Effect of Salt Addition and Fermentation Time on Phenolics, Microbial Dynamics, Volatile Organic Compounds, and Sensory Properties of the PDO Table Olives of Gaeta (Italy).

'Oliva di Gaeta' is almost certainly the most important and well-known PDO denomination for table olives in Italy. Their production is based on a specific two-stage trade preparation called the 'Itrana' method. In this work, we investigated how variations in the duration of the initial water fermentation (i.e., 15 and 30 days) and the salt concentration (i.e., 6% and 8% NaCl) influence the chemical features, microbial dynamics, polyphenols, volatile organic compounds, and sensory features of 'Oliva di Gaeta'. The time of the addition of salt did not affect the final concentration in the brine, but a longer initial water fermentation (before salt addition) led to lower pH values. The bacterial count constantly increased until the salt addition (i.e., either 15 or 30 days), while the yeast population peaked on day 30. Generally, the two different salt concentrations did not affect the count of microorganisms at the end of fermentation, with the only exception being a higher lactic acid bacteria count for the treatment with 6% salt added at 30 days. At commercial maturity, the crucial bitter tastant oleuropein was not completely removed from the drupes, and differences in salt concentration and the length of the first-stage water fermentation did not influence its content at the end of olive curing. Richer volatile profiles of olives were detected with higher-salt treatments, while the combination of low salt and early saline treatment provided a more distinct profile. Longer initial water fermentation caused a small increase in some phenolic compounds (e.g., iso-verbascoside, verbascoside, and hydroxytyrosol-glucoside). A panel test indicated that salt application at 30 days resulted in a more "Sour" and "Bitter" taste, irrespective of the salt concentration. The low salt concentration coupled with the late saline treatment resulted in more "Fruity" notes, probably due to the higher production of esters by lactobacilli. The slightly bitter perception of the olives was consistent with the partial removal of oleuropein. Our work revealed the characteristics of the 'Itrana' method and that the variation in salt concentration and its time of application changes parameters ranging from the microbial dynamics to the sensory profile. Specifically, our data indicate that 6% NaCl coupled with a longer initial water fermentation is the most different condition: it is less effective in blocking microbial growth but, at the same time, is more potent in altering the nutritional (e.g., polyphenols) and sensorial qualities (e.g., bitterness and fruitiness) of 'Oliva di Gaeta'.

Biophenolic Compounds Influence the In-Mouth Perceived Intensity of Virgin Olive Oil Flavours and Off-Flavours.

In this study, the influence of phenolic compounds on the sensory scores attributed to extra virgin olive oil (EVOO) by panel test was investigated. Two model olive oils (MOOs) with identical concentrations of volatile compounds, differing only in the amount of biophenols (297 vs. 511 mg kg-1), were analysed by two official panels and by SPME-GC/MS. Six other MOOs set up by the two previous models were also tested and analysed. They were formulated separately with the addition of three off-flavours ('rancid', 'winey-vinegary' and 'fusty-muddy'). While high levels of EVOO phenolic compounds did not produce any effect on the headspace concentration of volatile compounds, they did affect the scores of both positive and negative sensory attributes of EVOO, due to the well-known in-mouth interactions between EVOO phenols, saliva and volatile compounds. In particular, a decrease of about 39% in the positive fruity score was found in the presence of a higher concentration of phenols. Regarding EVOO off-flavours, the higher level of phenolic compounds decreased by about 23% the score of 'fusty-muddy' defect and increased the score of 'winey-vinegary' defect about 733%. No important effect of EVOO phenolics on the perceived intensity of the 'rancid' defect was found. These findings could be helpful in explaining some discrepancies of panel test responses observed during extra virgin olive oil shelf life.

Use of odorant series for extra virgin olive oil aroma characterisation.

