XRecent advances in canola oil hydrogenations

Rapeseed oil has been the source of edible oils in many parts of the world. In the last decade, Canadian plant breeders have developed new rapeseed cultivars which yield oil low in erucic acid and meal low in glucosinolates. These cultivars were named “canola” by the Canadian rapeseed industry. Literature on the hydrogenation characteristics of canola oil is limited; however, in recent years, several aspects of canola oil hydrogenations with commercial nickel catalysts have been reported including the formation ofrans-isomers, trisaturated glycerides and physical properties. In addition, as the methods for determination of sulfur compounds in canola oil developed, the effect of some isothiocyanates on the hydrogenation rate was further investigated to determine the relative catalyst poisoning ability of serveral of these sulfur compounds. However, during the last few years, most of the efforts were directed towards development of novel, selective and active catalysts for canola oil hydrogenations. These studies cover a wide range of homogeneous and heterogeneous catalysts including sulfur poisoned nickel, gold supported on silica, arene-Cr(CO)₃, RuCl₂(CO)₂(PPh₃)₂, palladium on carbon, palladium black and nickel and arene-Cr(CO)₃ mixtures. Effects of temperature, pressure, catalyst concentration and catalyst preparation procedure on the hydrogenation rate, selectivity, catalyst life and quality of the oil were examined and compared with that of commercial nickel catalysts. A brief discussion about continous hydrogenations of canola oil with commerical fixed bed catalysts is also included.     

Canola oil processing in Canada

Canola is the registered trademark of the Canola Council of Canada for the seed, oil and meal derived from rapeseed cultivars low in erucic acid and low in glucosinolates. Conversion to canola cultivars on a commercial scale started in 1976; in 1981, ca. 87% of the brassica-based oil crop in Canada was of canola quality. Canola oil is the most important oil in Canada. Processing of the oil is, in its essentials, conventional. A few problems not usually encountered with other oils are its chlorophyll content which requires extra processing and analytical effort, and certain limitations in crystallization behavior when highly hydrogenated. Advantages are that stable oils can be produced at moderate degree of hydrogenation, and without hydrogenation in the case of salad oil. New developments in processing of the oil have led to the production of acid-degummed, crude oil on a commercial scale. This opens the possibility to apply physical refining to the oil.     

劣质原油加工及其主要环境问题与对策研究

在渣油中,如果硫含量与金属含量较低,催化裂化是第一选择。对于油渣中,金属含量不高,而硫的含量又较高的油渣,就需要选用固定床加氢工艺,对于在油渣中,除了硫含量高以外,金属含量同样很高的油渣,就需要用到延迟焦化与溶剂脱沥青等技术。主要阐述了劣质原油加工工艺的选择、原油中硫在加工过程的分布、重金属在原油加工过程的分布,并提出了针对以上情况的主要环保对策。     

Desired quality attributes in winter and summer rapeseed

Quality assurance programs have played a significant role in rehabilitating and maintaining the importance of rapeseed and its products. In Europe, the processing of indigenous and Canadian rapeseed ensures unifrom plant utilization throughout the year which in itself contributes to improving quality. Indigenous rapeseed is predominantly of the high-yielding winter type. The European oil mills have learned to adapt to differences in low erucic acid seed characteristics during processing. The influence of different conditioning and pre-expelling parameters on the characteristics of expeller and extraction oil is especially receiving attention. Sulfur compounds, phosphatide content, color and analytical oxidation values are important criteria for the required refining techniques, which can range from classical methods to physical refining, and the quality of the fully refined product. While low erucic acid rapeseed oil can generally be regarded as an alternative to soyabean oil, crystallization behavior of hardened products can differ significantly, which appears to be a function of fatty acid composition. Progress is also being made in upgrading meal quality, especially for application in poultry feed, by developing cultivars with glucosinolate levels below 1%. Such new varieties might also contribute to reducing the problem of fishy egg taint observed with some breeds of layers. Decreased rumen degradability of rapeseed meal by treatment with formaldehyde may further improve flexibility of use. Various established and potential quality attributes for rapeseed, meal and oil are reviewed. The symposium contribution “Recent Advances in the Analysis of Glucosinolates,” by O. Olsen and H. S∳renson, was published in the September 1981 issue of JAOCS.     

