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In this study, reused sunflower cooking oil was investigated for rancidity. Three student cafeterias at the University of Dodoma (UDOM) were used for this particular study. Oil samples were analyzed at the University of Dodoma laboratories. Results showed that all parameters were beyond permissible limits by WHO/FAO standards. Acid values ranged between 0.841 and 4.319 mg KOH/g oil, which is beyond the allowable limits by WHO/FAO (0.6 mg KOH/g oil). Peroxide values were found to be 19.5 mill eq O2/kg oil (minimum), and 62 mill eq O2/kg oil (maximum), which are both above the recommended limits by WHO/FAO (10 mill eq O2/kg oil). Iodine values were found to be from 102.87 to 48.26‐g I2/100 g oil, and were all beyond the recommended limits by WHO/FAO, of between 118‐ and 141‐g I2/100 g oil. The study has further revealed that the number of customers that are saved by the three cafeterias exceeds the capacity of the cafeterias. This study also found out that many students (almost 74%) are not aware on general knowledge about rancidity, including health effects of using rancid oils. It is therefore recommended to the national regulatory authorities to formulate strict regulations to guide and control oil rancidity. [ABSTRACT FROM AUTHOR]

Deep frying is the most common method used for food preparation worldwide, which can lead to several chemical changes in used fat or oil in frying process including oxidation and polymerization. This study aimed to determine the effect of heating and different storage conditions on the disposal point of four types of the most common edible oils available in the Iranian market without and with the presence of food in terms of acid value (AV) and total polar compounds (TPC). AV and TPC of three types of marketed sunflower oil (especially for frying, cooking, solid vegetable) and ghee heated at 110, 150, 180, and 200°C with a portable oil meter DOM‐24 (ATAGO, Japan) were determined. They were measured without the presence of food at four different temperatures and four different times in five storage conditions and with the presence of frying food (chicken and potatoes) at 110°C for 20 min in three replicates. The results showed that the AV and TPC contents in the case of ghee were above national and international standards without the presence of food. Also, in the process of frying chicken and potato, the reusability of all the studied oils was not possible for the second time and reached the disposal point. The increase in the rate of AV and TPC of oils was: ghee (Kermanshahi oil) > liquid cooking oil > frying oil ≥ solid vegetable oil. [ABSTRACT FROM AUTHOR]

Background and Objectives: Quantifying the acid value of stored wheat is of great significance for timely treatment and avoiding waste. For the low‐fat content in wheat, the aim of this study is to propose a microchemical way for the acid value analysis. Findings: Twenty‐four wheat samples are taken from the grain reserve depot and the acid values of them are analyzed by the spectral response of one phthalocyanine dye, tetra‐α‐octoxy substituted zinc phthalocyanine, to a fatty acid. Under the experimental conditions, a linear relation exists between the absorbance of this dye at 749 nm (A749 nm) and the concentration logarithm (lncb) of fatty acid (palmitic acid) in chloroform, R2 = 1.000. Conclusions: By the aforesaid linearity, 1 µl of extracted wheat oil is enough to determine the acid values of wheat samples, which can avoid the interference from the color of the sample in traditional titration. Significance and Novelty: The UV‐visible method has great potential in the actual analysis of the acid value of wheat samples and has important reference value for the analysis of other related agricultural products, food and drugs, and so on. [ABSTRACT FROM AUTHOR]

In the present study, acid value optimization in continuous biodiesel production from high viscous nonedible rubber seed oil (RSO) is presented. Gradual reduction in acid value from 67.6 (mg KOH/g oil) (raw RSO) to 3.55 (mg KOH/g oil) (pretreated RSO) to 0.25 (mg KOH/g oil) (synthesized biodiesel) is detected at reaction conditions of 9:1 alcohol:feedstock (methanol:oil (molar ratio)) (mol/mol), 4 h of residence time, and 5 wt% (oil) of catalyst concentration. Optimization of experimental factors is studied using well‐known data‐based tools called response surface methodology (RSM) and artificial neural network (ANN), respectively. A significant second‐order quadratic model with alcohol:feedstock molar ratio (mol/mol) as most influencing experimental factor is observed from ANOVA analysis of RSM studies. A mean‐square error (MSE) of 0.001245 is observed with the best validation performance of 0.0014716 at epoch‐3 in ANN modeling. Comparing the coefficient of determination (R2) of value 0.8906 (from RSM studies) with the value of 0.99 (from ANN modeling) reveals that ANN is the best fit model with experimental value in acid value optimization of continuous biodiesel production from RSO. [ABSTRACT FROM AUTHOR]

