Fatty Acid Ethyl Esters (FAEE): A New,Green and Renewable Solvent for the Extraction of Carotenoids from Tomato Waste Products

Currently there is a drive towards the minimisation and reclamation of valuable materials from the waste products of the food and beverage industry. This can be achieved through the extraction of residual nutraceuticals from such materials. Tomato pomace contains carotenoids and other chemicals which can be extracted directly into edible oils to improve the health-giving properties of such oils. We report here a novel green solvent, fatty acid ethyl esters (FAEE), which is significantly more effective than sunflower oil and hexane for the extraction of lycopene and beta-carotene from tomato skin waste. FAEE are a non-toxic renewable resource that is environmentally friendly and to our knowledge has never been used as a vegetal extraction fluid. The efficiency of FAEE extraction was significantly improved relative to both sunflower oil and hexane under ultrasound-assisted extraction (UAE) conditions. In addition, FAEE have the additional and significant advantage that once enriched with the extracted nutraceuticals can be used directly as a food additive.     

Densities of FAMEs or FAEEs with ethanol at temperatures from 283.15 to 318.15 K

Ethanol is usually considered as an additive to blend with biodiesels to improve its cold flow characteristics. The thermophysical properties of ethanol with biodiesels are therefore of interest in its applications. In the present work, the densities of ethanol with six components of biodiesel (including methyl caprate, methyl laurate, methyl myristate, ethyl caprylate, ethyl caprate and ethyl laurate) mixtures were measured from 283.15 to 318.15 K and at atmospheric pressure in the overall composition range. Redlich–Kister equation was used to correlate the excess molar volumes of the mixtures, which were calculated from the experimental densities. In addition, Apelblat’s equation was extended to correlate and predict the densities of the studied mixtures as a function of concentration and temperature.     

Analysis of biodiesel conversion using thin layer chromatography and nonlinear calibration curves

Biodiesel (BD) is a fuel produced by the (trans)esterification reaction between the components of vegetable oil (or animal fat) and an alcohol. The presence of several substrates complicates analytical separation of the mixture, yet understanding of the complex reaction kinetics requires acquisition of a large body of data. The two well-established methods of gas chromatography (GC) and HPLC are time consuming and expensive when analyzing multiple samples. Additionally, it is not always possible to record all the reactants on one elution profile. We examined applicability of thin layer chromatography (TLC) for this purpose, where the detection was based on either flame ionization detector (FID) or a modified staining procedure. The suggested staining method gave no background and appeared well suited for quantitative analysis. The relevant calibrations are presented, and the general principles of analysis of nonlinear responses are discussed. Several experimental samples were produced by enzymatic conversion of rapeseed oil to BD. One reaction step resulted in 85-95% conversion (6h). The second step (after removal of glycerol and water) increased the yield to 97-98%. All components of the mixtures were separated and quantified. Relation of the BD contents measured by TLC and GC gave the values of 1.03±0.07 (TLC-staining) and 0.95±0.04 (TLC-FID), indicating applicability of the TLC-methods.