常减压装置加工沙特轻油(高硫油)腐蚀及防护

通过对沙特轻油油种性质的分析，摸清了沙特轻油加工过程中硫在常减压装置各部位的分布，结合在常压塔顶、减压塔三线的宏观腐蚀检查，从腐蚀机理及金相分析人手，分析产生腐蚀原因为高温硫腐蚀和氯离子应力腐蚀。经过采取设备材质升级、调整工艺防腐注剂、使用高温缓蚀剂，并强化腐蚀在线监测与注剂效果评价，有效地抑制了设备的腐蚀。     

渣油中总硫及硫化物分析测定方法研究进展

渣油中硫化物的存在对石油加工和油品性能产生诸多不利影响。综述了渣油中总硫、硫醚硫和噻吩硫的测定方法及其应用,并对各种方法优缺点进行了分析讨论。对渣油中硫化物组成和结构进行定量和定性分析,将对进一步研究和选择合理的渣油深加工方案提供理论依据和数据支持。     

New process for the production of better-quality rapeseed oil and meal. I. Effect of heat treatments on enzyme destruction and color of rapeseed oil

The thioglucosides (which are precursors of toxic principles) and the fibrous hulls of rapeseed are the two major factors which limit the utilization of rapeseed meal as a protein supplement in human foods. In commercial practice the enzyme responsible for the liberation of toxic principles from thioglucosides is destroyed by a dry-heat treatment, but no attempt is made to remove the thioglucosides or the fibrous matter from the meal. The new wet-heat method of processing to inactivate myrosinase also results in the production of an improved quality of oil. In this paper the advantages of a wet-heat treatment in processing rapeseed are discussed.     

含硫油品储罐腐蚀机理研究

综述了原油中活性硫和非活性硫的来源及分布情况、引起含硫油品储罐的腐蚀原因,重点剖析了含硫油品储罐的腐蚀机理,最后介绍了两种预防含硫油品储罐腐蚀的措施。     

Hydrotreatment of Cracked Light Gas Oil

Since worldwide conversion processes are used to upgrade heavy oil to distillates, the hydrotreatment of light gas oil (LGO) as a downstream process has been used more extensively. This fraction (LGO) is produced from thermal or catalytic cracking or hydrocracking processes. It contains high amounts of unsaturates, nitrogen, and sulfur compounds which cause instability while in storage due to gum formation. The use of LGO as a fuel oil for diesel engines plugs the filter and produces sulfur and nitrogen emissions. These sulfur and nitrogen compounds arise from the cracking of heavy cuts and are aromatic-type molecules which are difficult to hydrogenate. This cut also possesses a low cetane index (CI) which must be increased (by aromatic hydrogenation) because of its poor motor performance. Color and color stability are associated with a high bromine number (BN, unsaturated content), nitrogen, and aromatic content. In order to improve these properties, a deep hydrogenation is sometimes required.     

Hydrotreatment of Cracked Light Gas Oil

Since worldwide conversion processes are used to upgrade heavy oil to distillates, the hydrotreatment of light gas oil (LGO) as a downstream process has been used more extensively. This fraction (LGO) is produced from thermal or catalytic cracking or hydrocracking processes. It contains high amounts of unsaturates, nitrogen, and sulfur compounds which cause instability while in storage due to gum formation. The use of LGO as a fuel oil for diesel engines plugs the filter and produces sulfur and nitrogen emissions. These sulfur and nitrogen compounds arise from the cracking of heavy cuts and are aromatic-type molecules which are difficult to hydrogenate. This cut also possesses a low cetane index (CI) which must be increased (by aromatic hydrogenation) because of its poor motor performance. Color and color stability are associated with a high bromine number (BN, unsaturated content), nitrogen, and aromatic content. In order to improve these properties, a deep hydrogenation is sometimes required.     

Gesamtkonzept zur Glucosinolatbestimmung — Möglichkeiten zur Erstellung von Bilanzen in Rapssamen und -schroten

A New Concept for the Determination of Total Glucosinolate Content — Possibilities to Draw up Balances in Rapeseed and Rapeseed Meal The indirect analysis of the original total glucosinolate content of rapeseed and rapeseed meal via the determination of released sulfate anion is an interesting alternative to the other methods. While the total sulfate content always represents the total glucosinolate content at the time of harvest, the amount of decomposed glucosinolates in the seeds or meals is represented by the amount of free sulfate. In this way a balance can be made between rapeseed harvest or rapeseed entering the oil mill and rapeseed meal leaving the oil mill. Oil milling processes always lead to a partial degradation of glucosinolates and the resulting meal will contain a variable portion of the original intact glucosinolates. Glucosinolates are hydrolysed during drying, analysing or processing either enzymatically by the action of myrosinase or thermally by the action of heat. In both cases one molecule sulfate is produced from one molecule glucosinolate. With the aid of the sulfate method it is therefore possible to draw up balances especially in rapeseed meal.     

