Sterol, triterpen dialcohol and fatty acid profile of less- and well-known Istrian monovarietal olive oil

The aim of this study was to characterize monovarietal olive oils obtained from two less known autochthonous cultivars (Bova and Buža puntoža) on the basis of sterols, triterpene dialcohols and fatty acids profile for the first time, and three monovarietal olive oils obtained from the most widespread autochthonous cultivars (Buža, Istarska bjelica and Rosinjola) grown in Istria, Croatia. β-sitosterol, Δ-5-avenasterol and campesterol were the most abundant sterols in all samples. Campesterol, β-sitosterol and Δ-5-avenasterol most significantly differentiated investigated oils. Bova oil had the highest amount of total sterols (2964 ± 458 mg/kg). Istarska bjelica oil had a peculiar sterol composition with exceptionally low β-sitosterol (67%), high Δ-5-avenasterol (27%) and the highest triterpene dialcohols percentages. Rosinjola and Istarska bjelica oils had the highest monounsaturated fatty acids level, Buža oil had the highest polyunsaturated fatty acids level, while Bova oil showed the highest level of saturated fatty acids. Tested oils obtained from the most abundant cultivars fulfilled all the demands of the current EU regulation required for virgin olive oil regarding sterols, triterpene dialcohols and fatty acids, but Bova and Buža puntoža oil slightly exceeded the upper limit for linolenic acid. Since cultivar is the source of natural variation of sterols, triterpene dialcohols and fatty acids in virgin olive oils, the knowledge about the content of these particular compounds in different monovarietal oils from autochthonous cultivars is important to determine possible disagreements with the demands of the current legislation required for virgin olive oils, in order to anticipate possible false results indicating adulteration

The effect of olive fruit fly Bactrocera oleae (Rossi) infestation on certain chemical parameters of produced olive oils

Olives affected by active and damaging infestation (olive fruit fly Bactrocera oleae (Rossi)) were assayed for their chemical composition. Biophenols were determined by HPLC, sterols, triterpenic dialcohols, and fatty acids by gas chromatography analysis. The acquired data were statistically analyzed. Oils produced from %Istrska belica% fruit affected by active infestation compared to the oils made from fruit affected by damaging infestation showed higher amounts of total oleuropein biofenols (377.3 versus (vs.) 106.6 mg/kg), total biophenols (755 vs. 377 mg/kg), lignans (85.3 vs. 32.9mg/kg), the dialdehydic formof decarboxymethyl oleuropein aglycone (DMO-AgldA) (148.3 vs. 49.0 mg/kg), its oxidized form (DMO-Agl-dA)ox (35.2 vs. 8.5 mg/kg), the dialdehydic form of oleuropein aglycone (O-Agl-dA) (61.1 vs. 8.0 mg/kg), the dialdehydic form of ligstroside aglycone (L-Agl-dA) (63.5 vs. 28.0 mg/kg), the aldehydic form of oleuropein aglycone (O-Agl-A) (40.6 vs. 8.4 mg/kg), and lower amounts of tyrosol (Tyr) (6.0 vs. 13. 9 mg/kg) and the aldehydic form of ligstroside aglycone (L-Agl-A) (13.8 vs. 40.3 mg/kg). Higher values of stigmasterol (2.99%) and lower values of campesterol (2.25%) were determined in oils affected by damaging infestationan increase in triterpenic dialcohols was also observed (3.04% for damaging and 1.62% for active infestation). Oils affected by damaging infestation, compared to active infestation, showed lower amounts of oleic acid (73.89 vs. 75.15%) and higher amounts of myristic (0.013 vs. 0.011%), linoleic (7.27 vs. 6.48%), and linolenic (0.74 vs. 0.61%) acids

Evaluation of the acidity in samples of virgin olive oil for the 1995-2005 period and correlation between the collected data and the performed sensory analysis

The acidity and organoleptic characteristics of virgin olive oil produced in Slovenian Istra were studied. The acidity of 4,871 samples of virgin olive oils was determined for the 1995-2005 period. 135 samples produced in crop year 2002/2003 with acidity below 0.2% (w/w) and 291 samples of crop year 2005/2006 were sensory evaluated. According to sensory evaluation in crop year 2002/2003, 128 out of 135 samples were classified as extra virgin olive oils, while 7 samples did not reach the specified requirements. In crop year 2005/2006, it was established that 71.5% of the analysed samples complied with extra virgin category, 24.4% with virgin and 4.1% with lampante. Time of harvest, storage conditions before processing, and time from picking to processing all influenced the oil quality, whereas olive cultivars did not. Chemical and sensory analyses were performed according to the Commission Regulation (EEC) No 2568/91 and added annexes

Evaluation of measurement uncertainty for the methods of analysis used to assess the characteristics of olive oil and olive-pomace oil from commission regulations EEC 2568/91 and EC 1989/2003

