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1.
Minor compounds such as sterols, aliphatic alcohols, tocopherols, and chlorophylls in virgin olive oil from Chemlali cultivar were analyzed during the maturity process. The study concerns oils from the following three different olive growing areas of Tunisia: Sfax, Sidi Bouzid, and Enfidha. Analytical results showed that both the maturity process and the olive provenances influence the evolution of the content of these compounds.  相似文献   

2.
The stability of the antioxidant fraction in edible vegetable oils has been evaluated during a simulated deep frying process at 180 °C. Four edible oils (i.e., extra-virgin olive oil with a 400 μg/mL overall content in naturally existing phenols; high-oleic sunflower oil without natural content of these compounds but enriched either with hydrophilic antioxidants isolated from olive pomace or with an oxidation inhibitor, dimethylsiloxane; and sunflower oil without enrichment) were subjected to deep heating consisting of 20 cycles at 180 °C for 5 min each. An oil aliquot was sampled after each heating cycle to study the influence of heating on the antioxidant fraction composed of hydrophilic and lipophilic antioxidants such as phenols and tocopherols, respectively. The decomposition curves for each group of compounds caused by the influence of deep heating were studied to compare their resistance to oxidation. Thus, the suitability of olive pomace as raw material to obtain these compounds offers an excellent alternative to the use of olive-tree materials different from leaves. The enrichment of refined edible oils with natural antioxidants from olive pomace is a sustainable strategy to take benefits from this residue.  相似文献   

3.
The initial stability of virgin olive oil depends on various factors, among which are the variety and the degree of fruit ripeness. The former, which genetically determines the composition of the olive and its oil, also marks, to some extent, its stability. However, oil stability changes as the olive ripens, so it is obvious that the degree of ripeness is an important factor. The oils were obtained by the Abencor system. Acidity, peroxide index, UV absorption at 232 and 270 nm, sensory analysis, fatty acid composition, tocopherols, phenolic compounds, orthodiphenolic compounds, sterols, pigments, and oxidative stability were determined, and the results were analyzed statistically. During ripening there was a decrease in all of the parameters studied except linoleic acid, Delta-5-avenasterol, and oil content, which increased. Virgin oils showed very good correlation between stability and the concentrations of total phenols, o-diphenols, tocopherols, chlorophyll pigments and carotenoids, linoleic and linolenic acids, total sterols, beta-sitosterol, and Delta-5-avenasterol.  相似文献   

4.
The antioxidant activity of the phenolic fraction of extra virgin olive oil was assessed in samples that had a decreasing content of antioxidants in the presence and absence of copper ions as a catalyst of autoxidation. The oxidation process was evaluated by measuring primary and secondary oxidation products. Changes in phenols and tocopherols were investigated by high-performance liquid chromatography. Both the total phenol content and their antioxidant activity were monitored by spectrophotometric assays (with Folin-Ciocalteu and ABTS*+ reagents). The important role of phenolic compounds (particularly the o-diphenols) in protection from autoxidation was confirmed. However, the tocopherols were more quickly consumed in oils that had the lowest content of o-diphenols, which also showed evidence of an ability to chelate copper. In particular, a dramatic decrease was observed in the isomeric form of decarboxymethyl-oleuropein aglycone after addition of the metal, despite its significant increase in samples stored in the absence of copper.  相似文献   

5.
Structured lipid (SL) was synthesized from extravirgin olive oil (EVOO) and conjugated linoleic acid (CLA) via a lipase-catalyzed reaction. CLA provides a variety of health benefits, but it is not consumed in free fatty acid form. The synthesized SL olive oil contained 42.5 mol % CLA isomers, and the major isomers were cis-9,trans-11-CLA (16.9 mol %) and trans-10,cis-12-CLA (24.2 mol %). The antioxidant activity determined by the radical scavenging capacity with the 2,2-diphenyl-1-picrylhydrazyl radical was lower in SL olive oil than in EVOO. The oxidative stability was also lower in SL olive oil since it had a higher peroxide value, rho-anisidine value, and 2-thiobarbituric acid reactive substances values during 20 days of storage at 60 degrees C. This observation could be due to the reduction in the natural phenolic compounds (97%) and tocopherols (56%), and the incorporated CLA with two conjugated double bonds in the SL olive oil. The oxidative stability of SL olive oil was increased by added rosemary extracts at concentrations of 100, 200, and 300 ppm. The present study suggests that the SL olive oil may be a suitable way to incorporate or deliver CLA into human diets. However, the addition of a proper antioxidant would be required for improving its oxidative stability.  相似文献   