Trennpressen geschälter Rapssaat – Zielsetzung und verfahrenstechnische Probleme

Expression of dehulled rapeseed - Targets and processing problems. Environmental reasons are of prime importance for the use of rapeseed oil as raw material for lubrication oils and hydraulic fluids with a high biological decomposition rate. Thus, the task for oil processing is to minimize the loss of hexane in extraction meals. Hexane retention is essentially caused by rapeseed-hull oils. Only a small part of the hull lipids is released from the extremely strong structure of the hulls. The residual lipids absorb hexane. In order to reduce residual hexane in the extraction meal it is suggested to dehull the rapeseed during preprocessing. A process of dehulling rapeseed by defined deformation is described. The operation of a screw press separating oil is essentially determined by the elasticity and permeability of the compressed material. Therefore, the natural content of hull is considered indispensable in the practice of oil milling. The observed orientation of hulls in technical press cakes, however, challenges this assessment. As a result, questions arise concerning the properties of dehulled rapeseed in pressed state. It is necessary to determine the minimum content of hulls for a sufficient elasticity and permeability under compression and for a solid press cake on condition that there will be a considerable decrease of residual hexane by reducing hulls to this amount.     

Metabolic Changes during Sprouting of Rapeseed and Their Consequences for the Volatilome of Cold-Pressed Oil

All the procedures before pressing seeds have a great influence on the flavor of cold-pressed rapeseed oil. However, the studies on the modification of aroma caused by inappropriate storage leading to sprouting are scarce. Therefore, this study aims to determine the effects of sprouting on the metabolome and volatilome of rapeseed cold-pressed oil and press cakes. The presence of 56 and 21 nonvolatile metabolites is detected in seeds/press cakes and oil, respectively. Sprouting significantly affects the total contents of all groups of compounds, except sugars. At the same time, 375 volatile organic compounds (VOCs) are detected. The abundance of VOCs in sprouted oil is almost threefold higher compared to control oil, with the biggest contribution of sulfur-containing compounds (dimethyl sulfide), glucosinolate derivatives (4-isothiocyanato-1-butene), and aldehydes (3-methylbutanal). A similar tendency is observed in press cake. Moreover, sprouting results in the biggest number of VOCs detected only in this oil (61). The abundance of aroma-active compounds is much higher in sprouted products compared to corresponding controls, which has a confirmation in sensory analysis. This study shows that simultaneous volatilomics and metabolomics can be used to track the changes in the oil quality caused by the inappropriate storage of seeds. Sprouting leads to metabolic changes in seeds, which intensify the formation of new VOCs and consequently aroma of oils. Practical applications: The results of this study will help to understand the formation of volatile organic compounds (VOCs) during the processing and production of cold-pressed rapeseed oil. The combination of VOCs with nonvolatile precursors can help to understand the pathways involved in VOCs formation. Moreover, the oil obtained from sprouted seeds is characterized by many VOCs not present in control oil, which can potentially be used to develop tools for quick evaluation if the seeds used for pressing initiated sprouting, which can lead to changes in its sensory quality.     

Zur Kenntnis schwefelhaltiger Fette und ihres Härtungsverhaltens

Information about Fats Containing Sulfur and their Behaviour During Hydrogenation Commercial marine oils - whale oil and fish oil - can contain combined sulfur, which cannot be eliminated by means of the normal refining and therefore causes considerable difficulties during the hydrogenation. An analytical method for the determination of sulfur in fats is described. This method allows the quantitative determination of 0.5 to 100 μg sulfur per g fat with an exactness of 0.2 μg sulfur per g fat. Semi-refined fats to be hydrogenated, containing more than 2 μg sulfur, should be subjected to a hydrogenating desulfurization with nickel contacts at 120° to 130° C. By means of the method described a complete desulfurization is attained without any noticeable hydrogenation or isomerisation of the unsaturated fat constituents. Such pretreated fats can be hydrogenated as usual. Also rapeseed oil, sometimes containing sulfur constituents not easily to be eliminated, can be desulfurized in the same way.     

