Laboratory to pilot scale: Microwave extraction for polyphenols lettuce.

Microwave hydrodiffusion and gravity (MHG) technique has been applied to pilot-scale solvent-free microwave extraction (SFME) of polyphenols from Lettuce sativa. Following the dictates of green extraction and with the aim to save time and energy, the lab-scale knowledge on SFME was exploited for the development of a pilot-scale process. The investigation entailed the optimization of all main parameters (temperature, time, extracted water volume, etc.) and we showed that the polyphenols composition profile under SFME was similar to the classic methods though a bit lower in total content. The energy consumption in the optimized procedure (30min) was 1W/g of fresh matrix.

Comprehension of direct extraction of hydrophilic antioxidants using vegetable oils by polar paradox theory and small angle X-ray scattering analysis.

Since the polar paradox theory rationalised the fact that polar antioxidants are more effective in nonpolar media, extractions of phenolic compounds in vegetable oils were inspired and achieved in this study for obtaining oils enriched in phenolic compounds. Moreover, the influence of surfactants on the extractability of phenolic compounds was experimentally studied first, followed by the small angle X-ray scattering analysis for the oil structural observation before and after extraction so as to better understand the dissolving mechanism underpinning the extraction. The results showed a significant difference on the extraction yield of phenolic compounds among oils, which was mainly dependent on their composition instead of the unsaturation of fatty acids. Appropriate surfactant additions could significantly improve extraction yield for refined sunflower oils, which 1% w/w addition of glyceryl oleate was determined as the optimal. Besides, 5% w/w addition of lecithin performed the best in oil enrichments compared with mono- and di-glycerides.

Stabilization of polymerized vesicular systems: an application of the dynamic molecular shape concept.

A series of glycolipid surfactants derived from Tris(hydroxymethyl)acrylamidomethane (THAM) and bearing hydrocarbon or perfluorocarbon tails and an acryloyl group attached to their polar head was prepared to explore the aqueous behavior of the supramolecular systems they form. The dispersion of surfactants was achieved in water under ultrasonication conditions. Hydrocarbon compounds give heterogeneous vesicular assemblies. In the case of perfluorocarbon derivatives homogeneous vesicles were obtained. However after 1-day storage, all these systems fuse. To stabilize these vesicles, polymerization by ultra violet (UV) irradiation was carried out. During this reaction, a precipitation in water was observed for the hydrocarbon surfactants, whereas fluorocarbon structures provide stable vesicles without any alteration of their size. According to these results, the polymerization process was achieved, in the case of hydrocarbon glycolipid, in the presence of different cosurfactants bearing a single hydrocarbon tail or a polyhydroxylated head and a cholesterol terminus. In such conditions, homogeneous stable vesicles were prepared. Moreover, the THAM derived telomers bearing a cholesterol terminus were able to stabilize and reduce the size of vesicles formed with synthetic glycolipid surfactants. The drug encapsulation ability of these systems was investigated by measurement of the release kinetics of a fluorescent dye, carboxyfluorescein (CF), before and after polymerization.

Instant controlled pressure drop technology and ultrasound assisted extraction for sequential extraction of essential oil and antioxidants.

The instant controlled pressure drop (DIC) technology enabled both the extraction of essential oil and the expansion of the matrix itself which improved solvent extraction. The sequential use of DIC and Ultrasound Assisted Extraction (UAE) triggered complementary actions materialized by supplementary effects. We visualized these combination impacts by comparing them to standard techniques: Hydrodistillation (HD) and Solvent Extraction (SE). First, the extraction of orange peel Essential Oils (EO) was achieved by HD during 4h and DIC process (after optimization) during 2 min; EO yields was 1.97 mg/g dry material (dm) with HD compared to 16.57 mg/g d m with DIC. Second, the solid residue was recovered to extract antioxidant compounds (naringin and hesperidin) by SE and UAE. Scanning electron microscope showed that after HD the recovered solid shriveled as opposite to DIC treatment which expanded the product structure. HPLC analyses showed that the best kinetics and yields of naringin and hesperidin extraction was when DIC and UAE are combined. Indeed, after 1h of extraction, DIC treated orange peels with UAE were 0.825 ± 1.6 × 10(-2)g/g of dry material (dm) for hesperidin and 6.45 × 10(-2) ± 2.3 × 10(-4)g/g d m for naringin compared to 0.64 ± 2.7 × 10(-2)g/g of dry material (dm) and 5.7 × 10(-2) ± 1.6 × 10(-3)g/g d m, respectively with SE. By combining DIC to UAE, it was possible to enhance kinetics and yields of antioxidant extraction.

Green procedure using limonene in the Dean-Stark apparatus for moisture determination in food products.

In the past 10 years, trends in analytical chemistry have turned toward the green chemistry which endeavours to develop new techniques that reduce the influence of chemicals on the environment. The challenge of the green analytical chemistry is to develop techniques that meet the request for information output while reducing the environmental impact of the analyses. For this purpose petroleum-based solvents have to be avoided. Therefore, increasing interest was given to new green solvents such as limonene and their potential as alternative solvents in analytical chemistry. In this work limonene was used instead of toluene in the Dean-Stark procedure. Moisture determination on wide range of food matrices was performed either using toluene or limonene. Both solvents gave similar water percentages in food materials, i.e. 89.3+/-0.5 and 89.5+/-0.7 for carrot, 68.0+/-0.7 and 68.6+/-1.9 for garlic, 64.1+/-0.5 and 64.0+/-0.3 for minced meat with toluene and limonene, respectively. Consequently limonene could be used as a good alternative solvent in the Dean-Stark procedure.