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1.
Preparation of soybean oil-based greases: effect of composition and structure on physical properties
Vegetable oils have significant potential as a base fluid and a substitute for mineral oil in grease formulation. Preparation of soybean oil-based lithium greases using a variety of fatty acids in the soap structure is discussed in this paper. Soy greases with lithium-fatty acid soap having C12-C18 chain lengths and different metal to fatty acid ratios were synthesized. Grease hardness was determined using a standard test method, and their oxidative stabilities were measured using pressurized differential scanning calorimetry. Results indicate that lithium soap composition, fatty acid types, and base oil content significantly affect grease hardness and oxidative stability. Lithium soaps prepared with short-chain fatty acids resulted in softer grease. Oxidative stability and other performance properties will deteriorate if oil is released from the grease matrix due to overloading of soap with base oil. Performance characteristics are largely dependent on the hardness and oxidative stability of grease used as industrial and automotive lubricant. Therefore, this paper discusses the preparation methods, optimization of soap components, and antioxidant additive for making soy-based grease. 相似文献
2.
Sharma BK Adhvaryu A Perez JM Erhan SZ 《Journal of agricultural and food chemistry》2005,53(8):2961-2968
The biodegradable properties and lubricating ability of greases depend on both the base oil and the thickener. Mineral oils are the most widely used lubricant base fluids due to their inherent lubricity and low cost, but recent environmental awareness has forced consideration of the use of biodegradable fluids such as vegetable oils and certain synthetic fluids in grease formulations. This study presents data on the thermo-oxidation behavior and tribology of biodegradable greases formulated with soybean oil and different compositions of metal soap thickener. The composition of thickener has been varied by using fatty acids with different degrees of unsaturation and fatty acids of different chain lengths. The improvement of thermo-oxidation and tribological properties as a result of changing thickener/base oil ratio and the antioxidative effect of some suitable additives have also been evaluated. 相似文献
3.
Erhan SZ Sharma BK Liu Z Adhvaryu A 《Journal of agricultural and food chemistry》2008,56(19):8919-8925
The environment must be protected against pollution caused by lubricants based on petroleum oils. The pollution problem is so severe that approximately 50% of all lubricants sold worldwide end up in the environment via volatility, spills, or total loss applications. This threat to the environment can be avoided by either preventing undesirable losses, reclaiming and recycling mineral oil lubricants, or using environmentally friendly lubricants. Vegetable oils are recognized as rapidly biodegradable and are thus promising candidates as base fluids in environment friendly lubricants. Lubricants based on vegetable oils display excellent tribological properties, high viscosity indices, and flash points. To compete with mineral-oil-based lubricants, some of their inherent disadvantages, such as poor oxidation and low-temperature stability, must be corrected. One way to address these problems is chemical modification of vegetable oils at the sites of unsaturation. After a one-step chemical modification, the chemically modified soybean oil derivatives were studied for thermo-oxidative stability using pressurized differential scanning calorimetry and a thin-film micro-oxidation test, low-temperature fluid properties using pour-point measurements, and friction-wear properties using four-ball and ball-on-disk configurations. The lubricants formulated with chemically modified soybean oil derivatives exhibit superior low-temperature flow properties, improved thermo-oxidative stability, and better friction and wear properties. The chemically modified soybean oil derivatives having diester substitution at the sites of unsaturation have potential in the formulation of industrial lubricants. 相似文献
4.
Kodali DR 《Journal of agricultural and food chemistry》2005,53(20):7649-7653
High-stability oils are used as coatings on food products that require long shelf life. The high stability oils produced from high-oleic oils require less processing and bring additional nutritional benefits such as lower trans and saturated fat contents. Accurate and reproducible oxidative stability measurement of these oils is necessary to assess the performance. The accelerated oxidative stability measurement method often used in the fats and oils industry, the oxidative stability index (OSI, AOCS Cd 12b-92) is unreliable for higher stability oils due to poor reproducibility. This study presents a pressure differential scanning calorimetry (PDSC) method, which is highly reproducible and versatile and applies to oils from low to very high oxidative stability. PDSC has been used in industrial applications such as lubricants (ASTM D 6186-98) and measures the oxidative induction time (OIT) of oils under high temperature and pressure in the presence of pure oxygen. The OITs of a number of hydrogenated oils with different unsaturation and oxidative stability are measured. Unlike OSI data, the PDSC OIT measurement is highly reproducible and precise and requires only a small sample and a couple of hours. The regression analysis of the PDSC data indicated the natural log OIT of all samples linearly correlated with the temperature. The equation derived from this relationship helps to compare the oxidative stabilities of the same or different oils determined at different temperatures. The development of this method into an approved method will benefit the fats/oils and food industry. 相似文献
5.