Metrology has been present in our scientific knowledge for a long time, but mostly in physical measurements. Chemical measurement can be defined as a comparison of a quantity of measurand and relating it to a unit (e.g. mol/kg).When expressing a result of a measurement, the problem of traceability, validation and the measurement uncertainty (MU) evaluation must be challenged. It is well known that MU is a parameter associated with the result of a measurement that characterizes the dispersion of the values that could reasonably be attributed to the measurand. The EEC document 2568/91 with its annexes gives the methods of analysis to assess the characteristics of olive oils and olive-pomace oils with given limits. The EC document 1989/2003 gives the scheme, the algorithm, the pathway, the decision tree to differentiate between various types of olive oils using the particular determinations based on limits. The major lack of these EC methods is the non-existence of validation parameters, which are crucial in determining the MU (and in accreditation of a laboratory). There are several ways of evaluating (better term than calculating) the MU: with model equation, with use of a certified reference material (CRM) and with participation in a proficiency testing (PT) scheme. MU for a method of analysis is inherent to a laboratory and can serve as a tool for \u27measuring\u27 the quality of a laboratory. Unfortunately, there are practically no CRM\u27s in the olive oil testing field. The only way to achieve a usable MU is through participation in PT schemes

Karotenoidi v oljčnem olju

The pigments profile of virgin olive oil is determined by the pigments initially present in the fruits and their derivatives formed during the extraction process. The presence of other carotenoids or chlorophyll pigments at levels other than that associated with the extraction process indicate that oil has been adulterated or the extraction process was incorrect. The yellow pigments in olive oil are carotenoids and the green pigments are chlorophyll pigments. The amount of carotenoids in oil depends on variety, maturation index, treating of olive fruits before extraction, extraction process, and oil treating. Carotenes as well as xantophylls were identified in virgin olive oils. Lutein is usually the predominating compound in the carotenoid fraction of pigments, followed by B-carotene. The rest of carotenoid fraction are minor xantophylls, such as 5,6-epoxides, 5,8-epoxides or furanoids, and xantophyll esters. Cis-isomeres are also formed during the extraction process. The vitamin activity of cis-isomeres is lower as the activity of trans-isomeres. Pigment profile of olive oil is a useful tool for variety classification and authenticity determination. Carotenoids can act as antioxidants or prooxidants. Their antioxidant/prooxidant activity depend on concentration, solvent, and free radicals structure, presence of other antioxidants, metals and oxygen. The antioxidant activity of carotenoids has not been satisfactory explained as yet. There are three possible mechanisms of carotenoids antioxidant activity. Carotenoids are singlet oxygen quenchers and free radical scavengers and they act as light filters. Findings about carotenoids activity in vitro should not be translated to activity in biological systems. Carotenoids are an important part of human diet because of their antioxidant activity and some of them are also provitamins A. Carotenoids probably prevent some diseases, such as cardiovascular diseases and certain cancers, but can in certain circumstances increase the risk of disease

Dynamics of oil quality parameters changes related to olive fruit fly attack

In order to evaluate the role of intrinsic characteristics of olive cultivars on dynamics of oil quality parameters changes related to the olive fruit fly (Bactrocera oleae (Gmelin)) attack, two specific olive cultivars were compared, Istarska bjelica and Buža. I. bjelica is characterised by late ripening, a lower flesh/stone mass ratio and higher oleic/linoleic ratio, the total phenols content and oil mass fraction compared to Buža. Oil samples were obtained at two harvesting dates, from fruit lots with 0, 25, 50, 75 and 100% of infestation degree, expressed by mass. Oil and water content in olive paste, as well as total phenols, fatty acids composition and standard chemical and sensorial oil quality parameters were determined. At equal maturity level, the cultivar with a higher oil (24 +- 1% vs. 16 +- 1%) and lower water content (54 +- 2% vs. 61 +- 4%) was more susceptible to hydrolytic degradation, while the one with the lower total phenols content (231 +- 32 vs. 575 +- 124mg/kg) and oleicžlinoleic fatty acid ratio (5.7 vs. 9.1) was more liable to oxidative deterioration of oil. Lower susceptibility to negative flavours formation could be related to the absence of ripening induced by fly attack and less favourable environment for larvae growth (higher total phenols content, lower water content and flesh/stone mass ratio

Fatty Acid Composition of Cosmetic Argan Oil: Provenience and Authenticity Criteria

In this work, fatty-acid profiles, including trans fatty acids, in combination with chemometric tools, were applied as a determinant of purity (i.e., adulteration) and provenance (i.e., geographical origin) of cosmetic grade argan oil collected from different regions of Morocco in 2017. The fatty acid profiles obtained by gas chromatography (GC) showed that oleic acid (C18:1) is the most abundant fatty acid, followed by linoleic acid (C18:2) and palmitic acid (C16:0). The content of trans-oleic and trans-linoleic isomers was between 0.02% and 0.03%, while trans-linolenic isomers were between 0.06% and 0.09%. Discriminant analysis (DA) and orthogonal projection to latent structure—discriminant analysis (OPLS-DA) were performed to discriminate between argan oils from Essaouira, Taroudant, Tiznit, Chtouka-Aït Baha and Sidi Ifni. The correct classification rate was highest for argan oil from the Chtouka-Aït Baha province (90.0%) and the lowest for oils from the Sidi Ifni province (14.3%), with an overall correct classification rate of 51.6%. Pairwise comparison using OPLS-DA could predictably differentiate (≥0.92) between the geographical regions with the levels of stearic (C18:0) and arachidic (C20:0) fatty acids accounting for most of the variance. This study shows the feasibility of implementing authenticity criteria for argan oils by including limit values for trans-fatty acids and the ability to discern provenance using fatty acid profiling