This work investigated the effects of different storage periods (0 day, 90 days, 120 days) on the quality of large yellow croaker oil. The lipomics of large yellow croaker oil was quantitatively detected by GC‐MS, the content of triglyceride in large yellow croaker oil reached 52.56% at 0 day. With the extension of storage time, the content of large yellow croaker oil components decreased gradually. Differential lipid histogram clearly indicates that the extension of the storage period will affect the change of fish oil, due to the rise in the temperature of large yellow croaker oil; the color of the hot map is bright from the dark. Additionally, the fatty acid composition and volatile components were measured. At 120 days, the decomposition rate of lipid molecular in large yellow croaker oil is increased by oxidation of unsaturated fatty acids, and its oxidised metabolite produced small substance such as aldehydes, ketones, alcohols, and acids. During storage, the waxy, fat, and floral flavour in the oil aroma of large yellow croaker oil decreased gradually, while the yeast flavour and oil flavour increased gradually. These results provide insights for the study of lipid transformation and quality of large yellow croaker oil during different storage. [ABSTRACT FROM AUTHOR]

Waste cooking oil (WCO) is a problematic waste product that contains free fatty acids (FFAs), preventing it from being valorized easily as biodiesel and poses an environmental hazard if incorrectly disposed. The use of WCO as a carbon source for Rhodosporidium toruloides (R. toruloides) using a two‐phase culture system is developed. The normal growth of R. toruloides when cultured in WCO (OD600 52) reveals its ability to use a hydrophobic substrate as the carbon source compared to glucose (OD600 51.9). Interestingly, the extracellular lipase activity when R. toruloides is grown on WCO is 14.4 U mL−1 compared to when grown on glucose (2.4 U mL−1). Additionally, FFA levels in WCO are reduced from 2% to 0.2% at end of fermentation, suggesting that R. toruloides can consume FFA. Furthermore, higher yield of beneficial products: β‐carotene (4.57 µg mL−1), torularhodin (4.2 µg mL−1), fatty acids (1 mg mL−1), and phenylalanine ammonia‐lyase (PAL) enzyme (0.12 µmol mg−1) are produced when WCO is the carbon source, compared to glucose (4.1 µg mL−1 β‐carotene, 3.0 µg mL−1 torularhodin, 1 mg mL−1 of fatty acids, and 0.096 µmol mg−1 PAL enzyme). This is a first study that shows R. toruloides can grow on hydrophobic carbon source. [ABSTRACT FROM AUTHOR]

Summary: Oxidation stability is one of the most significant fuel quality standards for biodiesel and mainly distresses the stability of biodiesel. Therefore, the present work aims to report the Eucalyptus oil (EO) as a natural green antioxidant additive to evaluate the oxidation stability of biodiesel produced from dairy waste scum, Bauhinia variegata and Butea monosperma oil. The obtained results have also been compared with the conventional synthetic antioxidant, butylated hydroxy toluene (BHT). The oxidation stability of the biodiesel treated with these additives was evaluated using the professional biodiesel Rancimat instrument. Further, the fuel properties kinematic viscosity and acid value were measured during the storage period. The obtained results showed an increase in the induction period in the biodiesel sample treated with EO, indicating a protective effect and inhibiting the oxidation initiation step. As a result, the oxidation stability of dairy waste scum methyl ester (DWSME), B variegata methyl ester (BVME) and B monosperma methyl ester (BMME) was found to be ~10, ~8 and ~8 hours, respectively, during 90 days storage when the natural antioxidant EO with a concentration of 4000 ppm was used and these obtained values were in the limit of EN 14214 standard. Interestingly, these values were found to be on par with the oxidation stability of DWSME (~11 hours), BVME (~9 hours) and BMME (~9 hours), when the synthetic antioxidant BHT was used with a concentration of 3000 ppm during the 90 days storage. Although the addition of EO as antioxidant resulted in increase in kinematic viscosity and acid value of the biodiesel samples, those values well‐fall in the ASTM 6751 standard limit. On the other hand, synthetic antioxidant BHT showed enhanced results as compared to the EO. However, the effectiveness of the proposed natural antioxidant additive (EO) is on par with the synthetic antioxidant (BHT), which can be replaced for cost‐effectiveness, non‐toxic and safer consumption of biodiesel as compared to synthetic antioxidant‐treated biodiesel. [ABSTRACT FROM AUTHOR]