Sharma BK Liu Z Adhvaryu A Erhan SZ 《Journal of agricultural and food chemistry》2008,56(9):3049-3056
Vegetable oils are promising candidates as substitutes for petroleum base oils in lubricant applications, such as total loss lubrication, military applications, and outdoor activities. Although vegetable oils have some advantages, they also have poor oxidation and low temperature stability. One of the ways to address these issues is chemical modification of fatty acid chain of triglyceride. We report a one-pot synthesis of a novel class of chemically modified vegetable oils from epoxidized triacylglycerols and various anhydrides. In an anhydrous solvent, boron trifluoride etherate is used as catalyst to simultaneously open the oxirane ring and activate the anhydride. The reaction was monitored and products confirmed by NMR, FTIR, GPC, and TGA analysis. Experimental conditions were optimized for research quantity and laboratory scale-up (up to 4 lbs). The resultant acyl derivatives of vegetable oil, having diester substitution at the sites of unsaturation, have potential in formulation of industrial fluids such as hydraulic fluids, lubricants, and metal working fluids. 相似文献
6.
李志刚 《中国生态农业学报》2007,15(1):176-179
简介了陕甘宁接壤区生态产业、特别是生态农业发展的6点构想:一是按照不同地貌部位的特殊生态条件具体配置生态农业;二是根据本区生态环境的地域差异性,划分出南部旱塬农林区、中部黄土丘陵农牧区、北部长城沿线风沙牧林区、西北部沿黄灌区等4个生态区,提出分区指导生态农业发展的策略;三是发展草畜业,推进农业产业化经营;四是应用生态技术,保持农业生产的“生态性”,强调发挥传统耕作方式优点,减少化学物质施用;五是按地域生产综合体模式和“3R原则”组织工业生产,形式合理的地域工业循环体系,实现清洁生产;六是建立生态产业的激励和保护机制。 相似文献
7.
Soybean oil with an iodine value of 136 was hydrogenated to have iodine values of 126 and 117. The soybean oils with iodine values of 136, 126, and 117 were randomly interesterified using sodium methoxide. The oxidative stabilities of the hydrogenated and/or interesterified soybean oils were evaluated by measuring the headspace oxygen content by gas chromatography, and the induction time was measured using Rancimat. The melting points of the oils were evaluated by differential scanning calorimetry. Duncan's multiple range test of the headspace oxygen and induction time showed that hydrogenation increased the headspace oxygen content and induction time at alpha = 0.05. Interesterification decreased the headspace oxygen and the induction time for the soybean oils with iodine values of 136, 126, and 117 at alpha = 0.05. Hydrogenation increased the melting points as the iodine value decreased from 136 and 126 to 117 at alpha = 0.05. The random interesterification increased the melting points of soybean oils with iodine values of 136, 126, and 117 at alpha = 0.05. The combined effects of hydrogenation and interesterification increased the oxidative stability of soybean oil at alpha = 0.05 and the melting point at alpha = 0.01. The optimum combination of hydrogenation and random interesterification can improve the oxidative stability and increase the melting point to expand the application of soybean oil in foods. 相似文献
8.
In an effort to investigate the effect of positional distribution on oxidative stability of menhaden and seal blubber oils, Novozyme 435 was used as a random biocatalyst. Positional distribution of fatty acids was determined using gas chromatography. As some of the α-tocopherol was lost during randomization, its content was adjusted to the level prior to the process to eliminate this effect on oxidative stability of oils tested. Conjugated dienes (CD) and thiobarbituric acid reactive substances (TBARS) were used as indicators of oxidative stability. The results showed that the polyunsaturated fatty acids were distributed predominantly at terminal positions in randomized menhaden oil, whereas they were distributed more evenly among all positions in enzymatically randomized seal blubber oil, compared to their unrandomized counterparts. Results of CD and TBARS values indicated that randomized menhaden oil was more stable than the original oil, whereas randomized seal blubber oil was more vulnerable to oxidation compared to its counterpart. Changes of oxidative stability after randomization were mainly due to positional redistribution of fatty acids, especially those of the polyunsaturated types. 相似文献
9.
