Extraction of green absolute from thyme using ultrasound and sunflower oil

Absolute is the plant aroma isolate mostly used in the food and fragrance sectors. The use of organic solvents constitutes the most commonly used method for obtaining this aroma. However, this technique may leave trace amounts of solvents which are considered undesirable for these industries. In this work, a new green extraction approach was implemented using ultrasound (US) with sunflower oil (SO) as a natural solvent to produce green absolute from thyme (Thymus vulgaris). US optimal conditions for absolute yield were investigated using response surface methodology (RSM) and compared to conventional SO (SO-CV) and hexane (Hex-CV) extractions. The absolutes were analyzed by GC-MS for their chemical composition and tested for their antioxidant activities (total phenols, DPPH and frying test). Optimized conditions obtained by RSM for absolute yield were T = 50 °C, t = 22 min, P = 98 W. The US using SO as solvent offers important advantages: shorter extraction time, increase of 47% in absolute yield compared to SO-CV extraction. Although the absolute obtained by hexane extraction provided improved yield (8.64 g/100 g DW), it contained around 75% of waxy materials. GC-MS analysis showed no remarkable variation of the chemical composition of the absolutes compared to those obtained by hexane extraction. Moreover, the US extraction allowed the highest recovery of monoterpene phenols thymol and carvacrol (86.2%). The absolute obtained by SO-US was free from waxes and organic solvent residues and exerted the highest antioxidant activity. Results show that ultrasound extraction using SO is a good alternative. It suggests the possibility of the production of green absolutes on pilot and industrial scale

Water as a green solvent combined with different techniques for extraction of essential oil from lavender flowers

Using water as a green solvent with a variable geometry makes use of physical and chemical phenomena that are fundamentally different from those applied in conventional extraction techniques such as hydro-distillation, steam distillation or solvent extraction. Advantages and drawbacks of using water as a solvent with different physical and chemical states have been compared. A total of ten extraction techniques: hydro-distillation (HD), steam distillation (SD), turbo-hydro-distillation (THD), salt-hydro-distillation (NaCL-HD), enzyme-hydro-distillation (Enzyme-HD), micelle-hydro-distillation (Micelle-HD), ultrasound-hydro-distillation (US-HD) or subcritical water-hydro-distillation (SW-HD), solvent-free microwave extraction (SFME) and microwave steam distillation (MSD) were used to extract the essential oil from lavender (Lavandula L.) and their results were compared. The quantity was measured by the yield of essential oil and the quality was evaluated using the oil composition especially the content of linalyl acetate, linalool and terpin-4-ol compared with the corresponding control sample: Hydro-distillation. For environmentally friendly of the process: extraction time, total energy consumption and CO2 emission were considered and compared with conventional hydro-distillation. The mechanism explaining the linalyl acetate degradation has been resolved by using COSMORS software. Based on the present experimental conditions, it is recommended that lavender oil may be produced preferably by steam distillation assisted by microwave extraction to reduce the by-product formation by various chemical reactions and to getbetter oil recoveries

Review of Green Food Processing techniques. Preservation, transformation, and extraction

This review presents innovative food processing techniques and their role in promoting sustainable food industry. These techniques (such as microwave, ultrasound, pulse electric field, instant controlled pressure drop, supercritical fluid processing) in the frontiers of food processing, food chemistry, and food microbiology, are not new and were already used for> 30 years by academia and industry. We will pay special attention to the strategies and the tools available to make preservation, transformation and extraction greener and present them as success stories for research, education and at industrial scale. The design of green and sustainable processes is currently a hot research topic in food industry. Herein we aimed to describe a multifaceted strategy (innovative technologies, process intensification, bio-refinery concept) to apply this concept at research, educational, and industrial level.Industrial relevance: Green Food Processing could be a new concept to meet the challenges of the 21st century, to protect both the environment and consumers, and in the meantime enhance competition of industries to be more ecologic, economic and innovative. This green approach should be the result of a whole chain of values in both senses of the term: economic and responsible, starting from the production and harvesting of food raw materials, processes of preservation, transformation, and extraction together with formulation and marketing

Evaluation of alternative solvents for improvement of oil extraction from rapeseeds

This present study was designed to evaluate the performances of five alternative solvents (alcohols: ethanol, isopropanol and terpenes:ρ-limonene, α-pinene, p-cymene) compared to η-hexane in rapeseed oil extraction. The extracted oils were quantitatively and qualitatively analyzed to compare the solvents’ performances in terms of kinetics, fatty acid compositions, lipid yields, and classes. Moreover, micronutrients in extracted oils were also respectively quantified by high-performance liquid chromatography (HPLC) and gas chromatography (GC). In addition, the interactions between alternative solvents and rapeseed oil have been theoretically studied with the Hansen solubility methodology to get a better comprehension of dissolving mechanisms. The results indicated that pcymene could be the most promising solvent for n-hexane substitution with higher lipid yield and good selectivity, despite the micronutrient contents were relatively low