Antonello Paduano

Maldi-tof mass spectrometry profiling of polar and nonpolar fractions in heated vegetable oils.

Triacylglycerol oxidation of thermally stressed (6 h at 180 degrees C, simulating deep-frying conditions) edible vegetable oil (sunflower and olive) was studied using matrix-assisted laser desorption ionization-time-of-flight mass spectrometry (MALDI-TOF MS). Chromatographic separation of the nonpolar and polar components from the heated oil performed on silica gel prior to MS analysis significantly enhanced the detection of oxidized components. The spectra contained signals that were assigned to triacylglycerols (TAG), diacylglycerols (DAG), triacylglycerol oxidative dimers, oxidized TAG, and TAG fragments arising from the homolytic beta-scission of linoleyl, peroxy, and alkoxy radicals. Enrichment of the polar compounds prevented mass spectrometric ion suppression, thus allowing the detection of minor species originating from thermal oxidation. In addition, this allowed the monitoring of polar compounds in vegetable oils undergoing mild thermal treatment. As such, chromatographic separation coupled with MALDI-TOF MS analysis provided a rapid, sensitive, and specific tool to assess the thermal oxidation of vegetable oils.

Influence of some environmental factors on drupe maturation and olive oil composition

BACKGROUND Understanding the relationships between olive cultivars and the cultivation environment as well as optimising cultivation choices can lead to maximum expression of oil production in terms of both quantity and quality. For this purpose, samples of the Ortice olive cultivar grown in two different environments in southern Italy at altitudes of 500 and 50 m above sea level (a.s.l.) were harvested on various dates to monitor drupe maturation and determine the nutritional and chemical characteristics of the oils. RESULTS Fruits grown at 50 m a.s.l. ripened about 10-15 days earlier than those grown at 500 m a.s.l. The oil obtained at 500 m a.s.l. was characterised by a higher content of total polyphenols and a higher content of oleic and stearic acids. CONCLUSION The different heat accumulation related to the environment affected drupe development as well as the colouring trend and oil content. Consequently, the growth environment changed the content of Ortice oil fatty acids and polyphenols, while the flavour profile remained fairly stable in both environments, with the cultivar effect prevailing over the environment factor.

Healthy Virgin Olive Oil: A Matter of Bitterness

Virgin olive oil (VOO) is the pillar fat of Mediterranean diet. It is made from olive fruits and obtained by squeezing olives without any solvent extraction. Respect to the seed oils, an unique polar polyphenol-rich fraction gives VOO a bitter and pungent taste. The recent substantiation by European Food Safety Authority (EFSA) of a health claim for VOO polyphenols may represent an efficient stimulus to get the maximum health benefit from one of the most valuable traditional product of Mediterranean countries educating consumers to the relationship between the VOO bitterness and its health effect. Agronomical practices and new processing technology to avoid phenolic oxidation and hydrolysis and to enhance the aromatic components of the VOO have been developed and they can be used to modulate taste and flavor to diversify the products on the market. VOOs having high concentration of phenol compounds are bitter and pungent therefore many people do not consume them, thus loosing the health benefits related to their intake. In this paper, the chemists and nutritionists point of view has been considered to address possible strategies to overcome the existing gap between the quality perceived by consumer and that established by expert tasters. Educational campaigns emphasizing the bitter-health link for olive oils should be developed.

Olive oil phenolic compounds affect the release of aroma compounds.

Twelve aroma compounds were monitored and quantified by dynamic headspace analysis after their addition in refined olive oil model systems with extra virgin olive oil (EVOO) biophenols to simulate EVOO aroma. The influence of polyphenols on aroma release was studied under simulated mouth conditions by using human saliva, and SPME-GC/MS analysis. While few differences were observed in orthonasal assay (without saliva), interesting results were obtained for retronasal aroma. Biophenols caused generally the lowest headspace release of almost all volatile compounds. However, only ethyl esters and linalool concentrations were significantly lower in retronasal than orthonasal assay. Saliva also caused higher concentration of hexanal, probably due to hydroperoxide lyase (HPL) action on linoleyl hydroperoxides. Epicatechin was compared to EVOO phenolics and the behaviour was dramatically different, likely to be due to salivary protein-tannin binding interactions, which influenced aroma headspace release. These results were also confirmed using two extra virgin olive oils.

