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BACKGROUND: Nowadays, olive oil extraction is basically achieved by means of two-phase decanters, which allow a reduction of water consumption and the leaching of phenolic compounds. Despite this, most of the working settings derive from studies carried out on three-phase decanters. Hence, the aim of the present study was to assess the influence of two-phase decanter feed pipe position (FP) on the extraction efficiency and chemical-sensory characteristics of virgin olive oil. Three different positions were considered: at 825 mm (FP1), 610 mm (FP2) and 520 mm (FP3) from the outlet of the oily phase. RESULTS: Position FP3 allowed the highest oil recovery (up to 10%), the lowest percentage of oil in the olive pomace and, in general, a regular trend in terms of oil extraction efficiency. However, the oily must that came out of the decanter was not completely clean in terms of residual content of solid sediment and water. The feeding position partially affected the profile of antioxidant compounds. CONCLUSION: In two-phase decanters, loading the olive paste close to the outlet of the oily phase is recommended to increase the extraction efficiency without jeopardizing the chemical-sensory characteristics of virgin olive oil. © 2018 Society of Chemical Industry.

In recent years, an increasing number of typicality marks has been awarded to high-quality olive oils produced from local cultivars. In this case, quality control requires effective varietal checks of the starting materials. Moreover, accurate cultivar identification is essential in vegetative-propagated plants distributed by nurseries and is a pre-requisite to register new cultivars. Food genomics provides many tools for cultivar identification and traceability from tree to oil and table olives. The results of the application of different classes of DNA markers to olive with the purpose of checking cultivar identity and variability of plant material are extensively discussed in this review, with special regard to repeatability issues and polymorphism degree. The characterization of olive germplasm from all countries of the Mediterranean basin and from less studied geographical areas is described and innovative high-throughput molecular tools to manage reference collections are reviewed. Then the transferability of DNA markers to processed products – virgin olive oils and table olives – is overviewed to point out strengths and weaknesses, with special regard to (i) the influence of processing steps and storage time on the quantity and quality of residual DNA, (ii) recent advances to overcome the bottleneck of DNA extraction from processed products, (iii) factors affecting whole comparability of DNA profiles between fresh plant materials and end-products, (iv) drawbacks in the analysis of multi-cultivar versus single-cultivar end-products and (v) the potential of quantitative polymerase chain reaction (PCR)-based techniques.

Background: The study of pro- and anti-oxidant compounds is important for their influence on the shelf-life and nutritional value of food. The aim of this research was to evaluate the activity of monoacylglycerols (MAG), obtained by partial saponification of a purified olive oil, added in increasing amounts to the same oil and submitted to the Rancimat test and oven test at 60 C. Besides routine analyses, high-performance size exclusion chromatography analysis of polar compounds was performed. Results: The addition of MAG led in all cases to a significant slowdown of the oxidative processes. These trends were more evident as the oxidation went on. The purified oil added with 30 g kg-1 of MAG after 9 days of oven test at 60°C presented a level of oxidative degradation significantly lower than the control after only 4 days. Conclusion: The data showed a marked antioxidant effect of MAG in purified olive oil, contrary to what has been observed by other authors, who noticed either a pro-oxidant or a non-antioxidant activity of these compounds in soybean oil. A different behaviour of MAG during oxidation could depend on the different fatty acid composition of the oil matter they are added to. © 2010 Society of Chemical Industry.

Natural deep eutectic solvents (NADES) are a green, promising class of solvents. Phenolic compounds are among the targets of NADES’ use in foods. A health claim is admitted by European Regulations for olive oils (OOs) containing at least 250 mg kg−1 of selected polyphenols (hydroxytyrosol and its derivatives, included tyrosol, HTD), but their determination involves analytical issues that are being currently debated. A NADES based on glucose and lactic acid was here used to develop a green and rapid tool for correct labelling of OOs. 163 OOs were submitted to liquid/liquid extraction with the NADES. Regression and classification approaches were adopted to relate features of the UV spectra of extracts to HTD content. The models allowed to assess HTD content for screening purposes (R2prediction = 0.84, RMSEP = 35.5 mg kg−1). For labelling purposes, oils could be labelled according to health claim limits with an error of 0.6%.