BACKGROUND: Extra virgin olive oil (EVOO) volatile composition is mainly used as a means of characterisation and authentication, especially for protected denomination of origin (PDO) products. This work investigated the volatile compounds from 25 EVOOs from four Spanish (Cornicabra, Manzanilla Castellana, Picual and Manzanilla Cacereña) and four Italian (Ortice, Ravece, Nocellara del Belice and Itrana) cultivars in terms of odour activity value (OAV). Forty-seven volatile compounds were analysed by solid phase microextraction gas chromatography/mass spectrometry (SPME-GC/MS). OAVs of volatile compounds with similar descriptors were grouped in order to establish eight odorant series: fruity, grass, apple, tomato, floral, woody-spicy, fatty and mushroom. RESULTS: No differences in sensory descriptors were observed among the EVOOs analysed by official VOO sensory analysis. The method of odorant series applied herein was demonstrated to successfully characterise EVOO odour as expected from a sensory panel but using only instrumental analysis of volatile compounds, and giving additional reliable quantitative information. The results can be presented as a 'barcode', providing a visual and effective graphical representation allowing an easy and rapid description of EVOO sensory attributes using instrumental data. CONCLUSION: The odorant series have the potential to better differentiate the aroma of food products, opening new possibilities allowing a schematic and effective visual representation to be used for EVOO quality control and consumer information, especially in new olive oil consuming countries. © 2018 Society of Chemical Industry.

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 chemist's and nutritionist's 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.

Extra virgin olive oil: from composition to "molecular gastronomy".

The aim of this chapter is to provide a brief overview of the recent results of studies on extra virgin olive oil (EVOO) and its interactions with other food ingredients during cooking, to highlight basic molecular aspects of the "magic" of EVOO and its role in Mediterranean gastronomy. The use of raw EVOO added to foods after cooking (or as a salad oil) is the best way to express the original flavour and to maximize the intake of natural antioxidants and compounds related to positive effects on human health (hypotensive, anti-inflammatory, and anti-cancerogenic, among others). EVOO, however, also exhibits its protective properties during/after cooking. Different chemical interactions between biophenolic compounds and other food ingredients (water, milk proteins, carotenoids of tomato, omega-3 polyunsaturated fatty acids in canned-in-oil fish and meat or fish proteins) occur. Even during cooking, EVOO exhibits strong antioxidant properties and influences the overall flavour of cooked foods. The physical (partitioning, emulsion) and chemical (hydrolysis, covalent binding, antioxidant properties) phenomena occurring during cooking of EVOO are discussed with emphasis on the changes in the sensory (bitterness and fruity flavour) and nutritional qualities of some traditional Mediterranean foods. In particular, tomato-oil interactions during cooking, fish canning in EVOO, meat marinated in EVOO before cooking and roasting and frying in EVOO are examined. The interactions between EVOO antioxidants and flavours with milk proteins are also briefly discussed.

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 Campania's 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.

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.

Sensory evaluation and volatile compounds of an alternative ready-to-use therapeutic food for malnourished children.

Ready-to-use therapeutic foods (RUTFs) are special foods used to encourage rapid weight gain in 5-year-old malnourished children, avoiding hospitalization. The factors affecting sensory characteristics and acceptability of RUTFs have been not adequately described. The aim of this work was to evaluate both the sensory properties and volatile compounds of four alternative RUTFs, varying in soy and sorghum, icing sugar, and oil content. Nine nonoral sensory attributes were evaluated by nine selected and trained assessors. The perceived intensity of five oral sensory attributes and the overall liking were assessed by 100 adult consumers. The volatile compounds were extracted and concentrated by solid phase microextraction and analyzed by gas chromatography/mass spectrometry. RUTF formulations significantly differed for graininess between fingers (size of granules) (P = 0.007), viscosity (P = 0.013), adhesiveness to the spoon (P < 0.044), and meltability (P = 0.005), but in consumers' opinion, they differed only for difficulty in swallowing, intensity of global odor, flavor, and sweetness. A positive correlation between overall liking and sweetness was found. Volatile compounds arising from lipid oxidation (hexanal and octanoic acid) were positively correlated with global odor and flavor. These attributes negatively affected the overall liking and were mainly contained in one out of the four formulations. Sensory and instrumental characterization identified key attributes for this kind of food, such as difficulty in swallowing, global odor, and sweetness, suggesting how to formulate an alternative RUTF to be used for a future clinical trial on malnourished children. PRACTICAL APPLICATION: Starting from the world's need to fight child malnutrition, the present study tried to characterize alternative ready-to-use therapeutic foods (RUTFs), special foods used to encourage rapid weight gain in 5-year-old malnourished children, from several points of view, such as acceptability, stability, technological, and overall quality. Results obtained will be an aid to setup the technological conditions and scale-up parameters for local productions of RUTFs to be tested in real trials on malnourished children. Indeed, key sensory attributes that drive consumer acceptance for this special food, such as sweetness and difficulty in swallowing, came out from the present study.