Data interpolation and principal component transformation (PCT) were used to compute the discarding points of a frying oil by measuring the physicochemical parameters—acid value, carbonyl value, and total polar compounds. Herein, the discarding point refers to the time point (associated with the value of each physicochemical parameter) at which the frying oil should be discarded. First, a primary visual analysis was performed for the obtained data by using line charts. Second, a curve interpolation method was used to compute the discarding points for each parameter and thus determine the discarding points for the frying oil. At 190, 205, and 220°C, the frying oil reached the discarding points at 22.1, 17.7, and 13 hr, respectively. The discarding area was also visualized on the corresponding surfaces for the originally obtained data and the interpolated data to investigate the discarding points. Third, the PCT was conducted for the three parameters at each temperature; the discarding point estimation for the three parameters could be reduced to the estimation from the first principal component (FPC), thereby simplifying this process. At 190, 205, and 220°C, the frying oil reached the discarding points when the FPCs were 10.4524, 6.2881, and −1.7629 at the time points 22.1, 17.7, and 13 hr, respectively. Finally, a verification experiment revealed that the correlation between the results obtained by our interpolation method or PCT and the verified data was higher than 0.98, which demonstrates the effectiveness of our method. [ABSTRACT FROM AUTHOR]

Advanced four‐mask process a‐Si TFT array manufacturing method and good TFT stability is presented in this paper. We used an optimum half‐tone mask transmittance and half‐tone photoresist for the four‐mask process architecture. Data line open and photoresist peeling issues occurred in G8.6 TFT‐LCDs and solutions will be shown. [ABSTRACT FROM AUTHOR]

Abstract: BACKGROUND: In order to investigate the effect of ultrasound dielectric pretreatment on the oxidation resistance of vacuum‐fried apple chips, apple slices were pretreated at ultrasonic powers of 150, 250 and 400 W for times of 10, 20 and 30 min before vacuum frying. The quality and oxidation resistance of fried apple were evaluated by testing the dielectric properties and comparing the moisture content, oil uptake, color, acid value (AV) and peroxide value (PV) of apple chips. RESULTS: Ultrasonic treatment significantly changed the dielectric properties of apple slices. Moisture and oil contents of apple chips decreased with increasing ultrasonic power and time. During storage, the color retention of fried apple chips processed by ultrasound was improved. AV and PV values of fried apple chips processed by ultrasound were lower, which improved their antioxidant properties. CONCLUSION: The results of the present study indicated that ultrasound dielectric pretreatment improved not only the quality of vacuum‐fried apple chips but also their antioxidant properties. © 2018 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

Abstract: The quality of rapeseed oil largely depends on the quality of postharvest preservation of raw seeds. Fungal infestation at early stages of the storage of rapeseeds is a major cause of their spoilage. The knowledge of relations between the storage conditions, fungal contamination, and technological quality of rapeseeds is essential to specify key control points that can be used to improve postharvest management systems and maintain rapeseed quality. The aim of this study was to define decisive control points on the basis of the kinetics of early mold growth in ecosystems of rapeseeds in a hazardous initial microbiological state, stored under various water activity and temperature conditions (a w =0.78–0.96 and t =12–30 °C). A correlation between the acid value (AV), germination, and fungal infestation of seeds was found in ecosystems with significant mold activity. The analysis of the mold growth kinetics with regard to AV, seed germination, and visible mold time showed that the detection of early (invisible) fungal growth could be a good basis for determining the time during which rapeseeds should be protected from deterioration. The research results showed how to use the length of the lag phase to identify decisive control points, which are necessary to improve the existing control systems of rapeseed preservation and storage. [ABSTRACT FROM AUTHOR]

Advanced four‐mask process a‐Si TFT array manufacturing method and good TFT stability is presented in this paper. We used an optimum half‐tone mask transmittance and half‐tone photoresist for the four‐mask process architecture. Data line open and photoresist peeling issues occurred in G8.6 TFT‐LCDs and solutions will be shown. [ABSTRACT FROM AUTHOR]

