235,092 research outputs found

    Vitamin A Status of Women and Children in Yaoundé and Douala, Cameroon, is Unchanged One Year after Initiation of a National Vitamin A Oil Fortification Program.

    Get PDF
    Vitamin A (VA) fortification of cooking oil is considered a cost-effective strategy for increasing VA status, but few large-scale programs have been evaluated. We conducted representative surveys in Yaoundé and Douala, Cameroon, 2 years before and 1 year after the introduction of a mandatory national program to fortify cooking oil with VA. In each survey, 10 different households were selected within each of the same 30 clusters (n = ~300). Malaria infection and plasma indicators of inflammation and VA (retinol-binding protein, pRBP) status were assessed among women aged 15-49 years and children aged 12-59 months, and casual breast milk samples were collected for VA and fat measurements. Refined oil intake was measured by a food frequency questionnaire, and VA was measured in household oil samples post-fortification. Pre-fortification, low inflammation-adjusted pRBP was common among children (33% <0.83 µmol/L), but not women (2% <0.78 µmol/L). Refined cooking oil was consumed by >80% of participants in the past week. Post-fortification, only 44% of oil samples were fortified, but fortified samples contained VA concentrations close to the target values. Controlling for age, inflammation, and other covariates, there was no difference in the mean pRBP, mean breast milk VA, prevalence of low pRBP, or prevalence of low milk VA between the pre- and post-fortification surveys. The frequency of refined oil intake was not associated with VA status indicators post-fortification. In sum, after a year of cooking oil fortification with VA, we did not detect evidence of increased plasma RBP or milk VA among urban women and preschool children, possibly because less than half of the refined oil was fortified. The enforcement of norms should be strengthened, and the program should be evaluated in other regions where the prevalence of VA deficiency was greater pre-fortification

    Thermal Performance of Selected Oils in Uganda for Indirect Solar Domestic Cooking Applications

    Get PDF
    This study experimentally evaluated the thermal performance of selected oils in Uganda for indirect solar domestic cooking applications. The oil samples used were refined sunflower oil, refined palm oil and thermia B. These oils are locally available in Uganda. Thermal stratification, energy and exergy analysis were performed for each oil to determine their suitability for Thermal Energy Storage (TES) using a thermosiphon principle. The results showed that thermal stratification of refined sunflower oil was higher as compared to refined palm oil and thermia B during the first one hour. The stored energy and exergy for refined sunflower oil was generally higher than that of refined palm oil and thermia B. The thermal performance of refined sunflower oil was comparable to that of refined palm oil which was better than that of thermia B.Keywords: Thermosiphon; thermal stratification; energy; exergy; oi

    Olive oil

    Get PDF
    Analyses of phytosterol classes of olive and hazelnut oils collected from different countries by TLC, GC and GC-MS revealed considerable quantitative differences. The composition of 4-desmethyl- and 4-monomethylsterols was similar in both oils, but 4,4'-dimethylsterols composition differed. Lupeol and an unknown (lupane skeleton) compound were exclusively present in hazelnut oil 4,4´-dimethylsterols and could be used as markers to detect virgin olive oil adulteration with hazelnut oil at levels below 4%. Conventional TLC to separate phytosterol classes has a low recovery rate and is time-consuming. A new SPE method to separate phytosterol classes was developed with stepwise elution by increasing the polarity of the n-hexane:diethyl ether solvent mixture. Comparison of the results obtained for hazelnut and virgin olive oils with those of TLC revealed that the SPE method was faster and gave higher sterol recovery rates. Free and esterified forms of sterols provide detailed information on the identity and quality of vegetable oils, and therefore 4,4´-dimethylsterols were investigated in hazelnut oil and virgin olive oil. A sample of solvent-extracted hazelnut oil was refined to monitor the effects of processing on 4,4´-dimethylsterol levels and on specific marker compounds. Of the refining processes tested, only neutralisation and bleaching considerably reduced 4,4´-dimethylsterols. In fully-refined hazelnut oil, losses of marker compounds in free form were higher than losses in their esterified form. GC-MS analysis showed that adulteration of olive oil with fully-refined hazelnut oil could be detected at levels of 2% by tracing lupeol in total/esterified forms of 4,4´-dimethylsterols. Olive oil has many applications in the food industry, e.g. blended with oils such as palm stearin to produce margarine or shortening by chemical interesterification. Investigation on lipid and minor lipid components of an olive oil-palm stearin blend during chemical interesterification showed that sterols were esterified with fatty acids at a higher level at 120 °C (7%) than at 90 °C (4%). Despite heat treatment and several steps to produce an interesterified product, there were minor losses in phytosterol and tocopherol contents and no significant increases in phytosterol oxidation

