Comparison of oxidation stability of virgin olive oils from different locations of Turkey

Ten kinds of virgin olive oil of two major cultivars (Ayvalık and Memecik) produced in several areas of Turkey (Bayındır, Edremit, Ortaklar, Burhaniye, Ezine, Tire, Havran, Ayvalık, Altınoluk, and Küçükkuyu) were analysed. The quality characteristics, fatty acid composition, total phenol, ando-diphenol content of the samples were determined. Oxidative stability and free radical scavenging activity were determined using Rancimat test, Schaal oven test, and DPPH method. It was found that while Memecik oil from Ortaklar demonstrated the strongest oxidative stability, Ayvalık oil from Ezine had the lowest oxidative stability among the samples. Fatty acid composition and especially oleic acid/linoleic acid ratio was previously defined as a parameter that can help distinguish cultivars from one another; however, this study proved that total phenol, especially o-diphenol content of the oil, has the strongest effect on oxidative stability compared to other factors including fatty acid composition

Composición de ácidos grasos en aceites de semillas de cáñamo de diferentes localidades de Turquía

Recent interest in hempseed as a source of food has largely focused on its oil content and fatty acid profile. The oil content and fatty acid composition (15 fatty acids) of twenty one different hempseed samples of domestic origin from north-western Turkey were monitored. The samples were obtained from seed wholesalers and local spice shops and are of unknown genetic origin. The oil content of the hempseeds ranged between 29.6 to 36.5%. Out of the 15 detected fatty acids, the omega-6 linoleic acid (18:2n-6) was predominant and fluctuated from 55.4 to 56.9%, while the omega-3 α-linolenic (18:3n-3) acid ranged from 16.5 to 20.4% and the omega-9 oleic acid (18:1n-9) ranged from 11.4 to 15.9%. Of the minor fatty acids, the highest concentrations were found for γ-linolenic acid (18:3n-6), range 0.6-1.1%, followed by stearidonic acid (18:4n-3), range 0.3-0.5%. These results show that hempseed grown in north-western Turkey provides a well balanced and rich source of dietary omega-6 and -3 essential fatty acids and appears to be a potentially valuable source of food.El reciente interés por las semillas de cáñamo como alimento se ha enfocado en su contenido en aceite y su perfil de ácidos grasos. En este estudio se analizó el contenido en aceite y composición de ácidos grasos de 21 muestras diferentes de semillas de cáñamo de origen genético desconocido en el noroeste de Turquía. El contenido en aceite de las semillas varió entre 29,6 y 36,5%. De los 15 ácidos grasos detectados, el ácido linoleico (18:2n-6) (omega-6) fue predominante y fluctuó entre 55,4 y 56,9%; el ácido α-linolénico (18:3n-3) (omega-3) entre 16,5 y 20,4%; y el ácido oleico (18:1n-9) (omega-9) entre 11,4 y 15,9%. Entre los ácidos grasos minoritarios, se encontraron las mayores concentraciones (entre 0,6 y 1,1%) para el ácido γ-linolénico (18:3n-6), seguido del ácido estearidónico (18:4n-3), entre 0,3 y 0,5%. Estos resultados muestran que las semillas de cáñamo que se cultivan en el noroeste de Turquía pueden ser un alimento potencialmente valioso y constituirían para la dieta una fuente rica y equilibrada de ácidos grasos omega-6 y -3

Estabilidad y compuestos de oxidación volátiles de aceites prensados en frío de semillas de uva, lino y comino negro, afectados por la oxidación térmica