Omics approaches are recently being applied also in food lipid oxidation, to increase knowledge of oxidation and antioxidation mechanisms. The so-called oxidomics throws a wider spot of light on the complex patterns of reactions taking place in food lipids, especially in dispersed systems. This research aimed to investigate the radical scavenging activity of olive oil phenolic antioxidants (OPAs) in O/W emulsions, as affected by the phase in which they were added. This allowed one to assess whether different behaviors could be expected from antioxidants originally present in phenolic-rich olive oils compared to natural antioxidants added in the water phase during emulsion production. Hydroperoxide decomposition kinetics and the analysis of volatile pattern provided an outline of antioxidation mechanisms. Though being effective in slowing down oxidation when added both in the oil and water phase, OPAs interfered in different ways with oxidation pathways, based on the phase in which they were added. OPAs added to the water phase were more effective in slowing down hydroperoxide decomposition due to the hydrophilic radical initiator. On the other hand, OPAs present in the oil were more effective in preventing radical propagation, with relevant consequences on the volatile pattern.

Olive leaves are a waste of the olive oil processing industry and represent a good source of phenolic compounds. The aim of this work was to assess the influence of olive leaf extract (OLE) on lipid oxidation of baked snacks, like breadsticks, made with wheat flour, extra virgin olive oil (EVO), white wine, and salt. Two EVOs having different peroxide value and antioxidant profile (total phenol content, tocopherols, carotenoids, and antioxidant activity) were considered. The snacks were subjected to oven test or stored in the usual conditions of retailer shelves. The obtained data highlighted that EVO plays a key role both for the quality and for the shelf-life of baked snacks and the use of OLE is recommended especially when baked snacks are produced with low quality EVO which therefore does not have a good content of natural antioxidants. The OLE addition significantly reduced the forced oxidative degradation during oven test, as evidenced by a decrease of 27% in oxidation-related volatile compounds and of 42% in triacylglycerol oligopolymers compared to control snacks (CTR) without OLE. Moreover, OLE effectively acted also in normal storage conditions, improving sensory data, induction times, antioxidant activity, and volatile compounds compared to CTR (i.e. hexanal 165.49 vs 38.31 μg g−1 in OLE-added). The amount of oxidation-related volatile compounds showed an opposite trend with the quality level of oil used.

The determination of phenolic compounds in extra virgin olive oils (EVOO) by means of rapid, low-cost, environment-free methods would be a desirable achievement. A natural deep eutectic solvent (DES) based on glucose and lactic acid was considered as extraction solvent for phenolic compounds in EVOO. DESs are green solvents characterized by high availability, biodegradability, safety, and low cost. The spectrophotometric characteristics of DES extracts of 65 EVOO samples were related to the total phenolic content of the oils, assessed by methanol-water extraction coupled to the Folin-Ciocalteu assay. A regression model (ncalibration= 45, nvalidation= 20), including the absorbance at two wavelengths (257, 324 nm), was obtained, with an adjusted R2= 0.762. Therefore the DES could provide a promising and viable approach for a green screening method of phenolic compounds in EVOO, by means of simple spectrophotometric measurements of extracts, even for on-field analysis (for example in olive mills).

Background Determination of the total phenolic content (TPC) in olive oils is of great interest, as phenolic compounds affect the health benefits, sensory attributes and oxidative stability of olive oils. The aim of this study was to explore the feasibility of direct front-face fluorescence measurements coupled with chemometrics for developing multivatiate models for discrimination between virgin olive oils with low and high TPC and determination of TPC concentration. Results Parallel factor analysis and principal component analysis of fluorescence excitation-emission matrices (EEMs) of virgin olive oils revealed different fluorescent properties for samples with low and high TPC. A perfect discrimination of oils with low and high TPC was achieved using partial least squares (PLS) discriminant analysis. The best regression model for the prediction of TPC was based on the PLS analysis of the unfolded entire EEMs (R-2 = 0.951, RPD = 4.0). Conclusions The results show the potential of fluorescence spectroscopy for direct screening of virgin olive oils for TPC. This may contribute to the development of fast screening methods for TPC assessment, providing an alternative to conventional assays. The procedure is environmentally friendly and fulfils the requirements for green analytical chemistry. (c) 2018 Society of Chemical Industry info:eu-repo/semantics/publishedVersion

