Effect of extra virgin olive oil substitution for fat on quality of pork patty

BACKGROUND: Extra virgin olive oil (EVOO) is well known for its beneficial effects on human health. Thus, the purpose of this study was to investigate the effect of EVOO substitution for backfat on qualities of pork patty to avoid high consumption of animal‐originated fat, because it is closely related to development of cardiovascular disease and obesity. RESULT: Water‐holding capacity was higher in control (lean pork + 10% backfat) and T3 (lean pork + 5% backfat + 5% EVOO + 0.5% isolated soy protein + 0.5% carrageenan + 0.5% maltodextrin) than T1 (lean pork + 5% backfat + 5% EVOO + 0.5% isolated soy protein) and T2 (lean pork + 5% backfat + 5% EVOO + 0.5% isolated soy protein + 0.5% carrageenan). Hardness was higher in EVOO substitution for backfat patty samples than control. In sensory evaluation, the control was significantly higher in overall acceptability compared with EVOO substitution for backfat pork patty samples. CONCLUSION: The physical properties of pork patty made by EVOO substitution for backfat were stable as a commercial pork patty (control). However, sensory evaluation scores were higher in control compared to EVOO‐substituted pork patty samples. Copyright © 2008 Society of Chemical Industry     

Optimisation of extra virgin olive oil quality

This study investigated the correlation between total polyphenol content and the stability (ie induction time by Rancimat) of oil samples according to different regions, cultivars, extraction technologies and ripening times of raw material. Results indicate a correlation of oil stability with total polyphenols, (r=0·88), a chemical variable easy to determine. We have set up an oil quality index as a measure of desirability including legal parameters, especially the Council Olive Oil International score (COI Score), stability (phenol content) and process yield into account. The study of the effects of olive ripening and storage prior to processing and olive paste mixing times and temperatures on the quality index using an experimental factorial design (2⁴) were investigated. The process variables selected in the experimental factorial design were studied and the main effects on desirability were identified. Based on this information, the extraction process was optimised for quality index in relation to fruit ripening and olive paste mixing time using a response contour to identify optimal experimental conditions. This innovative procedure shows that process conditions can be optimised as a function of D_tot, evaluated according to scientific determinations. © 1998 SCI.     

Effect of crushing on olive paste and virgin olive oil minor components

The present study focuses on the influence of the olive crushing technique on the minor composition of olive pastes and their corresponding virgin olive oils since these compounds are strongly related to their quality and characteristics. Two different cultivars, Arbequina and Cornicabra—known for their different minor component composition—were processed at laboratory scale using hammer mills at various breakage forces and grid hole diameters, a blade cutter and a mortar. Crushing and kneading produce a profound change in the composition of the phenolic compounds in the olive paste and in the final oil. Hydroxytyrosol derivatives in virgin olive oil were most affected by the crushing conditions. The stronger the crushing conditions (i.e. hammer crushers using smaller grid holes and a higher rotation speed), the higher the phenolic content in both olive paste and oil in both varieties. Interestingly, the effect on volatile compounds of milder or stronger crushing conditions was opposite to that described for the phenolic compounds.     

Contribution of olive seed to the phenolic profile and related quality parameters of virgin olive oil

BACKGROUND: Conflicting results have been reported about the effect of fruit de‐stoning on the virgin olive oil (VOO) phenolic profile. The aim of the present study was to determine whether olive seed plays any role in the synthesis of this oil phenolic fraction. RESULTS: Increases of around 25% of total phenolic compounds were observed in oils obtained from de‐stoned olive fruits in three main Spanish cultivars. To investigate the involvement of olive seed in determining the phenolic profile of VOO, whole intact olive fruits were added with up to 400% olive stones. Excellent regression coefficients were found in general for the decrease of total phenolic compounds and, particularly, of o‐diphenolics in the resulting oils. On the other hand, it was found that olive seed contains a high level of peroxidase (POX) activity (72.4 U g^?1 FW), accounting for more than 98% of total POX activity in the whole fruit. This activity is able to modify VOO phenolics in vitro, similar to the effect of adding stones during VOO extraction. CONCLUSION: Olive seed plays an important role in determining VOO phenolic profile during the process to obtain an oil that seems to be associated with a high level of POX activity. Copyright © 2007 Society of Chemical Industry     

Effect of replacing beef fat with olive oil on quality characteristics of Turkish soudjouk (sucuk)