    Are product spreads useful for forecasting? An empirical evaluation of the Verleger hypothesis

    Get PDF
    Notwithstanding a resurgence in research on out-of-sample forecasts of the price of oil in recent years, there is one important approach to forecasting the real price of oil which has not been studied systematically to date. This approach is based on the premise that demand for crude oil derives from the demand for refined products such as gasoline or heating oil. Oil industry analysts such as Philip Verleger and financial analysts widely believe that there is predictive power in the product spread, defined as the difference between suitably weighted refined product market prices and the price of crude oil. Our objective is to evaluate this proposition. We derive from first principles a number of alternative forecasting model specifications involving product spreads and compare these models to the no-change forecast of the real price of oil. We show that not all product spread models are useful for out-of-sample forecasting, but some models are, even at horizons between one and two years. The most accurate model is a time-varying parameter model of gasoline and heating oil spot spreads that allows the marginal product market to change over time. We document MSPE reductions as high as 20% and directional accuracy as high as 63% at the two-year horizon, making product spread models a good complement to forecasting models based on economic fundamentals, which work best at short horizons

    Liquid cryogenic lubricant

    Get PDF
    Fluorinated polyethers are suitable lubricants for rolling-element bearings in cryogenic systems. Lubrication effectiveness is comparable to that of super-refined mineral oil lubricants operating at room temperature

    High performance size-exclusion chromatography analysis of polar compounds applied to refined, mild deodorized, extra virgin olive oils and their blends: An approach to their differentiation

    Get PDF
    An investigation was carried out to evaluate the use of High Performance Size-Exclusion Chromatography (HPSEC) of polar compounds of refined, mild deodorized, extra virgin olive oils as well as of their blends, in attempting to reveal significant differences in the amounts of the substance classes constituting polar compounds among these oils. Two sets of blends were prepared by mixing an extra virgin olive oil with both refined and mild deodorized olive oils in increasing amounts. The obtained data highlighted that the triacylglycerol oligopolymers were absent or present in traces in the extra virgin olive oil, while their mean amount was equal to 0.04. g/100. g and 0.72. g/100. g in mild deodorized and refined olive oils, respectively. Oxidized triacylglycerols and diacylglycerols were more abundant in mild deodorized oil and refined oil than in extra virgin olive oil. The Factorial Discriminant Analysis of the data showed that the HPSEC analysis could reveal the presence of refined/mild deodorized oils in extra virgin olive oils. In particular, the classification functions obtained allowed designation of mixtures containing at least 30. g/100. g of mild deodorized oil and all those containing refined olive oil as deodorized oil, therefore as oils subjected to at least a mild refining treatment. © 2011 Elsevier Ltd

    Oil price instability, hedging, and an oil stabilization fund : the case of Venezuela

    Get PDF
    The Venezuelan government and PDVSA (Venezuela's state oil companies) are both exposed to oil price instability. Given the existing tax structure, PDVSA has a higher exposure than the government, especially when prices drop below $18-20 a barrel. The authors show that the volatility of prices for crude oil is higher (but not significant) than the volatility of prices for refined oil products. And both prices are highly correlated. So, there is not much strength to the argument that Venezuela, being now mainly an exporter of refined products, faces less volatility than when it was exporting mainly crude oil. The basis risk for hedging Venezuelan crude oil was founded to be higher than for other crudes of comparable quality in the region. One explanation could be the pricing policies Venezuela follows, which leads Venezuelan crude oil prices to deviate for long periods from international prices. The basis risk in Venezuelan refined products is much lower and at acceptable levels for risk management. The issue of liquidity is concentrated in contracts for periods of less than a year. For products, the liquidity is concentrated in the nearest 4-5 months. So, for short-term hedges (6-9 months ahead), there is sufficient liquidity for Venezuela to hedge a substantial part of its exports. For longer-term hedges, the over-the-counter market is the more appropriate vehicle. In either case, it will not usually be the case that all production or exports should be hedged. The authors also examined the issue of an oil stabilization fund. For an oil stabilization fund to be effective several preconditions must be met. Most notably: oil prices should not follow a random walk; financial markets are incomplete; and there are large adjustment costs. These conditions do likely apply in Venezuela. Venezuela's best strategy would be to remove as much short-term oil price risk as possible by using short-dated hedging instruments (such as futures, options, or short-dated swaps) and to also do some longer term hedging (using mainly over-the-counter options and long-dated swaps). They also find that an oil stabilization fund should be complemented by using market-based risk management tools. The oil stabilization fund could then be used to manage any remaining interperiod oil price risk to the extent considered necessary.Markets and Market Access,Environmental Economics&Policies,Oil Refining&Gas Industry,Energy and Environment,Energy Demand

