Changes occurring in vegetable oils composition due to microwave heating

Hassanein, Minar M. M.; El-Shami, S. M.; El-Mallah, M. Hassan

doi:10.3989/gya.2003.v54.i4.219

Cited by 64 publications

(63 citation statements)

References 17 publications

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“…Low peroxide values and dienoic conjugation could explain the negligible changes of essential fatty acids observed during the microwave heating as reported in the literature (COSSIGNANI et al 1998;KIM & JOO 1995;HASSANEIN et al 2003), which is in agreement with the results of our preliminary experiments.…”

Section: Changes Of Conjugated Double Bond Systemssupporting

confidence: 93%

“…Free fatty acids present in oil enhance the oxidation ( YOSHIDA 1993), which may be important if cold-pressed unrefined oils are used in microwave treated systems. Similar results were obtained on comparison of sunflower, soybean, and peanut oils, and a mixture of soybean and peanut oils (HASSANEIN et al 2003). Five vegetable oils were treated in a microwave oven, and their stabilities were tested under Rancimat conditions at 100°C; the stability decreased by 29-65% of the original value, and the tocopherol content by 5-61% during 15 min heating (MARINOVA et al 2001).…”

mentioning

confidence: 52%

“…It means that not more than about 1% polyenoic acid was destroyed, as a change in the fatty acid composition would be otherwise observed. On the contrary, small changes of essential fatty acids and the formation of epoxides were observed in other experiments with several vegetable oils (HASSANEIN et al 2003). In the case that natural antioxidants of oils used for microwave heating have no satisfactory effect, it is possible to add other permitted antioxidants (GERTZ 2004).…”

mentioning

confidence: 91%

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Oxidative changes of vegetable oils during microwave heating

Lukešová¹,

Dostálová²,

Mahmoud³

et al. 2005

Czech J. Food Sci.

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DOSTÁLOVÁ J., HANZLÍK P., RÉBLOVÁ Z., POKORNÝ J. (2005): Oxidative changes of vegetable oils during microwave heating. Czech J. Food Sci., 23: 230-239.The oxidative stabilities of pork lard, sunflower, zero-erucic rapeseed, peanut and high-oleic peanut oils were tested under microwave heating conditions. Vegetable oils and lard were heated in a microwave oven for up to 40 min between 25°C and 200°C. The peroxide value, the contents of conjugated dienoic and trienoic acids, and polymers were used as markers of lipid degradation. Sunflower oil was found the least stable oil because of a high polyenoic acid content and a low content of γ-tocopherol. Rapeseed oil was more stable because of a lower polyenoic acid content and a high γ-tocopherol level. Conventional peanut oil was relatively stable, but substantially less stable than high-oleic peanut oil. Pork lard and high-oleic peanut oil formed only low levels of polymers due to a low polyenoic acid content.

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Section: Changes Of Conjugated Double Bond Systemssupporting

confidence: 93%

mentioning

confidence: 52%

mentioning

confidence: 91%

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Oxidative changes of vegetable oils during microwave heating

Lukešová¹,

Dostálová²,

Mahmoud³

et al. 2005

Czech J. Food Sci.

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“…The highest peroxide value was found for the extra virgin sunflower oil enriched in carotenoids by the MAE of dry tomato waste, a fact that is in agreement with the highest content of polyunsaturated fatty acids of this oil among the three investigated oils. Hassanein et al, (2003) also reported that in vegetable oils exposed to microwave energy, the higher the oil content in polyunsaturated fatty acids, the greater the rate of oils' quality deterioration.…”

