr injection. Western blotting revealed that TL decreased Carr-induced iNOS and COX-2 expressions at the 5th h in the edema paw. The anti-inflammatory mechanisms of TL might be related to the decrease in the level of iNOS, COX-2, IκBα, and MAPK pathway through the suppression of TNF-α, IL-1ß, and IL-6.

Use of differential scanning calorimetry to detect canola oil (Brassica napus L.) adulterated with lard stearin.

A study was conducted to detect and quantify lard stearin (LS) content in canola oil (CaO) using differential scanning calorimetry (DSC). Authentic samples of CaO were obtained from a reliable supplier and the adulterant LS were obtained through a fractional crystallization procedure as reported previously. Pure CaO samples spiked with LS in levels ranging from 5 to 15% (w/w) were analyzed using DSC to obtain their cooling and heating profiles. The results showed that samples contaminated with LS at 5% (w/w) level can be detected using characteristic contaminant peaks appearing in the higher temperature regions (0 to 70°C) of the cooling and heating curves. Pearson correlation analysis of LS content against individual DSC parameters of the adulterant peak namely peak temperature, peak area, peak onset temperature indicated that there were strong correlations between these with the LS content of the CaO admixtures. When these three parameters were engaged as variables in the execution of the stepwise regression procedure, predictive models for determination of LS content in CaO were obtained. The predictive models obtained with single DSC parameter had relatively lower coefficient of determination (R(2) value) and higher standard error than the models obtained using two DSC parameters in combination. This study concluded that the predictive models obtained with peak area and peak onset temperature of the adulteration peak would be more accurate for prediction of LS content in CaO based on the highest coefficient of determination (R(2) value) and smallest standard error.

Physico-chemical characteristics of papaya (Carica papaya L.) seed oil of the Hong Kong/Sekaki variety.

A study was carried out to determine the physicochemical characteristics of the oil derived from papaya seeds of the Hong Kong/Sekaki variety. Proximate analysis showed that seeds of the Hong Kong/Sekaki variety contained considerable amount of oil (27.0%). The iodine value, saponification value, unsaponifiable matter and free fatty acid contents of freshly extracted papaya seed oil were 76.9 g I2/100g oil, 193.5 mg KOH/g oil, 1.52% and 0.91%, respectively. The oil had a Lovibond color index of 15.2Y + 5.2B. Papaya seed oil contained ten detectable fatty acids, of which 78.33% were unsaturated. Oleic (73.5%) acid was the dominant fatty acids followed by palmitic acid (15.8%). Based on the high performance liquid chromatography (HPLC) analysis, seven species of triacylglycerols (TAGs) were detected. The predominant TAGs of papaya seed oil were OOO (40.4%), POO (29.1%) and SOO (9.9%) where O, P, and S denote oleic, palmitic and stearic acids, respectively. Thermal analysis by differential scanning calorimetry (DSC) showed that papaya seed oil had its major melting and crystallization transitions at 12.4°C and -48.2°C, respectively. Analysis of the sample by Z-nose (electronic nose) instrument showed that the sample had a high level of volatile compounds.