Four formulation of Turkish soudjouks were produced in three replicates by traditional methods as follows; one control (C) using 85% beef and 15% beef fat and three treatments by replacing 20, 40 and 60% of beef fat with virgin olive oil incorporated as pre-emulsified fat (PEF) with soy protein isolate (SPI), respectively. It was found that the moisture content and pH decreased while fat and ash content increased on the 21st day of fermentation and in the ripening period. Cholesterol content decreased depending on the amount of incorporated olive oil to the formulation, which shows the addition of olive oil in soudjouks reduces the cholesterol content (P<0.05). TBA values were affected by the amount of incorporated olive oil and the highest TBA value was found for with the 60% olive oil replacement. Oleic and linoleic acid contents were high while other fatty acid contents were low for the 40 and 60% olive oil samples compared with controls. Sausages with 40% olive oil received high evaluation from the panel for appearance and texture but there was no significant difference (P>0.05) between samples in the terms of color and general acceptability. It is concluded that replacement of beef fat with olive oil had a positive effect on sensory quality and on reducing the cholesterol content of soudjouks.     

Direct analysis of glucuronidated metabolites of main olive oil phenols in human urine after dietary consumption of virgin olive oil

In the present study we report on a UPLC-MRM validated method for the simultaneous direct analysis of main glucuronidated metabolites of olive oil phenols: tyrosol, hydroxytyrosol and its O-methyl metabolite homovanillyl alcohol in human urine after dietary olive oil ingestion. The developed method was linear within the concentration range 20–2000 ng/mL with adequate recovery of analytes (>86%). Intra- and inter-day precision and accuracy were according to standard requirements for method validation criteria. Using the developed method, urinary concentrations and excretion rates of glucuronides of olive oil phenols were successfully estimated in an intervention study with 11 healthy volunteers supplemented with a dietary dose of virgin olive oil (VOO) (50 mL). Therefore, about 13% of the consumed olive oil polyphenols were recovered in 24-h urine, where 75% of them were in the form of glucuronides (3′- and 4′-O-hydroxytyrosol glucuronides, 4′-O-glucuronides of tyrosol and homovanillyl alcohol) and 25% as free compounds.     

Effects of olive paste fast preheating on the quality of extra virgin olive oil during storage

The olive paste obtained after crushing was fast preheated under different time/temperature conditions and then malaxed in an industrial oil mill (600 kg Frantoio/Leccino olive blend). Legal parameters (peroxides, free acidity and sensory panel), oil yield, total phenolic content, oxidative stability and phenolic profile were monitored during 12 months of storage of the virgin olive oil (VOO) kept in closed bottles in the dark. A fast preheating not longer than 72 s at 38 °C without malaxation lead to an extra VOO with a shelf-life of at least 12-months, similarly to the traditional EVOO obtained with malaxation. A fast preheating not longer than 72 s at 38 °C followed by 10 min malaxation lead to an EVOO with a ‘mild’ sensory profile and a shelf life of at least 12-months. Thus, the use of a specific designed fast preheater instead or before (a shortened) malaxation allows to obtain an EVOO with a low bitter/pungent attribute from olives which are rich of (sometimes unpleasant) phenolic compounds with the aim to meet the preference of targeted groups of consumers. Time and temperature of fast preheating are the critical parameters of the process.     

Influence of different irrigation strategies in a traditional Cornicabra cv. olive orchard on virgin olive oil composition and quality

The olive tree is generally grown under rain-fed conditions. However, since the yield response to irrigation, even with low amounts of water, is great there is increasing interest in irrigated agriculture. The main goal of this study was therefore to optimize sustainable irrigation conditions in the Cornicabra olive cultivar grown in Castilla-La Mancha, a region where the aquifers are over-exploited, and to study the effect of different irrigation strategies on the composition and quality of Cornicabra virgin olive oil. Different irrigation treatments, based on regulated deficit irrigation (RDI), 100% ET_c, 125% ET_c, and rain-fed as control, were applied to a traditional olive orchard (cv Cornicabra) in a randomized complete-block design with four replications. The average olive production of the trees grown under rain-fed conditions was much lower, about 35%, than that obtained by applying the different irrigation treatments studied, between which practically no difference were observed. The total phenol content, which affected the sensory bitterness in the oils, decreased significantly as the amount of supplied water increased. This is very relevant, as high levels of phenols, typical of Cornicabra virgin olive oils, may decrease consumer preference. Notably, one of the RDI strategies produced olive oil similar in composition and quality to that obtained by 100% ET_c but with reduced water usage.     

