Forced Draft Oven Research Articles

Anti-Obesity Effect of Carom Seeds (Trachyspermum Ammi) Tea on Bmi and Lipid Profile Leading to Cardiovascular Diseases

Introduction: Obesity refers to the deposition of fat ratio in the fat tissues of muscles in which the BMI raised (obesity and hyperlipidemia) that may have a negative impact on health. Herbs from ancient times till today have been utilized as a solution for some infections and issues. Objectives: The purpose of this research was to evaluate the defensive impact of Carom seed (Trachyspermum ammi) against obesity and hyperlipidemia. Materials & Methods: Carom seed was acquired from the Faisalabad and was washed to expel the soil, dust, and outside materials clung to the test surface. The crude material was dried by utilizing an air forced draft oven. After planning, it was stuffed in water/airproof plastic containers and put away at 5 ± 1 °C until further analysis. Moreover, the blood samples were collected on 0-day, 15-day, 30-day, and 60-day by taking 15ml venous blood after a 12-hour night of fasting. Serum samples were separated by centrifugation and stored at -70?c until analysis. Low-density lipoprotein and high-density lipoprotein cholesterol were measured enzymatically. Concentrations of triglycerides and total cholesterol were measured by Peridochrom Triglyceride Kits. Sixteen subjects, separated into four groups were given carom seeds in the form of tea i.e. G0 (Control), G1 (500mg), G2 (1 mg) and G3 (1.5 mg) individually. This was an eight-week trial and all the parameters e.g. Body Mass Index, High-Density Lipid, Low-Density Lipid, Tri-Glycerides, and Total Cholesterol were measured at 0 days, 15 days, 30 days, and 60 days respectively. The yield data of carom seed tea for anti-obesity and anti-hyper-lipidemic effects obtained for each treatment were subjected to a paired t-test by using SPSS. Results: The significant change has been observed between the groups with the relevance of treatments given. G0 showed no significant changes among all the groups while G2 and G3 reported considerable changes because of the dosage concentrations of carom seed tea i.e. 1g and 1.5g respectively (p<0.05).

Characterization and Biological Activity of Fiber-Type Cannabis sativa L. Aerial Parts at Different Growth Stages.

Currently, there is a renewed interest in cannabis-related products in different fields because of the rich phytocomplex of this plant, together with its fiber and agricultural features. In this context, the current study aims to chemically characterize different samples of fiber-type Cannabis sativa L. grown in Italy as a potential health promoting source. An ultrasound-assisted solid-liquid extraction (UA-SLE) method was first developed and optimized to obtain a fingerprinting of the investigated phytocomplex. Analyses were carried out through an ultra high performance liquid chromatography equipped with a photodiode array detector in series with triple quadrupole system with an electrospray ionization (ESI) interface (UHPLC-UV-ESI-MS/MS) and showed that the phytocomplex mainly includes flavonoids and non-psychotomimetic cannabinoids. The method was then applied to characterize and compare 24 samples of fiber-type Cannabis sativa L. aerial parts (mainly stems and leaves), which differed for the growth stages (from mid-vegetative to early flowering), growth land plots, and methods of drying (forced-draft oven or freeze-drying). The quali-quantitative analysis showed that a freeze-drying method seems to better preserve the chemical composition of the samples, while the location of the land plot and the growth stage of the plant (which did not comprise inflorescences) had minor influences on the chemical pattern. These results were also supported by spectrophotometric in-vitro assays (scavenging of 2,2-diphenyl-1-picrylhydrazyl (DPPH•) and 2,2′-azinobis-3-ethyl-benzthiazoline-6-sulphonate (ABTS+•) radicals and inhibitory activity against tyrosinase and elastase enzymes) to investigate the potential biological activity of these samples and the contribution of non-psychotomimetic cannabinoids.

