Oil composition of advanced selections from an olive breeding program

Fifteen genotypes coming from crosses between the cultivars Arbequina, Frantoio and Picual were selected on the basis of their agronomic characteristics in a breeding program initiated in 1991. In the present work, the main components of the olive oil of these 15 advances selections have been characterized and compared to their genitors. A wide range of variation was observed for all the fatty acids, minor components and related characteristics evaluated, with significant differences between genotypes for all of them except for β‐tocopherol content. These results confirm the strong genetic influence on olive oil quality previously reported on olive oil cultivar evaluations. The values obtained in the selections have extended the range of variation of their three genitors for all the characters evaluated, except for γ‐tocopherol. Selections UC‐I 7‐8, UC‐I 5‐44 and UC‐I 2‐68 showed the highest average values for tocopherols, polyphenol and C18:1 contents, respectively. Finally, multivariate analysis allowed the classification of genotypes in four groups according to their olive oil composition. Practical applications: Olive oil composition is considered one of the most important objectives in breeding programs aiming at obtaining new olive cultivars. In the last decades olive breeding programs are being carried out in the main olive‐producing countries and several new cultivars and advanced selections have been described. The results of this work provide an initial characterization of virgin olive oils of advanced selections coming from crosses between the cultivars Arbequina, Frantoio and Picual and suggest a strong genetic influence on fatty acid composition, several minor components and related characteristics. These results, together with the agronomic characterization of these selections previously reported, will be used for the final selection of the best genotypes to be registered as new cultivars.     

Effect of Agronomical Practices on the Nutritional Quality of Virgin Olive Oil at Different Ripening Stages

There is a need to verify the quality of organically produced olive oils and to compare them to conventional ones. The objective of this study was to assess possible differences in nutritional quality between agronomic practices in Picual and Hojiblanca olive oil varieties at different stages of olive ripeness. The results showed that organic versus conventional cultivation did not consistently affect acidity, peroxide index or spectrophotometric constants of the virgin olive oils considered in this study. On the contrary, phenol content, oxidative stability, tocopherol content and fatty acid composition were affected by the agronomical practices. Principal component analysis indicated that linolenic acid and β‐tocopherol were mainly responsible for discriminating Hojiblanca organic oils, whereas total phenols, palmitoleic acid and α‐tocopherol were the major contributors to differentiating Picual conventional oils. Lignoceric and stearic acids were related to oils from unripe and ripe olive fruits, respectively. Long‐term experiments are required to confirm these results.     

Protein Content and Oil Composition of Almond from Moroccan Seedlings: Genetic Diversity, Oil Quality and Geographical Origin

The protein and oil content and the fatty acid profile of the kernels of selected almond genotypes from four different Moroccan regions were determined in order to evaluate the kernel quality of the plant material of these different regions. The ranges of oil content (48.7–64.5 % of kernel DW), oleic (61.8–80.2 % of total oil), linoleic (11.4–27.0 %), palmitic (5.6–7.7 %), stearic (1.3–3.1 %), and palmitoleic (0.4–0.9 %) acid percentages agreed with previous results of other almond genotypes, but the protein content (14.1–35.1 % of kernel DW) showed that some genotypes had higher values than any previously recorded in almond. Some genotypes from mountainous regions showed kernels with very high oil content as well as high and consistent oleic and linoleic ratio, establishing a possible differentiation according to the geographical origin. These differences may allow establishing a geographical denomination for almond products. In terms of genetic diversity, oleic and linoleic acids were confirmed to be the most variable components of almond oil chemical composition among genotypes. Additionally, the genotypes with extreme favorable values, such as high protein content, could be incorporated into an almond breeding program aiming at an increase in kernel quality.     

Effect of Temperature,Modified Atmosphere and Ethylene During Olive Storage on Quality and Bitterness Level of the Oil

Mill olives (Olea europaea L. cv. ‘Lechín’), harvested at the green mature stage of ripening, were stored for 72 h under six different storage conditions: in air, in a closed container, and in a closed container with 30 ppm ethylene either at 20 or at 40 °C. The use of 40 °C as the fruit storage temperature reduced oil bitterness, regardless of the atmosphere applied; however, it also induced a significant reduction in stability and pigment content of the oil extracted. At 20 °C, mill olives stored under air supplemented with 30 ppm ethylene engendered oils with middle bitterness intensity, whereas the oils obtained from fruit stored similarly, but without ethylene, or in an open container exhibited a strong intensity of this sensory attribute. Fruit respiration in the closed containers caused a CO₂ accumulation and an O₂ decrease in the storage atmosphere. This CO₂ concentration was increased by the previous ethylene addition, but O₂ presence did not suffer an additional reduction. The use of modified atmospheres in fruit storage induced off-flavor development in the oils extracted, producing a significant reduction in the overall grading of their sensory quality.     