Influence of O2 on the quality of virgin olive oil during malaxation

The aim of this work was to investigate the effect of malaxation operating conditions on virgin olive oil quality. Legal, sensory and nutritional parameters of olive oil were evaluated by identifying the role played by enzymes. A comparison was made between oil obtained from a traditional malaxation plant and oil obtained from malaxation equipment (LOM) able to work at low oxygen level and temperature. Research results showed that, during malaxation, oxygen had an effect on both phenolic compounds and fatty acids, mainly favouring enzyme phenomena. Malaxation at a low oxygen level was found to be selective for the formation of both phenolic and C₆ compounds. Oil obtained from malaxation LOM equipment was shown to be richer in both aldehydes such as trans‐2‐hexenal and phenolic compounds than oil obtained from traditional processing. Copyright © 2006 Society of Chemical Industry     

初榨橄榄油风味化合物研究进展

阐述了初榨橄榄油风味的主要来源途径即脂氧合酶途径,对影响初榨橄榄油风味特征的若干因素如品种和地理环境,油橄榄果实成熟度,加工工艺,储藏条件等因素进行了讨论和分析.介绍了初榨橄榄油中挥发性化合物的分析检测方法,并且展望了橄榄油风味化合物研究的应用和发展前景.     

Influence of the malaxation time and olive ripening stage on oil quality and phenolic compounds of virgin olive oils

The main objective of this study was to evaluate the influence of the malaxation time (Mt) and ripening stage on oil quality and phenolic compounds of Hojiblanca and Picual virgin olive oils. In both varieties of oil, phenolic content and oxidative stability decreased as ripening progressed. The total level of tocopherols diminished by up to 40% as fruit ripened. The compositions of palmitic, stearic, lignoceric, oleic, linoleic and linolenic acids were significantly influenced by the ripening process. The present work shows that an increased Mt promoted the increase of free acidity (up to 13.3%) and tocopherols (up to 11.6%) and negatively affected the oxidative stability and the concentration of phenols. Further research is required to determine ripening stages and malaxation conditions for all olive oil varieties to achieve a satisfactory balance between the improvement of both oil yield and oil quality and composition.     

Effect of olive collection regime on olive oil quality

The titratable acidity and the peroxide value of olive oil extracted from olives harvested by shaking the trees over subtented nets increase rapidly as the residence of the fruit on the nets is prolonged. It is recommended that the extraction of the oil from the fruits is not delayed for longer than 2 to 3 weeks.     

Influence of the exposure to light on extra virgin olive oil quality during storage

An experimental investigation was carried out to study the influence that exposure to light has on the quality of extra virgin oil during a 12-month storage period by comparing it with the quality of extra virgin oil stored in the dark. The results showed that the oils stored in the light had significantly lower tocopherol, carotenoid and chlorophyll contents than did the same oils kept in the dark. Moreover, the oils stored in the dark mainly contained primary oxidation products, while the oils kept in the light contained secondary oxidation products as confirmed by the K₂₇₀ values which exceeded the legal limits even after purification by means of alumina. Overall, the results obtained showed that the shelf life of the oils exposed to light is shorter than that of oils kept in the dark, and that after only 2 months of exposure to light the oils examined could no longer be considered as extra virgin.     

Evaluation of minor components,sensory characteristics and quality of virgin olive oil by near infrared (NIR) spectroscopy

Chemometric analyses of NIR spectral data (12,500–4000 cm^? 1) combined with analytical and sensory parameters measured in monovarietal Cornicabra virgin olive oils (VOOs) (n = 97) produced in the PDO (Protected Denomination of Origin) “Montes de Toledo” geographic area were used to generate calibration and validation models in order to be able to predict the minor composition of VOO, in particular its phenolic and volatile compounds as well as its organoleptic attributes, and thereby the global quality of the product. Acceptable multivariate algorithms were obtained for VOOs' degree of unsaturation (fatty acid profile) (r = 0.84–0.96), several minor components – in particular hydroxytyrosol derivatives (r = 0.86–0.88) and C6 alcohols (r = 0.69–0.80) – as well as for positive sensory attributes — ‘fruity’ (r = 0.87) and ‘bitter’ (r = 0.85). The results establish that near infrared is a very useful technique that allows rapid screening of VOO samples to estimate their minor composition and sensory characteristics, and thereby their quality and commercial grade. Furthermore, it may give real time information about olive oil composition during processing in order to automatically control technological parameters.     