The effect of extruder shear rate (500, 750, 1125, 1500 and 1750/s), feed temperature (5, 7, 10, 13 and 15 °C) and storage temperature (5, 7, 10, 13 and 15 °C) on the acid value, colour (L*, a* and b*values) and texture (hardness and adhesiveness) of organic butter was examined. The optimised conditions in terms of extruder shear rate, feed temperature and storage temperature were 1345/s, 13 °C and 7 °C, respectively. At the optimised conditions; the predicted responses were determined as hardness 42.5 g/cm, work softening 67.2%, adhesiveness 42.5 gf/cm, acid value 3.4 mg KOH/kg and L* value 99.57. [ABSTRACT FROM AUTHOR]

The consumption of fish oil-based dietary supplements has increased dramatically in recent years, which is mainly due to their high content of health promoting omega-3 fatty acids. However, these polyunsaturated fatty acids are extremely prone to oxidation. This study investigated the potential of 1H NMR spectroscopy for the assessment of the oxidative deterioration of fish oils. Nine raw fish oils of different fish species were stored for 3 months at room temperature at different degrees of sunlight exposure as well as under standardized accelerated storage conditions for 6 days (at 40°C and under constant light exposure). Fish oil samples were analyzed by 1H NMR spectroscopy as well as by traditional methods to determine the fat quality parameters peroxide value (PV), anisidine value (AnV), TOTOX value, and acid value (AV). PLS (partial least squares) regression models were used to predict these fat quality parameters based on the 1H NMR spectra. The best regression models reached an R2 of 0.949, 0.962, 0.991, and 0.977 for PV, AnV, TOTOX value, and AV, respectively. In conclusion, 1H NMR spectroscopy is a promising approach for a fast, reliable, and sustainable assessment of fish oil quality with regard to lipid oxidation. Practical applications: The results indicate a great potential of 1H NMR spectroscopy in the quality assessment of fish oils. This technology requires little time, work, amount of sample, and solvent and provides extensive information that can be obtained from a single spectrum. Such an approach is significantly more specific and detailed than traditional lipid oxidation parameters. Nine raw fish oils are stored under different conditions and analyzed by 1H NMR spectroscopy as well as by traditional methods to determine the lipid quality parameters peroxide value, anisidine value, TOTOX value, and acid value. Subsequently, PLS regression models are generated to predict these indices from the NMR spectra. [ABSTRACT FROM AUTHOR]

In this study, the effect of temperature (140, 160, 180 °C) and roasting time (5, 10, 15 min) on the bioactive compound content (canolol, tocopherol and plastochromanol-8) of cold-pressed oil from yellow-seeded rapeseed lines of different colors was investigated. Roasting increased the peroxide value in the seed oils compared to the oils from the control samples. However, roasting did not affect the acid values of the oils, which were 1.15-1.47 and 1.30-1.40 mg KOH/g, for line PN1 03/1i/14 (yellow seeds) and line PN1 563/1i/14 (brown seeds), respectively. In this study, the seeds of line PN1 03/1i/14 were characterized by different changes in canolol content during roasting than the seeds of PN1 563/1i/14. There was a 90-fold increase in canolol for the line PN1 03/1i/14 (768.26 µg/g) and a 46-fold increase for the line PN1 563/1i/14 (576.43 µg/g). Changes in tocopherol and PC-8 contents were also observed. There was an increase in the contents of γ-T and PC-8 in the oils obtained from the seeds roasted at 180 °C for 10 and 15 min. γ-T content increased by 17-18% after 15 min of roasting, whereas the PC-8 content increased twofold. [ABSTRACT FROM AUTHOR]

Enzymatic epoxidation of vegetable oils in the presence of free fatty acids has been well studied in recent years, by mainly using long chain fatty acids ( e.g., stearic acid) as the active oxygen carrier. However, for the previous enzymatic processes, the acid value (AV) of final epoxidized oils using long chain fatty acids is high, and the free fatty acid is not easily removed in the post treatment with water. Aiming at developing a more sustainable process, enzymatic epoxidation of sunflower oil was revisited using different free fatty acids catalyzed by Novozym 435 (lipase B from Candida antarctica, provided by Novozymes, Bagsvaerd, Denmark). When long chain stearic acid was introduced into the epoxidation in toluene solvent, the epoxy oxygen group content (EOC) of 6.41 ± 0.19 % was obtained. Due to the poor water solubility of stearic acid, the AV of the final epoxidized oil product was very high (53.40 ± 1.34) after it was washed with water. Alternatively, current study shows that the epoxidation process using short chain butyric acid produced the final epoxidized oil with lower AV of 2.57 ± 0.11. When the enzymatic epoxidation of sunflower oil was optimized in the presence of butyric acid and Novozym 435, EOC of 6.84 ± 0.21 % was obtained, reaching an oxriane conversion of 96.4 ± 3.0 %. Therefore, introducing short chain butyric acid as an active oxygen carrier will provide an alternative to the present enzymatic epoxidation process and produce the desired epoxidized oil products with much lower AV only after simple water-treatments, which will make the enzymatic epoxidation more attractive. [ABSTRACT FROM AUTHOR]