Investigation of Different Laboratory Aging Methods of Bituminous Mixtures

The predicted performance and service life of the pavement depend largely on the properties of bitumen used in the mixtures. The most important feature of bitumen, which has profound effect on the performance of the road is durability. The durability of bitumen is expressed as the resistance to aging. In this study, the bituminous mixture aging was performed instead of bitumen aging in order to represent the aging in the field in the best possible way. The aim of this paper is to evaluate different proposed laboratory aging methods (NCHRP 09-52, NCHRP 09-54 and RILEM) in relation with the current Standard AASHTO R30 (Standard Practice For Mixture Conditioning of Hot Mix Asphalt standard) and to make comparison with the samples performance taken from the field in terms of Indirect Tensile Strength (ITS). The level of aging has also been compared with the samples taken from recently constructed pavement surface and from the five years old pavement surface. Results depicted that, laboratory aging methods revealed the field aging properties on the unaged bitumen. Based on the results, 2 hours forced draft oven aging at 135°C is recommended as short term aging condition because, 2 hours or 4 hours short term forced draft oven aging did not yield significant variation in terms of ITS values. Additionally, 120 hours (5 days) oven aging of compacted samples at 85°C can be recommended as long term aging condition.

Influence of Long-Term Aging on HMA Made with Gel and Sol Asphalt Cements

This study evaluated the effect of long term ageing (LTA) on the performance traits of dense graded asphalt mixes (DGAMs) made from gel and sol asphalt cement binders. The LTA was adopted at 85 °C and between four and eight days using forced draft oven to reproduce the in-service aging that occurs over many years in the field. The performance assays contains: Marshall traits, tensile and compressive strength under wetting and drying conditions, bending strength at zero and -10°C, cohesion at 60°C, tensile strength ratio, and recovered strength index were adopted on DGAMs. A mechanistically-design tool was explored for estimating the enhancement in paving life or thickness reduction of DGAMs and base course for similar service life caused from LTA of DGAMs. Assays results notified that the LTA increases DGAMs strength towards: (1) rutting; (2) moisture sensitivity; (3) cracking; and (4) cohesion failure. In addition, it was found that sol asphalt cement performs slightly better than gel asphalt cement, especially in the case of moisture susceptibility and flexural strength properties.

The Excretion of Ca, Mg, Zn and Cu Through Excreta of Laying Hens Fed Two Different Levels of Protein with and without Phytase

An 8-week experiment was conducted to study the effect of added Natuphos® 5000 phytase in corn–soybean meal-based diets on laying hens fed different levels of crude protein (CP) (14 and 17%). Two levels of phytase enzyme were used: 0 and 600 Phytase Units (FTU)/kg feed. The experiment used 144 Hisex Brown laying hens in a 2 × 2 factorial design. Four treatments and three replicates per treatment with 12 hens per replicate were used. Egg production was recorded daily while egg weight was assessed on 13th and 14th day of each two-week period to calculate total egg mass. Total excreta were collected and approximately 10% of the amount was used for analysis after drying in a forced draft oven. The results showed no significant effect of added phytase on excreta Calcium (Ca) content, but significantly lower Magnesium (Mg) content was observed with phytase (3.54, 2.48, 3.13 and 2.75 % for hens fed 14% CP no phytase, 14% CP + phytase, 17% CP no phytase, and 17% CP + phytase, respectively). Added phytase also significantly decreased Mg excretion measured as grams/kg of egg mass (21.43, 12.47, 16.76 and 14.75 g/kg egg mass for hens of respective dietary treatments. Phytase had a strong effect on Zink (Zn) levels with 438.96, 369.17, 434.38 and 374.58 mg Zn/kg dry excreta of hens. Similar results were observed with Cu. Added phytase significantly reduced the excreta content and the excretion of Cu. The results of this experiment indicate that adding 600 FTU to laying hen diets containing 14% CP decreases the excretion of Mg, Zn and Cu without any adverse effects on the egg mass produced of laying hens.

Aging of bituminous mixes for rap simulation

The use of reclaimed asphalt pavement (RAP) has gained considerable importance due to increasing environmental concerns and the search of more economic ways in road paving. Although a large amount of RAP is produced each year, only a part of it can be recycled in a suitable way. The efforts have been towards increasing the RAP content, and if possible, making complete use of RAP in road pavement construction. There have been many studies conducted on the aging of bitumen and compacted bituminous mixes, however the effects of aging conditions on the loose bituminous mixture to simulate RAP has not been examined in detail. As part of a research project on hot mix asphalt recycling, the effect of temperature, aging duration, humidity, oxygen concentration, and sample thickness on loose asphalt aging for the production of RAP was investigated. Bituminous mixture was aged in the forced draft oven in a special aging box and representative samples of asphalt were taken at defined time intervals for rheological tests. Hyperbolic-like curves were observed for rheological properties of bitumen versus aging duration. Asphalt aging was shown to be not only affected by the temperature, oxygen content, aging duration, and humidity but also the presence of trace substances in the air. No effect of layer thickness on the bitumen aging was found.