The old-pressed oils (CPO) from grape seeds (GSO), flax seeds (FSO) and black cumin seeds (BSO) were analyzed for their fatty acid profiles, tocopherols, total phenolics, bioactives and phenolic compositions. The stability of CPO under thermal oxidation conditions was evaluated. The main fatty acid in FSO was linolenic acid (56.5% of total fatty acids); while GSO and BSO were rich in linoleic acid, which accounted for 66.8 and 56.8%, respectively. GSO was rich in ?-tocopherol (123.0 mg/kg), while ?-tocopherol was a prevalent isomer in FSO and BSO (137.9 and 128.9 mg/kg, respectively). The total phenolic contents in the oils ranged from 554 mg GAE/kg oil (FSO) to 1140 mg GAE/kg oil (BSO). Luteolin, dihydroquercetin and benzoic acids were the dominant bioactives and phenolics in FSO, GSO and BSO, respectively. Based on the oxidative stability index (OSI) value, BSO showed the highest value (6.14 h) among the other oils. The oxidative stability of FSO and BSO were higher than GSO according to peroxide value (PV) and conjugated diene (CD) values of the oils during storage at 60 °C. Hexanal, 2,4-heptadienal and (E,E)-2,4-heptadienal were the major volatile oxidation compounds (VOC) in FSO. Hexanal and (E)-2-heptanal were the main identified VOC in the GSO and BSO under the same oxidation conditions.Los aceites prensados en frío (CPO) de semilla de uva (OSG), semilla de lino (FSO) y semilla de comino negro (BSO) se analizaron para determinar su perfil de ácidos grasos, tocoferoles, compuestos fenólicos totales, compuestos bioactivos y composición fenólica. Se evaluó la estabilidad del CPO en condiciones de oxidación térmica. El ácido graso principal en FSO fue ácido linolénico (56,5%), mientras que GSO y BSO fueron ricos en ácido linoleico que representó el 66,8% y 56,8%, respectivamente. La OSG fue rica en ?-tocoferol (123,0 mg/kg), mientras que el ?-tocoferol fue el tocoferol mayoritario en el FOE y BSO (137,9 y 128,9 mg/kg, respectivamente). El contenido fenólico total de los aceites varió de 554 mg GAE/kg de aceite en FSO a 1140 mg GAE/kg de aceite en BSO. La luteolina, la dihidroquercetina y los ácidos benzoicos fueron los bioactivos y fenólicos dominantes en FSO, GSO y BSO, respectivamente. En base al valor del índice de estabilidad de la oxidación (OSI), BSO mostró el valor más alto (6,14 h) entre los otros aceites. La estabilidad oxidativa de FSO y BSO fue mayor que la OSG según el valor de peróxido (PV) y los valores de dieno conjugado (CD) de los aceites durante el almacenamiento a 60 °C. Hexanal, 2,4-heptadienal y (E, E) -2,4-heptadienal fueron los principales compuestos de oxidación volátiles (VOC) en FSO. Hexanal y (E) -2-heptanal fueron los principales VOC identificados en la OSG y la BSO en las mismas condiciones de oxidación

Lípidos bioactivos, actividad antirradical y estabilidad de aceites de semillas de rosa mosqueta bajo oxidación térmica y fotoinducida