6.
为研究陇南市不同种植地对不同品种油橄榄果实生长的影响,对陇南市武都区种植的莱星、鄂植8号、奇迹、皮削利等4个油橄榄品种,分别在其果实生长的受精和坐果期、种子生长期、果核变硬期、中果皮形成期和果实成熟期比较判断果实表型性状,分析果实生长期间含水率和含油率的变化,以探明不同油橄榄品种的适宜栽培区,为优化陇南地区油橄榄种植资源配置提供支持。结果表明,在陇南市武都区锦屏村和稻畦村种植的不同品种油橄榄果实外观均呈长圆形,且锦屏村种植的莱星油橄榄果实百粒鲜质量和含油率均高于稻畦村,中果皮形成期百粒鲜质量和含油率分别高于稻畦村34.82%和72.53%。稻畦村种植的鄂植8号油橄榄果实百粒鲜质量在果实生长前期低于锦屏村,生长后期则高于锦屏村,中果皮形成期稻畦村油橄榄果实百粒鲜质量高于锦屏村26.00%。锦屏村种植的鄂植8号油橄榄果实含油率均高于稻畦村,果实成熟期含油率高于稻畦村84.48%。锦屏村种植的奇迹油橄榄果实百粒鲜质量和含油率均高于稻畦村,果核变硬期百粒鲜质量高于稻畦村36.00%,果实成熟期的含油率高于稻畦村53.71%。锦屏村种植的皮削利油橄榄果实含油率高于稻畦村,中果皮形成期的含油率高于稻畦村76.13%。由此可知,锦屏村种植的油橄榄莱星、奇迹均优于稻畦村,且果实用途偏向于油用,油橄榄鄂植8号和皮削利作为油果兼用型果实,在锦屏村和稻畦村均可种植。且生长良好。  相似文献   

7.
Three different HPLC detection systems were compared for the determination of tocopherols and tocotrienols in olive oil: fluorescence and diode array connected in series, ultraviolet, and evaporative light scattering. The best results were obtained with the fluorescence detector, which was successfully applied in the quantification of tocopherols and tocotrienols in 18 samples of Portuguese olive oils. To support the validity of the method, the parameters evaluated were linearity, detection limits, repeatability, and recovery. All of the studied samples showed similar qualitative profiles with six identified compounds: alpha-T, beta-T, gamma-T, delta-T, alpha-T3, and gamma-T3. Alpha-tocopherol (alpha-T) was the main vitamin E isomer in all samples ranging from 93 to 260 mg/kg. The total tocopherols and tocotrienols ranged from 100 to 270 mg/kg. Geographic origin did not seem to influence the tocopherol and tocotrienol composition of the olive oils under evaluation.  相似文献   

8.
Soil properties and soil water conditions were assessed for different land use (forest, arable land, grassland) on a silty Calcaric Regosol in the Yangjuangou Catchment of the Chinese Loess Plateau. The loess here is unimodal, poorly sorted with abundant coarse silt, has very low dry bulk density (1.11?–?1.38?g cm???3) and little organic carbon content (1.6?–?3.7?g kg???1). The soils are hydrophilic, have high porosity (0.5?–?0.55 cm3?cm???3), unsaturated hydraulic conductivity, and plant available water content (0.34?–?0.4 cm3?cm???3). Soil properties are quite uniform in space. Land use had no significant effects on soil properties and soil water conditions.  相似文献   

9.
The partition coefficient (K(p)) of the natural phenolic antioxidant compounds in the olive fruit between aqueous and olive oil phases was determined. The antioxidants of olive oil are either present in the olive fruit or formed during the olive oil extraction process. The antioxidants impart stability to and determine properties of the oil and are valuable from the nutritional point of view. The olive oil antioxidants are amphiphilic in nature and are more soluble in the water than in the oil phase. Consequently, a large amount of the antioxidants is lost with the wastewater during processing. The determination of antioxidants was performed using HPLC, and the K(p) was estimated to be from as low as 0.0006 for oleuropein to a maximum of 1.5 for 3,4-DHPEA-EA (di-hydroxy-phenyl-ethanol-elenolic acid, oleuropein aglycon). Henry's law fitted very well to the experimental data. The partition coefficients were also estimated by applying the activity coefficients of the antioxidants in the two phases using a predictive group contribution method, the UNIFAC equation. The K(p) values estimated with UNIFAC method were of the same order of magnitude but varied from the experimental values. Nevertheless, this method may be a rough predictive tool for process optimization or design. Because the K(p) values were very low, some changes in the process are recommended in order to achieve a higher concentration of antioxidants in the oil. A temperature increase may lead to increasing the partition coefficient. Also, limiting the quantity of water during oil extraction could be a basis for designing alternative processes for increasing the antioxidant concentration in the olive oil.  相似文献   