According to the Regulation (EU) 2016/2095, extra virgin olive oils (EVOO) must contain a maximum of 35 mg kg−1 of fatty acid ethyl esters (FAEE). The official method for FAEE quantification is time-consuming and requires the use of a large amount of toxic solvents. Thus, the aim of this work was the application of FT-IR spectroscopy for the development of classification models (i.e. Linear Discriminant Analysis, LDA; Soft Independent Modelling of Class Analogy, SIMCA) able to discriminate EVOO from non-EVOO based on FAEE content. To the aim, 113 EVOO and 46 non-EVOO samples were analysed. Since the Principal Component Analysis revealed that the whole FT-IR spectral range (both raw or pre-treated) was not promising in EVOO and non-EVOO distinction, a variable selection strategy was applied (i.e. SELECT algorithm). All the classification models were validated both by cross validation and with three different external test sets. The best and more robust LDA model was obtained with the raw FT-IR selected variables, reaching 96–100% of correct classification in prediction. SIMCA models resulted less reliable. In particular, the low specificity values (40–67%) revealed that there is a high probability of assignment of non-EVOO to the EVOO class. In conclusion, FT-IR spectroscopy coupled with a discriminant classification approach is a useful tool for a rapid and fast discrimination of EVOO and non-EVOO based on FAEE content. Since the variable selection strategy was effective, the development of simplified and cheap instruments can boost the FT-IR spectroscopy application also in small enterprises, giving the opportunity to acquire many important information about olive oils.

This data article refers to the paper “Towards green analysis of virgin olive oil phenolic compounds: extraction by a natural deep eutectic solvent and direct spectrophotometric detection” [1]. A deep eutectic solvent (DES) based on lactic acid and glucose was used as green solvent for phenolic compounds. Eight standard phenolic compounds were solubilized in the DES. Then, a set of extra virgin olive oil (EVOO) samples (n=65) were submitted to liquid–liquid extraction by the DES. The standard solutions and the extracts were analyzed by UV spectrophotometry. This article reports the spectral data of both the standard solutions and the 65 extracts, as well as the total phenolic content of the corresponding oils, assessed by the Folin–Ciocalteu assay. Keywords: Natural deep eutectic solvents, Extra virgin olive oil, Phenolic compounds, UV spectrophotometry

The European Food Safety Agency recommends low intakes of saturated fatty acids. This study evaluated the replacement of 50% and 100% of butter in shortbread cookies with an emulsion filled gel (EFG) based on inulin and extra virgin olive oil (EVOO), and investigated its impact on product characteristics (volatile profile, fracture behaviour and crumb pore size, sensory properties). Cookies containing both 50% and 100% EFG had thinner pore walls than the control cookies, without EFG. The total substitution of butter with EFG gave products with higher number of small-sized pores and lower level of fracture stress, with poorer sensory properties than control cookies. The replacement of 50% of the butter fraction of shortbread with EFG based on inulin and EVOO did not substantially affect cookie microstructure, compared to control. Cookies with 50% butter replacement showed comparable fracture properties, and were well accepted by consumers, resulting a product with potentially healthier properties (19% less total fat, 39% less saturated fats) respect to control cookies.