In the present report, the fatty acids, tocopherols, and sterol profiles as well as the total phenolics and carotenoids of rosehip (Rosa canina) seed oil were determined. The major fatty acids in the oil were linoleic and linolenic acids, comprising 54.80% and 23.47% of the total fatty acids, respectively. Other bioactive lipids in the oil included total tocopherols (786.3 mg/kg), total phenolics (37.97 mg/kg) and total carotenoids (218.8 mg/kg). Rosehip oil was rich in γ-tocopherol (472.0 mg/kg) and β‑sitosterol (78.0% of total sterols). The DPPH· (2,2′-diphenyl-1-picrylhydrazyl) radical scavenging activity of the oil showed 1.08 mg α-tocopherol/g oil and 4.18 μmol TEAC (Trolox equivalent antioxidant capacity)/g oil, respectively. The ABTS+ (2,2′-Azino-bis-3-ethylbenzothiazoline-6-sulphonic acid) radical scavenging activity of the oil showed 1.00 mg α-tocopherol/g oil and 3.02 μmol TEAC/g oil, respectively. The induction period (IP) of the oil was 3.46 h for the Rancimat test (110 °C), while the IP of oil in differential scanning calorimetry (DSC) test (100-150 °C) ranged between 0.26 and 58.06 min. The oxidative stability of the oil was determined under thermal and photo oxidation conditions. The progression of oxidation at 30 °C (under UV light) and at 60 °C (in the dark) was followed by recording the ultraviolet absorption (K232 and K270) and degradation of total tocopherols, γ-tocopherol and total carotenoids. Rapid deterioration occurred in the oil stored under UV light conditions. The information provided in the present work is of importance for using rosehip seed oil in different food and non-food applications.En este trabajo se determinaron los ácidos grasos, tocoferoles, el perfil de esteroles, así como los fenoles totales y los carotenoides de aceites de semillas de rosa mosqueta (Rosa canina). Los principales ácidos grasos fueron linoleico y linolénico, que representan el 54,80% y 23,47% de los ácidos grasos totales, respectivamente. Otros lípidos bioactivos incluyen tocoferoles totales (786,3 mg/kg), fenoles (37,97 mg/kg) y carotenoides (218,8 mg/kg). El aceite de rosa mosqueta es rico en γ-tocoferol (472,0 mg/kg) y β-sitosterol (78,0% del total de los esteroles). La actividad captadora de radicales DPPH· (2,2’-difenil-1-picrilhidrazilo) fue 1,08 mg de α-tocoferol/g de aceite y 4,18 μmol de TEAC (capacidad antioxidante equivalente de Trolox)/g de aceite, respectivamente. La actividad captadora de radicales ABTS+ (2,2’-Azino-bis-3-etilbenzotiazolin-6-sulfónico) fue de 1,00 mg de α-tocoferol/g de aceite y 3,02 μmoles de TEAC/g de aceite, respectivamente. El período de inducción (IP) del aceite fue 3.46 h Rancimat (110 °C), mientras que el IP del aceite para la prueba de calorimetría de barrido diferencial (DSC) (100-150 °C) osciló entre 0,26-58,06 min. La estabilidad oxidativa del aceite se determinó en condiciones térmicas y de fotooxidativas. El progreso de la oxidación a 30 °C (bajo luz ultravioleta) y 60 °C (en oscuridad) fue determinado mediante las medidas del K232 y K270 mediante la degradación de tocoferoles totales, γ-tocoferol y carotenoides totales. El rápido deterioro se produjo en el aceite almacenado bajo condiciones de luz UV. La información proporcionada en el presente trabajo es de importancia para usar aceite de semilla de rosa mosqueta en diferentes aplicaciones alimentarias y no alimentarias

Effect of harvest time on physicochemical quality parameters, oxidation stability, and volatile compounds of extra virgin olive oil

The aim of this study was to determine the changes in some physicochemical properties of olives (fruit weight, water content and oil content) and olive oils (total chlorophyll, carotenoid, pheophytin a, peroxide value and free acidity), and in the chemical properties (fatty acids, tocopherols, phenolics, oxidation stability and volatile profiles) of oils during ripening.Ripening indices (RI) of olive samples were 1.93 (unripe), 4.28 (ripe) and 5.89 (overripe). Most of the mentioned features changed with ripening. During ripening there was a sharp decrease in total chlorophyll, carotenoid and pheophytin a contents. An increase in oleic and linoleic acids and a decrease in palmitic acid were found in the fatty acid composition. Olive oils showed strong relations among oxidation stability, tocopherol content, total phenols content, and antiradical actvity of phenol extracts and these parameters decreased with maturation. Nevertheless, higher amounts of trans-2-hexenal were found in the oil from ripe olives than from unripe and overripe olives. On the other hand, the highest concentration of hexanal was found in the oil from overripe olives.In general, significant differences were observed in fruit weight, pigments, free acidity, fatty acid, tocopherol, and total phenolics contents, radical scavenger activity, oxidation stability, phenolic profile and volatile profile between the olive oils from the Gemlik cultivar at different stages of maturation