10.
This study evaluates soil properties in organically managed olive groves and natural zones in a mountainous area of Andalusia, Spain. Two soil types (Eutric Regosol and Eutric Cambisol) and the most common soil management methods (tillage and two intensities of grazing) were studied. Both soil types in the groves had values not much lower than those in the natural areas. Average (±SE) values in the groves were 1.58 ± 0.71% for organic carbon, 323 ± 98 g kg?1 for macroaggregate stability, 1.11 ± 0.16 g cm?3 for bulk density, 3.5 ± 1.6 mm h?1 for saturated hydraulic conductivity and 1209 ± 716 mg CO2 kg?1 for soil respiration. Overall, these values tended to be lower in the tilled compared with that in the grazed groves. The average phosphorus soil content (5.83 ± 5.22 mg kg?1) was low for olive production and within adequate ranges for N (0.12 ± 0.05%) and K (142 ± 81 mg kg?1). Soil erosion was high in the tilled groves (35.5 ± 18.2 t ha?1 year?1) with soil loss correlating with indicators of soil degradation such as organic carbon content and water stable macroaggregates. In the grazed groves, soil loss was moderate with no clear indications of soil degradation. Overall, there was significant farm‐to‐farm variability within the same soil and land management systems. Olive production had a moderate effect on soil degradation compared with natural areas and olive cultivation could be sustained in future if cover crop soil management replaced tillage, especially in the most sloping areas.  相似文献   

11.
Adulteration of vegetable oil is of concern for both commercial and health reasons. Compositional based fingerprints can potentially reveal both the oil source and its possible adulteration. Here, electrospray ionization (ESI) Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) resolves and identifies literally thousands of distinct chemical components of commercial canola, olive, and soybean oils, without extraction or other wet chemical separation pretreatment. In negative-ion ESI FT-ICR MS, the acidic components of soybean oil are easily distinguished from those of canola and olive oil based on relative abundances of C(18) fatty acids, whereas olive oil differs from canola and soybean oil based on relative abundances of tocopherols. In positive-ion ESI FT-ICR MS, the three oils are readily distinguished according to the relative abundances of di- and triacylglycerols with various numbers of double bonds in the fatty acid chains. We demonstrate the detection of soybean oil as an adulterant of olive oil, based on relative abundances of members of each of several chemical families. We suggest that the detailed chemical compositions of vegetable oils can be used to characterize them and to detect and identify adulterants.  相似文献   

12.
Phosphatidylethanolamine (PE), phosphatidylcholine (PC), lysine (Lys), and mixtures of them were tested for antioxidative activity in a tocopherol-stripped olive oil (TSO) and the same oil after addition of 250 microg of alpha-tocopherol g of oil/(tocopherol-added olive oil, TAO) to evaluate the role of tocopherol in the antioxidant activity of oxidized lipid-amine products. Neither PE nor PC nor Lys protected TSO when tested alone, but both PE and Lys increased the induction period (IP) of TAO. On the contrary, PE/Lys and PC/Lys mixtures, but not PC/PE mixtures, protected both TSO and TAO. These results were a consequence of both the formation of oxidized lipid-amine products, which were determined by gas chromatography-mass spectrometry after their conversion into volatile derivatives, and a synergism between alpha-tocopherol and the produced compounds. These results were confirmed by analyzing the antioxidative activity of two of the produced carbonyl-amine products: 6-amino-2-(1H-pyrrol-1-yl)hexanoic acid (1) and 2,3-dipalmitoylpropyl 2-(1H-pyrrol-1-yl)ethyl phosphate (2). The hydrophilic compound 1 was more antioxidant than the analogous lipophilic compound 2, and this antioxidative activity was observed in TAO and not in TSO. All these results suggested that antioxidative activity of carbonyl-amine products may be greatly increased with the addition of tocopherols, and those products derived from Lys are more antioxidant in bulk oils than those derived from PE.  相似文献   