Emulsion filled gels (EFG) can help food producers to reduce fat content in foods. The present study evaluated the physical, chemical, sensorial and microbiological properties of emulsion filled gels based on inulin, a gel-forming prebiotic carbohydrate, and extra virgin olive oil (EVOO), well-known for its high nutritional value and phenolic antioxidant content. EFG based on inulin and EVOO were produced by means of both mechanical shearing and ultrasound homogenization. Three different ingredient ratios lead to high, medium and low oil content EFG (H, M, L respectively). H EFG had also lower inulin/water ratio. The resulting gels could be considered as a healthy alternative to spreads, rich in fiber, unsaturated fatty acids and phenolic antioxidants. Compared to mechanical shearing, ultrasound homogenization gave more consistent EFG, characterized by lower lightness respect to mechanical processing. Lower coarseness and fusion-like behavior and higher greasiness, perceived by panelists, confirmed the structural and textural differences conferred by ultrasound. Higher inulin content and inulin/water ratios determined consistency increase. The EFG with the best sensory profile (melting, less coarse texture, higher consistency, greasy mouthfeel) was submitted to consumer test and liked by over 70% consumers ( n = 80). The volatile pattern was characterized by compounds found in fresh oils, mainly 2-hexenal. Oxidized triacylglycerols showed a slight increase in the EFG oil fraction respect to the fresh oil, particularly when using ultrasound homogenization. The residual phenolic compounds were in the range 50–76%, with losses minimized in mechanically sheared EFG. Ultrasound improved the microbiological stability of EFG.

One sample of lampante olive oil, neutralised and bleached by a laboratory-scale refining plant, was deodorised at the two most frequently adopted temperatures in olive oil refining (220°C and 230°C). The samples of deodorised oil were subjected to oven test at 60°C for 25 days. Aliquots of the oils were sampled at fixed times for analytical determinations, and the oxidative stability was evaluated by measuring the time needed to reach the peroxide value of 20 meq O2/kg. The sample that showed the highest oxidative stability was the oil deodorised at the highest temperature. This oil presented a higher level of TAG oligopolymers (TAGP) and lower amounts of oxidised TAGs (ox-TAG) respect to the oil deodorised at lower temperature. These findings could be explained by the greater pro-oxidant effect of ox-TAG respect to TAGP. Practical applications: The results of this paper can help to choose the right deodorisation temperature for an oil. In fact, increasing the deodorisation temperature – other parameters being equal – leads to an increase in the oxidative stability of the refined oil. Therefore it could be an option when refining oils with potentially low stability. Nevertheless, it should be preferred submitting to refining slightly oxidized oils, with lower deodorisation temperatures, in order to obtain oils with low amounts of both ox-TAG and TAGP. Effect of different deodorisation temperatures on the oxidative stability of an olive oil.

The aim of the work was to improve the nutritional quality of biscuits and to enrich them with anthocyanins. The steps were (i) evaluation of various raw materials as sources of anthocyanins and optimization of anthocyanin extraction procedure; (ii) conduction of six biscuit-production trials by using anthocyanins extracted from the selected source, at different enrichment levels and with progressively less fat and sugar; and (iii) conduction of a paired-preference test to compare the best anthocyanin-enriched biscuits to control plain biscuits. Grape marc extract was selected for biscuit making. Also, the use of durum wheat semolina and extra virgin olive oil was proposed. A fat level as low as 100 g/kg was achieved, with a notable decrease of saturated fatty acids. Total anthocyanins accounted for 103 × 10−3 g/kg. The color of biscuits was characterized by more intense redness and minor lightness compared to the control, and acceptability was adequate, as assessed by 103 consumers.

In this work, differential scanning calorimetry (DSC) was for the first time applied to evaluate cooling and heating curves and related thermal properties of olive oil during refining process steps starting from two series of samples at different initial peroxide values (low, 15meqO2/kg and high, 30meqO2/kg). Thermal properties were statistically correlated by means of principal component analysis (PCA) to those substance classes (products deriving from oxidation, polymerization and hydrolysis of triacylglycerols (TAG)) that could exert adverse effects on consumer health and a negative contribution to the shelf-life of the refined oil. A concomitant significant increase of K270 and polymerized TAG, as a general decrease of oxidation level was exhibited by oils during bleaching. Crystallization significantly shifted towards lower temperatures as well as onset temperature of heating, enlarging transition range, starting from bleaching and at both oxidation levels. PCA was performed to tentatively discriminate among samples according to different refining steps and/or initial level of oxidation correlating thermal properties and chemical results. The first principal component clearly clustered samples according to different refining steps and this differentiation was possible on the basis of the relation of thermal parameters with polymerized TAG conjugated dienes and trienes (K232 and K270, respectively). This preliminary goal should lead to deepen the study of DSC application in the evaluation of the quality of olive and other vegetable oils during refining. Practical applications: DSC is a thermal technique that nowadays covers a large set of applications in lipid technology due to its indisputable advantages as it does not require sample preparation and use of solvents, resulting in a reduced environmental impact. The preliminary findings of this study promote the application of the technique in the evaluation of olive oil quality during refining steps in relation with molecular species formed as polymerized TAG and conjugated trienes discriminating crude and neutralized samples to bleached and deodorized oils. DSC could be also applied on other vegetable oils where refining process is more frequently applied. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

