Universität GH Essen, D-4300 Essen 1 Department of Oenology and Beverage Technology, Technological Educational Institute (T.E.I.) of Athens, Ag. Spiridonos Street, 122 10 Egaleo, Athens, Greece
Abstract: Cloud point extraction (CPE), a promising and simple technique for the separation of organic compounds using surfactants (Genapol X-080 [oligoethylene glycol monoalkyl ether] and PEG 8000 [polyethylene glycol with molecular weight of 8000]), was used to recover polyphenols from wine sludge (wine production waste). The effect of various parameters such as surfactant concentration, temperature, and pH on the percentage of phenol recovery and phase volume ratio during phenol separation from wine sludge was investigated, and the derived optimum parameters were used as the basis for the selection of CPE conditions. When a two-step CPE with a total of 4% v/v of Genapol X-080 (pH = 3.5, temperature 55 °C, and time = 30 min) or 10% v/v of PEG 8000 (pH = 2.5, temperature = 55 °C, and time = 30 min) was applied the phenol recovery values achieved were 75.8 or 98.5%, respectively. Phenols recovered from wine sludge using the above surfactants maintained high antiradical activity as determined by the 1,1-diphenyl-2-picrylhydrazyl method.
Abstract: Red wine from the Greek grape cultivar Aghiorghitiko, was aged in stainless steel with and without wood
chips toasted to different degrees (heavily, medium, lightly) and in a 225L American standard oak barrel
for 32 days. Headspace concentrations of four wood-derived congeners (furfural, guaiacol, cis and trans
oak lactones) were determined over this period after which the wines were bottled, stored and subjected
to sensory descriptive analyses. Of the 36 attributes for appearance, aroma and oral characters, 14 were
significant in univariate analyses and differentiated wines in a multivariate (principal component analysis)
product space explaining 72% variance in two factors. Wines from medium toast wood chips scored
highest for woody, vegetative and smoky aromas and flavours but also for bitter taste and astringent
mouthfeel and after 14 days had the highest headspace concentrations of furfural and cis oak lactone.
Wood-related notes were ranked from heavily and lightly toasted chips, barrel and steel control.
2008 Elsevier Ltd. All rights reserved.
Abstract: The possibility of applying cloud point extraction (CPE) using Genapol X-080 as surfactant for the separation of phenolic compounds from olive mill wastewater was examined. The ability of the surfactant to recover individual and mixtures of polyphenols and tocopherols in various concentrations from aqueous solutions was tested before its application for the recovery of phenols from olive mill wastewater. Many of the examined individual polyphenols were recovered at high percentage. Especially, in the case of Luteolin, low surfactant concentrations
were sufficient for quantitative removal. The recovery appeared proportional to the surfactant concentration.
The complete recovery of tocopherols was also possible. Total phenol recovery by simple and successive
CPE of olive mill wastewater with various concentrations (2, 5 and 20%, v/v) of Genapol X-080 was up to 89.5%.
Abstract: The performance of olive oil during intermittent frying of potato slices and cod fillets was compared to those of selected vegetable oils (corn, oliveresidue and 50/50 mixture of olive and corn oils) using conditions resembling
those used in home food preparations. The main scope of this study was to decide what is the best substitute for olive oil in home frying applications. Free fatty acid content, peroxide value, polar compounds, color and viscosity were increased, whereas iodine value, polyunsaturated fatty acids content and tocopherol concentration decreased. The organoleptic quality of potato slices and cod fillets fried in all oils was determined. Significant differences in the physicochemical changes were observed. The analytical and sensory data showed that the lowest deterioration occurred in olive oil and the highest in corn oil. The 50/50 (w/w) olive/corn oil mixture proved to be a good substitute for olive oil in domestic frying applications.
Abstract: Fruits are valuable sources of natural phenolic antioxidants , which are known to have beneficial health promoting properties. Some rarely consumed fruits ( almondleaved pear) in the Greek province and peels processed to traditional homemade pastries (bitter orange, quince) as well as some wild types (wild pomegranate and wild pear) where investigated in relation to their phenol content and antioxidant activity potential of the methanolic extracts and compared to well known fruits (apple, pomegranate). Total
phenols (TP) values of fruit flesh and peel where estimated by the Folin-Ciocalteu reagent after extraction with ethyl acetate and n-propanol in acid hydrolyzed and non hydrolyzed samples, while antioxidant activities values of methanolic extracts where estimated by the DPPH method. The obtained TP and antioxidant activity values where compared to the corresponding values of green apple, red apple and pomegranate.
