Flow properties of vegetable oil-diesel fuel blends

Straight vegetable oils provide cleaner burning and renewable alternatives to diesel fuel, but their inherently high viscosity compared to petroleum based diesel is undesirable for diesel engines. Lowering the viscosity can be simply achieved by either increasing the temperature of the oil or by blending it with diesel fuel, or both. In this work the rheological properties of diesel fuel and vegetable oil mixtures at different compositions were studied as a function of temperature to determine a viscosity-temperature-composition relationship for use in design and optimization of heating and fuel injection systems used in diesel engines. The vegetable oils used were corn, canola, olive, peanut, soybean and sunflower oils which are of commercial food grade. All the vegetable oils and their blends with No. 2 diesel fuel showed time-independent Newtonian behaviour within the test temperatures between 20 °C and 80 °C. Viscosities of the pure oils and diesel were satisfactorily correlated with temperature by means of the Arrhenius typed relationship. The Arrhenius blending rule was found applicable to describing the composition dependence of viscosity all vegetable oils-diesel blends at a fixed temperature. These relations were combined to develop a simple mixture viscosity model to predict the viscosity of the vegetable oil-diesel blends as functions of temperature and composition based on properties of the pure components.     

Correlation between physicochemical analysis and radical‐scavenging activity of vegetable oil blends as affected by frying of French fries

The main goal of the present work was to compare and correlate the results of physicochemical parameters and antiradical performance of some oil blends during deep‐frying, which will be an initial indicator for applying antiradical tests for monitoring deep‐frying oils. Two oil blends were prepared. The first blend was a mixture (1 : 1, wt/wt) of sunflower seed oil and palm olein (SO/PO) and the second was a mixture (1 : 1, wt/wt) of cottonseed oil and palm olein (CO/PO). The oil blends were evaluated during intermittent frying of French fries on two consecutive days for 16 h, with oil replenishing after 8 h. Changes in the fatty acid profile and some physicochemical parameters (peroxide value, color index, viscosity, total polar compounds and UV absorbance at 232 and 270 nm) were used to evaluate the alterations during frying. A quick spectrophotometric method was developed to assess deep‐frying oil quality. With the 2,2‐diphenyl‐1‐picrylhydrazyl (DPPH) method, the neutralization of the stable radical DPPH by antioxidants present in the oil during frying was measured. Radical‐scavenging activity (RSA) of both oil blends was recorded during frying, wherein the results showed that the SO/PO blend had the highest RSA. It was evident from the results that a proportional correlation and positive relationship existed between the levels of fatty acids and the physicochemical characteristics of the vegetable oil blends and their RSA. The initial results obtained allow us to suggest that antiradical measurements could be used to quantify the oxidative and hydrolytic deterioration of vegetable oils upon frying.     

滇产植物油理化指标测定

研究滇产食用植物油的理化特征与储藏期品质变化规律。以两种特色植物油为对照,对云南出产的五种植物油脂的理化指标进行评价和对比。同时使用过氧化值和酸价,对所研究的油脂的储藏期品质变化进行初步探索。结果表明:云南产植物油质量均满足国标要求。但由于其加工工艺原因,植物油级别较低。含有不饱和脂肪酸的植物油在光照情况下过氧化值和酸价明显改变,可作为质量变化的主要指标。云南出产的四种特色植物油脂不饱和脂肪酸含量较高,是良好的食用油产品;但仍需改善加工工艺以提高其级别。葡萄籽油、红花籽油需添加额外抗氧化剂稳定其品质;过氧化值是最适于进行日常油品质量控制的指标。     

Extraction of omega‐6 fatty acids from speciality seeds

‘Omega‐6 vegetable oils’ are a small but important group of vegetable oils used widely in the food, neutraceutical, cosmetic and pharmaceutical industries for their linoleic acid (18:2 n‐6) and more importantly gamma linolenic acid (18:3 n‐6) content. These omega‐6 fatty acids have numerous health benefits recognized worldwide. With linoleic acid being readily available from many dietary sources, one wonders why there is a need to extract the oil from speciality oilseeds, however those that suffer with many of the conditions that omega‐6 fatty acids are said to be beneficial for are frequently advised to take extra supplements of these fatty acids. Due to their wide use as a nutraceutical, omega‐6 fatty acids are in high demand, causing a niche market for extraction of these oils from speciality seeds.     

