Impact of texturing/cooling by Instant controlled pressure drop DIC on pressing and/or solvent extraction of vegetal oil
Abstract
Instant controlled pressure drop process (DIC) was used as a texturing pretreatment in order to recover the highest part of oil content of various oleaginous materials such as jatrophacurcas, rapeseeds, camelina seeds and date seeds at 5% to 6% (dry basis) water content. Pressing and n-hexane 95% solvent extraction of oil from both DIC-textured and nontreated raw material RM seeds was achieved using separately ASE (Accelerated Solvent Extraction at high pressure and temperature,and short time) for quantifying the oil content, and conventional industrial solvent extraction of 2-hour Dynamic Maceration (DM) extraction at 68 oCto establish extraction kinetics and practical yields. Whatever the extraction process and the oilseed species were, optimized DIC treatment allowed increasing oil yields and extraction kinetics whilst perfectly preserving oil quality. It was possible to perform comparative studies and to optimize DIC treatment based on oil extraction yields. DIC treatment performed at 0.63 MPa between 45 and 105 s depending on oleaginous varieties allowed getting much higher oil yields: 96.4% instead of 81%, 92.6% instead of 76%, 93.4%, instead of 86.3%, and 79% instead of 63% of oil contents from rapeseeds, camelina seeds, Jatropha and date seeds, respectively. Besides, in terms of fatty acid composition, instant cooling via DICenabled the preservation of the oil lipid profile.
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Introduction
Rapeseed is one of the most important oil seeds, which contains an oil quantity between 40 and 55%% wt% wt. The composition is as follows: triglycerides 97-99%% wt% wt, fatty acids 0.5–2%% wt% wt and minor lipids 0.5–1%% wt% wt[1]. Rapeseed contains oil (fatty acids), proteins, water, cellulose and mineral elements. Rapeseed oil mainly contains unsaturated fatty acid. The main fatty acid composition of rapeseed oil is palmitic acid C16:0 (3.49%), stearic acid C18:0 (0.85%), oleic acid C18:1 (64.4%) and linoleic acid C18:2 (22.3%), linolenic acid C18:3 (8.23%) and other fatty acids (3%) [2].The production of rapeseed oil has been highly developed over many years for commercial use. Conventional processes employ both mechanical and/or solvent extraction methods. Indeed the most popular method is seed pressing followed by meal solvent extraction.
The ever-growing demand of vegetable oils has resulted in intensive work within the food industry, the oleo-chemistry industry, and regarding environmental concerns. Oils are the highest energy source between the three basic food compounds, carbohydrates, proteins, and fats. They also are good carriers of oil soluble vitamins and many fatty acids essential for health and that are not produced by the human body [3].
To find different lipid resources of vegetable oils, efforts have been focused on producing oil from annual plants, grown in relatively temperate climates and triggered from seeds. Oleaginous oil production is of great interest in terms of quality, titer, production rate and yield.
Conclusion
The industrial scale of intensification of oil extraction from various oleaginous was carried out using Instant controlled pressure drop (DIC) texturing. This technology had the capacity of increasing yields of oil obtained from both pressing (more than 10%) and Dynamic Maceration with hexane (about 12% more). The coupled operation of DIC, pressing and solvent extraction of meals shows a great impact and defined the most adequate intensification technology with total oil extraction of DIC textured seeds as 378 instead of 317 and 363 instead of 298 kg/ton of raw material for rapeseeds and Camelina, respectively. The higher availability and better kinetics of solvent extraction triggered by DIC were proved by the highest extraction yields obtained with ASE for DIC textured seeds. All these quantitative aspects were systematically coupled with a consequent preservation of the product quality defined through the profiles of fatty acids. Finally, compared with cooking and flacking, DIC needs about 1 min treatment time and much lower energy consumption.