Pekka Vähäoja Petteri Piltonen Anna Hyvönen Jouko Niinimäki Jorma Jalonen Toivo Kuokkanen 《Water, air, and soil pollution》2005,165(1-4):313-324
This study focuses on the biodegradability measurements of tall oil-based wood preservatives and their raw materials in groundwater as determined by the respirometric BOD OxiTop method. Certain substances were also analyzed in standard conditions described by OECD 301 F. Results show that creosote oil, a traditional wood preservative, does not biodegrade at all in groundwater over a period of 28 days, while tall oil and linseed oil biodegrade to some degree (13.4% and 14.8%, respectively). On the other hand, degrees of biodegradation of linseed oil, tall oil and creosote oil in the extra mineral and microbe including conditions described by OECD 301 F were 72.9%, 54.3% and 24.9% after 28 days, respectively. Studied raw materials of tall oil-based wood preservative production biodegrade to some degree in groundwater (variability from 11.9% to 18%) and quite effectively in OECD 301 F test (variability from 39% to 71.7%) over a period of 28 days. Abiotic degradation may also be significant with the studied substances. 相似文献
10.
Lante A Nardi T Zocca F Giacomini A Corich V 《Journal of agricultural and food chemistry》2011,59(10):5318-5324
The search for renewable and abundant sources of antioxidants has recently focused on agricultural byproducts, especially promising due to their natural origins and low costs. In particular, plant raw materials are sources of important compounds such as dietary fiber, carotenoids, tocopherols, and polyphenolics, which are mostly discarded during harvesting and processing. Among these vegetal crops, red chicory is attractive because of the large quantity of its byproducts (residues as leaves and stems); moreover, there is no information on its role as a food and feed ingredient. In this study, red chicory leaf residue was evaluated as a natural substitute for synthetic antioxidants for the food and feed industry. After lyophilization, a red chicory extract (RC) was characterized for its phenolic profile and its oxidative stability as compared to BHT. RC was shown to reduce lipid peroxidation of different oils in the Rancimat test. In addition, the antioxidant property of RC was studied in a model system by evaluating the Saccharomyces cerevisiae response to oxidative stress by means of gene expression. In this analysis, the RC extract, added to the yeast culture prior to oxidative stress induction, exhibited a pleiotropic protective effect on stress responsive genes. 相似文献
11.
黄土高原重点水土流失区农业资源合理利用的动态模拟 总被引：5，自引：0，他引：5
<正> 黄土高原重点水土流失区包括黄河河口镇至龙门段沿线的35个县(图1),总面积86378.5km~2,1985年总人口602.69万人,平均人口密度约70人/km~2。这一地区地形复杂,植被稀少,水土流失严重,农林牧业生产基础薄弱,生态环境问题严重,因此,该区一直被作为黄土高原水土保持重点治理区及遥感应用动态监测的重点研究区。本文通过动态仿真模型模拟该区土地利用方式对水土流失和社会经济的潜在影响,优选出能促进该区农林牧业协调发展的土地利用模式,并提出了应采取的对策。 相似文献
12.
Algal oils, namely, arachidonic acid single-cell oil (ARASCO), docosahexaenoic acid single-cell oil (DHASCO), and a single-cell oil rich in both docosahexaenoic acid and docosapentaenoic acid (OMEGA-GOLD oil), were evaluated for their oxidative stability, as such and after stripping of their minor components, in the dark at 60 degrees C and under fluorescent light at 27 degrees C. Several analytical methods were used to assess the oxidative stability of these oils. Oil extracts were also investigated for their scavenging of 1,1-diphenyl-2-picrylhydrazyl radical by a spectrophotometric method and by measuring their total phenolic contents. The results indicated that minor oil constituents play a major role in their oxidative stability in the dark as well as under fluorescent light. The stability of the oils was dictated by their fatty acid composition, total tocopherols, and the type of pigment present. DHASCO contained a significant level of natural radical scavengers and phenolic compounds that contributed to its higher stability compared to the ARASCO and OMEGA-GOLD oils. Thus, the importance of minor components in the stability of the oils examined was demonstrated. 相似文献
13.
基于区位商法的北京都市型现代农业产业布局研究 总被引：8，自引：0，他引：8
本文基于区位商法分析了北京与周边省份农业各行业的比较优势,研究了农业结构内部各行业在北京18个区县的比较优势,提出了北京都市型现代农业产业发展的布局。结果表明：与周边省份相比,北京农业总体上没有比较优势,但林业和牧业比较优势明显,种植业和渔业完全没有比较优势。北京各区县比较,延庆县、密云县、平谷区、大兴区、通州区、顺义区、房山区农业占相当大比重。从农业内部结构看,种植业在丰台区、平谷区、昌平区、大兴区、通州区的比较优势明显,林业在门头沟区、朝阳区、丰台区、昌平区、怀柔区、海淀区比较优势明显,牧业在怀柔区、密云县、房山区、顺义区、门头沟区、延庆县有一定的比较优势,农业服务业在海淀区、朝阳区比较优势非常突出。籍此,结合北京市的资源禀赋、区位条件等,北京都市型现代农业产业的发展应按照近郊农业圈、远郊农业圈、山区生态涵养发展圈、合作农业圈4个圈层进行布局。 相似文献
14.
