Improving Waste Cooking Oil Quality for Biodiesel Production with the Ethanolic By-product of Soybean Oil Extraction

Waste cooking oils (WCO) can be used as feedstock for biodiesel (fatty acid ethyl or methyl esters—FAEE or FAME) production. Their usual high acidity, high moisture, and low stability can impair the reaction yield and generate a low-quality biodiesel. Here, we performed liquid–liquid washings using WCO and ethanol-based solvents with the goal of generating oil-rich miscella as FAEE feedstocks with a higher quality than WCO. Three different solvents were evaluated: 99% ethanol, 95% ethanol, and the soybean oil extraction ethanolic phase (SEP), a by-product with immense unexplored antioxidant potential obtained by extracting soybean oil using ethanol. Washings were performed in a 1000 mL flat-bottom flask at 78.1 °C, using a 1:2 (w/v) oil/solvent ratio, under magnetic stirring (1200 rpm) for 10 min. Ethyl esters were prepared via homogeneous alkali transesterification using WCO and oil-rich miscella as feedstocks. Treatments reduced the acid value by 40–61% and the peroxide value by 15–50%. Improvements in feedstock quality generated 24–54% higher biodiesel yields. The oil-rich phase produced with SEP was 15% more resistant to oxidation than WCO. This was attributed to the transference of isoflavones from the SEP. However, biodiesel from treated samples presented equal or lower oxidative stability than FAEE from WCO. High-performance liquid chromatography (HPLC) analysis showed that no isoflavones remained in biodiesel after purification. Pretreatment of WCO with ethanol-based extracts such as the SEP has great potential to improve WCO quality for biodiesel production as it can be a source of plant-based antioxidants.     

Investigation of Conjugated Soybean Oil as Drying Oils and CLA Sources

Better sources of drying oils for coatings and conjugated linoleic acid (CLA) for potential health benefits are of continuing interest. Iodine under photochemical conditions in hexanesB at reflux temperatures was investigated as a catalyst for conjugating soybean oil (SBO) for use as drying oils and as a potential source of CLA. Variations in catalyst loading, SBO, light source, free radical catalyst, solvent and temperature strongly affected the efficiency of the process. Changes in fatty acid isomer distributions in conjugated SBO (CSBO) influenced drying properties of CSBO. Conjugated dienes formed were predominantly trans-9,trans-11, which contrasts distributions found with catalysts such as strong base and metal compounds. Drying times of some of the CSBOs were superior to that of raw linseed oil. Iodine was partially recovered.     

Effect of Water on the Ethanolysis of Waste Cooking Soybean Oil Using a Tin(II) Chloride Catalyst

Biodiesel production from cheap lipid raw materials is economically welcome, but a high free fatty acids (FFA) content makes it incompatible with traditional alkaline catalysts. Although liquid mineral acids are alternatively used, serious drawbacks such as high corrosiveness and large effluent generation, as well as the impossibility of catalyst reuse compromises its application. Contrarily, solid acid catalysts appear to be an attractive option; however, the water present or generated during FFA esterification provokes the leaching and deactivation of these catalysts. Thus, in this work we have evaluated the use of tin chloride SnCl₂, which is less corrosive, water tolerant, and a recyclable Lewis acid catalyst, on FFA ethanolysis using waste cooking oil samples (WCO). Additionally, the main kinetic parameters of the reactions were assessed. Compared to pTSA (p-toluenesulfonic-acid), a catalyst also evaluated, SnCl₂ efficiently promoted FFA ethanolysis even in the presence of high amounts of water (ca. 0.1–5.0% w/w). Moreover, the homogeneous SnCl₂ catalyst was easily recovered and reused successively, without loss of activity.     

A Comparative Study of the Properties of Selected Melon Seed Oils as Potential Candidates for Development into Commercial Edible Vegetable Oils