Low trans hydrogenation of edible oils

Hydrogenation of edible oils is an important process in the food industry to produce fats and oils with desirable melting properties and an improved shelf life. However, beside the desired hydrogenation reaction trans fatty acids are formed as well. As several studies indicate a negative health effect of trans fatty acids, consumer demands will urge the food producers to lower the content of trans fatty acids in their products. This article describes the option to reduce the trans levels in the hydrogenation of an edible oil by changing process conditions and by applying alternative low trans heterogeneous catalysts.     

Current advances in sunflower oil and its applications

The fatty acid and triacylglycerol composition of a vegetable oil determine its physical, chemical and nutritional properties. The applications of a specific oil depend mainly on its fatty acid composition and the way in which fatty acids are arranged in the glycerol backbone. Minor components, e. g. tocopherols, also modify oil properties such as thermo‐oxidative resistance. Sunflower seed commodity oils predominantly contain linoleic and oleic fatty acids with lower content of palmitic and stearic acids. High‐oleic sunflower oil, which can be considered as a commodity oil, has oleic acid up to around 90%. Additionally, new sunflower varieties with different fatty acids and tocopherols compositions have been selected. Due to these modifications sunflower oils possess new properties and are better adapted for direct home consumption, for the food industry, and for non‐food applications such as biolubricants and biodiesel production.     

Density and viscosity of vegetable oils

A generalized method was developed to estimate the liquid density of vegetable oils and fatty acids. The correlation for vegetable oils was based on fatty acid critical properties and composition of the oil. The correlations predicted the density of vegetable oils and fatty acids with an average absolute deviation of 0.21 and 0.77%, respectively. The present method is slightly more accurate in predicting vegetable oil density and simpler than the method of Halvorsen et al. Also, a method is introduced that predicts viscosity from density data, thus relating two key properties of vegetable oils.     

Optimization of Deodorization Design for Four Different Kinds of Vegetable Oil in Industrial Trial to Reduce Thermal Deterioration of Product

Trans fatty acids (TFA) have been shown to be associated with various health disorders. Due to thermal stress, one major source of dietary TFA is high-temperature deodorization of vegetable oils. In this study, precision minimal deodorization was proposed to obtain healthier “zero-TFA” vegetable oils (TFA ≤0.3%). By optimizing temperatures for different deodorizers, dual columns with dual temperatures (DCDT) deodorizers were proposed, transformed, and industrially implemented among dozens of plants. The deodorization temperatures were optimized and customized, respectively, for four kinds of vegetable oil (soybean oil and rapeseed oil: tray column 205 °C and packed column 225 °C, maize oil and sunflower seed oil: tray column 210 °C and packed column 230 °C). Industrial trials showed that all four kinds of oils can achieve “zero-TFA” by DCDT deodorization at the customized mild temperatures, and meanwhile oil physicochemical qualities and shelf-life stabilities were compared with corresponding conventional refining oils. The initial free fatty acid and color were a little higher than that of conventional refining oils, but no significant differences were shown in change trends of these physicochemical indexes during the shelf life, which indicated a good and stable oil quality of “zero-TFA” oils for future industrial productions and sales.     

Quality characteristics of edible vegetable oil blends

Two edible oil blends, namely groundnut oil:rice-bran oil and mustard oil:rice-bran oil, were prepared in different proportions and stored for a period of three years. Their physicochemical characteristics were determined. The results agreed with expected values except for free fatty acid percents and butyrorefrac-tometer readings, presumably due to rancidity. Fatty acid compositions of the blends were determined and ratios of characteristic fatty acids, like lignoceric to palmitic for groundnut oil:rice-bran oil blends, and erucic to palmitic for mustard oil:rice-bran oil blends, were calculated to identify individual oils in the blend.     