Section: Oxidative Stabilitymentioning

confidence: 99%

Effect of carotenoids, extracted from dry tomato waste, on the stability and characteristics of various vegetable oils

et al. 2018

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SUMMARY:In this study, various vegetable oils were enriched with carotenoids originating from dry tomato waste using ultrasound-assisted extraction, microwave-assisted extraction and maceration. Analyses of total carotenoids, color and oxidative stability (determined by free radical scavenger activity, peroxide value, Rancimat method and DSC analysis) were carried out. Commercial oils without enrichment were used for comparison. The results showed that the carotenoid contents of the oils increased significantly by increasing incorporation of dry tomato waste. Also, maceration proved to extract significantly higher amounts of these compounds. In some oils the extraction of dry tomato waste improved their oxidative and thermal stability while in others it caused an increase in the peroxide value and a decrease in induction time. Finally, the color parameters of the oils were significantly influenced. Enriched oils could be a potential source of bioactive compounds and might have significant antioxidant activity when ingested as part of a dietary regime. KEYWORDS:Carotenoids; Color; Extraction; Oxidative Stability; Tomato waste; Vegetable oils RESUMEN: Efecto de los carotenoides, extraídos de residuos de tomates secos, sobre la estabilidad y caracterís-ticas de aceites vegetales. En este estudio varios aceites vegetales se enriquecieron con carotenoides obtenidos a partir de residuos de tomates secos utilizando extracción asistida por ultrasonido, extracción asistida por microondas y maceración. Se llevó a cabo un análisis de los carotenoides totales, el color y la estabilidad oxidativa (determinada por la actividad captadora de radicales libres, el índice de peróxidos, el método Rancimat y el análisis DSC). Los aceites comerciales sin enriquecimiento se usaron como testigos. Los resultados mostraron que el contenido de carotenoides de los aceites aumentó significativamente al aumentar la incorporación de residuos secos de tomate. Además, la maceración demostró extraer cantidades significativamente más altas de estos compuestos. En algunos aceites, el residuo seco de tomates mejoró su estabilidad oxidativa y térmica, mientras que en otros causó un aumento en el índice de peróxido y una disminución en el tiempo de inducción. Finalmente, los parámetros de color de los aceites se vieron significativamente influenciados. Los aceites enriquecidos podrían ser una fuente potencial de compuestos bioactivos y podrían tener una actividad antioxidante significativa cuando se ingieren como parte de un régimen dietético.

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“…Since its invention and development, the use of the microwave oven increased constantly, both at home and in the industry sector, due to its advantages, that includes capacity to rapidly transmit heat due to its high penetration power (Hassanein et al, 2003;Burfoot et al, 1990), convenience, ease of use (Caponio et al, 2003;Cossignani et al, 1998) and time and energy savings (Albi et al, 1997a). Another reason to the constant increase in the use of the microwave oven is the tendency of the industry to produce pre-prepared food products especially to defrost, heat or cook using this kind of equipment (Albi et al, 1997b).…”

Section: Introductionmentioning

confidence: 99%

Effect of microwave heating with different exposure times on physical and chemical parameters of olive oil

Malheiro¹,

Oliveira²,

Vilas‐Boas³

et al. 2009

Food and Chemical Toxicology

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a-tocopherol a b s t r a c tThis study reflects the effect of different microwave heating times (1, 3, 5, 10 and 15 min) on physical and chemical characteristics of three Portuguese olive oils from three protected designation of origin (PDO), ''Azeite de Trás-os-Montes PDO", ''Azeites da Beira Interior PDO", and ''Azeite de Moura PDO". The parameters evaluated were free acidity, peroxide value, specific extinction coefficients (K 232 and K 270 ), color and chlorophylls and carotenoids content. A differential pulse voltammeter was also used to monitor the changes in a-tocopherol content. The results showed that microwave heating produce losses in the quality of the different analysed olive oils. The heating time did not promote the occurrence of hydrolysis in the samples since no changes in free acidity values were found. All other parameters were affected by exposure time in a similar way: in the firsts 3 min no marked changes were observed, after that the quality of the oil decrease significantly. The microwave heating time also affects the total chlorophylls, carotenoids and a-tocopherol contents which clearly decreased as long as the exposure time increases. After 15 min of heating the electrochemical signal, due to the a-tocopherol, disappear completely in the voltamogram.

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Changes occurring in vegetable oils composition due to microwave heating

Cited by 64 publications

References 17 publications

Oxidative changes of vegetable oils during microwave heating

Oxidative changes of vegetable oils during microwave heating

Effect of carotenoids, extracted from dry tomato waste, on the stability and characteristics of various vegetable oils

Effect of microwave heating with different exposure times on physical and chemical parameters of olive oil

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