Influence of Olive Oil Phenolic Compounds on Headspace Aroma Release by Interaction with Whey Proteins

The release of volatile compounds in an oil-in-water model system obtained from olive oil-whey protein (WP) pairing was investigated by considering the effect of phenolic compounds. Human saliva was used to simulate mouth conditions by retronasal aroma simulator (RAS) analysis. Twelve aroma compounds were quantified in the dynamic headspace by SPME-GC/MS. The results showed significant influences of saliva on the aroma release of virgin olive oil (VOO) volatiles also in the presence of WP. The interaction between WP and saliva leads to lower headspace release of ethyl esters and hexanal. Salivary components caused lower decrease of the release of acetates and alcohols. A lower release of volatile compounds was found in the RAS essay in comparison to that in orthonasal simulation of only refined olive oil (without addition of saliva or WP), with the exception of hexanal and 1-penten-3-one, where a significantly higher release was found. Our results suggest that the extent of retronasal odor (green, pungent) of these two volatile compounds is higher than orthonasal odor. An extra VOO was used to verify the release in model systems, indicating that WP affected aroma release more than model systems, while saliva seems to exert an opposite trend. A significant increase in aroma release was found when phenolic compounds were added to the system, probably due to the contrasting effects of binding of volatile compounds caused by WP, for the polyphenol-protein interaction phenomenon. Our study could be applied to the formulation of new functional foods to enhance flavor release and modulate the presence and concentrations of phenolics and whey proteins in food emulsions/dispersions.

Characterization and evaluation of olive germplasm in southern Italy

BACKGROUND The southern Italian region of Campania has suitable pedo-climatic conditions and a large varietal heritage able to produce oils with high typicality. The aim of this study was to characterize 20 cultivars belonging to Campanias olive germplasm, evaluating their vegetative and production aspects and their oil quality characteristics. The study was conducted from 2003 to 2009, observing the following aspects in six plants per variety: entry into production, vigour, ripening and drupe oil content. The following analyses were carried out on monovarietal oils, obtained by microextractor: acid composition, polyphenol content and aromatic profile. RESULTS The agronomic results showed early entry into production for the cultivars Racioppella, Ortolana, Biancolilla and Carpellese. However, entry into production was delayed for Ritonnella, Ortice, Cornia and Rotondella. As regards vegetative behaviour, Asprinia, from the province of Caserta and Pisciottana and Carpellese, from the province of Salerno, proved the most vigorous cultivars. CONCLUSION Groups of similar cultivars emerged from chemical and sensory analysis of their oils, while other accessions were well characterized and separated from each other, showing a high level of diversity and specificity.

Effect of Thermally Oxidized Oil and Fasting Status on the Short-Term Digestibility of Ketolinoleic Acids and Total Oxidized Fatty Acids in Rats

Western diets contain substantial amounts of lipid oxidation products. The effects of fasting status and oil oxidation on short-term digestibility of oxidized fatty acids (ox-FA) and ketolinoleic acids (keto-LA) of sunflower oils were evaluated. Twelve rats were fasted overnight for 3 days, whereas another 12 rats had free access to diet. From day 4, and for 4 days, two groups of rats, nonfasted (NFT) and fasted (FT), received 1 g/100 g body weight of sunflower oil reused from 40 deep-frying processes, and two control groups of rats, nonfasted (NFC) and fasted (FC), received the same amount of fresh oil. Ox-FA and keto-LA were determined 5 h after the last administration in the various gastrointestinal compartments together with the intraintestinal MDA. Oil digestibility was highest in NFC and lowest in FT rats. NFT and FT rats had higher (at least P < 0.05) intraintestinal MDA, ox-FA, and keto-LA than NFC and FC; MDA and keto-LA concentrations correlated with each other (P < 0.05). Ox-FA and keto-LA levels found in the gastric lumen suggest that digestion contributes to the formation of these compounds. Total ox-FA and keto-LA were efficiently absorbed during the first 5 h after test oil administration, but poorly absorbed in the case of fresh oils. Oil alteration influenced the digestibility of these compounds more than fasting, although the digestibility of oxidized oil was significantly affected by fasting.