Recovery and Laboratory Testing of Asphalt Emulsion Residue

This study involves application of two new test methods to the recovery of asphalt emulsion residue, long-term oxidative aging of the residue, and mechanical testing of the unaged and aged residue to determine low- and intermediate-temperature rheological properties. The new methods are the simple aging test (SAT), which is a thin-film (300 μm) oxidative aging test, and a dynamic shear rheometry technique (commonly referred to as 4-mm DSR), which allows testing to −40°C and requires only 25 mg of material. Three polymer-modified emulsions are recovered by two methods: AASHTO PP 72-11 Method B and use of an SAT plate. Both methods use the same evaporative technique to recover the residue (6 h at 60°C in a forced draft oven). The rheological properties (m-value, G* sin d, and ductility) of the recovered emulsion residues by both methods are reported as well as the rheological properties of the aged emulsion using the SAT. The rheological properties of the unaged emulsion residues recovered are roughly equivalent. The proposed SAT recovery method and application of 4-mm DSR offer significant improvements over Method B and current DSR methodology. The recovery process is simpler with the SAT plate than with Method B, and the SAT plate has been designed so that it can be placed directly in a standard pressure aging vessel (PAV) for long-term aging, and the time required for standard PAV aging is reduced from 20 to 8 h. There is no extrapolation of intermediate-temperature DSR data to low temperature. The error from instrument compliance at low temperature is corrected in the 4-mm DSR procedure.

Rheological Behavior of Emulsion Residues Produced by Evaporative Recovery Method

The increasing use of surface treatments has generated a need for the development of specifications and test methods for performance of construction and in-service properties of emulsions. A major impediment in characterizing emulsion is the establishment of a generally accepted residue recovery method. ASTM recently approved a procedure for a low-temperature evaporative recovery method. It involves consecutive 24-h curing periods at 25°C and 60°C in a forced-draft oven. Initial rheological evaluation of emulsion residues indicates that residue properties far exceed those of the unaged base binder and are closer to those of aged materials. Also, concerns have been expressed about the length of this procedure and the possibility for reducing the time required. This study focused on evaluating whether the full 48-h curing period is required and identifying the cause of different behaviors relative to base binders. Evaluation was conducted at high and intermediate temperatures on emulsion residues and base binders subjected to different aging conditions, with the dynamic shear rheometer. The study included neat and polymer-modified base asphalts, and latex, polymer-modified, and conventional cationic rapid set emulsions. Results indicate that oxidative aging contributes significantly to the change in rheology with time of curing, compared with unaged base binder. Especially for modified emulsions, the full 48-h curing period is needed for full development of rheological properties. However, the properties should be compared with short-term aged binders rather than unaged binders. Results support the ASTM method but suggest that residue be considered rolling thin-film oven-aged material rather than unaged material.

Mild experimental climate warming induces metabolic impairment and massive mortalities in southern African quartz field succulents

Current thermal regimes for many southern African succulent species of the subfamily Ruschioideae, which rapidly diversified during the cooler Pleistocene period, may be close to their tolerable extremes, and likely exceeded with anticipated future climate warming. This hypothesis was tested by exposing succulent species of different size and architecture to differently elevated temperatures approximating future African climate scenarios (2.5–3.8 °C increases in mean annual daily temperature maxima) using transparent hexagonal open-top chambers of different heights. Air temperatures, soil water potentials and amounts of fog and dew precipitation were monitored hourly in the differently heated open-top chambers and ambient environment, and changes in species leaf densities and canopy covers precisely determined in these chambers and ambient environment from high resolution digital images taken at 3-monthly intervals spanning a 12-month monitoring period. Photochemical efficiencies and activities of the photosynthetic enzyme Rubisco were also measured in one widespread dwarf succulent species following 2-h exposures of its populations in a forced draft oven to eight different heat intensities (range: 40–54 °C), the highest closely matching the temperature extreme of 54.8 °C recorded in the most intensively heated open-top chambers. After 12-months warming, all succulent species displayed massively (up to 90.2%) reduced leaf densities and canopy covers in the differently heated open-top chambers, with small sparsely branched species comprising single leaf pairs per axis exhibiting much greater reductions than large, shrubby or creeping species with multiple leaves. Noteworthy, was that fog and dew precipitation levels and soil water potentials at the centres of the least intensively heated chambers did not differ significantly from those in the ambient environment, even during the critical dry summer and early autumn seasons. However, leaf density and canopy reductions in these chambers were of similar magnitude to those in the most intensively heated chambers where fog and dew precipitation levels and soil water potentials were significantly reduced. These findings identified elevated temperatures as the principal cause of the observed massive reductions in leaf density and canopy cover and supported the hypothesis that mild anthropogenic warming could exceed the thermal thresholds of many southern African quartz field succulents leading to metabolic impairment. This impairment explained by an observed loss in the catalytic efficiency of Rubisco at daytime temperature extremes exceeding 54 °C, preceded by a decrease in PSII electron transport commencing at temperatures much lower than the threshold for Rubisco de-activation.

