Search

Crude palm oil, consumed as a healthy food oil, contains a 3-monochloro-propane-1,2-diol (3-MCPD) ester in the range of 0.04-0.05 ppm. The 3-MCPD compound is one of the contaminants belonging to the chloropropanol group that is genotoxin carcinogen. It is therefore necessary to develop an integrated palm oil refining through adsorption with a modified palm empty fruit bunch bioadsorbent to reduce 3-MCPD ester (

Majoritairement constituées de triglycérides et de leurs acides gras, les huiles végétales contiennent également entre 1 et 5 % de micronutriments tels que les tocophérols, les phytostérols, les polyphénols et les coenzymes Q. Naturellement présents dans les graines de colza, soja et tournesol, ces composés sont connus pour leurs effets bénéfiques sur la santé. Leur transfert et leur préservation de la graine jusqu’à l’huile apparaissent dès lors comme primordiaux. Pourtant, une grande part de ces micronutriments est partiellement à totalement détruite au cours des procédés de trituration et de raffinage conventionnels. La préparation des graines (aplatissage, broyage, cuisson), l’extraction par solvant et le raffinage des huiles (neutralisation, décoloration et désodorisation) sont, en effet, autant d’étapes qui ont une influence significative sur les teneurs en constituants mineurs des huiles brutes et raffinées. Des travaux visant à démontrer l’efficacité de différentes méthodes alternatives ont dès lors été conduits.

Sunflower oil is well known because of its diversity of fatty acids profiles which allow different uses (food: dressing salads, margarines; nonfood: agrofuel, lubricants). Besides, crude oil contains high amounts of desirable minor components (tocopherols, phytosterols, polyphenols, phospholipids...) that present important nutritional features with a positive impact on human health. The different steps of the refining process have as main objective to remove contaminants and other compounds that could hamper the continuity of the process or alter oil during storage. An indirect consequence of this treatment used to preserve food safety is that micronutriments of interest are also partially eliminated reducing the nutritional quality of the oil. This review describes in the first part the chemical composition of sunflower oil focusing on desirable and undesirable components. In the second part the refining process is detailed following the losses of micronutriments at each step of the process and the elimination of unwanted compounds.

Crude fish oil is an important ingredient in fish feed for fish farming; it can be used as functional food or neutraceutical (cod liver oil, EPA/DHA concentrates) or incorporated in healthy foods after refining. Major components of fish oil have positive nutritional properties. Polyunsaturated fatty acids can go up to 40% with variable proportions of EPA (C20:5) and DHA (C22-6) [ω-3 fatty acids]. Content of fat soluble vitamins is usually high. Unfortunately, fish oil is also sensitive to degradation products (polymeric and oxidized fat, increased polar content, off-flavor problems…). The beneficial nutritional properties of fish oil are in great contrast with the presence of heavy metals and persistent organic pollutants (POPs) such as polychlorinated dibenzo-dioxins and -furans (PCDDs/PCDFs) and polychlorinated biphenyls (PCBs), mainly originating from the environment. Usual steps for fish oil refining are neutralization, bleaching, winterization (optional) and deodorization. Processing difficulties consist in finding the best operating conditions for an effective removal of unwanted contaminants and a maximal preservation of the nutritional qualities (processing duality). In this work, different adsorbents (filter aid, silica powder, bleaching earth and active carbon) were tested for the best removal of PCDDs/PCDFs and PCBs; it was shown that filter aid, silica and bleaching earth have no significant effect on decontamination while removal of majority non ortho PCBs and PCDDs/PCDFs was possible with active carbon. Mono-ortho PCBs were significantly less absorbed by active carbon. Deodorization was further investigated. Processing temperature had a very pronounced effect on the reduction of PCDDs/PCDFs and PCBs. Already at 210 °C, all of them were removed efficiently to a level below the limit set by European Legislation. But temperature increase was limited by the risk of degradation of EPA/DHA (ω-3). Combination of active carbon treatment and deodorization was shown to be the best compromise to remove majority of the contaminants and to preserve the nutritional quality of fish oil. At low active carbon dosage and deodorization temperature below 200 °C, the total contamination level of PCDDs/PCDFs and PCBs can be reduced below level imposed by European Legislation.

