Chemical changes in extra virgin olive oils from Slovenian Istra after thermal treatment

Bešter, E.; Butinar, Bojan; Bučar-Miklavčić, Milena; Golob, Terezija

doi:10.1016/j.foodchem.2007.10.061

Cited by 50 publications

(52 citation statements)

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“…Chromatographic analytical techniques (gas chromatography, GC; with mass spectroscopy, GC-MS, and high performance liquid chromatography, HPLC) have been utilized to quantify major 32,33 and minor component classes. [34][35][36][37][38][39][40][41] There has been many studies in the recent years that used nuclear magnetic resonance [42][43][44] (NMR) with the aim to distinguishing olive oils of different geographical areas. The major advantage of ATR 45,46 over chromatographic techniques and NMR is that complex sample preparation is not necessary.…”

Section: Introductionmentioning

confidence: 99%

Chemometric Analysis of Croatian Extra Virgin Olive Oils from Central Dalmatia Region

et al. 2013

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Abstract. Extra virgin olive oil samples were collected from different geographical areas of Central Dalmatia region in Croatia including locations both on the coast and islands. This set included 41 oils of cultivar Oblica, 1 per cultivars Coratina and Leccino, and 5 of mixed cultivars Lastovka and Oblica. Attenuated total reflectance (ATR) spectra of non-treated samples were recorded and principal component analysis (PCA) was carried out on a set of obtained spectra, as well as their first and second derivatives. The quality of PCA models was assessed using leave-one-out cross-validation and optimal number of principal components was determined. In the case of ATR spectra, the first principal component accounted for 42.92 % of the total variance among the samples and the optimal number of components was 6, whereas in the case of second derivatives the first principal component accounted for 95.76 % of the total variance and the optimal number of components was 3. Classification of olive oils on the basis of geographical origin was proposed and underlying spectral differences among the spectra were determined by investigating principal component loadings. These differences arise as a result of variations in fatty acid composition. It was found out that ATR in combination with PCA could easily distinguish between samples collected from the coastal area and those from the islands. Classification results were further confirmed by using spherical principal components procedure, projection pursuit and robust PCA, as well as hierarchical cluster analysis.(doi: 10.5562/cca2377)

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Section: Introductionmentioning

confidence: 99%

Chemometric Analysis of Croatian Extra Virgin Olive Oils from Central Dalmatia Region

et al. 2013

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“…Bešter et al [21] confirmed a progressive decrease in linolenic acid (C18:3ω3) and li-noleic acid (C18:2ω6) contents. The rapid loss of hydroxy-tyrosol (HO-Tyr) compared with fatty acids translated its effective antioxidant activity in protecting lipids against oxidation.…”

Section: Introductionmentioning

confidence: 95%

Comparative Study of the Effects of Thermal and Photochemical Accelerated Oxidations on Quality of “Green Type” and “Black Type” French Olive Oils

Plard¹,

Dréau²,

Rébufa³

et al. 2016

AJAC

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Oxidative stability of two commercial olive oils of different specificity (green type and black type) has been studied during thermal and photochemical accelerated processes through the evolution of quality indices. It might help to assure a good utilisation of olive oil. In most of works described in literature, they are measured individually. In this study, a Principal Component Analysis (PCA) has been performed to emphasize their variation and describe in concise way the quality and the safety of extra-virgin olive oil after two oxidative stresses. No difference had been detected between both type oils when they are heated. Peroxides, aldehydes and conjugated dienes and trienes were formed but rapidly degraded into final oxidation compounds, mainly acid compounds. During the photochemical process, similar changes occurred slower and the green type oil had shown better stability because of its higher phenolic content. The fatty acids had been more impacted (higher disappearance of monounsaturated fatty acids (MUFA) and polyunsaturated fatty acids (PUFA)) when the oils were heated than when irradiated. Saturated fatty acids (SFA), MUFA and PUFA were the most relevant indicators to characterize non-oxidized oils and PV characterized the early stage of oil oxidation.