Effects of Olive Trees Age on the Minor Components of Oueslati Virgin Olive Oils Produced from Olives Harvested at Different Ripening Degrees

Phenolics, volatiles, squalene, tocopherols, and fatty acids of virgin olive oils (VOO) from adult and young olive trees of the Oueslati variety, typically cultivated in the Center of Tunisia, were analyzed at three different harvesting periods. Significant differences in contents of saturated fatty acids (p < 0.05), squalene (p < 0.05), alpha-tocopherol and total tocopherol (p < 0.02) and oxidized form of decarboxymethyl oleuropein aglycon (p < 0.05) were seen between VOO from adult and young trees during maturation. Moreover, the volatile profiles of VOO from adult and young trees showed significant differences in the amounts of hexanal, 1-penten-3-ol (p < 0.05), (Z)-3-hexenal and (Z)-2-penten-1-ol (p < 0.01). Principal component analysis showed that olives from adult trees should be harvested at the cherry stage of maturation to obtain a satisfactory level of oil quality, while olives from young trees should be harvested at the black maturation stage.     

Frying Quality Characteristics of French Fries Prepared in Refined Olive Oil and Palm Olein

The objective of this study was to compare two oils with different polyunsaturated/saturated (P/S) fatty acid ratios, refined olive oil (P/S 0.75) and palm olein (P/S 0.25), in frying French fries. The chemical qualities of the oil residues extracted from the French fries were assayed for five consecutive batches fried at 1-h intervals. The levels of total polar compounds, free fatty acids, p-anisidine value and phytosterol oxidation products (POPs) were elevated in French fries fried in both oils. The level of total polar compounds increased from 4.6 in fresh refined olive oil to 7.3% in final batches of French fries. The corresponding figures for palm olein were 9.8–13.8%. The level of free fatty acid in fresh refined olive oil increased from 0.06 to 0.11% in final products. These figures for palm olein were 0.04–0.13%. The p-anisidine value increased from 3.7 to 32.8 and 2.5 to 53.4 in fresh oils and in final batches of French fries in refined olive oil and palm olein, respectively. The total amount of POPs in fresh refined olive oil increased from 5.1 to 9.6 μg/g oil in final products. These figures were 1.9 to 5.3 μg/g oil for palm olein.     

Effects of Foliar Applications of Zinc in the Forms of Free Mineral or Amino Acid Complexed on Qualitative Characteristics of Olive Oil

An orchard experiment was conducted during two successive years to evaluate the effectiveness of the foliar application of zinc (Zn) in mineral form (ZnSO₄) or chelated with various amino acids (AAC) on the oil content, qualitative indices, and fatty acid profile of olive oil. All Zn sources were applied at a rate of 0.2% during two growth stages; at full bloom (FB) and 15 days after FB. The results showed that Zn, regardless of applied sources, accumulated more Zn in leaves and fruits compared to the control. The effectiveness of Zn-AAC in increasing leaf and fruit Zn concentration was higher than ZnSO₄. In both years, an increase in oil content and concentration of phenolic compounds and chlorophyll in the oil was observed when trees were treated with Zn, although these effects were dependent on the Zn sources. In general, the Zn-AAC treatments, especially Zn-methionine (Met), was more effective than ZnSO₄. Zn-AAC treatments increased the L* value and b* intensity, while decreasing the a* value of olive oil compared to the control. However, ZnSO₄ had a slight or no significant effect on oil color. The oil fatty acid profile was also affected by Zn. The Zn-Met and Zn-Glycine (Gly) were more effective than the other Zn sources in increasing monounsaturated fatty acid, specifically oleic acid of oil in both years, respectively. These results could suggest that the application of Zn-AAC, especially Zn-Met and Zn-Gly, can be considered as a new strategy to improve olive oil quality and quantity in Zn-deficient soils.     

