Overview of the soybean process in the crushing industry

A minimal residual oil content in the meal coming out of the hexane extractor is a clear benefit for a crushing plant; the more oil yield the better revenue for the crusher. In a modern and efficient extraction plant, a residual oil content ≤ 0.5% for soybean meal is expected. The first step for an efficient solvent extraction is a good preparation process; its optimization makes it possible to shape the seeds for effective leaching and washing of the oil. Preparation also goes through an optimized dehulling (warm or hot dehulling) allowing, in an economical way, to maximize the protein content. The seed flaking can optionally be complemented by expanding which permits rupture of a more efficient portion of the cell walls. Solvent extraction consists in washing the prepared material in a countercurrent multistage process to enable a reasonable quantity of solvent to extract a maximal amount of oil. Major progresses in solvent extraction relate to plant production capacity increases which propelled technological improvements. Following extraction, the solvent is distilled from the miscella and recovered. A mineral oil system absorbs the residual solvent out of the effluent air stream. A single integrated unit also called desolventizer/toaster/dryer/cooler removes the solvent, toasts the meal in order to control the anti-nutritional factors and reduces moisture and temperature to levels appropriate for storage and transport. Although today the industry is mostly based on the solvent extraction process, certain strict constraints in the environmental aspects suggest alternative processes to minimize hexane emissions and even the return to mechanical operations (for example full press) allowing to completely eliminate the use of solvent at the expense of lower efficiency

Fractionnement à sec de l'huile de palme avec mélange de stéarine

Palm oil is the most consumed oil worldwide. Its composition confers technological properties that no other vegetable oil can afford. It is also the most fractionated oil with a huge potential in multi-step dry fractionation. Different routes are clearly established leading to specialty products like low IV super stearin (solid route), high IV top olein (liquid route) and hard palm mid fraction (ingredient for CBE). This work focused on the liquid route, more particularly on the first step: production of olein (IV 56) and stearin from palm oil. The initial objective was to find a way to improve the olein yield thanks to an optimization of the palm oil composition with stearin blending. To this end, palm oil was blended with increasing amounts of palm stearin to obtain matrices with variable tri-saturated triglyceride contents; five blends were investigated. Dry fractionation was carried out on pilot scale using a Tirtiaux crystallizer coupled to a high-pressure membrane press filter. After optimization of the cooling curves, on-going crystallization was monitored by sampling using optical microscopy and powder X-Ray diffraction. Crystallization kinetics were derived from solid fat content of the slurry by p-NMR, iodine values and DSC cloud points of the olein after vacuum filtration. Press filtrations were then performed at identical temperature after the same crystallization time. Fractions quality was evaluated based on iodine value, DSC cloud point and triglyceride composition by HPLC. It was shown that one specific matrix could release more olein after press filtration in identical conditions. This olein was characterized by slightly higher iodine value and surprisingly higher DSC cloud point. This matrix was also the fastest to achieve a steady state during the crystallization kinetics. All the analytical tools used helped in understanding and trying to elucidate this unexpected behavior