The effect of the surrounding molecular environment (β-lactoglobulin as an emulsion stabilizer and maltodextrin as a viscosity modifier) on the antioxidant activity of three olive oil phenolic compounds (PCs) in olive oil-in-water emulsions was investigated. Oxidation potential, phenolic partitioning, and radical quenching capacity were assessed in solution and in emulsion for oleuropein, hydroxytyrosol, and tyrosol; the influence of β-lactoglobulin and maltodextrin concentration was also evaluated. Finally, the observed properties were related to the oxidative stability of the emulsions containing the PCs to explain their behavior. The order hydroxytyrosol > oleuropein > tyrosol was observed among the antioxidants for both oxidation potential and radical quenching activity. Radical quenching capacity in emulsion and anodic potential were complementary indices of antioxidant effectiveness. As the intrinsic susceptibility of an antioxidant to oxidation expressed by its anodic potential decreased, the environmental conditions (molecular interactions and changes in continuous phase viscosity) played a major role in the antioxidant effectiveness in preventing hydroperoxide decomposition.

In oil-mills, olive-pomace recentrifugation is a common way to reduce pomace moisture and, at the same time, to recover the oil therein. According to current rules, the obtained oil is defined as “crude olive-pomace oil.” The aim of this work is to verify the effect of recentrifugation on specific chemical and molecular parameters of the crude olive-pomace oil, by comparing it with the corresponding virgin olive oil obtained from the same olive lots. In particular, the following were considered: (i) the polar compounds of the oils that include compounds originated from oxidative and hydrolytic degradation, analyzed by high-performance size exclusion chromatography (HPSEC), and (ii) the profile of DNA microsatellite molecular markers that was analyzed by using the High Resolution Melting (HRM) technique. The obtained results evidenced the significantly higher hydrolytic degradation of crude olive-pomace oil, compared with the corresponding virgin olive oil, but at an extent unlikely able to allow the detection of fraudulent admixtures with virgin olive oils. In addition, the findings demonstrated the feasibility of the application of the HRM analysis of DNA microsatellites to crude olive-pomace oil, able to reveal the alteration of the declared varietal profile of a virgin olive oil sample by simply checking the HRM curve profiles.

The aim of the research was to evaluate the effect of calcium carbonate (1%, 2%, and 4% of addition) at two different particle sizes (2.7 μm and 5.7 μm), added at the beginning of the malaxation phase, on both the extraction yield and the quality of oil obtained from Coratina olives at different ripening index. The results showed that calcium carbonate significantly increased the extraction yield of olive oil, more than affecting chemical indices. In particular, for less ripened olives, 1-2% of larger particle size calcium carbonate addiction determined a significant increase of the extraction effectiveness, ranging from 4.0 to 4.9%, while more ripened olives required higher amounts of coadjuvant (2-4% when using the larger particle size and 4% when using the smaller one), with a significant increase of the extraction yield up to 5%. Moreover, an increase of pungent perception was observed in some cases when adding calcium carbonate to more ripened olives.