Olive oil from the 79 A.D. Vesuvius eruption stored at the Naples National Archaeological Museum (Italy).

Using a range of chromatographic, spectroscopic, and mass spectrometric analytical techniques, we characterized one of the "edible items" found at the Vesuvius archeological sites and guarded at the National Archaeological Museum of Naples (MANN) in Naples, Italy. We authenticated the specimen contained in a glass bottle (Mann-S1 sample) as originally olive oil and mapped the deep evolution throughout its 2000 years of storage. Triacylglycerols were completely hydrolyzed, while the resulting (hydroxy) fatty acids had partly condensed into rarely found estolides. A complex pattern of volatile compounds arose mainly from breakdown of oleic acid. With excellent approximation, radiocarbon dating placed the find at the time of the Plinian Mount Vesuvius eruption in 79 A.D., indicating that Mann-S1 is probably the oldest residue of olive oil in the world found in bulk amount (nearly 0.7 L).

Ripening Indices, Olive Yield and Oil Quality in Response to Irrigation With Saline Reclaimed Water and Deficit Strategies.

The 70% worldwide surface of olive orchards is irrigated. The evaluation of non-conventional water resources and water-saving techniques has gained importance during the last decades in arid and semiarid environments. This study evaluated the effects of irrigation with two water sources: low-cost water DEsalination and SEnsoR Technology (DESERT) desalinated water (DW) ECw ∼1 dS m-1) and reclaimed water (RW) (ECw ∼ 3 dS m-1) combined with two irrigation strategies: full irrigation (FI) (100% of ETc) and regulated deficit irrigation (RDI, 50% of ETc) on fruit yield, ripening indices, and oil yield and quality of olive trees cv Arbosana planted in Mediterranean conditions. Our results showed that RW without water restrictions increased the fruit yield by 35% due to a slight increase in the fruit weight and, mainly, to a greater fruit set than the control trees; although this did not result in a higher oil yield (g tree-1) since the oil content per fruit dry weight was reduced. The RDI strategy did not decrease the fruit yield despite the fact that olive weight tended to decrease, and it increased the oil yield by ∼14.5%. The combination of both stresses (RW and RDI) neither decreased the fruit yield; however, it significantly reduced oil yield (25% less in 2018) since oil content per fruit dry weight was strongly reduced (40%) compared to control trees. Both RDI treatments, regardless water source, determined acidity levels in olive paste lower than in FI treatments; however, it reduced oil extractability and fatty yield. The finding about oil quality indicated that olive exposure to RW, regardless of the water amount, decreased oil quality mainly due to the reduction of oleic acid and the increase of C18:2/C18:3 ratio and peroxides; on the contrary, both RW and RDI improved the total polyphenols. In all cases, the parameters met the legislation. In short, with appropriate management, RW and RDI have great potential to manage oil olive production; nevertheless, studies subjected to long-term use of these techniques should be experienced to ensure the sustainability of oil yields and quality.

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.

Engineering design and prototype development of a full scale ultrasound system for virgin olive oil by means of numerical and experimental analysis.

The aim of the virgin olive oil extraction process is mainly to obtain the best quality oil from fruits, by only applying mechanical actions while guaranteeing the highest overall efficiency. Currently, the mechanical methods used to extract virgin oils from olives are basically of two types: the discontinuous system (obsolete) and the continuous one. Anyway the system defined as "continuous" is composed of several steps which are not all completely continuous, due to the presence of the malaxer, a device that works in batch. The aim of the paper was to design, realize and test the first full scale sono-exchanger for the virgin olive oil industry, to be placed immediately after the crusher and before the malaxer. The innovative device is mainly composed of a triple concentric pipe heat exchanger combined with three ultrasound probes. This mechanical solution allows both the cell walls (which release the oil droplets) along with the minor compounds to be destroyed more effectively and the heat exchange between the olive paste and the process water to be accelerated. This strategy represents the first step towards the transformation of the malaxing step from a batch operation into a real continuous process, thus improving the working capacity of the industrial plants. Considering the heterogeneity of the olive paste, which is composed of different tissues, the design of the sono-exchanger required a thorough fluid dynamic analysis. The thermal effects of the sono-exchanger were monitored by measuring the temperature of the product at the inlet and the outlet of the device; in addition, the measurement of the pigments concentration in the product allowed monitoring the mechanical effects of the sono-exchanger. The effects of the innovative process were also evaluated in terms of extra virgin olive oil yields and quality, evaluating the main legal parameters, the polyphenol and tocopherol content. Moreover, the activity of the polyphenol oxidase enzyme in the olive paste was measured.