In this study, the levels of polychlorinated biphenyls ( PCBs), heavy metals and omega-3 polyunsaturated fatty acids (docosahexaenoic acid; DHA and eicosapentaenoic acid; EPA), as well as chemical indices including acid and peroxide values were determined among twenty-four commercially available functional fish oil supplements. The sum of indicator PCB congeners (congeners 28, 52, 101, 118, 138, 153 and 180) was below the limit of quantification of 0.043 mg kg−1. Metallic compounds (Cd, Pb, Hg and As) were not detected in all fish oil supplement samples. The relative percentages of EPA and DHA in fish oil supplements ranged from 25% to 80%. The acid values ranged from 0.1 to 1.4 mg KOH per g oil, and peroxide values ranged from 2.7 to 28.8 meq per kg oil. All fish oil supplement samples tested in current study met the safety standard for fish oil supplements set by Korean government as well as International standard. [ABSTRACT FROM AUTHOR]

The aim of this study was to determine the oxidative stability of rapeseed oils cold pressed from seeds roasted at 140, 160, or 180°C for 5, 10, or 15 min versus the control (oil from unroasted seeds). The oils were stored for a period of 1 year. After 6 and 12 months of storage, the samples were analyzed to determine their peroxide and acid values, the levels of bioactive substances (tocopherols, plastochromanol-8, and canolol), as well as antioxidant activity (DPPH test). It was shown that roasting the rapeseeds had a significant effect on the oxidative stability of the oils, which increased by almost 50%. In the case of oils pressed from seeds roasted at 140 and 160°C, it was shown that the longer the seeds were roasted, the smaller the reduction in canolol content. After 6 months of storage, the percentage decrease in the canolol content of oils from roasted seeds was recorded to be at a level comparable to that of the control. After 1 year of storage, the percentage loss of canolol was markedly lower (from 18 to 45%) than in the control (61%). The reduction in tocopherol levels was dependent on the duration of storage and on the type of sample. Principal component analysis (PCA) confirmed that the oxidative stability of oils produced from roasted seeds, particularly from those roasted at 180°C, was markedly higher than that of the other samples obtained from roasted seeds and the control. Practical applications: Studies concerning oxidative stability are most typically conducted by applying so-called accelerated aging tests performed at high temperatures (Rancimat, Oxidograph test). In practice, this undermines the reliability of the results, since it is difficult to draw conclusions about the actual shelf life of a product, on account of the various mechanisms of the oxidation process. At high temperatures, the primary reactions are connected with polymerization and cyclization, which are not comparable to the reactions taking place under normal conditions. The analysis conducted here made it possible to follow the changes during the storage of the oil and the rate of degradation of bioactive substances reflecting cold-storage conditions. [ABSTRACT FROM AUTHOR]

The effects of water content, acid value, and peroxide value on interesterification catalyzed by potassium glycerolate (in situ KOH/glycerol) were investigated using lard as a model fat. SEM analysis of KOH/glycerol powder showed that numerous 0.5- to 5-μm porous structures were formed and may play an important role in the interesterification reaction. Water content (up to 10 %, oil weight) and peroxide value (4.29 and 7.11 mmol/kg) significantly extended the induction period of interesterification but complete randomization was still achievable. However, when the acid value reached 5.13 mg KOH/g, complete deactivation of the catalyst was observed at 1 % catalyst content (by oil weight). The sn-2 fatty acid composition of fully randomized lard was similar to that of non-randomized lard. Interesterification resulted in substantial rearrangement of the triacylglycerol species and alteration of thermal behaviors. The interesterified lard exhibited a predominant β′ polymorph, as opposed to the dominating β-form crystals found in the original lard. [ABSTRACT FROM AUTHOR]