Short-term aging characterization of asphalt binders using gel permeation chromatography and selected Superpave binder tests

Both the rolling thin film oven test (RTFOT) and the short-term oven aging (STOA) methods are used in the laboratory to represent the aging of an asphalt binder during plant mixing, transportation and paving. The RTFOT is conducted at 163 °C for 85 min, and the recommended STOA methods are to heat the loose mix in a forced draft oven either at 135 °C for 4 h or at 154 °C for 2 h dependent on the asphalt binder’s stiffness. The actual time of short-term aging in the field varies depending on hauling distances or paving times. This research was initiated to compare the aging effects of the RTFOT and the STOA methods using the gel permeation chromatography (GPC) and selected Superpave binder tests. For this study, nine asphalt binders were prepared, and five aging periods were used for the RTFOT and four aging treatments were selected for the STOA. Loose asphalt mixes were obtained from six field projects. The results of GPC test showed that the RTFOT method has less aging effect on the binders than the STOA methods for asphalt mixtures prepared in the laboratory. Given the limited number of samples from the field, it was difficult to find any correlation of short-term aging between the laboratory and the field. The longer the aging time in the RTFOT led to an increase in the high temperature viscosity and the high failure temperature of asphalt binders, the only exception being the rubber-modified binders. The GPC was effective in evaluating the aging effect of rubber-modified binders using different RTFOT aging times.

EFFECTS OF NITROGEN FERTILIZER ON PRODUCTIVITY OF MEDICINAL PUMPKIN

EFFECTS OF NITROGEN FERTILIZER ON PRODUCTIVITY OF MEDICINAL PUMPKIN

Poind Soil pH Measurement

Soil pH often is measured in samples from the bottoms of aquaculture ponds. Several different techniques for soil pH are used. This study considered the differences in pH obtained by the different methods and determined which methods appeared most useful. Dual electrodes (indicating and reference) and a single-probe combination electrode gave similar pH values when inserted into 1:1 mixtures of dry soil and distilled water. There were slight differences in pH between readings with dual and combination electrodes when the dual electrodes were arranged with the indicating electrode in the sediment phase and the reference electrode in the supernatant phase of the mixture. The two-phase method with the dual electrode does not appear warranted because of greater difficulty in making measurements. Dry soil: distilled water ratios of 1:2.5, 1:5, and 1:10 had progressively greater pH readings than obtained at a 1:1 ratio. Measurements made in 0.01 M CaCl2 and 1.0 M KCl had much different values than those made in distilled water. Higher pH resulted when pH was measured without stirring or in filtrates of soil-water mixtures. A 20-min period of intermittent stirring before making measurements was necessary for a stable pH value. Particle size did not influence pH in aliquots passing 0.053 to 2.36-mm sieves. Drying temperature had a strong influence on pH, and measurements made on samples dried at 40 to 60 C are probably most reliable. Measurements of in situ pH in wet soil with standard pH electrode or a portable acidity tester differed greatly from those made in 1:1 dry soil to distilled water mixtures. Pond bottom soil pH measurement should be standardized. Based on findings of this study, the following method is suggested: dry soil at 60 C in a forced-draft oven; pulverize soil to pass a 2-mm sieve; mix soil and distilled water in a 1:1 ratio (weight: volume); stir intermittently with glass rod for 30 min; insert dual electrodes or a combination electrode into the mixture; measure pH while stirring.