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“…The value of K 232 and K 270 specific extinction coefficients in this study exceeded the limits established by European Community Regulation (Annexes II and IX in EEC/2568/91) for VOO. Allouche et al, 2007;Bester et al, 2008;Ayadi and Grati-Kamun, 2009;Mahmoud et al, 2009;Malheiro et al, 2009;Farhoosh et al, 2012).…”

Section: Figure 2 Effect Of Temperature On the K 232 Specific Extincmentioning

confidence: 99%

Thermal Stability of Chlorophyll Pigments in Virgin Olive Oil

Rasul¹,

İnanç²

2014

KSÜ Doğ. Bil. Derg

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Abstract:The aim of the present study was to determine the changes in the chlorophyll content and the K 232 and K 270 specific extinction coefficient values in virgin olive oil (VOO) subjected to high temperatures for 24 h. VOO, was obtained from Kahramanmaraş city, Turkey, and subjected to 150, 160, 170, 180. 190 and 200ºC for 2, 4, 6, 8, 10, 12 and 24 h, and the chlorophyll content and the K 232 and K 270 specific extinction coefficient values were determined. The chlorophyll content of VOO decreased significantly as the treatment temperature and the extent of heat treatment increased (P<0.05) Especially, the temperature above 180ºC, the chlorophyll content decreased below 3% after 24 h. The K 232 and K 270 specific extinction coefficient values of VOO increased significantly with increasing the treatment temperature and time (P<0.05). The values of K 232 and K 270 specific extinction coefficients reached to 9.12 and 5.28 (1%, 1 cm), respectively, at 200ºC after 24 h. However, the rates of the increase in these values did not change with respect to different temperature and time. A significant inverse relationship was found between the chlorophyll content and the K 232 and K 270 specific extinction coefficient values (P<0.05). This study showed that chlorophyll, as one of the major quality criteria for olive oils, is heat-liable, and decomposes at high temperatures and long treatment times. In addition, increases in the conjugated diene and triene contents of VOO indicate the accelerated oxidation reactions at high temperatures; therefore VOO is no longer classified as "virgin olive oil" according to the official standards. Keywords: Virgin olive oil, chlorophyll, conjugated diene and triene, thermal stability Natürel Zeytin Yağındaki Klorofil Renk Maddelerinin Isısal KararlılığıÖzet: Bu çalışmanın amacı, yüksek sıcaklıklara maruz bırakılan natürel zeytinyağında klorofil ve konjuge bağların miktarlarındaki değişimi 24 saat süresince belirlemektir. Kahramanmaraş, Türkiye'den temin edilen natürel zeytinyağı, 150, 160, 170, 180. 190 ve 200ºC sıcaklıklarda 2, 4, 6, 8, 10, 12 ve 24 saat bekletilmiş ve natürel zeytinyağının klorofil miktarı ve 232 ve 270 nm'deki absorbans değerleri ölçülmüştür. Natürel zeytinyağının klorofil miktarı sıcaklık ve süre arttıkça istatistiksel olarak önemli oranda düşüş göstermiştir (P<0,05). Özelikle, 180ºC üzeri sıcaklıklarda 24 saat işlem gören sızma zeytinyağında klorofil miktarı %3'ün altına düşmüştür. Natürel zeytinyağının K 232 ve K 270 absorbans değerleri, sıcaklık ve sürenin artışına paralel istatistiksel olarak önemli oranda artmıştır (P<0,05). 200ºC sıcaklıkta ve 24 saat sonunda natürel zeytinyağının K 232 absorbans değeri 9,12 (1%, 1cm) ve K 270 absorbans değeri 5,28 (1%, 1 cm)'ye ulaşmıştır. Ancak, farklı sıcaklık ve süreler sonunda K 232 ve K 270 absorbans değerlerindeki artış hızı hemen hemen sabit kalmıştır. Lineer regresyon analizinde, klorofil miktarındaki düşüş ile K 232 ve K 270 absorbans değerlerindeki artış arasında istatistiksel olarak önemli negatif bir ilişki b...

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Chemical changes in extra virgin olive oils from Slovenian Istra after thermal treatment

Cited by 50 publications

References 20 publications

Chemometric Analysis of Croatian Extra Virgin Olive Oils from Central Dalmatia Region

Chemometric Analysis of Croatian Extra Virgin Olive Oils from Central Dalmatia Region

Comparative Study of the Effects of Thermal and Photochemical Accelerated Oxidations on Quality of “Green Type” and “Black Type” French Olive Oils

Thermal Stability of Chlorophyll Pigments in Virgin Olive Oil

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