Palm oil: Features and applications

Palm fruits are the source of two distinct but related vegetable oils, namely palm oil and palm kernel oil. Palm oil has many food and industrial applications. Ever‐increasing demands for palm oil have substantially impacted its industry, creating some environmental concerns. Both types of oil are high in saturated fatty acids with potential cardiovascular risks. Several attempts have been made to reduce undesirable health and environmental impacts. However, additional research and development activities are needed to meet the concerns of the medical professionals and environmental activists.     

Seed roasting improves the oxidative stability of canola (B. napus) and mustard (B. juncea) seed oils

Animal fats and partially hydrogenated vegetable oils (PHVO) have preferentially been used for deep‐frying of food because of their relatively high oxidative stability compared to natural vegetable oils. However, animal fats and PHVO are abundant sources of saturated fatty acids and trans fatty acids, respectively, both of which are detrimental to human health. Canola (Brassica napus) is the primary oilseed crop currently grown in Australia. Canola quality Indian mustard (Brassica juncea) is also being developed for cultivation in hot and low‐rainfall areas of the country where canola does not perform well. A major impediment to using these oils for deep‐frying is their relatively high susceptibility to oxidation, and so any processing interventions that would improve the oxidative stability would increase their prospects of use in commercial deep‐frying. The oxidative stability of both B. napus and B. juncea crude oils can be improved dramatically by roasting the seeds (165 °C, 5 min) prior to oil extraction. Roasting did not alter the fatty acid composition or the tocopherol content of the oils. The enhanced oxidative stability of the oil, solvent‐extracted from roasted seeds, is probably due to 2,6‐dimethoxy‐4‐vinylphenol produced by thermal decarboxylation of the sinapic acid naturally occurring in the canola seed.     

Insights into the compatibility of vegetable-based plasticizers on the performance of filled rubber vulcanizates

Substitution of petroleum-based processing oils with eco-friendly sustainable plasticizers in rubber compounds has gained much global attention due to their toxicity. In this regard, so far, the major attempts have focused on substituting aromatic oils with fatty acid based vegetable oils. In this work, the chemical and physical effects of canola oil as a model of fatty acid based vegetable oils on the process-ability, vulcanization kinetics, and final properties of carbon-black filled styrene–butadiene rubbers are systematically investigated. In contrast to the previous studies, it was shown that although these types of vegetable oils have a plasticizing impact, they can indeed threaten the requirements of reinforcing criteria in rubber vulcanizates. The final properties of the vulcanizates were found to be deteriorated due to the incompatibility of canola oil fatty acids constituents with rubber matrix and especially as a result of chemical interference of their unsaturated bonds in sulfur vulcanization kinetics.     

Recent developments and perspectives of industrial rapeseed breeding

Due to substantial progress in breeding and cultivation practice rapeseed has become the world's third most important source of vegetable oil. Modification of the fatty acid composition to make rapeseed oil more competitive in various segments of the food and industrial oil markets has been an important objective of plant breeding and molecular genetics in recent years. While making up the primary demand by food and animal feed industry furnished by “double-low” quality rapeseed, so-called “canola”, interest increased to produce “Biodiesel” feedstocks or special materials being directed to several industrial niche markets, because of their higher value than commodity oils. Rapeseed oil is unique in having a large spectrum of usability and good properties for non-food applications, such as relatively homogeneous composition, high degree of refinement, freedom from contaminants, and also biodegradability, giving it advantages over petrochemicals. Consequently, one of the most important objectives of rapeseed breeding is the genetic modification of the seed oil by maximizing the proportion of specific fatty acids, like laurate, erucate or functionalized acids, in order to obtain tailor-made raw materials suited for industrial purposes.     

