Carla Da Porto

Comparison of ultrasound-assisted extraction with conventional extraction methods of oil and polyphenols from grape (Vitis vinifera L.) seeds

Ultrasound-assisted extraction (US) carried out at 20 KHz, 150 W for 30 min gave grape seed oil yield (14% w/w) similar to Soxhlet extraction (S) for 6 h. No significant differences for the major fatty acids was observed in oils extracted by S and US at 150 W. Instead, K232 and K268 of US- oils resulted lower than S-oil. From grape seeds differently defatted (S and US), polyphenols and their fractions were extracted by maceration for 12 h and by ultrasound-assisted extraction for 15 min. Sonication time was optimized after kinetics study on polyphenols extraction. Grape seed extracts obtained from seeds defatted by ultrasound (US) and then extracted by maceration resulted the highest in polyphenol concentration (105.20mg GAE/g flour) and antioxidant activity (109 Eq αToc/g flour).

Ultrasound-assisted extraction coupled with under vacuum distillation of flavour compounds from spearmint (carvone-rich) plants: Comparison with conventional hydrodistillation.

Ultrasonically assisted extraction of flavour compounds from different varieties of Mentha spicata, using 70% ethanol, have been carried out for 5, 10 and 15min and coupled with under vacuum distillation. The ultrasound distilled extracts have been analysed by GC-MS and compared with essential oils obtained by hydrodistillation. The results have showed that ultrasonically assisted extraction in combination with under vacuum distillation have provided extracts with higher flavouring strength due to the increased concentration of desirable oxygenated compounds (from 5 to 8 times) compared with hydrodistillation. Extraction yields of flavour volatiles have been calculated giving a range 0.04-0.13% by ultrasound and 0.01-0.02% by hydrodistillation.

Grappa and Grape-Spirit Production

ABSTRACT: Grappa and grape-spirit are alcoholic beverages of viticultural origin. Grappa is a distillate made in Italy from direct steam marc distillation or distilled after adding water or wine lees. The production process can be divided into three steps: marc ensilage, distillation, and maturation. Grape-spirit is a fruit distillate. Stemmed, crushed, and fermented grape and juice are the raw materials of grape-spirit. The distillation of these raw materials is generally carried out with the same discontinuous distillation systems used for grappa production. A modified distillation technology is suggested for this alcoholic beverage.

Analysis of the Volatile Compounds of Flowers and Essential Oils from Lavandula angustifolia Cultivated in Northeastern Italy by Headspace Solid-Phase Microextraction Coupled to Gas Chromatography-Mass Spectrometry

Headspace solid-phase microextraction (HS-SPME) coupled to gas chromatography and mass spectrometry using the divinyl/carboxen/polydimethylsiloxane (DVB-CAR-PDMS) fibre was applied for the analysis of aroma profiles of Lavandula angustifolia L. flowers and the corresponding essential oils. The optimal sampling time was determined by studying the equilibrium time profile of the major volatile compounds for the lavender flowers (50 min) and the essential oil (20 min). Comparative analysis of L. Angustifolia L. cultivated in Friuli Venezia Giulia (northeastern Italy) highlighted that the contents of linalool and linalyl acetate were the major differences between the composition of flowers and the hydro-distilled products. Lavender essential oil from Middle-Friuli Venezia Giulia was evaluated as the highest quality for its high level of linalyl acetate (31.7 %) and linalool (45.0 %) and low percentage of camphor (0.5 %). The use of headspace SPME was shown to be a convenient and effective analytical tool for the sampling of volatile compounds and it could be used to test the quality of flowers and essential oils from Lavandula species.

Towards multi-purpose biorefinery platforms for the valorisation of red grape pomace: production of polyphenols, volatile fatty acids, polyhydroxyalkanoates and biogas

The development of a multi-purpose four step-cascading biorefinery scheme for the valorization of red grape pomace (GP) was proposed. The consecutive processes were respectively dedicated to (a) the recovery of polyphenols by supercritical CO2 extraction, (b) the production of volatile fatty acids (VFAs) by anaerobic acidogenic digestion, (c) the exploitation of produced VFAs as the precursors for the biotechnological production of polyhydroxyalkanoates (PHAs) and (d) the production of a CH4-rich biogas by the anaerobic digestion of solid leftovers from the acidogenic process. More than 2.7 g of total polyphenols (as gallic acid equivalents) per 100 g of dry matter were extracted. A high content of valuable proanthocyanidins occurred in the recovered polyphenolic fraction. The dephenolized GP was anaerobically digested under batch acidogenic conditions, obtaining about 20 g L−1 of total VFAs in the liquid effluent. The latter matrix was employed to feed a pure culture of a Cupriavidus necator strain, which was induced to produce and store PHAs under nitrogen-limiting conditions. The process was carried out in 0.5 L-shake flasks by using a two-step production approach. In particular, pre-grown biomass was fed with different concentrations of the acidic effluent (20 or 40% v/v) in two sequential batch processes. Poly(3-hydroxybutyrate) was accumulated up to 63% of the cells dry weight when pre-grown biomass was fed with 40% of the acidic effluent. No inhibitory effects due to non-VFA compounds occurring in the actual acidogenic effluent were observed. Finally, the anaerobic digestion of the exhausted solid fraction from the acidogenic process allowed obtaining 113 mL of biomethane per gram of fed volatile solids.