In this research, modified diesohol blends were characterized with cashew nut shell liquid (CNSL) and biodiesel as additives. Different proportions of CNSL, diesel, and ethanol were prepared to study the properties of the fuel blends such as viscosity, heating value, acid value, and cetane index. The minimum threshold limit of 6 % by volume of CNSL provided a stable mixture. The viscosity increased slightly with increasing CNSL content whereas the heating value was not significantly affected. All of the fuel blends did not meet the fuel standard in terms of the acid value. Biodiesel was used as a substitute for a fraction of CNSL to lower the acid value. The final fuel blend was DE20 (diesohol with 20 % ethanol content) with 0.5 % CNSL and 12 % biodiesel (by volume). The acid value, viscosity, and heating value were 0.78 mg(KOH) g−1, 2.69 cSt, and 40.11 MJ kg−1, respectively. The economic analysis showed that the ex-refinery and retail prices of the fuel blend were 22.83 and 28.32 baht L−1, respectively (≈32 Thai baht=$1 US, with the current exchange rates). [ABSTRACT FROM AUTHOR]

The ' Joint Committee for the Analysis of Fats, Oils, Fatty products, Related Products and Raw Materials ( GA FETT)' has developed the following method for the fast determination of polar compounds, polymerized TAGs, acid value and anisidine value in used frying fats and oils. It will be included to Section C, Chapter VI of the German Standard Methods and will be part of the 19th amemdment to the second edition of the German standard method in autumn 2013. This very important method reflexes the need of the control laboratories to get fast and reliable results for the analyses of used frying fats and oils, it is with safe money and time. The method has been evaluated in an interlaboratory test with 11 laboratories. [ABSTRACT FROM AUTHOR]

SUMMARY In the present work, catalytic cracking of fish oil industrial residue was investigated to study the effect of temperature, type of catalyst and the heating rate on the yield of organic liquid fraction (OLF) and its acid value. The highest bio-oil yield of 72% (wt.) was obtained at temperature range of 300-500 °C and heating rate of 10 °C/min with the mixture of Al2O3 and Na2CO3 as a catalyst. It was found that the mixture of Na2CO3 and MgSO4 as a catalyst gives lowest acid value of 8.75 mgKOH/goil and 68.1% of OLF yield. Furthermore, the acid value is reduced to 0.36 mgKOH/goil using Na2CO3 as an absorbent. The results show that the catalytic cracking process represents a sustainable method to produce bio-oil from fish oil industrial residues with physicochemical characteristics similar to the diesel fuel. Copyright © 2012 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Given the critical need to address smuggling and unauthorised usage of subsidised diesel, the Malaysia Government introduced fuel marking for subsidised diesel under the NanoTag Program in April 2006. NanoTag markers mixture consists of VisioTag (dye) and NanoTag (immunoassay marker) were spiked into palm methyl esters (PME) and its diesel blends. The blending ratio tested was 5, 10 and 20% (by volume) of fatty acid methyl esters (FAME) in diesel fuel. Both NanoTag and VisioTag markers were found to be stable in PME and blended fuel after 9 months of storage. The concentration of the NanoTag marker (MTK-021) remains consistent as determined by HPLC-UV detector. No colour change or discolouration was observed for the VisioTag marker. Other important fuel quality parameters such as acid value, oxidative stability, and moisture content of the samples were studied. The results showed that NanoTag markers pose no significant measurable effects on blended PME and diesel fuel quality upon storage up to B20. [ABSTRACT FROM AUTHOR]

Four common beans (black, kidney, great northern, and pinto) were extracted with hexane and found to contain about 2% triacylglycerols. The fatty acids in these bean oils were mainly linolenic (41.7-46 wt%), linoleic (24.1-33.4 wt%), palmitic (10.7-12.7 wt%) and oleic (5.2-9.5 wt%). Because of the high levels of polyunsaturated fatty acids, the bean oils had iodine values between 174 and 177 g/100 g (compared to 130 g/100 g for soybean oil). Yet, the bean oils exhibited high oxidative stability due to the presence of high amounts of tocopherols (2,670-2,970 ppm). The bean oils had lower pour points (−18 to −11 °C) compared to −9 °C for soybean oil. Among the four bean oils, kidney bean oil had the highest acid value (15.4 mg KOH/g) and kinematic viscosities over a wide range of temperatures. [ABSTRACT FROM AUTHOR]