An investigation was carried out to evaluate the use of High Performance Size-Exclusion Chromatography (HPSEC) of polar compounds of refined, mild deodorized, extra virgin olive oils as well as of their blends, in attempting to reveal significant differences in the amounts of the substance classes constituting polar compounds among these oils. Two sets of blends were prepared by mixing an extra virgin olive oil with both refined and mild deodorized olive oils in increasing amounts. The obtained data highlighted that the triacylglycerol oligopolymers were absent or present in traces in the extra virgin olive oil, while their mean amount was equal to 0.04. g/100. g and 0.72. g/100. g in mild deodorized and refined olive oils, respectively. Oxidized triacylglycerols and diacylglycerols were more abundant in mild deodorized oil and refined oil than in extra virgin olive oil. The Factorial Discriminant Analysis of the data showed that the HPSEC analysis could reveal the presence of refined/mild deodorized oils in extra virgin olive oils. In particular, the classification functions obtained allowed designation of mixtures containing at least 30. g/100. g of mild deodorized oil and all those containing refined olive oil as deodorized oil, therefore as oils subjected to at least a mild refining treatment. © 2011 Elsevier Ltd.

An extra virgin olive oil was used as seasoning for three different types of focaccia produced on an industrial scale. This oil and samples of the oil extracted from the focaccias after baking were submitted to routine analyses and to silica gel column chromatography to separate polar compounds. These were then subjected to high performance size-exclusion chromatographic (HPSEC) analysis and it allowed to determine oxidative and hydrolytic degradation products. The results were compared with those obtained from artisan focaccias, seasoned with the same oil and toppings, by statistical analyses. The different technologies and the toppings employed directed in different ways the oxidative and hydrolytic processes in the oil. Copyright © Taylor & Francis Group, LLC.

Monitoring or preventing oxidation processes in foods, particularly heterogeneous systems or highly oxidizable lipids, has become a primary issue. Traditional approaches often fail in pursuing this aim. At the same time, the prediction in laboratory of the efficacy of antioxidant molecules and technologies often fails when challenging reality. A change in the traditional paradigm used to conceive oxidation processes and their monitoring could be a key. In the present work, an “omics” approach is suggested for the evaluation of oxidation in food lipids and of the role played by minor compounds. This holistic and comprehensive, hypothesis-generating approach is applied to a typical research case: highly-purified olive oil added with increasing amounts of purified free fatty acids (FFA). A comprehensive profile (“oxidome”) of oxidation products is outlined during the accelerated oxidation. The pathways considered are FFA and triacyglycerol oxidation, triacyglycerol polymerization, volatile compounds formation as well as their further oxidation. FFA affectes the overall balance of the oxidation pathways and consequently causes a drift in the evolution of the pattern of oxidation products. The balance between accelerating activity of FFA toward triacylglycerol oxidation and their high susceptibility to undergo oxidation turnes out to be dose-dependent and time-related, and shiftes the resulting oxidation profile of the oil. The omics approach to oxidation products profiling provides new insight into oxidation processes. “Oxidomics” could be helpful to deepen the insight into unresolved issues of oxidation, going beyond the usual single- or few-marker approach. Practical Applications: This research suggests a new paradigm for approaching food lipid oxidation. Unresolved practical issues regarding food spoilage and shelf-life, waste reduction, keeping of healthy properties are increasing along the increasing formulation of complex and dispersed systems, use of healthy highly unsaturated fatty acids and bioactive antioxidants, attention paid by consumers and industries to nutritional, sensory, health properties of foods. The new paradigm suggests going beyond the usually adopted single- or few-marker approach and to consider the pattern of oxidation reactions and products as a whole, in order to better describe and predict its changes and the effects of external factors as well as added molecules. “Oxidomics” is a new paradigm for lipid oxidation, with a holistic approach to the system and evaluating a pattern of oxidation products and its changes.

Several studies have investigated the interaction of free fatty acids with the oxidative phenomena involving oils during processing and storage. Nevertheless, the available information is insufficient and, in some cases, contradictory.The aim of this work was to throw light upon this matter, by evaluating - by means of different analytical approaches - the effect of adding increasing amounts of free fatty acids (0.25%, 0.5%, 1%, 3%) on the oxidative processes occurring in purified olive oil during oxidation at 60°C.The results obtained showed that oxidized forms of triglycerides and polar oligopolymers of triglycerides increased during oxidation. Low amounts of added FFA caused a further increase of the levels of oxidized triglycerides and triglyceride oligopolymers - pointing out a pro-oxidant activity - while higher doses of added free fatty acids lead to lower amounts of oxidized forms of triglycerides respect to the purified oil. This could be due to an increase in peroxide decomposition exerted by free fatty acids when present in higher amounts. © 2010 Elsevier Ltd.

