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This article constitutes the fifth part of a series dedicated to the comparative analysis of extraction solvents for oilseeds. This section evaluates the impact of various solvents on oil quality, focusing on enzymatic activity, oil acidity, peroxide value, fatty acid profiles, phospholipids, polyphenols, tocopherols, and sterols. For alcohols, such as ethanol, isopropanol, and methanol, results indicate an interesting suppression of enzymatic activity due to protein denaturation. Alcohols also lead to higher tocopherol content and lower acidity when solvent recycling employs a non-distillation process. Ketones, particularly acetone and methyl ethyl ketone, show potential for enzyme denaturation and exhibit low miscibility with phospholipids, which may impact the extraction process. Ethyl acetate is recognized for potentially enhancing enzymatic activity and extracting higher levels of antioxidants. Dichloromethane is effective in extracting more phospholipids compared to hexane. The use of 2-methyloxolane (2-MeOx) presents a potential issue of peroxide formation, leading to higher peroxide values in extracted oils. Additionally, 2-MeOx extracts higher amounts of phospholipids, polyphenols, and tocopherols, but results in lower sterol content for reasons not fully understood. Regarding fatty acid profiles, no study has shown a significant effect of solvent choice. These results highlight the complex interactions between solvents and oil components, illustrated by surprising findings such as the higher extraction of free fatty acids by alcohols. Despite a substantial number of studies, the presented results should be interpreted cautiously, as they were obtained under conditions not fully representative of industrial operations.

This article constitutes the sixth part of a series dedicated to the comparative analysis of extraction solvents for oilseeds. This section examines the effects of various solvent extraction methods on the quality of oilseed meals, particularly focusing on antinutritional factors and protein value. The study discusses the impact of these solvents on glucosinolates (GLS) in rapeseed meal, trypsin inhibitors in soybean meal, phytic acid and phosphorus digestibility, gossypol in cottonseed, and phenolic compounds. Alternative solvents with higher water miscibility may lead to more effective reduction of GLS in rapeseed meal due to increased moisture in the desolventizer. They also could denature trypsin inhibitors in soybeans before desolventization, but this effect is negligible due to sufficient toasting conditions in the desolventizer. The intensity of heat treatment can affect phosphorus digestibility, but this intensification often comes with undesirable effects on protein digestibility. For cottonseed, ethanol with added acids has been shown to be able to extract gossypol, while isopropanol was less effective. Phenolic compound extraction with more polar solvents has the potential to improve meal taste and appearance, but without major effect on the feed value of the proteins. Desolventization conditions significantly impact protein value, with mild cooking potentially improving digestibility, while excessive heat treatment can lead to Maillard reactions, reducing protein and the digestibility of sensitive amino acids. Non-hexane solvents have water miscibility, latent heat of vapourisation and solvent hold-up in the marc that lead to increasing the temperature, moisture and residence time required for effective desolventization likely to promote stronger reduction in protein digestibility. Further experimental data would be necessary to better assess this issue.

In the context of potential regulatory changes, this study compares the properties of various solvents for the extraction of edible oils. The solvents considered are hexane isomers, alcohols, ketones, ethyl acetate, dichloromethane and 2-methyloxolane. The study presents a detailed table of physical properties for each solvent, including boiling point, density, vapour pressure, flash point and miscibility with water. It also addresses chemical stability, reactivity and potential interactions of these solvents with oilseeds. Particular attention is given to solvent-substrate interactions measured by Hansen solubility parameter. Normal hexane and its isomers show high affinity for neutral lipids, a lesser one for polar lipids and fair selectivity for non-lipids. Due to their hydroxyl group, alcohols (methanol, ethanol, isopropanol) exhibit only a modest affinity for non-polar lipids, though this affinity increases with the number of carbon atoms in the alcohol molecule. They demonstrate a higher efficacy in extracting polar lipids; however, this extraction process also extends to numerous non-lipidic molecules. Ketones (acetone, MEK) offer a balance, with theoretically good affinity for both polar and non-polar lipids, although in practice they do not dissolve phospholipids. Ethyl acetate shows good solvent power for various lipids, its ester group being found in most of lipid molecules. Dichloromethane is a good solvent for lipids in general but raises potential safety concerns. 2-Methyloxolane is noted for its ability to efficiently extract both polar and non-polar lipids, offering a potential compromise between hexane-like and more polar solvents however, it is potentially hindered by its price and its limited availability.

This study compares various solvents for edible oil extraction, focusing on their energy consumption impacts. The research examines traditional hexane and alternative solvents, using both theoretical calculations and experimental data. The article presents a thermodynamic analysis of solvent-water separation using ChemSep software for rectification simulations. Results show significant differences in energy requirements, with acetone being potentially the most efficient and alcohols (ethanol and isopropanol) requiring substantially more energy at desolventization step. Solvent hold-up in the marc is a crucial factor affecting desolventization energy consumption. Experimental data from a pilot plant study on rapeseed cake extraction is presented, showing higher retention rates for ethanol and isopropanol compared to hexane. For other solvents, retention rates are estimated using the Hansen solubility parameter δh. Energy requirements for meal desolventization are calculated, considering factors such as solvent properties, marc composition, and steam usage. Alternative solvents generally show higher energy consumption compared to hexane. With a hypothetical non-distillation scheme the heat required is +76% for ethanol, +32% for isopropanol, −21% for acetone. It is +42% for the acetone solvent in traditional miscella evaporation. Methyl ethyl ketone (MEK) would require +66%, ethyl acetate 33% and 2-methyloxolane +35% more heat. Dichloromethane and isohexane require a little less energy because of their low boiling point while cyclohexane requires 5% more. The study also discusses the implications of solvent choice on desolventizer-toaster-dryer-cooler (DTDC) design and operation, highlighting potential challenges with high-moisture in the meal resulting from intensive use of direct steam.