A comprehensive compositional and characterization study was carried out on five seed oils from varieties of the melons Citrullus lanatus and C. colocynth in order to evaluate their suitability for large-scale exploitation as edible vegetable oils. The oils were extracted by Soxhlet with a 3:1 mixture of n-hexane/2-propanol with yields that ranged from 24.8 to 30.0% (wt/wt). The refractive indices and relative densities of the oils fell within the narrow ranges of 1.465–1.469 and 0.874–0.954 g/cm³, respectively. Saponification values ranged between 182.1 and 193.8 mg KOH/g, whilst iodine values (IV) ranged from 95.8 to 124.0 (Wijs). The ranges of the values for free fatty acid (AV), 1.2–4.0 mg KOH/g, peroxide (PV), 1.1–10.9 meq/kg and p-anisidine (p-AV), 0.2–9.0, indicated that secondary oxidation products were barely present. GC analysis gave total unsaturation contents of 67.93–82.36%, with linoleic acid (18:2) being the dominant fatty acid (55.21–66.85%). The GC results agreed closely with those from proton NMR analysis of the fatty acid classes. The physicochemical and compositional properties determined in this study show that the qualities of the test Cucurbitacea seed oils are highly comparable to those of soybean, sunflower and groundnut seed oils. Therefore, the test melon seed oils could be developed into commercial products to serve as alternate vegetable oils in Southern and West Africa, the regions where these melons grow.     

Identification of Recycled Cooking Oil and Edible Oils by Iodine Determination and Carbon Isotopic Analysis

Elemental iodine determination by ICP‐MS and carbon isotope analysis by EA‐IRMS were jointly employed to identify recycled cooking oil from edible oils. Iodine in 204 oils demonstrated that recycled cooking oils can be distinguished from soybean oil, maize oil, colza oil, peanut oil, sunflower oil and olive oil with the exception of tea oil and mixed oil. These two types of oils can be definitively distinguished from recycled cooking oil in the carbon isotope ratio analysis. It was proposed to use total iodine analysis as the primary screening method and the carbon isotope ratio measurement as a secondary method for confirmation and verification. For routine screening, threshold values of Iodine determination and δ¹³C measurement were determined to be 20 ng g^?1 iodine and a range of ?27.3 to ?28.5 of δ¹³C, respectively.     

Infrared Spectroscopy and Multivariate Calibration for Quantification of Soybean Oil as Adulterant in Biodiesel Fuels

This work quantifies the adulteration of ethyl and methyl soybean biodiesels/diesel (B5) blended with soybean oil using mid‐infrared spectroscopy associated with multivariate calibration. The models constructed by the method of partial least squares (PLS) presented low values of root‐mean‐square error of prediction 0.22 % (w/w) and 0.26 % (w/w), respectively, for models containing ethyl and methyl soybean biodiesel. Along with the parameters of error, accuracy was evaluated by the use of an elliptical joint confidence region (EJCR). The EJCR for the both PLS models showed there was no significant difference between the prepared concentration values and PLS predicted concentration values, and that there was no evidence of bias within the 95 % confidence level. The PLS models showed excellent correlation in the prediction set (R = 0.999) and did not present systematic errors according to the ASTM E1655 standard. Therefore, the models presented excellent performance in quantifying soybean oil as an adulterant in B5 blends, in concentrations within the range 1.00–30.00 % (w/w). The proposed methodology showed itself to be efficient for quality control of B5 contaminated with vegetable oil.     

Evaluation of Transesterified Hardened and Liquid Soybean Oils as Raw Materials for Margarine Oils

Margarine oils have been prepared by transesterification of blends of hardened and liquid soybean oils or by blending of transesterified hardened oils with liquid soybean oil. The dilatometric characteristics of those oils and their nutritional values (as characterized by the L/S ratio of linoleic acid to total saturated acids) have been compared with the same parameters of margarine oils from local and foreign table margarines. It was concluded that margarine oils of suitable melting characteristics and of an average nutritional value (L/S ratio of about 0.70) can be prepared from blends of soybean oils alone, using transesterification process.     

油井原油计量装置的静态标定及计量精度分析研究

针对常规计量方法不能满足油田原油开发精细管理要求的现状,研制了基于力矩平衡原理的采油井原油产量计量装置,介绍了计量装置的原理、结构、主要计算公式和系统组成。以计量装置的核心部件计量料斗单元为研究对象,在实验室采用清水来模拟原油产量,对计量料斗进行静态标定实验,验证了计量装置的精度,并提出了减小计量误差的合理化建议。     

固体碱催化大豆油制备生物柴油

以Na2Si O3·9H2O为原料制备固体碱催化剂,大豆油和甲醇酯交换反应为模型,优化固体碱焙烧条件。再以最优条件制备的Na2Si O3·9H2O固体碱催化剂优化大豆油和甲醇酯交换工艺。结果表明:硅酸钠固体碱最佳制备条件为煅烧温度400℃、煅烧时间1 h。大豆油和甲醇酯交换反应优化工艺为:反应温度65℃、醇油摩尔比6∶1、反应时间2 h。     