Quinchia LA Delgado MA Valencia C Franco JM Gallegos C 《Journal of agricultural and food chemistry》2011,59(24):12917-12924
Knowledge of the oxidative stability of vegetable oils for lubricant applications is a key point, because vegetable oil oxidation potential is the main disadvantage for its use as a lubricant. Oil degradation after an oxidation process can seriously affect its lubricating function and increase wear. In this work, two different methods for evaluating the oxidation stability of lubricating vegetable oils, the oxidation onset temperature, characterized through DSC measurements (ASTM E 2009-08), and the pressure drop in the oxygen pressure vessel (ASTM D 942-02), have been used. Additionally, thermogravimetric analysis and FTIR studies have also been carried out. High-oleic sunflower (HOSO) and castor (CO) oils were selected and blended with natural ((+)-α-tocopherol (TCP), propyl gallate (PG), l-ascorbic acid 6-palmitate (AP)) or synthetic antioxidants (4,4'-methylenebis(2,6-di-tert-butylphenol) (MBP)), with the aim of formulating biodegradable vegetable-based lubricants according to REACH regulation. (1) The results showed that the most effective biodegradable antioxidant is PG, comparable to MBP, whereas lower effectiveness was obtained for TCP and AP. In relation to the methods tested, DSC measurements achieve accurate data more quickly for evaluating the oxidation stability of these basestocks, showing a linear correlation with the traditional method based on the oxygen bomb test. The empirical equation obtained depends on the mechanism involved in the antioxidant activity. 相似文献
15.
胶质芽孢杆菌(Bacillus mucilaginosus)是一种广泛分布于土壤和岩石中的常见细菌,由于该菌具有一定的分解矿物能力,胞外具有肥大的荚膜,并能分泌一些酸类和促生长物质,因此一直被广泛应用于农业、矿物相关工业、环境治理等领域。胶质芽孢杆菌从发现伊始就一直受到国内外研究人员的广泛关注,并在分离鉴定、发酵条件、矿物分解及风化作用、农业及工业领域应用等方面做了许多研究。根据以往的研究结果,从胶质芽孢杆菌的分类地位、生物学特征、功能特性、培养条件及应用研究等几方面对已有的一些研究成果做一综述,以期对该菌的进一步应用提供参考。 相似文献
16.
Bio-based additives are desirable commodities due to their eco-friendly nature. These additives can demonstrate physical and chemical properties comparable to those of conventional mineral oil-based products. Sulfur incorporated triacylglycerol can function as an antiwear/antifriction additive for lubricants. The synthesis of four useful hydroxy thio-ether derivatives of vegetable oils, from commercially available epoxidized soybean oil and common organic thiols, is reported in this paper. The common thiols used herein were 1-butanethiol, 1-decanethiol, 1-octadecanethiol, and cyclohexyl mercaptan. Currently, there is no reported literature describing the synthesis of hydroxy thio-ether derivatives of vegetable oil. The reaction was monitored, and products were confirmed by NMR and FTIR spectroscopies. Experimental conditions involving various thiols, solvent, catalyst amount, time, and temperature were optimized for research quantity and laboratory scale-up. The synthetic process retains the vegetable oil structure, eliminates polyunsaturation in the molecule, and adds polar functional groups on triacylglycerol. These products can be used as agriculturally-based antiwear additives for lubricant applications. 相似文献
17.