Traditionally fish oil industry was associated to fish meal industry and the processing methods were mostly adapted to the raw material form: whole fish or part of fish (liver, head, by-products). Now, the processing line are more and more technically advanced when the customer requests for deodorized, uncontaminated and rich in PUFA oils increase. New process of extraction as cold press extraction emerges coming from vegetable oil industry. Refining including Deodorization and Decontamination is completed by stripping and molecular distillation decreasing the level of contaminants close to the detection limit of analytical methods. The lipochemistry allows to concentrate the natural content of omega 3: esterification then concentration by molecular distillation or CO2 supercritical plus transesterification (chemical/enzymatic) for TG form. Possibility of fish oil process is “unlimited” to offer to the market the benefice of omega 3 with safe, traceable, tasty fish oils.

The Unilever Food Safety Assurance system for refined oils and fats is based on risk assessments for the presence of contaminants or pesticide residues in crude oils, and refining process studies to validate the removal of these components. Crude oil risk assessments were carried out by combining supply chain visits, and analyses of the contaminant and pesticide residue levels in a large number of crude oil samples. Contaminants like poly-aromatic hydrocarbons and hydrocarbons of mineral origin, and pesticide residues can largely be removed by refining. For many years, this Food Safety Assurance System has proven to be effective in controlling contaminant levels in refined vegetable oils and fats.

Fish oils are rich in nutritionally valuable omega-3 components, mainly eicosapentaenoic (EPA) and docosahexaenoic (DHA) fatty acids. Unfortunately, they could also be contaminated with a series of toxic pollutants like PCDD/Fs and PCBs. This article focuses on the methods for removal of these unwanted compounds and at the same time preserving the nutritional quality of fish oil. Adsorption, deodorization, packed column stripping, and a combination of processes are reviewed here. Activated carbon at 0.5% dosage was efficient in adsorbing PCDD/Fs and no- PCBs, but only 58% of the mo- PCBs could be removed. Adsorption treatment did not significantly alter the quality of the oil. Simple packed column stripping and/or deodorization removed no-PCBs, and especially mo-PCBs in a better manner, its efficiency increasing with temperature. Nutritional properties were preserved until 210°C, beyond which significant EPA and DHA degradation was observed. Combination of activated carbon treatment and deodorization was a good method to remove contaminants, yet preserving the nutritional quality of fish oil. At deodorization temperature of 190°C and 0.1% AC dosage, the total contamination level of PCDD/Fs and dioxin-like PCBs could be reduced, independent of the process sequence, from 35 to below 10 pg TEQ/g, in accordance with the European Union (EU) regulation.

Coal gasification and the production of gaseous fuels include three principal directions related to the production of fuel gas: 1) composition and heat capacity of the produced gas; 2) gas generator structures; 3) characteristic properties of the obtained alternative product - low CO content and gas toxicity, which allow making full use of this gas for domestic purposes. In industrial processes of coal conversion, the following combined technologies are used most often: - semi-coking + gasification of fixed ash (low-temperature coke); - semi-coking + hydrogenation of liquid product (tar); - gasification + synthesis of high molecular weight hydrocarbons from the produced SYN gas (СО+Н) (Fischer-Tropsch synthesis). The choice of the layout for obtaining SLF (synthetic liquid fuel) can be based on specific conditions, the cost and quality of coal, energy supply, market conditions. The products obtained in the process of gasification and hydrogenation of coals pollute the atmosphere much less than the coal burned in electrical power plants. When implementing the organizational and technological model of innovative production, the first stage includes the following combined approaches for the processing of mineral raw materials and new products: 1. processing of carbonic mineral raw materials: calcium carbide, carbon dioxide (in a gaseous, liquid or solid state); 2. acetylene, plant growth regulators (PGRs), plant protection products (TAKAR). The second stage includes fuel and non-fuel products: 1. synthetic ethyl alcohol (ethanol), antifreeze, ethylene glycol, dichloroethane, synthetic drying oils, acetone, etc .; 2. carbamide (urea), ammonia, nitrogen in gaseous and liquid states, methanol, gasoline, etc.