Determination of aroma profiles of olive oils from Turkish olive cultivars

This study analyzed volatile aromatic compounds present in the oils of Turkish olive cultivars. The cultivars Gemlik, AyvalIk, Memecik, Domat, Uslu, HalhalI, Kilis ya?lIk, Nizip ya?lIk, Haşebi and Karamani were harvested from important Turkish olive-growing locations, such as BalIkesir, Bursa, Manisa, AydIn, Mu?la, İzmir, Kilis, Mersin, Hatay and Gaziantep during the 2007-2008 and 2008-2009 growing seasons. Olive samples were collected in two harvest years, at almost the same maturity stage, and processed under the same conditions. Headspace solid-phase microextraction (HS-SPME) was used to analyze volatile aroma compounds in the olive oil samples. Forty-seven compounds were characterized and quantified using gas chromatography-mass spectrometry/flame ionization detector (GC-MS/FID). The most abundant identified compounds were trans-2-hexenal, hexanal and 3-methyl-1-butanol. The trans-2-hexenal, hexanal and 3-methyl-1-butanol contents of oil samples varied between 0.86-67.15, 3.93-61.82 and 0.48-84.74 %, respectively. © 2013 AOCS

Comunicación corta.Variabilidad en el contenido de ácidos grasos y minerales en diferentes líneas de origen europeo de lino (Linum usitatissimum)

Linseed (Linnum usitatissimum) has recently gained popularity as a health food product. It has high levels of fatty acids and minerals, giving it characteristics beneficial for functional foods. This research is a comparative analysis of the fatty acid and mineral content of 23 European linseed lines. The levels of seven fatty acids were analysed using an Agilent 6890 N GC. Alfa-linolenic acid (ALA) (C18:3, n-3) was the most predominant, ranging from 49.4 to 56.4%, followed by oleic (C18:1, n-9; 19.8 to 28.8%), linoleic (C18:2, n-6; 10.8 to 16.0%), palmitic (C16:0, 4.1 to 6.2%) and stearic (C18:0, 3.3 to 7.1%) acids. In contrast arachidonic (C20:0) and gadoleic (C20:1) acids were only found at trace levels. One-way ANOVA test showed significant differences between the lines in terms of saturated and unsaturated fatty acid content (p < 0.05). A negative correlation (r = –0.74) exists between levels of ALA and oleic acid. The levels of ten minerals (Ca, Mg, Na, K, P, Cu, Fe, Mn, Zn and B) were also determined and showed significant variability between lines. The results can be used to assist variety selection in targeted breeding programs.La semilla de lino (Linnum usitatissimum) o linaza ha ganado recientemente popularidad como producto alimenticio, ya que sus altos niveles de ácidos grasos y minerales le proporcionan las características beneficiosas de los alimentos funcionales. Esta investigación es un análisis comparativo del contenido de ácidos grasos y minerales de 23 líneas europeas de linaza. Se analizaron los niveles de siete ácidos grasos utilizando Agilent 6890 N GC. El ácido alfalinolénico (ALA, C18:3, n-3) fue el más predominante (49,4-56,4%), seguido del oleico (C18:1, n-9; 19,8-28,8%), linoleico (C18:2, n-6; 10,8-16,0%), palmítico (C16:0; 4,1-6,2%) y esteárico (C18:0; 3,3-7,1%). Solamente se encontraron trazas de los ácidos araquidónico (C20:0) y gadoleico (C20:1). La prueba de ANOVA con un solo factor, para el contenido de ácidos grasos saturados o insaturados, mostró diferencias significativas entre líneas (p < 0,05). Existe una correlación negativa (r = –0,74) entre los niveles de ALA y ácido oleico. En las diferentes líneas se determinó también una variabilidad significativa entre los niveles de diez minerales (Ca, Mg, Na, K, P, Cu, Fe, Mn, Zn y B). Estos resultados pueden ser utilizados para asistir a la selección de variedades en programas de mejora