Organophosphorus pesticide residues in Greek virgin olive oil: levels, dietary intake and risk assessment

The occurrence of organophosphorus pesticide (OPs) and their metabolite residues was investigated in 167 samples of Greek virgin olive oil during a 2-year (2004-2005) sampling campaign. A total of 30.5% of samples contained detectable residues, although only one sample contained dimethoate residues above the maximum residue limit. Among the seven detected OPs, fenthion and fenthion sulfoxide residues were detected in 10.8 and 14.4% of the samples, respectively, at levels of 0.003-0.61 mg kg(-1). Dimethoate was detected in 10.2% of the samples at 0.003-0.057 mg kg(-1). The acute dietary risk assessment was undertaken by determining the national estimated short-term intake (NESTI); for chronic dietary risk assessment, the national theoretical maximum daily intake (NTMDI) and national estimated daily intake (NEDI) were calculated. The estimated intakes (NESTI and NEDI) of each pesticide were <7 and <0.86% of the corresponding acute reference doses (ARfDs) and acceptable daily intakes (ADIs), respectively. A cumulative risk assessment was performed using the hazard index (HI) and toxicity equivalence factor (TEF), taking into account that OPs share the same toxicological mechanism. The determined HI and TEF values were found to represent only a small portion of the respective ADIs or ARfDs. These results indicate that there is neither acute nor chronic risk for the Greek population through olive oil consumption.     

Organophosphorus pesticide residues in Greek virgin olive oil: levels,dietary intake and risk assessment

The occurrence of organophosphorus pesticide (OPs) and their metabolite residues was investigated in 167 samples of Greek virgin olive oil during a 2-year (2004–2005) sampling campaign. A total of 30.5% of samples contained detectable residues, although only one sample contained dimethoate residues above the maximum residue limit. Among the seven detected OPs, fenthion and fenthion sulfoxide residues were detected in 10.8 and 14.4% of the samples, respectively, at levels of 0.003–0.61 mg kg^?1. Dimethoate was detected in 10.2% of the samples at 0.003–0.057 mg kg^?1. The acute dietary risk assessment was undertaken by determining the national estimated short-term intake (NESTI); for chronic dietary risk assessment, the national theoretical maximum daily intake (NTMDI) and national estimated daily intake (NEDI) were calculated. The estimated intakes (NESTI and NEDI) of each pesticide were <7 and <0.86% of the corresponding acute reference doses (ARfDs) and acceptable daily intakes (ADIs), respectively. A cumulative risk assessment was performed using the hazard index (HI) and toxicity equivalence factor (TEF), taking into account that OPs share the same toxicological mechanism. The determined HI and TEF values were found to represent only a small portion of the respective ADIs or ARfDs. These results indicate that there is neither acute nor chronic risk for the Greek population through olive oil consumption.     

Effect of extraction systems and cultivar on the quality of virgin olive oils

This research was carried out to compare the effects of two industrial scale processes (super press and triple phase systems) and a traditional Tunisian family-sized operation with laboratory milling for two varieties of olives: Chemlali and Chemchali. Analyses of the effect of the extraction system, on the oils' characteristics, revealed statistically significant differences in some parameters, mainly in antioxidant compounds ( P  < 0.05). Major fatty acids presented significant differences ( P  < 0.05) with respect to the cultivar kind (55.93% vs. 72.21%). Oxidative stability of Chemchali was nearly two times higher than Chemlali (94.58 vs. 50.37 day kg⁻¹). Results appear to confirm the general consensus that Chemchali oils are of much higher quality compared with the tolerable quality of Chemlali . The traditional method is a valid form of producing high quality oil with very high stability (48.87 and 109.07 day kg⁻¹ for Chemlali and Chemchali oil, respectively). However, industrial mills showed that triple-phase scale could cause considerable loss in polyphenols. Finally, olive oil quality is mainly dependant on the quality of the olives and on the extraction method.     

Recovery and characterisation of DNA from virgin olive oil

European Food Research and Technology - The characterisation of the genetic identity of DNA recoverable from olive oil could facilitate the assessment of its place of origin and conformity to type...     

Diacylglycerol isomers in extra virgin olive oil: Effect of different storage conditions

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.