Evaluation of anaerobic digestates from different feedstocks as growth media for Tetradesmus obliquus, Botryococcus braunii, Phaeodactylum tricornutum and Arthrospira maxima

In this paper, two freshwater microalgae (Tetradesmus obliquus and Botryococcus braunii), a marine diatom (Phaeodactylum tricornutum) and a photosynthetic cyanobacterium (Arthrospira maxima) were investigated for their ability to grow on liquid digestates (LDs). Three LDs were obtained from anaerobic digestion of different organic wastes: zootechnical (ZW LD), vegetable biomass (VW LD) and the organic fraction of municipal solid wastes (MW LD). All the strains showed the same growth performance on VW LD as on the respective standard media (SM), while ZW LD was efficient only for growth of T. obliquus and B. braunii. MW LD was the poorest growth medium for all the strains. Data on nutrient removal efficiency showed that A. maxima and T. obliquus made the best use of NH4+-N with removal values ranging between 98.9-99.8%, while P. tricornutum and B. braunii showed values of 79.0 and 88.5% respectively. Applying repeated batch cultivation in photobioreactors, the biochemical composition of A. maxima and T. obliquus biomass grown on ZW LD and VW LD, showed an increase of lipid, carbohydrates and ash in both microalgae. Biomass biochemical profiles suggest possible applications in feed, chemicals and energy sectors.

Ultrasound in Olive Oil Extraction

Each olive oil extraction system should combine the best product quality and the highest efficiency. At the same time, the innovative technologies can develop only if they provide sustainable processes. To reach these goals, academic and industrial researchers need to understand the key elements that allow to modulate the events that occur during oil extraction. In the past years, many emerging technologies, that is techniques perceived as capable of changing the present situation, have been developed. Among these, ultrasounds applications seem to be the most promising for their mechanical and slightly thermal effects, without affecting sustainability. In order to explain the maturity of this emerging technology, the main effects of the ultrasounds application in the olive oil extraction process are discussed, the developed plants are presented, and the patents are reported.

Characterization of Volatile Compounds in Cilento (Italy) Figs ( Ficus carica L.) cv. Dottato as affected by the Drying Process

ABSTRACT The present paper reports on the characterisation of white figs cv. “Dottato” from Southern Italy for their volatile compounds as a function of drying treatment, i.e. natural sun-drying or oven-drying. A comparison of the volatile profile of commercial dried figs from Turkey was also reported. Forty-two volatile compounds were identified in Dottato figs by solid-phase micro extraction coupled with gas-chromatography and mass spectrometry (SPME-GC/MS), while 55 were identified in Turkish figs. Aldehydes were the main chemical class, while ethyl alcohol, isopentyl alcohol, isopentyl alcohol acetate, ethyl acetate, 3-mehtylbutanal, hexanal, and benzaldehyde were the major compounds in both fresh and dried Dottato figs. Principal Component Analysis (PCA) explained 76.5% of the observed variance, allowing discrimination between Cilento and Turkish dried figs, and even between sun-dried and oven-treated samples. Oven treatment of Dottato figs significantly affected their volatile profile, while fig pollination is also hypothesised to have an influence. Further work could be undertaken on this aspect, potentially progressing into possible molecular markers to distinguish between fig varieties.