Sit Foon Cheng

A study of production and characterization of Manketti (Ricinodendron rautonemii) methyl ester and its blends as a potential biodiesel feedstock

Globally, more than 350 oil-bearing crops are known as potential biodiesel feedstocks. This study reports on production and characterization of Manketti (Ricinodendron rautonemii) methyl ester and its blends with diesel. The effect of Manketti biodiesel (B5) on engine and emissions performance was also investigated. The cloud, pour and cold filter plugging points of the produced biodiesel were measured at 1, 3 and 5 °C, respectively. However, the kinematic viscosity of the biodiesel generated was found to be 8.34 mm2/s which was higher than the limit described by ASTM D6751 and EN 14214. This can be attributed to the high kinematic viscosity of the parent oil (132.75 mm2/s). Nevertheless, blending with diesel improved this attribute. Moreover, it is observed that at all engine speeds, B5 produced lower brake power (1.18%) and higher brake specific fuel consumption (2.26%) compared to B0 (neat diesel). B5 increased the CO and HC emissions by 32.27% and 37.5%, respectively, compared to B0. However, B0 produced 5.26% higher NO emissions than B5.

Stearic acids at sn -1, 3 positions of TAG are more efficient at limiting fat deposition than palmitic and oleic acids in C57BL/6 mice

In the present study, we investigated the effect of long-acyl chain SFA, namely palmitic acid (16:0) and stearic acid (18:0), at sn-1, 3 positions of TAG on obesity. Throughout the 15 weeks of the experimental period, C57BL/6 mice were fed diets fortified with cocoa butter, sal stearin (SAL), palm mid fraction (PMF) and high-oleic sunflower oil (HOS). The sn-1, 3 positions were varied by 16:0, 18:0 and 18:1, whilst the sn-2 position was preserved with 18:1. The HOS-enriched diet was found to lead to the highest fat deposition. This was in accordance with our previous postulation. Upon normalisation of total fat deposited with food intake to obtain the fat:feed ratio, interestingly, mice fed the SAL-enriched diet exhibited significantly lower visceral fat/feed and total fat/feed compared with those fed the PMF-enriched diet, despite their similarity in SFA-unsaturated fatty acid-SFA profile. That long-chain SFA at sn-1, 3 positions concomitantly with an unsaturated FA at the sn-2 position exert an obesity-reducing effect was further validated. The present study is the first of its kind to demonstrate that SFA of different chain lengths at sn-1, 3 positions exert profound effects on fat accretion.

Critical considerations for fast and accurate regiospecific analysis of triacylglycerols using quantitative 13C NMR

Quantitative 13C NMR (qCNMR) has been used as an appealing methodology for regiospecific analysis of triacylglycerols in edible oils and fats. It has advantages of shorter analysis time, precision and accuracy over laborious conventional Grignard or enzymatic hydrolysis method. Previous reported studies have recommended diversified NMR acquisition and processing parameters for the same quantification work. Different quantitative data were obtained by using a distinct sets of NMR parameters. To overcome this problem, we conducted a systematic investigation to examine the role of each acquisition and processing parameters to obtain high accuracy and repeatability data. Principal acquisition parameters, for instance pulse flip angle, repetition delay and temperature were investigated to correlate the targeted accuracies and practical experimental conditions. New data on spin-lattice relaxation times (T1) for carbonyl carbons in a variety of oils and fats had been obtained and analyzed comprehensively. With this set of acquisition parameters and free induction decay (FID) data processing method, error of less than 2.0 mol% were obtained with high repeatability and versatility for the analysis of oils and fats from diverse sources, including the reaction intermediates by chemical interesterification, lipids content extracted from biological samples and those natural occurring oils without their regiospecific data reported up-to-date. Instead of the semi-quantitative approach in previous reports on fish oil, we used narrower spectral width targeting sn-position in triacylglycerols to obtain full quantitative data in a shorter analysis time. The present selection of data acquisition and processing parameters led to a blueprint for a generic approach to performing a routinely practiced qCNMR regiospecific analysis.

Biological properties of sodium alkyl methyl ester sulfonate/alkyltrimethylammonium bromide surfactant mixtures

Quaternary ammonium compounds (QACs) are commonly used as disinfectant in medical care, food industry, detergents and glue industries. This is due to a small concentration of QACs is sufficient to inhibit the growth of various bacteria strains. In this work, the inhibitive power of cationic surfactants, alkyltrimethylammonium bromide (C(n)TAB) in the presence of anionic surfactants, sodium alkyl methyl ester α-sulfonate (C(n)MES) was studied. The growth inhibition test with gram-positive (Staphylococcus aureus) and gram-negative (Escherichia coli and Pseudomonas aeruginosa) bacteria were used to determine the toxicity of single and mixed surfactants. Results from this work showed that certain mixed surfactants have lower minimum inhibition concentration (MIC) as compared to the single C(n)TAB surfactants. Besides that, it was also found that alkyl chain length and the mixing ratios of the surfactants play a significant role in determining the mixture inhibitive power.

A combined microwave pretreatment/solvent extraction process for the production of oil from palm fruit: optimisation, oil quality and effect of prolonged exposure

BACKGROUND Conventional palm oil milling involves multiple stages after fruit collection; in particular, oil clarification introduces water into the pressed oil, which results in a large quantity of wastewater. RESULTS A combined process of microwave pretreatment and solvent extraction to mill crude palm oil, without introducing water or steam, is described. An excellent yield (up to 30%) of oil was obtained with pretreatment in a 42 L, 1000 W and 2450 MHz microwave oven followed by hexane extraction. The optimum conditions (10 min microwave pretreatment and 12 h solvent extraction) yielded an oil with a low free fatty acid content (<1.0%) and an acceptable anisidine value (<3.0 meq kg-1 ). The oil had a fatty acid composition not resembling those of conventional crude palm oil and crude palm kernel oil. In the pretreatment, the leached oil had 6.3% lauric acid whereas the solvent extracted oil had only 1.5% lauric acid. Among the factors affecting the oil quality, microwave pretreatment affected the oil quality significantly; however, an optimised duration that would ensure high efficiency in solvent extraction also resulted in ruptured fruitlets, although not to the extent of causing excessive oxidation. In fact, microwave pretreatment should exceed 12 min; after only 15 min, the oil had 1-methylcyclopentanol (12.96%), 1-tetradecanol (9.44%), 1-nonadecene (7.22%), nonanal (7.13%) and 1-tridecene (5.09%), which probably arose from the degradation of fibres. CONCLUSION Microwave pretreatment represents an alternative milling process for crude palm oil compared with conventional processes in the omission of wet treatment with steam.

1,10-Phenanthrolin-1-ium hydrogen d,l-tartrate dihydrate

In the title hydrated molecular salt, C12H9N2 +·C4H5O6 −·2H2O, the cation is almost planar (r.m.s. deviation = 0.014 Å); the carbon skeleton of the anion assumes a trans conformation [C—C—C—C torsion angle = −179.86 (14)°]. The carboxyl end of one hydrogen tartrate anion forms a short hydrogen bond to the carboxylate end of another anion [O⋯O = 2.508 (2) Å] in a head-to-tail manner, forming a chain; the chains and water molecules interact, generating an O—H⋯O hydrogen-bonded layer. The cation binds to the layer by an N—H⋯O hydrogen bond.