Abstract: Recent developments in Fourier transform infrared (FT-IR) spectroscopy instrumentation extend the application of this technique to the field of food research, facilitating particularly the studies on edible oils and fats. In this work, FT-IR spectroscopy is used as an effective analytical tool in order: (a) to determine extra virgin olive oil adulteration with lower priced vegetable oils (sunflower oil, soyabean oil, sesame oil, corn oil) and (b) to monitor the oxidation process of corn oil samples undergone during heating or/and exposure to ultraviolet radiation. A band shift observed at 3009 cm(-1) assigned to the C_H stretching vibration of the cis-double bond, allows the determination of extra virgin olive oil adulteration. Changes in the 3050-2800 and 1745 cm(-1) spectral region appear after heating at elevated temperatures and aid the oxidation process monitoring. In addition, an analytical technique for the measurement of carbonylic compounds in oils, produced after heating, is applied. The possible antioxidant effect of oregano is also discussed.
Abstract: The possibility of the application of Cloud Point Extraction (CPE) procedure on the isolation of natural antioxidants (phenols) from olive mill wastewater (OMW) was determined. The efficiency of the technique was firstly tested on individual phenols and phenol mixtures. The use of a surfactant (Triton X-114) was proven to be, in most of the cases, very efficient for the CPE of individual phenols from their aqueous solutions. The CPE with Triton X-114 achieved a quantitative extraction of individual phenols with recovery values higher than 96%, with one or more successive CPE steps and with a total of 4-6% of surfactant. This procedure was used on OMW (after the removal of fatty substances), and achieved recoveries higher than 60% when 6% of surfactant was used. Since Triton X-114 is a relatively non-toxic reagent and the CPE technique is a simple, fast, low-cost, sensitive and selective procedure, the extracted organic substances from OMW can be applied as natural antioxidants in food technology.
Abstract: Physical antioxidant isolation by means of solid âliquid extraction of plant sources, require extreme high volumes (12-15 fold of the liquid sample) of toxic volatile organic solvents such as methanol, ethyl acetate
and n-propanol. In contrary, cloud point extraction methodology requires surfactant volumes 6 to 10% of the
liquid sample. The objectives of this study were to examine the extraction conditions and recovery yields of
phenolics in aqueous solutions of individual phenolics, i.e. caffeic acid, o-coumaric acid, tyrosol, oleuropein ,
apigenin, luteolin, gallic acid, p-coumaric acid, routin, epicatechin, protocatechuic acid , and hydroxy-tyrosol. In
addition , mixtures of the above phenolics were treated in similar way and recoveries of over 95 % were
achieved. This methodology is allowing a highly pre-concentration of the analytes in the surfactant phase The
cloud point extraction technique was also applied on liquid olive waste water (OMW) with recoveries of up to
60%. Optimisation of the procedure for a quantitative phenols recovery from OMW needs more research.
Abstract: The possibility of quantitative determination of organic compounds in aqueous solution or in the gaseous phase by FT-IR/ATR spectroscopy by the aid of polymer-covered internal reflection elements has been studied. In general this method has three effects: (1) exclusion of water from the measurement, (2) lowering of the limit of detection because of the continuous and reversible enrichment of organic compounds, and (3) reduction of the half-width of the absorption bands for gases by insertion of the molecules in a polymer film. The enrichment of some halogenated hydrocarbons in three different polymer materials was used to determine the concentrations of these substances in water by IR spectroscopy with very good limits of detection (sometimes less than 1 mg/dm3). In all cases a linear relationship between concentration of the sample and apparent extinction of the absorption band of interest is recorded. The time constants for 90% saturation of the polymer are several seconds for measurements of gases and some minutes for aqueous solutions, depending on the polymer material and the character of the substance.