Fatty Acid Composition,Oxidative Stability,and Radical Scavenging Activity of Vegetable Oil Blends with Coconut Oil

Coconut (Cocos nucifera) contains 55–65% oil, having C12:0 as the major fatty acid. Coconut oil has >90% saturates and is deficient in monounsaturates (6%), polyunsaturates (1%), and total tocopherols (29 mg/kg). However, coconut oil contains medium chain fatty acids (58%), which are easily absorbed into the body. Therefore, blends of coconut oil (20–80% incorporation of coconut oil) with other vegetable oils (i.e. palm, rice bran, sesame, mustard, sunflower, groundnut, safflower, and soybean) were prepared. Consequently, seven blends prepared for coconut oil consumers contained improved amounts of monounsaturates (8–36%, p < 0.03), polyunsaturates (4–35%, p < 0.03), total tocopherols (111–582 mg/kg, p < 0.02), and 5–33% (p < 0.02) of DPPH (2,2-diphenyl-1-picrylhydrazyl free radicals) scavenging activity. In addition, seven blends prepared for non-coconut oil consumers contained 11–13% of medium chain fatty acids. Coconut oil + sunflower oil and coconut oil + rice bran oil blends also exhibited 36.7–89.7% (p < 0.0005) and 66.4–80.5% (p < 0.0313) reductions in peroxide formation in comparison to the individual sunflower oil and rice bran oil, respectively. It was concluded that blending coconut oil with other vegetable oils provides medium chain fatty acids and oxidative stability to the blends, while coconut oil will be enriched with polyunsaturates, monounsaturates, natural antioxidants, and a greater radical scavenging activity.     

Characteristics and composition of vegetable oil-bearing materials

A survey of the commercially most important oil-bearing fruits and seeds is presented. Their place in the nutrition of the world’s population is sketched, both as a source of fat and as a potential source of protein. Origin and occurrence of a number of oil fruits and seeds are treated, and their relative importance is discussed. Characteristics of the vegetable oils are described in the light of their fatty acid compositions. Nutritional aspects of polyunsaturated fatty acids are discussed briefly, as well as the antinutritional properties of erucic acid. Oilseed proteins are discussed from the point of view of their growing importance as a source of food for man, and compositions of their essential amino acids are discussed in relation to their nutritive value.     

生物基绿色涂料的研究进展

植物油、纤维素、甲壳素等生物基材料,由于其原材料来源丰富、挥发性低、无毒性、生物相容性和生物可降解性良好,成为理想的可再生绿色资源。植物油的主要成分为甘油三酸酯,其包含脂肪酸长链;可以通过化学方法对脂肪酸进行羟基化、环氧化、甘油醇解、马来酸酐化等处理。因此,植物油基聚合物材料已经广泛地应用于醇酸树脂、环氧树脂、丙烯酸酯树脂以及聚氨酯涂料等方面。纤维素和甲壳素是自然界中最广泛的生物多糖大分子,利用它们含有的羟基或是经过化学改性处理后可以发展新型的生物基材料。本文综述了这几类生物基可再生资源在涂料中的研究和发展趋势。     

Oxidative stability and acceptability of camelina oil blended with selected fish oils