13.
The application of a new process based on the hydrothermal treatment of olive oil waste (alperujo) led to a final solid rich in pomace olive oil (POO) enriched in minor components with functional activities. The effects of the time (15-90 min) and the temperature (150, 160, and 170 °C) of the thermal processing of alperujo on the yield, quality, and enrichment of minor components of crude POO were evaluated. The final treated solid had an increase in oil yield up to 97%, with a reduction in solids up to 35.6-47.6% by solubilization. Sterols increased up to 33%, aliphatic alcohols increased up to 92%, triterpenic alcohols increased up to 31%, squalene increased up to 43%, tocopherols increased up to 57%, and oleanolic acid increased up to 16% by the new treatment. The increase maintains a high concentration of functional substances probably even in the refining POO.  相似文献   

14.
The aim of the present work was to establish the limiting factors affecting the biosynthesis of volatile esters present in virgin olive oil (VOO). Oil volatile fractions of the main Spanish olive cultivars, Arbequina and Picual, were analyzed. It was observed that acetate esters were the most abundant class of volatile esters in the oils, in concordance with the high content of acetyl-CoA found in olive fruit, and that the content of C6 alcohols is limited for the synthesis of volatile esters during the production of VOO. Thus, the increase of C6 alcohol availability during VOO production produced a significant increase of the corresponding ester in the oils in both cultivars at two different maturity stages. However, the increase of acetyl-CoA availability had no effect on the VOO volatile fraction. The low synthesis of these C6 alcohols seems not to be due to a shortage of precursors or cofactors for alcohol dehydrogenase (ADH) activity because their increase during VOO production had no effect on the C6 alcohol levels. The experimental findings are compatible with a deactivation of ADH activity during olive oil production in the cultivars under study. In this sense, a strong inhibition of olive ADH activity by compounds present in the different tissues of olive fruit has been observed.  相似文献   

15.
This study investigated the effect of both the degree of ripening of the olive fruit and irrigation management-rain-fed, two different regulated deficit irrigations (RDI), the method proposed by the Food and Agriculture Organization of the United Nations (known as FAO), and 125 FAO (125% FAO)-on the phenolic and volatile composition of Cornicabra virgin olive oils obtained during two crop seasons. Secoiridoid phenolic derivatives greatly decreased upon increase of both irrigation and ripening, for example, the 3,4-DHPEA-EDA content decreased from 770 to 450 mg/kg through fruit ripening under rain-fed conditions and from 676 to 388 mg/kg from rain-fed conditions to FAO irrigation treatment (at a ripeness index of approximately 4). Moreover, secoiridoid derivatives of hydroxytyrosol decreased more than those of tyrosol. The levels of major volatile components decreased in the course of ripening but were higher in irrigated olive oils: for example, the E-2-hexenal content ranged between 4.2 and 2.6 mg/kg (expressed as 4-methyl-2-pentanol) over fruit maturation under rain-fed conditions and between 8.0 and 3.5 mg/kg under FAO scheduling. It is important to note that where water was applied only from the beginning of August (RDI-2), when oil begins to accumulate in the fruit, the resulting virgin olive oil presented a phenol and volatile profile similar to those of the FAO and 125 FAO methods, but with a considerable reduction in the amount of water supplied to the olive orchard.  相似文献   

16.
The effect of olive stone removal before processing on the degradation level, secoiridoid and tocopherol contents, and antioxidant activity of monovarietal extra virgin olive oils (EVOOs) was studied. EVOOs were extracted from olives of the Leccino, Moraiolo, Frantoio, Pendolino, Taggiasca, and Colombaia varieties both in the presence and in the absence of the stones. The degradation level of EVOOs was evaluated by acidity, peroxide number, and spectroscopic indices K(232) and K(270), according to EU regulation. The secoiridoid compounds typical of EVOO, namely, the oleuropein and ligstroside derivatives, hydroxytyrosol, tyrosol, and tocopherols were analyzed by HPLC. The antioxidant activity was evaluated by the xanthine oxidase/xanthine system, generating superoxide radical and hydrogen peroxide, and by the 2,2-diphenyl-1-(2,4,6-trinitrophenyl)hydrazyl test. Results showed that EVOOs obtained from both stoned and destoned olives had a very low degradation level, which was not affected by destoning. Destoning lowered slightly the alpha-tocopherol content in EVOOs but increased the total secoiridoid content and the antioxidant activity of EVOOs (up to 3.5-fold). However, these effects were variety-dependent and negligible in some conditions. It was concluded that a better knowledge of the reactions occurring during olive processing, and particularly on the involvement of endogenous pulp and stone enzymes, is essential to predict the effect of destoning on EVOO quality.  相似文献   