Assessment of Variation in Castor Genetic Resources for Oil Characteristics

Castor (Ricinus communis L.) oil is used in production of wide range of industrial products because of the presence of nearly 85% of ricinoleic acid in it. Any increase in the ricinoleic acid level would be great benefit to industry. None of the existing castor cultivars possess ≥90% ricinoleic acid because donors with this level of ricinoleic acid are not available to develop high ricinoleic type cultivars. In order to search for high ricinoleic acid genotypes, the present investigation was under taken. Fatty acid and oil content were assayed in 392 castor genotypes comprising 335 Indian and 57 non-Indian collections. Great variation was observed among the collections for oil content and fatty acid composition. Oil content ranged from 38.5 to 53.5% while ricinoleic acid was between 71.15 and 93.68%. Diversity analysis was done using K-means clustering which clustered the entire collection into 30 diverse groups by minimizing the dissimilarity within each cluster while maximizing the dissimilarity between clusters. Finally, 15 accessions having high oil (52–54%), high ricinoleic acid (91.12–93.68%) and high monounsaturates (92.8–94.95%) levels were identified. These would be of great value as donors to develop high oil, high ricinoleic type castor cultivars.     

Effect of Ozonated Water Treatment on Fatty Acid Composition and Some Quality Parameters of Olive Oil

The organic olives from Çine-Ayd?n (Turkey) were washed with tap or ozonated water for 2 and 5 min, respectively, and pressed to olive oil. The effects of wash treatments on fatty acid composition and several quality parameters of the oils were determined. The maximum values after 2-min ozonated water washes were 9.58 meqO₂/kg, 0.73%, 2.44 and 0.16 for peroxide, free acid, K₂₃₂ and K₂₇₀ values, respectively, which were under the standard limits for extra-virgin olive oil. Five min of ozonated water washes also yielded acceptable results, except for a slight excess on K₂₃₂ value. Ozonated water washes had almost no effect on fatty acid composition.     

Antioxidants in Fish Oil Production for Improved Quality

There is an increasing demand for fish oil containing omega-3. By-products (e.g., heads, tails, belly flaps, backbones, and viscera) from fish fillet production are currently utilized for production of fish oil and fish meal for feed but can be a valuable source of omega-3 for human consumption. However, the quality of some oil is not good enough for human consumption due to oxidation during processing. The aim of this work was to decrease oxidation during oil production by adding antioxidants to herring by-products early in the production process. Of several antioxidants the most potent were selected by a fast screening test. Butylated hydroxytoluene, propyl gallate and citric acid were further evaluated on a labaroatory scale and pilot plant production of herring oil. The selected antioxidants resulted in lower total oxidation during processing [up to 71% reduction in TOTOX (2 times the peroxide value plus the anisidine value)]. In addition, higher oil stability was achieved by adding antioxidants during processing (improved stability up to 400%).     

Effect of Industrial Chemical Refining on the Physicochemical Properties and the Bioactive Minor Components of Peanut Oil

The effect of the industrial chemical refining process on the physicochemical properties, fatty acid composition, and bioactive minor components of peanut oil was studied. The results showed that the moisture and volatile matter content, acid value, peroxide value, and p‐anisidine value were significantly changed (P < 0.05) after the complete refining process. No significant variation (P > 0.05) in the iodine value was observed among all the peanut oil samples. Similar changes were observed in the DPPH radical scavenging activity and the total tocol content during chemical refining. In addition, chemical refining did not have much effect on the fatty acid composition, except for certain changes of several individual fatty acids. Moreover, the chemical refining resulted in 23.6, 23.1, and 9.5 % losses of squalene, total phytosterols, and total tocols (α, β, γ, δ‐tocopherols and α, β, γ, δ‐tocotrienols), respectively. The degumming–neutralization step caused the greatest overall reduction of these bioactive minor components. However, the concentrations of α‐tocotrienol and γ‐tocotrienol increased after full refining. Furthermore, chemical refining slightly changed the relative proportions of individual phytosterols and individual tocols.     

Physicochemical and Stability Characteristics of Flaxseed Oils During Pan-heating

Flaxseed oils are used in stir-frying in parts of China. In this study, flaxseed oils were heated at approximately 150 °C as a thin film in a frying pan for 3 and 6 min, respectively. Pan-heating caused loss of tocopherols, plastochromanol-8, phenolic acids and chlorophyll pigments. There was a significant decrease in the linolenic acid resulting in a concomitant relative increase in palmitic, stearic, oleic and linoleic acids in the oils after pan heating. Positive CIELAB “b*” color value, which indicates yellowness and levels of β-carotene and lutein in these oils showed a 42–56% and 8–53% decrease, respectively. Peroxide values, p-anisidine values, percentage of conjugated dienoic acid, specific extinction at 232 and 270 nm and food oil sensor readings of these oils showed significant increases to levels exceeding good oil quality indices. Acid values only showed one to twofold increase from fresh oil values of 0.65–2.23 mg KOH/g of sample. These results indicate that significant levels of oxidation products would be present in flaxseed oils after pan heating. The flaxseed oil with a lower amount of PUFA appeared to be more degraded suggesting that the major factor affecting the oxidative stability of the flaxseed oils during pan-heating was not the degree of unsaturation but was dependent on the complex interaction between the fatty acids and minor constituents in the oils. Presented at the American Oil Chemists’ Society 97th Annual Meeting & Expo, St. Louis, MO, 30 April–3 May, 2006.     