Palm oil is rich in minor components that impart unique nutritional properties and need to be preserved. In this context, refining technologies have been improved, with the dual temperature deodorizer, the double condensing unit and the ice condensing system. The DOBI is a good tool to assess quality of the crude palm oil and its ability to be properly refined. Specially refined oils open a market for new high quality products (golden palm oil, red palm oil, white soaps, etc.). Palm oil is a good candidate for the multi-step dry fractionation process, aiming to the production of commodity oils and specialty fats (cocoa butter replacers). New technological developments allow quality and yield improvements. Palm oil and fractions are also valuable feedstock for enzymatic interesterification in which applications are for commodity oil (low-trans margarines and shortenings) and for special products (cocoa butter equivalents, infant formulation, …).

INRA has initiated a comprehensive approach to food loss and waste for all the plant and animal sectors, from field to distribution. In this study, all comestibles that leave the human food chain and are not recycled into animal feed are considered as losses and waste. The main French oilseed sectors are studied (rapeseed, sunflower and soya, as well as tofu). In order to identify the key sources of loss, all of the various steps in the process of the oleaginous production chain are described, from harvesting through to distribution, including storage, transport, crushing, refining and packaging. For tofu, the study also examines the chain from harvest through to distribution, including as soy milk and tofu paste. Published data are lacking; they were therefore primarily collected directly from professionals in the sectors concerned. Although oilseeds and vegetable oils are apt to have a relatively long shelf-life compared to other products, losses of vegetable oil from field to distribution are substantial (approximately 71.4 kT, equivalent to 10% of the amount consumed in France). We establish that the principal steps giving rise to losses are harvesting and refining. Total losses in French rapeseed oil, sunflower and soybean were estimated at 9.8%, 7.0% and 6.0% of their respective total potential production, worth approximately 50.6, 14.3 and 6.5 € million and equivalent to the annual consumption of approximately 3 030 000, 855 000 and 390 000 people. In the case of tofu, harvest is the most important area of loss. Total losses of tofu are equivalent to 8.2% of potential production. We discuss potential measures to improve the efficiency of the individual steps of French oilseed production.

The presence of undesirable compounds in vegetable and animal oils and fats may have many different origins such as environment, crop protection, production processes, transport and storage, packaging and industrial utilisation like frying. Although the potential toxicity of most of these undesirable compounds is real, poisoning risks are rather limited due to the efficient elimination during oil-refining steps, careful conditioning, choice of efficient packaging and industrial quality control management. For some undesirable compounds representative of the major origins listed above, the analytical methods used (sensitivity, precision), the existing regulations (EU and Codex) and an idea of their content in fats and oils are presented. Main conclusions are: For most of the undesirable compounds possibly found in oils and fats, standardised test methods do exist or are in progress. Results presented prove that oil-refining steps are efficient for elimination of most undesirable compounds. Oils and fats present in general low level of undesirable compounds such as lead, cadmium, hexane, PAHs, pesticide residues or mycotoxins. In order to get reliable and up to date data and to check the conformity of the products regarding the present regulations, the creation of survey plans on potential contaminants such as pesticide residues and benzo[a]pyrene is suggested for refined oils and for cold pressed oils, lead and ochratoxin A have to be added to the list.

As a result of the general concern for food safety, the removal of minor contaminants (PAH, pesticides, dioxins, PCB’s…) from oils and fats has the be examined in detail. Also, in recent years a lot of attention has been given to the lowering of the trans fatty acids content in oils and fats for food products; the reason for this move is the potential negative health impact of trans fatty acids. In general, contaminants can be removed either during neutralization, by adsorption on activated carbon or during the deodorization process. To reach an efficient removal, the process conditions applied need to be optimised to achieve almost complete detoxification but with minimal costs. Traditionally, partially hydrogenated fats were used in nearly all food products because of their interesting melting properties. Nowadays, these products are replaced by trans free alternatives in most food products (margarines, bakery products…). This has created renewed interest for other modification processes: multiple dry fractionation and chemical and enzymatic interesterification. The challenge is to produce trans free fats with the same functionality as the trans rich products, but at comparable cost.