The aim of this work was to evaluate the effectiveness of the use of cassava flour in bread making, and the sensory acceptability of the final product. Different baking trials were carried out by using egg white and extra-virgin olive oil, in consideration of their high nutritional value with respect to other food additives (i.e., hydrocolloids). Significant (p < 0.05) improvements of loaf specific volume (from 2.24 to 3.93 mL/g) and crumb firmness (from 9.14 to 4.67 N) were achieved by contemporarily including egg white and extra-virgin olive oil in the formulation. Cassava breads containing both these ingredients obtained the best scores from panelists for all the test breads examined and resulted attractive as the wheat bread prepared as reference. Copyright © Taylor & Francis Group, LLC.

Four different types of "focaccia" (Italian flat bread) prepared with the same dough and the same extra virgin olive oil but with different seasonings, were analyzed. Lipids were extracted from each sample using the Folch method. The indices commonly used to assess oil quality, the amounts of trans fatty acids and compounds of triglyceride polymerization, oxidation and hydrolysis, were determined in all the samples to better assess the degree of oxidation and hydrolysis of the oils. The findings showed that, once baked, the oil sampled from the different types of focaccias could not be included in the virgin category. The level of oxidation of the baked samples was greater than that in the uncooked oil. However the results obtained showed that the level of degradation of the extracted oils was lower than that found in edible refined oils and it seemed to be influenced by the topping used to flavour the focaccias. © 2007 Elsevier Ltd. All rights reserved.

The capability of different spectroscopic techniques in estimation of adulteration of extra virgin olive oil with mild deodorized and refined olive oils was investigated. The visible absorption and ultraviolet-visible fluorescence spectra were distinctly different for oils of different quality grades. Differences in the near- and mid-IR absorption spectra were less pronounced and could only be revealed by principal component analysis. The calibration models for estimation of adulterant oil in the blends obtained using partial least squares (PLS) and principal component regression (PCR) showed similar performance using all of the examined spectroscopic techniques. The simultaneous analysis of combined spectra using concatenated matrix did not improve the calibration results. The prediction parameters for the set of 20 samples were: R2>0.96, the relative error of prediction (REP) was in the range 5.6-12.0%. The RPD (ratio of the SD of reference values to RMSEP) were in the range of 5.1-10.9, indicating that all models were at least suitable for quality control.

An experimental investigation was carried out with the aim to investigate on the isomerisation of 1,2-diacylglycerols to 1,3-diacylglycerols as a function of the storage conditions, as well as to identify indices useful to evaluate the freshness of the oils. Two oils derived from two different cultivars (Coratina and Ogliarola barese) were stored for two years as follows: in bottles at dark; in clear glass bottles at light; in green glass bottles at light; in bottles at dark, the latter subjected to repeated opening and samplings to simulate domestic use. The obtained results evinced that during the storage period a significant increase in the 1,3-isomers was observed due to an isomerisation from the 1,2 to the 1,3 isomeric form, consequently the 1,3/1,2 ratio increased in both oils. The covariance analysis of the data showed that the isomerisation of diacylglycerols, taking place during time, was affected by the type of oil, probably due to the different initial hydrolysis level, but was not affected by the storage conditions. Among the parameters considered, the total diacylglycerols/1,3-diacylglycerols ratio could be used as freshness index of extra virgin olive oil, since it is not affected by either oil or storage conditions. © 2012 Elsevier Ltd. All rights reserved.

Summary: The lipid fraction of bakery products undergoes a significant degradation during baking, with an increase in undesirable oxidised substances, that can act as catalysts for further oxidative reactions during storage reducing the product shelf life. The use of extra virgin olive oil in bakery products rich in fat in place of refined oils was studied, assessing the evolution of the oxidative and hydrolytic degradation during storage. Two-way analysis of variance, followed by Tukey's HSD test for multiple comparisons, covariance and principal component analyses were carried out to compare the effect of the type of oils. The data obtained showed that the evolution of the oxidation levels in the analysed samples during storage was related to the type of oil used in the production process. Particularly, the use of extra virgin olive oil led to significantly lower values of hydroperoxides, ultraviolet absorption constants, triacylglycerol oligopolymers and oxidised triacylglycerols. © 2012 The Authors. International Journal of Food Science and Technology © 2012 Institute of Food Science and Technology.