    Determination Of Hydrophilic Phenolic Compounds In Palm Oil And Palm Kernel Oil

    Get PDF
    The quantification of total phenolic content expressed as gallic acid equivalent (GAE) was based on the Folin-Ciocalteau colorimetric method. The total phenolic contents (TPC) of palm oil samples were determined from crude to refined palm and palm kernel oils obtained from palm oil mills. The samples was crude palm oil (CPO), refined palm oil (RPO), refined palm olein (RPOo), crude palm kernel oil (CPKO), refined palm kernel oil (RPKO), and palm kernel olein (PKOo). All samples were utilized to determine the TPC. Quantification of phenolics extracted from palm and palm kernel oils showed the highest level of TPC in CPO and refining reduces the TPC in the oil. The TPC in CPO ranged from 31.73 – 70.18 mg/kg, bleached palm oil (BPO) from 18.36 – 22.25 mg/kg, RPO from 16.90 – 26.89 mg/kg, RPOo from 11.36 – 12.20 mg/kg and palm fatty acid distilled (PFAD) from 1.07 – 5.48 mg/kg. While that the TPC for CPKO ranged from 16.80 –27.25 mg/kg, RPKO from 3.16 – 3.82 mg/kg and PKOo from 2.52 – 8.60 mg/kg. Furthermore, the reduction of phenolic content were obtained in the different stages of the refining step

    Evaluation of the emulsifying property of solid phase purified Garcinia kola seed oil

    Get PDF
    Background:Crude seed oils consist essentially of naturally occurring mixtures of triacylglycerols (˃95%). They are purified to improve their overall quality. Oil purification facilitates elimination of impurities and toxicants.Objective: The objective of the study is to purify Garcinia kola seeds crude oil and to evaluate the purified oil for its emulsifying character.Materials and Methods:Crude seed oil of G. kola, obtained from the dried, powdered seed, was purified by passing the crude oil in n-hexane through silica gel and charcoal arranged in tandem. The crude and refined oils were evaluated by thin layer chromatography and infra-red spectroscopy. Emulsions of the refined oil at 30% and 20% concentrations were prepared and evaluated.Results: With the purification process, there was removal of dissolved polar solutes and pigments in the crude oil relative to the purified oil as revealed by the thin layer chromatographic profile and infra-red spectra. At 20% concentration of the refined oil, a lotion with viscosity of 25.67 ± 1.20 cP was formed while a creamy emulsion was produced with the refined oil at 30% concentration with viscosity of 46.00 ± 1.16 cP. This suggests the suitability of the purified oil as a base in the formulation of lotions and creams.Conclusion: The purified oil of G. kola possesses emulsifying property and could find applications in cosmetic and pharmaceutical industries.Keywords: Garcinia cola, seed oil, solid phase purification, emulsifying propert

    Propane from the North Slope: Could It Reduce Energy Costs in the Interior?

    Get PDF
    Could propane from the North Slope cut energy costs in Fairbanks and other Interior communities that heat buildings or generate electricity with fuel oil or naphtha? The Alaska Natural Gas Development Authority (ANGDA) thinks it could. That’s because a North Slope producer has agreed to sell ANGDA propane for considerably less than what it might otherwise cost, if there were a natural gas pipeline. Propane is a component of North Slope natural gas—and right now there’s no way to get that gas to market.* Naphtha and fuel oil, by comparison, are refined from oil—so their prices are closely tied to the volatile price of crude oil. ANGDA hopes getting a price break on propane could make it cheaper, at least until a pipeline is built—and it asked ISER to analyze the potential effects of one idea.Alaska Natural Gas Development Authorit
    corecore