Liquefied gases as alternative solvents for green extraction of natural products

In recent years, the industrial sector of vegetable extraction has been evolving due to the growing interest of consumers for natural food ingredients combined with growing environmental concerns. Therefore, it seems essential to replace existing processes using toxic petroleum bases solvents with greener extraction processes with lower energy consumption, less wastes but higher extract quality. The objective of this thesis has consisted in the research and development of a new extraction process using liquefied gases as liquid solvents. First, this manuscript will outline the state of the art on the liquefied gases and how they are used for extraction of natural products. After this survey, 3 liquefied gases (n-butane, HFO-1234ze and DME) have been selected for laboratory scale experiments performed using a dedicated extraction unit whose design is detailed in Chapter II. Then, the tests performed with these 3 gases for extraction of lipophilic compounds from several plant materials has been described. The experimental approach has been combined with a predictive one using decision tools: Hansen Solubility Parameters and COSMO-RS model. This survey demonstrated that liquefied gases are interesting solvents for solubilization and extraction of lipophilic compounds of interest. In parallel, the impacts of the process on environment, safety regulation and quality showed that liquefied gas extraction could be easily transposed at industrial scale. (author)