The refining process is essential to make edible both lampante olive oils and solvent-extracted vegetable oils. The aim of this work was to evaluate the influence of the crude oil oxidation level and of the standard refining process on the amount of oxidized triacylglycerols (ox-TAG) and triacylglycerol oligopolymers (TAGP) in the corresponding refined oil. A virgin olive oil was let to progressively autoxidize at room temperature and was used at different oxidation levels in the experimental trials. Samples were submitted to the same refining process, utilizing a laboratory-scale pilot plant. The results obtained showed that the steps of the refining process caused the increase of oligomeric oxidation products in the refined oil respect to the corresponding raw oil. In this study the oxidative degradation in the crude oil resulted to be correlated to the final amounts of ox-TAG and TAGP. These findings point out that the final levels of oxidation products in refined oils depend both on the adopted standard refining steps and on the oxidative level of the crude oils. In particular, being ox-TAG highly pro-oxidant substances, the oxidative status of the crude oil can severely affect the shelf-life of the refined oil. © 2011 Elsevier Ltd.

An experimental investigation was carried out with the aim to evaluate the pro-oxidant activity of oxidized triacylglycerols and compare it with that observed for polar triacylglycerol oligopolymers. The research on these classes of substances, that form during processing and storage of fats and oils, has a great concern with the study of the effect of heat in technologic processes, such as vegetable oils refining, frying and cooking. Oxidized triacylglycerols and polar triacylglycerol oligopolymers, obtained in purity by preparative gel permeation chromatography, were added in amounts of 0.25-1 g/100 g both to a purified and an unpurified olive oil. Regarding the oxidized triacylglycerols, the accelerated oxidation tests showed that the induction times of both oils significantly decreased at increasing concentrations of these compounds, demonstrating their pro-oxidant effect. Moreover, the data showed that the pro-oxidant activity of oxidized triacylglycerols was greater than that of polar triacylglycerol oligopolymers. © 2010 Elsevier Ltd.

The fatty substances used in bakery products vary a lot in nature and content. The most largely used lipids are butter, lard, hydrogenated vegetable oils, margarines, olive oil and olive-pomace oil; their content may range from 5 to 15% for some bread substitutes, such as focaccia, rusks, crackers, breadsticks, and up to 20-30% in the case of pastry products, such as biscuits and cakes. The choice of the most suitable kind of lipid and the optimal amount needed in the formulation is closely related to the desired bakery product, and is based on different parameters such as the dough workability, the product's rheological and sensory properties, the shelf-life and the consumers' needs. During the first processing step the "lipid binding" starts up: chemical and physical interactions are established between the lipids and other ingredients, such as starch and proteins (gluten). This process also involves free endogenous lipids (naturally contained in flours), i.e., lipids not chemically bound to cell structures or to other meal components. The formation of gliadine-lipid-glutenine complexes allows the dough to incorporate the gases, which develop during fermentation, and to retain them in the gluten mesh, thus giving volume and softness to the leavened product. © 2010 Copyright © 2010 Elsevier Inc. All rights reserved.

The aim of the research was to evaluate the pro-oxidant action of oxidized triglyceride oliogopolymers, a class of oxidation compounds present in refined vegetable oils. Silica gel column chromatography was used to obtain the polar compounds from a thermally oxidized oil and preparative gel permeation chromatography to separate and collect the oxidized triglyceride oligopolymers. A purified oil that was practically free of oxidation and hydrolytic degradation products, pigments and anti-oxidants was prepared in the laboratory to evaluate pro-oxidant activity without interferences. Addition of percent amounts of oxidized triglyceride oligopolymers of 0.25 to 1.0% to both the purified and unpurified oils clearly evidenced the pro-oxidant activity of this class of compounds. © 2007 Springer-Verlag.