Study of Some Volatile Compounds of Raw Grappa Obtained Using Marc Treated in Different Ways and Stored in Plastic Tunnels

Marc stored in plastic tunnels was treated as follows: without any treatment; with the addition of lysozyme; with the addition of potassium metabisuphite solution in water; and with the addition of potassium metabisulphite powder, selected yeast, sugar and N-compounds. After a storage period of 80 d, marc was distilled in batches. The raw grappa made with treated marc resulted in lower levels of fusel alcohols and higher concentration of ethyl esters from C8 to C12 compared with grappa made with untreated marc. Sensory evaluation indicated that the marc treated with selected yeast was preferred.

Design of a continuous distillation plant for the production of spirits originating from fermented grape

Abstract An industrial de-alcoholizing plant and a distillation column were designed, for processing 0.56 kg/s (2000 kg/h) of fermented grape with an ethanol concentration of 9.0% weight/weight, (w/w) and a content of solids in suspension, expressed as dry matter, of 5–6% (w/w), to obtain a grape-spirit at 80% ethanol (w/w). Mass flow rates, heat flux rates and temperatures were first measured in a small-scale de-alcoholizing pilot plant. Then, the industrial plant was designed on the basis of results from experimental tests on the pilot plant. The industrial de-alcoholizing apparatus consisted of 28 plates, each fed by steam at 250 kPa, to obtain an alcoholic waste composition of 1% ethanol. By applying the McCabe–Thiele method, the number of actual trays in the distillation column has been estimated to be 10, in order to increase the alcohol content in the product from 13.1% to 80% ethanol (w/w). Technical changes to the de-alcoholizing plant to improve its performance are also suggested.

Potential Oil Yield, Fatty Acid Composition, and Oxidation Stability of the Hempseed Oil from Four Cannabis sativa L. Cultivars

ABSTRACT The cultivation of four industrial hemp cultivars (Felina 32, Chamaeleon, Uso31, and Finola) was investigated for oil production in the north-east of Italy along two years. The oils of all cultivars resulted in rich amount of linoleic acid (ω-6) and α-linolenic acid (ω-3). Felina 32 and Chamaeleon oils exhibited the highest amount of linoleic acid (59%) and α-linolenic acid (18%). Finola and Uso31 oils resulted in the richest of γ-linolenic acid (5–6%). All hempseed oils presented high oxidation stability and an acceptable initial quality. It is suggested that these oils can be used to produce EFA dietary supplements high in ω-6 and ω-3 of vegetal origin.

Analysis of the Volatile Compounds of Aerial Parts and Essential Oil from Thymus serpyllum L. Cultivated in North East Italy by HS-SPME/GC-MS and Evaluation of its Flavouring Effect on Ricotta Cheese

Abstract Headspace solid-phase microextraction (HS-SPME) coupled to gas chromatography and mass-spectrometry using the divinylbenzene/carboxen/polydimethylsiloxane fiber was applied for the analysis of flavor profiles of Thymus serpyllum L. aerial parts and the corresponding essential oil. At 30°C, the optimal sampling time determined by the equilibrium time of the major volatile compounds both for the thyme aerial parts and the essential oil was 30 min. Twenty-six volatile compounds were identified. Carvacrol and carvacrol methyl ether were the main compounds (44.9 %). The flavoring effect of different amounts (0.26, 0.33 and 0.40 g ) of essential oil for 100 g of ricotta cheese was studied by HS-SPME/GC-MS. Significant differences (p≥0.05) were found for monoterpene hydrocarbons and oxygenated monoterpenes for 0.40 g essential oil/ 100 g ricotta cheese. Interactions between thyme essential oil and ricotta cheese highlighted that hydrocarbons monoterpene and sesquiterpene were retained by ricotta, whilst oxygenated monoterpenes were released.

Effects of raw material on the partition of some volatile compounds of grappa, a typical Italian spirit

Abstract Fractional distillation was used to study the effect of raw materials on grappa composition. Grape marc and grape marc with the addition of an amount of wine lees (42%) greater than the European Community regulations limit (25%) permits were investigated. The concentration of all the volatile compounds considered, the percentage of extraction of acetalde‐hyde, methanol, ethylacetate and ethyl lactate, but not the kinetics of extraction of higher alcohols, acetic acid and ethyl lactate, are affected by this addition of lees to marc. Overall, the hygienic characteristics of grappa are improved.