The production of cold-pressed oil from nonroasted naked pumpkin seeds by pressing with screw presses started in the Republic of Serbia at the end of 1990s. This oil has the characteristic flavour of raw-dried seeds, and is a specific product of this region. The oil samples were prepared by pressing naked pumpkin seeds and pumpkin seeds with the hulls in a 3:2 ratio using a screw press. The changes of the oil sensory characteristics, basic chemical quality and oxidative stability were followed over a 2-year period. The results obtained showed that the oil sensory quality was stable during the first 12 months of storage, after which the flavour became musty. Although the chemical quality of the oil deteriorated to some extent, both the acid and peroxide values satisfied the legislative minimum during the whole investigation time. The oxidative stability of oil determined by a Rancimat apparatus was good, although the induction period after 2 years decreased by 25-40%. To ensure the use of only the highest quality oil, a 12-month shelf life is recommended. [ABSTRACT FROM AUTHOR]

The aim of this study was to characterize aromatherapy massage oils prepared from virgin coconut oil (VCO) and some essential oils. VCO extracted from fresh coconut endosperm by a centrifugation method, which was the most effective method to prepare VCO, was composed mainly of saturated fatty acids, in particular myristic acid. Three essential oils (lemon, eucalyptus and lavender oils) at concentrations of 1, 3 and 5% w/w were blended with the VCO to prepare massage oils. Physical and chemical properties as well as microbial analysis of the massage oils were assessed to evaluate quality characteristics of the preparations. Results showed that types and concentrations of essential oils used somewhat affected viscosity, refractive index and three chemical characteristics (acid, peroxide, and iodine values) associated with oxidative stability of the massage oils. Generally the rank order of acid, peroxide and iodine values of the freshly prepared massage oils appeared to be lemon oil > lavender oil > eucalyptus oil. The results of a accelerated storage stability study (45 °C, 4 months) clearly showed a dramatic increase in both acid and peroxide values of VCO and the blended massage oils compared to initial values, whereas the iodine values of these preparations decreased slightly. The plain VCO and the blended massage oils did not exhibit antimicrobial activity on the test microorganisms and were free from microbial contamination. [ABSTRACT FROM AUTHOR]

Fourier transform near infrared (FT-NIR) spectroscopy was used to analyze multiple measurement parameters in lecithin production samples and soybean oil refining by-products. For lecithin, partial least squares (PLS) calibration models were developed for acetone insolubles, acid value and moisture and leave-one-out cross validation of the calibration models yielded root mean square error of cross validation (RMSECV) values of 0.37%, 0.59 (mg KOH/g) and 0.050%, respectively. An independent test set consisting of 40% of the lecithin production samples were predicted from the PLS calibration models and a root mean square error of prediction (RMSEP) of 0.41%, 0.53 (mg KOH/g) and 0.056% were obtained for acetone insolubles, acid value and moisture, respectively. Comparison of FT-NIR predictions and corresponding reference method values of 10 lecithin samples using a two-tailed t test showed no significant difference at the p = 0.05 level. A set of 51 samples of soybean oil refining by-products, including acidulated soapstock, fatty acids and black oil, were used for developing PLS calibration models for measuring acid value, moisture and iodine value and leave-one-out cross validations for each model gave values for RMSECV of 6.59 (mg KOH/g), 0.046% and 0.42 (mg I2/g), respectively. Overall, the results of this study demonstrate the suitability of FT-NIR spectroscopy for the routine analysis of lecithin production samples and soybean oil refining by-products for quality control purposes. [ABSTRACT FROM AUTHOR]

A new diaphragm electrochemical system was devised and tested for hydrogenation of soybean oil under moderate processing temperature and atmospheric pressure. With proper loading of the catalyst Pd-C, the reactor was operated successfully for 6 h and yielded hydrogenated soybean oil containing 8.62% TFAs with an IV of 88.86 g I2/100 g oil and an AV of 0.7 mg KOH/g oil. The low AV (acid value) of the hydrogenated oil, indicative of the oxidization tendency of the oil, is highly desirable from the industrial application standpoint. The low specific isomerization index was reached with 0.4 mol/L of formate ions at pH 5.0 under 60 °C using a constant applied current density (10 mA/cm2). The extent of hydrogenation was found to increase with increasing current density, formate ion concentration, reaction temperature, catalyst loading, and speed of agitation. It was characterized that the extent of hydrogenation under low pH (2.0–5.0) was controlled by the regeneration of formate ion, whereas under high pH (6.0–10.0) the hydrogenation was influenced strongly by the formate ion stability. [ABSTRACT FROM AUTHOR]