Determination of Oil Content and Fatty Acid Composition of Sesame Mutants Suited for Intensive Management Conditions

Sesame mutants with closed capsules, determinate growth habit and wilt resistance, have been proposed to be suitable for intensive management conditions facilitating mechanized harvesting. The objective of our experiment was to determine the oil content and fatty acid composition of these mutants before they are placed on the market. Oil content and fatty acids were studied in 19 mutants, 6 breeding lines and 4 control source genotypes. The oil contents of the seeds ranged from 46.4 to 62.7%. The mutants had generally a lower oil content than the control genotypes except the wilting tolerant group. For unsaturated fatty acids, oleic acid was higher in the mutants and breeding lines while linoleic acid was lower in the seed oil. However, no mutants or breeding lines were found with radically different composition or with any undesirable lipid component. The closed capsule and determinate growth habit mutants need to be improved for oil content while their fatty acid composition is fine.     

Oil Quality and Yield of Different Carthamus tinctorius Cultivars: Promising Oilseeds for Biodiesel in Semi-Arid Regions

In this study, seed productivity and oil content of three safflower genotypes (IMAMT 1750, IMAMT 946 and IMAMT 894) cultivated in the Brazilian semi-arid region were evaluated to identify which genotype has the best in-field performance. The acidity and saponification index were evaluated, as well as the efficiency of lipid extraction through thermal analysis, aiming to estimate the species' potential for biofuel production in semi-arid regions. Field cultivation under semi-arid conditions lasted for ~75 days and no herbivory were observed on the plants. The IMAMT 894 genotype presented higher seed yield than the other genotypes, IMAMT 1750 presented 34% oil, and IMAMT 946 and IMAMT 894 presented 32% oil with efficient extraction in the Soxhlet system and high oil content and quality; higher than traditionally used crops such as soybean and cotton. The IMAMT 894 genotype showed higher seed productivity, but all three genotypes presented good oil yield and quality for biodiesel production. Oil extraction in the Soxhlet system was efficient since the thermogravimetric analysis showed no oil in the residual biomass after oil extraction.     

Simplex-Centroid Mixture Design Applied to the Aqueous Enzymatic Extraction of Fatty Acid-Balanced Oil from Mixed Seeds

A one-step method was developed to extract oil from a mixture of soybeans, peanuts, linseeds, and tea seeds using an aqueous enzymatic method. The proportion of the four seeds was targeted in accordance with a fatty acid ratio of 0.27 (SFA, saturated fatty acid(s)): 1 (MUFA, monounsaturated fatty acid(s)): 1 (PUFA, polyunsaturated fatty acid(s)), and the oil extraction yield was maximized by applying the simplex-centroid mixture design method. Three models were developed for describing the relationship between the proportion of the individual seeds in the mixture, the fatty acid ratio in the extracted oil, and the oil extraction yield, respectively. The developed models were then analyzed using an ANOVA and were found to fit the data quite well, with R ² values of 0.98, 0.93, and 0.93, respectively. The three models were validated experimentally. The results indicated that the ratio of fatty acids in the oil ranged between 0.98 and 1.12 (MUFA:PUFA) and between 0.26 and 0.28 (SFA:MUFA), which were quite close to the target values of 1 and 0.27, respectively. The oil extraction yield of 62.13 % was slightly higher than the predicted value (60.32 %).     

Effect of Moisture and Heat Treatment of Corn Germ on Oil Quality

The changes in the quality of crude corn oil caused by moisture and two different thermal pretreatments (oven heating and steam heating) of wet‐milled corn germ were evaluated and compared with those of untreated oil. Increasing the moisture content of the corn germ from 8 to 25% before oil extraction increased the acid value (AV) (3.02–4.01 mg KOH g^?1), peroxide value (PV) (0.52–1.05 meq kg^?1), and the red value (7.3–8.7) and decreased the content of total tocopherols by 37% and that of γ‐tocopherols by 31%. Oven heating tended to decrease the AV and PV while steam heating significantly increased the total and individual tocopherol contents (P < 0.05). The different moisture contents and thermal pretreatments of corn germ caused no significant differences in the fatty acid composition and the contents of total and individual phytosterols of the crude oils. The γ‐tocopherol contents were found to be highly correlated with the red values (the corresponding R² reached 0.9977 and 0.9089 for moisture and heat pretreatments, respectively).     