Kumar R Devakumar C Sharma V Kakkar G Kumar D Panneerselvam P 《Journal of agricultural and food chemistry》2007,55(4):1389-1393
The technology for the production of neem oil coated urea (NOCU) developed by the Indian Agricultural Research Institute is in the pipeline for adaption by several Indian fertilizer industries. Use of nitrification inhibitors is one of the methods of improving the nitrogen use efficiency (NUE) of nitrogenous fertilizers in agriculture. However, standard specifications for the neem oil as a raw material of NOCU are desired. Accordingly, the present study was undertaken to evaluate 25 samples of neem oils comprising 11 samples of expeller grade (EG) oils, 8 samples of cold-pressed (CP) oils, 3 samples of solvent-extracted oils, and 2 commercial formulations. NOCU was prepared using these oils (5000 ppm of urea-N). The soils fertilized with NOCUs (200 ppm of urea-N) were incubated at 27 degrees C and 50% water-holding capacity for a period of 15 days. Nitrapyrin (0.5% of N) coated urea served as the reference and prilled urea as control. Samples were analyzed for NH4+-N, NO2--N, and NO3--N using standard methods. The percent nitrification inhibition (NI) was calculated, and the results revealed that all of the neem oils caused NI ranging from 4.0 to 30.9%. Two samples of EG oils and two commercial formulations were found to be the best, causing 27.0-30.9% NI. Iodine, acid, and saponification values and meliacin content of all of the oils were analyzed and correlated with NI. The results revealed the direct influence of meliacin content of the neem oils on NI, which, however, was found to be negatively correlated with saponification and iodine values. There is, therefore, a need to introduce new Bureau of Indian Standards (BIS) specifications for neem oils as raw materials of NOCU. 相似文献
18.
The oxidative stability of selected tree nut oils was examined. The oils of almond, Brazil nut, hazelnut, pecan, pine nut, pistachio, and walnut were extracted using two solvent extraction systems, namely, hexane and chloroform/methanol. The chloroform/methanol system afforded a higher oil yield for each tree nut type examined (pine nut had the highest oil content, whereas almond had the lowest). The fatty acid compositions of tree nut oils were analyzed using gas chromatography, showing that oleic acid was the predominant fatty acid in all samples except pine nut and walnut oils, which contained high amounts of linoleic acid. The tocopherol compositions were analyzed using high-performance liquid chromatography, showing that alpha- and gamma-tocopherols were the predominant tocopherol homologues present; however delta- and beta-tocopherols were also detected in some samples. The oxidative stability of nonstripped and stripped tree nut oils was examined under two conditions, namely, accelerated autoxidation and photooxidation. Progression of oxidation was monitored using tests for conjugated dienes, peroxide value, p-anisidine value, and headspace volatiles. Primary products of oxidation persisted in the earlier stages of oxidation, whereas secondary oxidation product levels increased dramatically during the later stages of oxidation. Hexanal was the major headspace aldehyde formed in all oxidized samples except walnut oil, which contained primarily propanal. Results showed that chloroform/methanol-extracted oils were more stable than hexane-extracted oils in both the accelerated autoxidation and photooxidation studies. Oils of pecan and pistachio were the most stable, whereas oils of pine nut and walnut were the least stable. 相似文献
19.
Stevenson DG Eller FJ Wang L Jane JL Wang T Inglett GE 《Journal of agricultural and food chemistry》2007,55(10):4005-4013
Twelve pumpkin cultivars (Cucurbita maxima D.), cultivated in Iowa, were studied for their seed oil content, fatty acid composition, and tocopherol content. Oil content ranged from 10.9 to 30.9%. Total unsaturated fatty acid content ranged from 73.1 to 80.5%. The predominant fatty acids present were linoleic, oleic, palmitic, and stearic. Significant differences were observed among the cultivars for stearic, oleic, linoleic, and gadoleic acid content of oil. Low linolenic acid levels were observed (<1%). The tocopherol content of the oils ranged from 27.1 to 75.1 microg/g of oil for alpha-tocopherol, from 74.9 to 492.8 microg/g for gamma-tocopherol, and from 35.3 to 1109.7 microg/g for delta-tocopherol. The study showed potential for pumpkin seed oil from all 12 cultivars to have high oxidative stability that would be suitable for food and industrial applications, as well as high unsaturation and tocopherol content that could potentially improve the nutrition of human diets. 相似文献
20.
甘肃黄土高原生态环境建设与农业可持续发展战略研究 总被引：6，自引：13，他引：6
甘肃黄土高原地区生态环境建设与农业可持续的战略思路在总体建设上突出水土保持 ,在区域建设上突出黄土高原丘陵沟壑区 ,在行业建设上突出水利和草林业 ,在产业发展上突出绿色产业 ,在项目选择上突出综合效益 ,在技术选择上突出高新技术。另外 ,还提出了生态环境建设与农业可持续发展的总体战略目标和种植业、林业、畜牧业和草业等行业发展的明确目标。同时也提出了建立商品生产基地 ,发展农业特色产业 ,发展雨水的资源化利用 ,优化现代农业生产要素与技术投入 ,把生态环境的恢复与重建摆在重要的战略位置 ,调整和优化畜种、畜群结构 ,加大扶贫力度 ,实行荒地使用权的拍卖与利益监控和促进农村经济全面发展等生态环境建设与农业可持续发展的建议与对策 相似文献