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.

Partition behavior of virgin olive oil phenolic compounds in oil-brine mixtures during thermal processing for fish canning.

The chemical modifications and partitioning toward the brine phase (5% salt) of major phenol compounds of extra virgin olive oil (EVOO) were studied in a model system formed by sealed cans filled with oil-brine mixtures (5:1, v/v) simulating canned-in-oil food systems. Filled cans were processed in an industrial plant using two sterilization conditions commonly used during fish canning. The partitioning of phenolic compounds toward brine induced by thermal processing was studied by reversed-phase high-performance liquid chromatographic analysis of the phenol fraction extracted from oils and brine. Hydroxytyrosol (1), tyrosol (2), and the complex phenolic compounds containing 1 and 2 (i.e., the dialdehydic form of decarboxymethyl oleuropein aglycon 3, the dialdehydic form of decarboxymethyl ligstroside aglycon 4, and the oleuropein aglycon 6) decreased in the oily phase after sterilization with a marked partitioning toward the brine phase. The increase of the total amount of 1 and 2 after processing, as well as the presence of elenolic acid 7 released in brine, revealed the hydrolysis of the ester bond of hydrolyzable phenolic compounds 3, 4, and 6 during thermal processing. Both phenomena (partitioning toward the water phase and hydrolysis) contribute to explain the loss of phenolic compounds exhibited by EVOO used as filling medium in canned foods, as well as the protection of n-3 polyunsaturated fatty acids in canned-in-EVOO fish products.

Phenolic compounds in fresh and dried figs from Cilento (Italy), by considering breba crop and full crop, in comparison to Turkish and Greek dried figs.

UNLABELLED: Fresh and dried figs are important components of the Mediterranean diet. In Cilento (Southern Italy), figs belonging to cultivar "Dottato" are used for the production of "PDO Cilento white figs," as dried figs. In this article, we reported the characterization of the phenolic compounds in 19 fig samples: 9 fresh figs cultivar "Dottato" from Cilento (Italy), 10 dried fig samples from Cilento (2), Turkey (6), and Greece (2). The following phenolic compounds were identified and quantified by high-performance liquid chromatography (HPLC)/UV-DAD: chlorogenic acid, protocatechuic acid, vanillic acid, luteolin-3,7-di-O-glucoside, luteolin 7-glucoside, apigenin-7-O-rutinoside, rutin, quercetin-3-glucoside, and cyanidin-3-O-rutinoside. A discriminative analysis between the peel and pulp of the samples was carried out. The 1st crop ("breba") and the 2nd one (full crop) from Dottato figs were considered, as well as the effect of fig pollination. The majority of the phenolic compounds were predominant in the fig peel. Significant quantitative differences were found among fresh figs, whereas also some qualitative differences were obtained between fresh and dried figs from the same origin in Dottato cultivar, and among dried figs from different origins. Breba crop resulted richer in phenolics than figs of the 2nd crop. Considering the dried figs, the Turkish ones had the highest concentration in phenolic compounds. Other compounds such as the aminoacids tyrosine and tryptophan were also detected by HPLC-DAD analysis in Dottato figs, probably due to the similarity of their chemical structure. PRACTICAL APPLICATION: The results of this research could be useful to deepen the knowledge about the phenolic composition of a fruit that is particularly appreciated in Mediterranean area and presents an increasing interest worldwide. We also characterized a typical Italian fig (Cilento Dottato) that has relevant economical importance in Southern Italy; thus, our work could be applied by producers and industries for the valorization of dried figs as high-quality products. From the consumer viewpoint, a comparison among dried figs from different origins found on the retail market has a huge significance to inform about what the market offers and what product is the richest one in polyphenol content.

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.

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.