The effects of blending camelina oil with a number of fish oils on oxidative stability and fishy odour were evaluated. Camelina oil was found to be more stable than tuna oil, ‘omega‐3’ fish oil and salmon oil as indicated by predominantly lower ρ‐anisidine (AV), thiobarbituric acid reactive substances (TBARS) and conjugated triene levels (CT) during storage at 60 °C for 20 days (p < 0.05). Peroxide values (PV) were similar for all oils until Day 13 when values for camelina oil were higher. Values for blends of the fish oils (50, 25, 15, 5%) with camelina oil were generally between those of their respective bulk oils indicating a dilution effect. Camelina oil had a similar odour score (p < 0.05) to sunflower oil (9.2 and 9.6, respectively) indicating, as expected, an absence of fishy odours. In comparison, the fish oils had lower scores of 6.1 to 6.6 (p < 0.05) indicating mild to moderate fishy odours. Odour scores were improved at the 25% fish oil levels (p < 0.05) and were not different to camelina oil at the 15 or 5% levels (p < 0.05). Practical applications: Camelina oil is a potentially important functional food ingredient providing beneficial n‐3 PUFA. Oil extracted from Camelina sativa seeds contains greater than 50% polyunsaturated fatty acids of which 35‐40% is α‐linolenic acid (C18:3ω3, ALA), an essential omega‐3 fatty acid 1 . While EPA and DHA from fish oils are more potent nutritionally, they are less stable than ALA. This work evaluated innovative blends of fish oil with camelina oil for stability and acceptability. The results demonstrate that there is potential for use of blends of camelina oil with fish oils in food products, as the results show some benefits in terms of reduction of fishy odours. Such information could be valuable in relation to formulation of food products containing high levels of n‐3 PUFA from both plant and fish sources.     

Use of rice bran oil and epoxidized rice bran oil in carbon black–filled natural rubber–polychloroprene blends

In the present study we report the results obtained on the use of rice bran oil (RBO), a naturally occurring nontoxic oil, and its epoxidized variety (epoxidized RBO, or ERBO) in the compounding and vulcanization of different natural rubber–chloroprene rubber (NR–CR) blends. The processability, cure characteristics, and physical properties of the blends prepared with these oils were compared with those of control mixes prepared with aromatic oil. The optimum cure time and scorch time values of the different blends prepared with these oils were found to be lower than those of the respective control blends prepared with aromatic oil. Evaluation of physical properties of the different experimental blends showed that replacement of aromatic oil with these oils did not adversely affect their physical properties. Because RBO contains a good amount of free fatty acids it was tried as a coactivator in addition to its role as a processing aid. The level of these oils required for the blend preparation was optimized in a Brabender plasticorder. Physical properties such as tensile strength, elongation at break, tear strength, swelling index, and abrasion loss, for example, were evaluated for both experimental and control mixes. Comparison of cure characteristics and physical properties of the blends prepared with aromatic oil and with these oils showed that these oils could be used in place of aromatic oil in the above blends. It is also to be noted that aromatic oil is of petroleum origin and is reported to be carcinogenic. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 4084–4092, 2003     

Vitamin E und Haltbarkeit von Pflanzenölen

Vitamin E and stability of vegetable oils. The main occurrence of vitamin E basing on its synthesis and its lipophilic character are vegetable oils, seeds, nuts and cereals. The most important task of tocopherols are their antioxidative capacity in food lipids. The antioxidative potential of tocotrienols in comparison to their corresponding tocopherols is lower. According to the chemical structure γ- and δ-tocopherol are more effective than α-tocopherol. An improvement of the antioxidative capacity is possible by controlled adding to tocopherol compounds as well as by the use of synergists like ascorbylpalmitate. For this improvement the composition of fatty acids, the tocopherol content in native oil and the circumstances of the oxidation should always be considered.     

Conjugated linoleic acids and conjugated vegetable oils: From nutraceutical to bio‐polymer

Recent interest from academia, nutritionists, the chemical as well as the feed and food industry in conjugated linoleic acids (CLAs) and conjugated vegetable oils has grown spectacularly. CLA isomers, either in their natural or synthetic forms, have not only been associated with diverse health and physiological effects, but they are also interesting renewable compounds in the production of industrial products such as paints, glues, and polymers, due to their very reactive conjugated double bond system. Due to the depletion of the world crude oil reserves and the increasing trend to use renewable feedstock in the chemical industry, it is to be expected that the use of conjugated fatty acids and oils will continue to grow in the near future. As high amounts of CLAs and conjugated vegetable oils will be needed and natural resources are limited, efficient production processes are urgently needed. An efficient process for the production of CLA from methyl linoleate, using the Wilkinson catalyst, is described by Behr et al. in this issue of European Journal of Lipid Science and Technology.