Biodiesel derived from transesterification of soybean oil and methanol is an attractive alternative fuel for combustion in direct-injection compression ignition (diesel) engines. During long-term storage, oxidation due to contact with air (autoxidation) presents a legitimate concern with respect to maintaining fuel quality of biodiesel. This work examines the effects of oxidation under controlled accelerated conditions on fuel properties of methyl soyate (SME). SME samples from four separate sources with varying storage histories were oxidized at elevated temperature under a 0.5 standard cm3/min air purge and with continuous stirring. Results showed that reaction time significantly affects kinematic viscosity (ν). With respect to increasing reaction temperature, ν, acid value (AV), PV, and specific gravity (SG) increased significantly, whereas cold flow properties were minimally affected for temperatures up to 150°C. Antioxidants TBHQ and α-tocopherol showed beneficial effects on retarding oxidative degradation of SME under conditions of this study. Results indicated that ν and AV have the best potential as parameters for timely and easy monitoring of biodiesel fuel quality during storage. [ABSTRACT FROM AUTHOR]

Our work is about the extraction of sunflower seed oil in a twin-screw extruder with or without the injection of 2-ethylhexanol and acidified 2-ethylhexanol. 2-Ethylhexanol is mixed with phosphoric acid. The oil recovery is increased to 90% by the co-injection of acidified alcohol. Mixing phosphoric acid with the alcohol enhances the lability of the oily spherosomes. Its addition increases the destruction of the membranes enveloping the lipid-containing organelles to release the oil more easily. Phosphoric acid exhibits an extracting and a degumming role. The best oil quality was obtained at a low extraction temperature (80°C), when 88% of the oil was removed. After alcoholic distillation, the oil exhibited a total acid value (mineral acidity plus organic acidity) of 4 mg KOH/g of oil and an organic phosphorus content below 30 ppm. [ABSTRACT FROM AUTHOR]

The rapidity and uncertainty of the acid value determination in oilseeds are defined by the rate and completeness of the free fatty acid extraction. The strategy of reagent development for extraction has been discussed, and a set of reagents that provide rapid and complete extraction has been obtained. The set consists of two reagents. Reagent A contains triethanolamine in a mixture of water, isopropanol, and heptane. Reagent B contains a strong acid and inorganic salt in water. Reagent A allows the carrying out of rapid (1-2 min) solid-liquid extraction of the free fatty acids and some other acids from oilseeds. Reagent B provides the separation of the free fatty acids only into the heptane phase (∼5 min), which can be used directly for the free fatty acid determination. Two techniques for this determination have been applied: pH-metric and titrimetric. The advantages of the proposed set of reagents are described. [ABSTRACT FROM AUTHOR]

A new method for determining acid values in vegetable oils has been developed for a nontitration pH-metric technique with a reagent consisting of 0.20 M triethanolamine in a 1∶1 solution of water and isopropanol. The emulsive properties of this reagent provide rapid (within a minute) and quantitative extraction of free fatty acids from an oil into the solvent phase. Acid values were determined by measuring conditional pH of the emulsified reagent in a pH-meter with an aqueous reference electrode. Three different applications of this technique are discussed. [ABSTRACT FROM AUTHOR]

Thevetia peruviana seed showed characteristic changes in physicochemical properties when heated at 180, 200, and 220°C over a period of 15 h. There is no striking significant difference in the five parameters (iodine value, acid value, peroxide value, saponification value, and polar compounds) studied for the three working temperatures. Thevetia seed oil showed good thermal stability and will be a good frying and cooking oil. [ABSTRACT FROM AUTHOR]

Nuclear magnetic resonance (NMR) was used to evaluate the oxidative deterioration of oil in salted dried fish. The ratios of olefinic proteons (Ro) and divinylmethylene protons (Rm) to aliphatic protons in the oil of salted dried fish, as determined by NMR, decreased steadily during storage. On comparing Ro and Rm with data for peroxide value (PV) and acid value, Ro was shown to serve as an index of the oxidative deterioration of the oil of salted dried fish, particularly in the case of oil whose PV had decreased. [ABSTRACT FROM AUTHOR]