Oven drying improves the nutritional value ofCalliandra calothyrsus andGliricidia sepium as supplements for sheep given low-quality straw

Leaves from the tree legumes Gliricidia (Gliricidia sepium) and Calliandra (Calliandra calothyrsus) were fed as supplements (200 g dry matter) to sheep (n=3) given a basal diet of barley straw ad libitum. Tree leaves were fed either freshly harvested (F=fresh) or after drying at 60°C in a forced draught oven (D=dried). Voluntary intakes, digestibility and aspects of nitrogen (N) and phenolic compound metabolism were measured in all sheep. Drying decreased the condensed tannin (CT) content of Calliandra (F 117, D 82 g CT kg−1 DM). Total phenolics (TP) were significantly decreased when Gliricidia was dried (F 39, D 21 g TP kg−1 DM), and CT content was reduced from 20 g CT kg−1 DM to zero. Sheep given Gliricidia had higher rumen ammonia concentrations (73–85 mg N litre−1) than did sheep given Calliandra (37–40 mg N litre−1). For both species, drying significantly increased the voluntary consumption of straw, increased DM digestibility, decreased faecal N excretion and increased N balance. For calliandra, drying decreased the apparent degradability of N in the rumen (DNR) from 0·40 to 0·28 g N g−1 N ingested, and increased the apparent digestibility of N (ADN) in the post-ruminal tract from 0·20 to 0·52 g N absorbed g−1 N flowing into the small intestines. For Gliricidia, DNR decreased from 0·64 to 0·51 and ADN increased from 0·41 to 0·56. There were no significant effects of drying on rates of microbial N synthesis. The above changes were discussed in relation to changes in tannin content and it was concluded that drying facilitates the formation of protein–tannin complexes which protect proteins from degradation in the rumen. These proteins are subsequently released in the small intestines, thereby promoting an increased efficiency of dietary N utilisation. ©1997 SCI

Endotoxin Reduction in Cotton Fibers: Effect of Flash Heating on Endotoxin Content, Fiber Physical Properties, and Processability

Raw cotton fiber was heated by three processes ( metal plates, forced draft laboratory oven, and gas-fired pilot plant dryer) to compare their effect on endotoxin content of the fiber. To achieve about 90% reduction in endotoxin content, it was necessary to treat the cotton between the metal plates for 120 seconds at 215°C (419°F), in the forced draft oven for 60 seconds at 250°C (482°F), or in the pilot plant dryer for 15- 20 seconds at 250°-255°C (500°F). Fabric could be knit from heated cotton despite reductions in fiber bundle tenacity and elongation and yarn tenacity caused by the heat treatment. Heat-induced discoloration could be eliminated by a desize / scour / bleach treatment of fabric knit from heated cotton.

Recovery of Fecal Chromium Used as a Digestibility Marker in Cattle

Chromium content of fecal samples that were mixed with Cr-mordanted rumen contents at 5 or 10 g/200g feces in Experiment 1 and at 5 or 10 g/300 and 200g feces in Experiment 2 was determined by atomic absorption spectroscopy. Recovery of Cr was estimated after digesting fecal samples, which were frozen fresh and later thawed or dried in either a forced draft oven at 60°C or in a microwave oven in Experiment 1. Experiment 2 evaluated the efficacy of each of three methods of digestion in recovery of Cr from fecal samples. Recoveries of Cr from feces were calculated relative to the Cr content of the Cr-mordanted rumen contents, which were determined by atomic absorption spectroscopy of samples digested with concentrated nitric acid in the presence or absence of the wetting agent Tween 80. Recovery of Cr from fecal samples frozen fresh and later thawed was greater than that from either forced draft oven or from microwave oven-dried samples, especially when the concentrated nitric acid digestion was used. Neither the double ashing procedure nor the digestion with the weaker nitric acid did not improve Cr recoveries from the samples.

Drying of bananas using microwave and air ovens

SummaryDrying tests for ripe and green banana (Musa cv. Giant Cavendish AAA) slices and for a foam made from ripe banana puree were performed in a household microwave oven and in a laboratory forced draft warm air oven. Weight change of the banana slices as a function of time in both ovens, and temperature and relative humidity (RH) of air leaving the microwave oven were recorded. Drying rates were calculated and the data fitted to a variable diffusion model. Drying time in the microwave oven was seventeen to twenty times less than in the forced draft oven. The drying energy efficiency in the microwave oven was about 30%.