17.
Olive mill wastewater (OMW) is annually produced in enormous quantities and it constitutes a serious environmental problem. For several years OMW was used as an amendment in olive orchards which given beneficial effects on growth and soil properties. The present work aimed to study the effect of OMW used after one year from the oil extraction, where phenol content decreased. One-year-old plants of “Chemlali” olive cultivar were subjected to three treatments. C0, C1, and C2 were respectively 0%, 30%, and 45% of OMW used for amendment. Each rate was adjusted with water supplied every 15?days (1?L/plantlet). Results showed significant differences between treatments especially for growth, chlorophyll content of leaves (SPAD), and leaf nutrient content (P, K, Ca, and Na). Always C2 was better than C1. Substrate properties were clearly ameliorated particularly an increase of organic matter but the pH and the electric conductivity were unaffected.  相似文献   

18.
Proteins of olive fruit mesocarp are not very well-known at present. However, they have been shown to pass, at least partially, to the olive oil during its elaboration and therefore might be contributing to some of the special characteristics of this vegetable oil. In this study, protein content and composition were determined in olive fruits, cv. Arbequina and Picual, at three stages of ripening: green, spotted, and purple. Mesocarp proteins constituted 1.3-1.8% of the dry weight of the olive fruit, and cultivar and fruit ripening did not produce important changes in mesocarp protein content or composition. In addition, this composition was also similar to the amino acid composition of a 4.6-kDa polypeptide, which is the major protein component of olive oils and of oil bodies of olive fruit mesocarp, suggesting that this polypeptide is likely to be a major component of mesocarp proteins. There was, also, a relationship between the oil content of the olive fruit and the protein content determined, suggesting a stabilizing function of these proteins in the oil bodies of the olive fruit, analogously to the role suggested for oleosins. This stabilizing function does not seem to be extended to olive oils because when the polypeptides isolated were added at 20 ppm to soybean oil, the stability of the oil increased only slightly, suggesting that if these compounds play some role in the stability of the oils, this should be mostly a consequence of the possible interactions among these protein components and other olive oil antioxidant constituents.  相似文献   

19.
Effects of tocopherols on the oxidative stability of stripped vegetable oils were studied by adding pure tocopherols--alpha, beta, gamma, and delta--in their naturally occurring proportions in soybean and sunflower oils to the triacylglycerols (TAG) of soybean and sunflower oils. Soybean and sunflower oils were purified by stripping all minor constituents, leaving the triacylglycerols. Pure tocopherols in the proportion typical of sunflower oil--high alpha, low gamma, and low delta--were added to purified sunflower oil and to purified soybean oil. Pure tocopherols in the proportion typical of soybean oil--low alpha, high gamma, and high delta--were added to the purified oils. Oils were subjected to accelerated autoxidation using oven storage at 60 degrees C in the dark and accelerated photooxidation at 7500 lx light intensity at 30 degrees C. Oxidation levels of aged oils were measured by the formation of both peroxides and volatile compounds and by flavor analysis. Results from substituting the tocopherol profile from one oil type to another varied on the basis of whether they were oxidized in the dark or in the light. For example, during autoxidation in the dark, soybean oil with the typical soybean tocopherol profile had the lowest levels of peroxides and total volatile compounds, whereas sunflower oil with the sunflower tocopherol profile had the highest levels. In flavor analyses of the same oils, sunflower oil with the soybean tocopherol profile was the most stable. Soybean oil with the profile of sunflower tocopherols was the least stable in dark oxidation. In contrast to the data from autoxidation in the dark, addition of tocopherols typical of sunflower oil significantly improved light stability of both oil types compared to the addition of soybean tocopherols to sunflower oil. The tocopherol profile typical of soybean oil was significantly more effective in inhibiting autoxidation in the dark; however, the tocopherol profile typical of sunflower oil inhibited light oxidation significantly more than the soybean tocopherol profile.  相似文献   

20.
Sea buckthorn berries ( Hippophae rhamnoides L.) are used in foods, cosmetics, and pharmaceutical products. They are of particular interest for their high content of healthy phytochemicals, including vitamin E-related compounds (tocopherols and tocotrienols). This study investigated the content of tocopherols and tocotrienols during ripening in berries from four cultivars of sea buckthorn over a three-year period. The results showed large variations in tocopherols and tocotrienols depending on harvest date, cultivar, and year. Levels of alpha-tocopherol were higher early in the ripening period, while at later dates, delta-tocopherol levels increased. Great differences in amounts and composition of tocopherols and tocotrienols were observed between cultivars. Tocopherol levels were positively correlated with daily temperature, but this trend varied between years. Variations in tocopherols and tocotrienol levels in sea buckthorn berries due to cultivar, year, and ripening stage should therefore be considered in the production of nutritional products.  相似文献   

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