利用大豆毛油合成生物柴油技术研究

研究了利用大豆毛油与甲醇在超临界条件下制备生物柴油的工艺条件,考查了反应温度、压力、醇油摩尔比和反应时间对大豆毛油与甲醇进行酯交换反应转化率的影响,并得到最优反应条件:温度320℃,压力10MPa,醇油摩尔比10∶1,反应时间60min。     

How to Efficiently Remove tert-butylhydroquinone from Commercial Soybean Oils to Obtain Stripped Oils: Eliminating tert-butylhydroquinone's Influence on Oxidative Stabilities of Model Oil-in-Water Emulsions

The present study proposes an efficient method to effectively strip tert-butylhydroquinone (TBHQ) from commercial soybean oils. Ethanol, a typically common and relatively safe organic solvent, can successfully strip TBHQ by employing a liquid-liquid extraction strategy. The results show that the volume ratio of ethanol to oil is a key factor for stripping efficiency (SE), and 4:1 (v/v) is considered the optimal parameter. When compared with traditional stripping methods via adsorbing materials (such as activated charcoal or alumina powder), the proposed ethanol extraction method can more effectively strip TBHQ from commercial oils with lower adsorption loss and higher SE. Moreover, the model O/W emulsion systems prepared using ethanol stripped oils showed the highest degree of lipid oxidation. The method can completely strip TBHQ from commercial soybean oils, thereby eliminating its influence on oxidative stabilities of model oil-in-water emulsions. Practical Applications : The ethanol stripping method can be applied as a pretreatment method to completely strip TBHQ from commercial soybean oils, and subsequently eliminate the influence of TBHQ on lipid oxidation in model O/W emulsion systems during storage.     

Authentication of Edible Vegetable Oil and Refined Recycled Cooking Oil Using a Micro-UV Spectrophotometer Based on Chemometrics

We have developed a new method to make a clear distinction between edible oil and refined recycled cooking oil by using a micro-ultraviolet spectrophotometer and analysis of spectra full data combined with principal component analysis (PCA) and cluster discriminant analysis (CDA). This method shows an excellent capability of distinguishing edible oil from refined recycled cooking oil, which is difficult to accomplish by previous methods using physical and chemical properties. Edible oils and refined recycled cooking oils have the different positions on the resulting plot of PCA and CDA. The oil samples are respectively concentrated relatively distribution and distinct from other kinds, with a certain amount of edge intersection between samples. But the edible oil and refined recycled cooking oil samples have a clear divisional interface. By the increase in sampling and the improvement of modeling, the edge intersection or overlap of commonality between samples can be reduced. Using this method, it is possible to determine qualitatively the identity of unknown samples.     

Glycerol Esters from Real Waste Cooking Oil Using a Robust Solid Acid Catalyst

Notwithstanding the food-for-fuel debate, turning waste cooking oil and fat (WCO) into a valuable product is a classic example of green chemistry. We demonstrate that sulfated zirconia and lanthanum-supported sulfated zirconia are good catalysts for the esterification of WCO free fatty acids (FFAs) with glycerol, giving high-value monoglycerides. Various catalysts were first screened using palmitic acid as a model FFA. Subsequently, six 10-kg batches of actual WCO were collected from commercial cookeries over a period of 28 weeks, pre-treated in a purpose-built decanter and esterified with industrial grade glycerol using heterogeneous catalysis. Good yield and turnovers were obtained. The pre-treatment stage and the catalytic esterification experiments are described and discussed.     

Glycerol Esters from Real Waste Cooking Oil Using a Robust Solid Acid Catalyst

Notwithstanding the food-for-fuel debate, turning waste cooking oil and fat (WCO) into a valuable product is a classic example of green chemistry. We demonstrate that sulfated zirconia and lanthanum-supported sulfated zirconia are good catalysts for the esterification of WCO free fatty acids (FFAs) with glycerol, giving high-value monoglycerides. Various catalysts were first screened using palmitic acid as a model FFA. Subsequently, six 10-kg batches of actual WCO were collected from commercial cookeries over a period of 28 weeks, pre-treated in a purpose-built decanter and esterified with industrial grade glycerol using heterogeneous catalysis. Good yield and turnovers were obtained. The pre-treatment stage and the catalytic esterification experiments are described and discussed.