Effects of processing on the functional properties of canola/rapeseed protein

Canola rapeseed is a major oilseed in Canada, Europe and Japan. Recently, Generally Recognized As Safe (GRAS) status was granted to low erucic acid rapeseed oil for use in the U.S. market. Commercial oil extraction of the seed results in a meal that contains 44% protein and which has been subjected to considerable heat. The meal is presently utilized as livestock feed supplement. A number of processes for the preparation of protein concentrates and isolates from canola/rapeseeds and meal have been proposed, although none have proven commercially viable. In addition to protein concentration, a successful process must reduce the levels of glucosinolates, phenolics, phytates and fiber. These antinutrients present a barrier to the use of canola/rapeseed protein materials in foods. Processes to produce protein concentrates have included water extraction of undesirable compounds from heat denatured, dehulled seed followed by solvent extraction for oil recovery and the isopropanol washing of dehulled, defatted flours. Isolates have been prepared by traditional alkaline extraction, and by acid or water extractions followed by isoelectric, heat or polyelectrolyte precipitation of the protein. Isolates have been chemically and enzymatically modified to improve fooduse properties. In this paper, the effects of various processing methods on the functional properties of solubility, color and flavor of canola protein products are reviewed. Presented at the 78th American Oil Chemists' Society Annual Meeting, May 17–21, 1987, New Orleans, LA.     

浆态床油溶性加氢催化剂前体的研究进展

浆态床渣油加氢工艺是加工劣质油品的有效方法,由于原料具有高沥青质、高金属含量的特点,工艺的核心在于提供稳定高效的加氢裂化催化剂。油溶性催化剂前体能够原位转化为纳米级尺寸的催化剂活性相,其分散度高、加氢活性高,因而成为浆态床渣油加氢工艺的首选。本文主要介绍了4类常见的油溶性有机钼化合物,即二烷基(芳基)二硫代氨基甲酸钼(Mo-DTC)和二烷基二硫代磷酸钼（Mo-DTP）、环烷酸钼（MoNaph）、异辛酸钼、六羰基钼,比较它们在氢气和硫作用下的转化过程以及对重质原料的加氢性能,找出各自在应用过程中的优缺点,为深入研究和设计开发油溶性催化剂前体提供思路和借鉴。     

Agricultural and genetic potentials of cruciferous oilseed crops

Oilseed crops of the Cruciferae are widely adapted and are of particular importance to countries in the northern latitudes. Cruciferous seed oils from the crops, rapeseed, mustard, Camelina, oilseed radish and Crambe, enter edible or industrial markets, or both. The oil-seed meal can be used either as a high protein feed supplement or as an organic fertilizer. The spring and winter forms of the two species of rapeseed,Brassica napus andB. campestris, are commercially the most important. Advances in crop management and plant breeding have resulted in a 40% to 50% increase in seed yield over the past 25 years. In the next 10 to 15 years, application of newer plant-breeding techniques will result in varieties even higher in yield and seed with improved oil and meal quality. Some of the quality improvements will be new patterns in fatty acid composition, higher oil and protein content, lower fiber content, and removal of the undesirable glucosinolate compounds from the meal. The mustard cropsBrassica juncea andB. hirta are important condiment crops which have considerable potential as edible oil sources. Oilseed radish,Raphanus sativus, yields significantly less seed and oil than other cruciferous oil crops but its oil, which contains a low level of erucic acid (3.7%) and a relatively high content of 16-carbon fatty acids (9.3%), may be useful in blending with normal or zero erucic acid rapeseed oils.Camelina sativa or false flax has many desirable agronomic characteristics but the oil of camelina seed contains too high a level of linolenic acid (36%) to penetrate the edible oil market and too low to compete industrially with linseed oil.Crambe abyssinica andC. hispanica are potentially important producers of high erucic acid industrial oils. Factors limiting Crambe development are the high cost of seed transportation due to the high volume to weight ratio of the threshed seed and the need for extra seed processing steps to render the meal suitable as a high protein feed supplement for livestock and poultry. One of 9 papers presented at the Symposium, “Cruciferous Oilseeds,” ISF-AOCS World Congress, Chicago, September 1970. Contribution No. 425, Research Station, Canada Department of Agriculture, Saskatoon, Saskatchewan, Canada.     