The Determination of the Moisture of Rapeseed, Rapeseed Meal, and Soybean Meal, and the Oil Content of Rapeseed

To improve the reproducibility of data for the moisture content determination of repeseed, the effects of drying temperature and drying time on moisture content, and those of sample grinding conditions on oil content were examined.The same was also done for rapeseed meal and soybean meal. The moisture content of 10g of whole rapeseed after 3h at 130°C in a forced draft oven was higher and showed less deviation than that of rapeseed processed by the present standard method, i.e., 5g of ground rapeseed after 3h 105°C in the forced draft oven. The oil content of rapeseed was affected by the amount of sample grinding. The oil content of a sample ground by a mechanical device, such as a coffee mill, was higher than that ground by a mortar and pestle. Mechanical grinding probably produced more uniformly five particles. The moisture content of rapeseed meal and soybean meal after 3h at 130°C was higher than that of the present standard method, i.e., after 3h at 105°C and after 2h at 130°C respectively. The moisture content of rapeseed meal after 3h at 130°C showed less significant deviation than that of the present standard method, after 3h at 105°C.

Automatic karl fischer titration of moisture in sunflower seed

AbstractAn automatic Karl Fischer (KF) titrator of the motor‐driven buret type was applied to the determination of moisture in sunflower seed. A study of the effect of sample size on KF moisture analysis showed a significant decrease in moisture content with increase in sample size from 1 to 5 g. In the moisture range of 5.5–10.5%, a sample size of 3–4 g gave moisture values closest to those obtained by the AOCS official oven method for sunflower seed. Comparison of KF moisture analysis with oven methods on 6 samples with moisture contents ranging from 5.4 to 12.7% showed that KF moisture values were not significantly different from air oven and vacuum oven methods. The mean standard deviation of KF determinations of whole sunflower seed was 0.11% moisture content, whereas for forced draft oven moistures, the mean standard deviation was 0.05%. KF moisture values generally were slightly lower than the air oven moisture values. Using KF and vacuum oven methods to measure moisture contents, sunflower seed were found to lose 0.6% moisture from a sample containing 8.9% moisture when grinding the sample with Hyflo Super Cel as in the AOCS official method.

Performance of High Producing Cows in Early Lactation Fed Protein of Varying Amounts, Sources, and Degradability

Eighty-four multiparous Holstein cows were fed a standard ration from 0 to 21 days postpartum and treatment rations from 22 to 91 days. Treatments varied in amount and source of protein, and only cows averaging at least 26kg milk daily from 8 to 21 days postpartum were used. Experimental variables included protein percent (11.3, 14.5, 17.5), ammoniated versus untreated corn silage, and heated (2.5h at 140°C in forced draft oven) versus normal soybean meal. Treatments by protein percent and supplement types were: 1) 11%, untreated silage, normal soy; 2) 14%, ammonia silage, heated soy; 3) 14%, untreated silage, heated soy; 4) 14%, untreated silage, normal soy; 5) 17%, ammonia silage, heated soy; 6) 17%, untreated silage, heated soy; and 7) 17%, untreated silage, normal soy.Milk production and dry matter intakes increased with increased protein. Differences were greater between 11 and 14% than between 14 and 17%. At 14 and 17% protein, cows fed normal soy produced less than those fed heated soy, but silage treatments were not different. The 17% ration containing ammonia silage and heated soy resulted in greatest milk production and highest income over feed costs. A combination of heated soybean meal to limit rumen degradabihty and ammonia in corn silage to furnish nonprotein nitrogen was the most productive and profitable of several rations compared for cows early in lactation.

The use of chromic oxide as a food marker —a warning

AbstractFour mixtures of ground barley and soya bean meal were prepared; the first had no further additive, the second had 10% soya bean oil, the third 0.05% chromic oxide and the fourth both 10% soya bean oil and 0.05% chromic oxide. Each of these mixtures was then dried in three ways: at 30°C in vacuo and at 60 and 100°C in a forceddraught oven. The total fatty acid content and the fatty acid composition of each sample was determined either by direct esterification of the fatty acids with methanolsulphuric acid or by extraction into chloroform‐methanol followed by esterification with sodium methoxide. When the mixture containing both oil and chromic oxide was heated at 100°C, about 25% of the polyunsaturated fatty acids were lost when they were directly esterified and about 50% when the fat was first extracted from the mixture. It is concluded that this loss is probably due to oxidation of the polyunsaturated fatty acids by the chromic oxide and that the additional loss observed when the extraction method was used is due to partial insolubilisation of the triglyceride by these oxidised fatty acids.