Isolation of a Series of Fatty Acid Components of Ongokea gore Seed (Isano) Oil and their Detailed Structural Analysis

The total oil production capacity of isano oil is estimated at about 10,000 tons annually. Previous studies of this oil revealed that it is rich in fatty acids including a conjugated diyne moiety. This makes isano oil an excellent candidate for sustainable applications development. However, only a few of its fatty acids have been isolated and identified so far. In this study, we have reinvestigated this oil by characterizing its physicochemical properties and isolating several of its fatty acids as ethyl esters for their detailed structural analysis and identification. Six ethyl esters of fatty acids constituting isanic oil were isolated by flash column chromatography and semipreparative HPLC. The detailed structural analysis of these fatty acid esters by infrared, high resolution, mass spectroscopy, and nuclear magnetic resonance (1‐D and 2‐D) allowed determining unequivocally their chemical structure. The main fatty acid component of the oil (35.7 %) was identified as isanic acid. Four minor acids were found to possess also two conjugated triple bonds, while the sixth fatty acid does not contain carbon–carbon triple bonds nor double bonds but possessed a cis epoxide function. Results obtained in this study are currently being used to explore potential applications of isano oil.     

Study of Ozonated Olive Oil: Monitoring of the Ozone Absorption and Analysis of the Obtained Functional Groups

The peculiarities of ozone absorption during olive oil ozonolysis have been studied by continuous monitoring of ozone concentrations at the bubbling reactor outlet. The determined amount of ozone, consumed during the ozonolysis of the double bonds, was used as alternative way for evaluation of the degree of unsaturation of the oil. The basic functional groups, products of the reaction: ozonides and aldehydes have been quantitatively characterized by means of ¹H-NMR spectroscopy, whereupon their ratio was found to be 93.4:6.6 (mol. %), respectively. The determined ratio between the cis and trans ozonides was 46:54.     

Yield Analysis of Oil Palm Cultivated Under Irrigation in the Brazilian Savanna

The oil palm is currently a major source of oil used worldwide for biofuel production and food. In Brazil, it is grown in high rainfall and high temperature regions. The high cost of this oil crop in the Brazilian Amazonia, combined with environmental and land ownership issues and the occurrence of diseases, has aroused considerable interest in growing it in other regions of the country, including the Savanna (Cerrado) Biome. This study aimed to evaluate, for 1 year, the fruit bunch, the oil yield, and other parameters of two oil palm cultivars (BRS C1001 and BRS C2501) under the typical Savanna conditions in the Federal District, Brazil. Differences between these cultivars were observed in some parameters evaluated throughout the year (p < 0.05). The oil yield/bunch ranged from 25 to 32 and 29 to 36 % for BRS C2501 and BRS C1001 cultivars, respectively and similar to those obtained for the same cultivars in the Brazilian Amazonia and for other genotypes in Indonesia, Sumatra, and Malaysia. Both cultivars proved to be promising in terms of oil yield in a trail carried out at 1000 m of altitude under irrigation at Cerrado Biome in Brazil.     

Effects of High Temperatures and Duration of Heating on Olive Oil Properties for Food Use and Biodiesel Production

Heating deteriorates the physicochemical properties of a vegetable oil for both edible and biofuel uses. The parameters for edible olive oil are established by European Union regulations and by the International Olive Council. The properties of a vegetable oil to be used as a source for biodiesel production are indicated by the German DIN 51605 for rapeseed oil. Biofuel properties are described by the European EN 14214 and the North American ASTM 6751 standards for biodiesel. It is useful to know how temperature and heating duration influence the physicochemical properties of olive oil. Free acidity, refractive index and myristic acid were not significantly influenced by temperature and heating duration. K232, K266, K270, K274, p-anisidine value, totox index, kinematic viscosity (at 30, 40, 50 °C), estimated higher heating value, relative density, and cetane number increased during olive oil heating. The biological properties: iodine value, oxidative stability index, antiradical (2,2-diphenyl-1-picrylhydrazyl radical, DPPH?) activity, and phenol content, decreased when time and temperature increased. Fatty acid methyl esters were highly influenced by the applied variables. Almost all the fatty acid methyl esters, except myristic, stearic, and arachidic acid esters, were influenced by the combined effect of temperature and time in a very highly significant level. These results show how temperature and duration of heating influence extra virgin olive oil degradation for both edible use and biodiesel production.