Place of rapeseed in the edible oil market

The potential for rapeseed oil in the world edible oil market is evident in the statistics of net exports of the principal vegetable oilseeds from primary producing countries. The last complete year for which figures are available is 1970, and in that year soybeans accounted for some 52% and rapeseed only 7.5% in oil equivalent. Since soybeans have only ca. 50% of the oil content of rapeseed, they are bought mainly for their yield of high protein meal. Conversely, rapeseed is bought for its oil content and produces a meal that is not only lower in protein but up to this time has been less acceptable as an ingredient in animal feed formulations. Fortunately for rapeseed, these problems are being tackled diligently and should be overcome in the near future. When this point has been reached, rapeseed will be a much stronger competitor in world markets for protein meal. The trend in the use of rapeseed oil in the Canadian domestic market is an indicator of the potential in world markets. It is displacing other edible oils that have dominated the Canadian market in the past. In the 1971 calendar year, 35.6% or 160.5 million pounds, i.e., 73,000 metric tons, of vegetable oil used in the manufacture of margarine, shortening and salad oils was rapeseed oil. Rapeseed oil is competing keenly with soybean oil in the Canadian market and in the future should be able to greatly enlarge its share of world trade. One of six papers presented in the symposium “Rapeseed Marketing and Breeding,” AOCS Meeting, Ottawa, September 1972.     

煤焦油加氢脱硫催化剂的研究进展

随着石油资源的日趋减少,煤焦油加工技术受到关注。汽车尾气中含有的硫化物严重污染环境,如何高效脱除煤焦油中含硫化合物的硫原子是开发煤焦油加氢脱硫催化剂的研究重点。简述煤焦油中含硫化合物的分布状况及其特点,并分别从贵金属、非贵金属、过渡金属磷化物、氮化物、碳化物及金基双金属催化剂方面综述煤焦油加氢脱硫催化剂的研究现状,针对煤焦油中含硫组分复杂多样的特性,提出研发高效和高活性煤焦油加氢脱硫催化剂的新方向。     

Antioxidant capacity of rapeseed meal and rapeseed oils enriched with meal extract

Response surface methodology (RSM) was used to evaluate the quantitative effects of two independent variables: solvent polarity and temperature of the extraction process on the antioxidant capacity (AC) and total phenolics content (TPC) in meal rapeseed extracts. The mean AC and TPC results for meal ranged between 1181–9974 µmol TE/100 g and 73.8–814 mg sinapic acid/100 g of meal. The experimental results of AC and TPC were close to the predicted values calculated from the polynomial response surface models equations (R² = 0.9758 and 0.9603, respectively). The effect of solvent polarity on AC and TPC in the examined extracts was about 3.6 and 2.6 times greater, respectively, than the effect of processing temperature. The predicted optimum solvent polarity of ε = 78.3 and 63.8, and temperature of 89.4 and 74.2°C resulted in an AC of 10 014 µmol TE/100 g and TPC of 863 mg SAE/100 g meal, respectively. The phenolic profile of rapeseed meal was determined by an HPLC method. The main phenolics in rapeseed meal were sinapine and sinapic acid. Refined rapeseed oils were fortified with an extract – rich in polyphenols – obtained from rapeseed meal. The supplemented rapeseed oil had higher AC and TPC than the refined oil without addition of meal extracts. However, AC and TPC in the enriched oils decreased during storage. The TPC in the studied meal extracts and rapeseed oils correlated significantly (p<0.0000001) positively with their AC (R² = 0.9387). Practical applications: Many bioactive compounds extracted from rapeseed meal provide health benefits and have antioxidative properties. Therefore, it seems worth to consider the application of antioxidants extracted from the rapeseed meal for the production of rapeseed oils with potent AC. Moreover, antioxidants extracted from the rapeseed meal were added to refined rapeseed oil in order to enhance its AC. AC was then tested by FRAP assay. FRAP method is based on the reduction of the ferric tripyridyltriazine (Fe³⁺‐TPTZ) complex to the ferrous tripyridyltriazine (Fe²⁺‐TPTZ), and it is simple, fast, low cost, and robust method. FRAP method does not require specialized equipment and can be performed using automated, semi‐automatic, or manual methods. Therefore the proposed FRAP method can be employed by the fat industry laboratories to asses the AC of rapeseed oils and meal.