     

大豆油加氢高活性催化剂的研究

采用并流沉淀法制备了Cu－Ni二元催化剂，研究了SiO2的加入量和焙烧温度对催化剂活性的影响。结果表明加入SiO2可明显提高Cu－Ni二元催化剂活性，加入量以Cu(Ni):SiO2=1.5为好，最佳焙烧温度300℃。文中方法制备的催化剂用于大豆油的催化加氢，表现出很高的催化活性。     

Genetic Gain for Soybean Seed Protein,Oil, and Yield in a Recombinant Inbred Line Population

The use of soybean [Glycine max (L.) Merrill] is widespread, with applications in food, fuel, livestock feed, and industrial products. We developed a soybean population of 239 F₄-derived recombinant inbred lines (RIL) from the cross “5601T” × U99-310255 to estimate the heritability and genetic gain for seed protein, oil, and yield, and to assess the utility of making selections for these important traits. Heritability estimates on an entry means basis for protein (0.78), oil (0.65), seed yield (0.38) varied by trait with regard to genetic influence. Genetic gain was calculated for each trait at 5%, 10%, 15%, and 20% selection intensities. With the genetic gain that was obtained through the selections for each trait, some lines excelled above that of the checks and parents in this population. The second and third highest yielding selections (56U99-081 and 56U99-244) are notable in producing 50.2% and 49.8% meal protein, respectively, while maintain high yields above the high-yielding parent, 5601T. Seeking balance for these important soybean traits is essential for breeders looking to make optimal improvements for the wide variety of soybean uses. Further research on this population could prove to be of value to breeding programs wishing to increase seed yield, oil, and protein.     

Oxidative Stability of Microencapsulated Kenaf Seed Oil Using Co-extrusion Technology

This study investigates the effect of microencapsulation (via co‐extrusion technology using high methoxyl pectin‐enhanced alginate as a shell formulation) on the storage stability and antioxidant properties of kenaf seed oil. Microencapsulated kenaf seed oil (MKSO) and unencapsulated oil were stored at 25 °C for 28 days and at 65 °C for 24 days. The oils were then subjected to stability and quality evaluation based on peroxide, p‐anisidine, and total oxidation values, conjugated diene and triene levels, thiobarbituric acid reactive substances, free fatty acids, total phenolic content, and the radical scavenging activity assays of 2,2‐diphenyl‐1‐picrylhydrazyl and 2,2′‐azino‐bis(3‐ethylbenzothiazoline‐6‐sulphonic acid). The results showed that there was a significant increase (p < 0.05) in oxidation and a significant decrease (p < 0.05) of antioxidant activity in the unencapsulated oil while oxidation changes generally occurred more slowly in MKSO. It was demonstrated that the current microencapsulation method is a feasible approach to enhance oxidative stability of kenaf seed oil.     

餐饮废油资源化利用研究进展

餐饮废油是制备化学品的良好资源原料,对其再利用研究可有效解决食品安全、废油污染等问题。从废弃物资源化再利用和环境保护的角度,阐述了其资源化利用的研究现状,展望了其深化利用的研究方向。为更好的实现餐饮废油的再利用,应加强技术研发、应用领域拓展和制度建设与保障三方面的研究。     

Deacidification of Soybean Oil Using Membrane Processing and Subcritical Carbon Dioxide

Vegetable oils have been deacidified using supercritical carbon dioxide and membrane processing. However, the pressures required are substantially greater than those used in industry. Therefore, the feasibility of using subcritical carbon dioxide (at much lower pressures) and membrane processing to separate free fatty acids (FFA) from triacylglycerols (TAGs) was examined. First, FFA/TAG solubility tests were completed (10–25 °C and 68–136 atm). The oil samples were separated using a FilmTec NF90 or a FilmTec BW30 membrane in a dead-end type cell. Within the range examined, the greatest solubility for oleic acid was at 25 °C and 136 atm. For soybean oil TAGs, the greatest solubility was at 20 °C and 136 atm. However, for the separation of the two components, 20 °C and 68 atm was best among the condition combinations examined. The solubility of oleic acid ranged from 0.294 to 0.455 mg/mL in subcritical carbon dioxide, while the solubility of triacylglycerols ranged from 0.066 to 0.139 mg/mL. The FilmTec BW30 membrane provided significantly better separation of FFAs from TAGs than did the NF90 membrane. Both membranes were selective for oleic acid, although the BW30 had greater selectivity for oleic acid (β _{oleic acid} = 2.12, β _TAGs = 0.24) than the NF90 membrane (β _{oleic acid} = 1.26, β _TAGs = 0.81).