Microwave Heating Effects on Relative Stabilities of Tocopherols in Oils

Yoshida, Hiromi; Hirooka, Nobuhisa; Kajimoto, Gorō

doi:10.1111/j.1365-2621.1991.tb14637.x

Cited by 44 publications

(30 citation statements)

References 29 publications

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“…Therefore, it was not found necessary to determine the time course of the changes in the fatty acid composition under our experimental conditions. The changes of tocopherols during microwave heating of edible oils were studied by YOSHIDA et al (1991YOSHIDA et al ( , 1993YOSHIDA et al ( , 2002. Therefore, it was considered as unnecessary to repeat their experiments under our heating conditions.…”

Section: General Considerationsmentioning

confidence: 99%

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: General Considerationsmentioning

confidence: 99%

Oxidative changes of vegetable oils during microwave heating

Lukešová¹,

Dostálová²,

Mahmoud³

et al. 2005

Czech J. Food Sci.

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“…Tocopherols have already been the subject of many studies describing their content in plant materials and some papers describe the effect of physical treatments like frying at 180°C (BarreraArellano et al, 2002) and subjecting them to microwave heating (Yoshida et al, 1991;1999), but none on the effect of roasting.…”

Section: Discussionmentioning

confidence: 99%

Effect of roasting on tocopherols of gourd seeds (<i>Cucurbita pepo</i>)

François¹,

Barouh²,

Jean-Pierre³

et al. 2006

Grasas y Aceites

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Se ha estudiado el efecto del tostado a alta temperatura sobre la vitamina E en semillas de calabaza Cucurbita pepo. El tostado a 140°C durante 5 min indujo una hinchazón de la semilla con un aumento en el volumen del 43 %, y una pér-dida de peso del 6,5 %. La semilla adquirió la apariencia deseada después del tostado. La actividad del agua en la semilla cruda fue de 0,544 y disminuyó durante el tostado a 0,105. Las semillas de Cucurbita pepo contenían un 51,0 % de grasa. El contenido de tocoferol de las semillas tostadas fue de 68mg/100g y el de las semillas no tostadas de 107mg/100g de aceite. El γ-tocoferol representó el 96% de los tocoferoles totales. La pérdida de tocoferoles totales durante el tostado fue del 36% siendo la má alta la del β-tocoferol con un 50%; la del α-tocoferol fue del 41% y la del γ-tocoferol del 36%. PALABRAS-CLAVE: Calabaza -Cucurbita pepo -Tocoferol -Tostado -Vitamina E. SUMMARY Effect of roasting on tocopherols of gourd seeds (Cucurbita pepo)The effect of roasting at high temperatures on the Vitamin E in hulled gourd seeds of Cucurbita pepo was studied. Roasting at 140°C for 5 min induced a swelling of the seed with an increase in volume of 43 %, and a weight loss of 6.5 %. The seed acquired the desired puffed-up appearance. The water activity of raw seeds was 0.544 and decreased during roasting to 0.105.Cucurbita pepo seeds contained 51.0 % fat. Tocopherol content of roasted seeds was 68mg/100g oil and of non roasted seeds was 107mg/100g oil. γ-tocopherol represented 96% of the total tocopherols. Total tocopherol loss during roasting was 36%. β-tocopherol loss was the highest at 50%; for α-tocopherol it was 41% and for γ-tocopherol it was 36%.

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“…Concerning the type of tocopherols, the relative stability of a-, β-, g-and d-tocopherol at high temperatures has been studied in detail and there is agreement that a-tocopherol is less stable than d-tocopherol, while β-and g-tocopherols would degrade at intermediate rates (Yoshida et al, 1991a(Yoshida et al, , 1991b(Yoshida et al, , 1992(Yoshida et al, , 1993Gordon and Kourimska, 1995a;Lampi and Kamal Eldin, 1998;Barrera Arellano et al, 1999. In this respect, new sunflower lines that contain g-tocopherol as the major natural antioxidant instead of a-tocopherol, which is characteristic of standard sunflower oil, are of special interest (Demurin et al, 1996;Velasco et al, 2004;Marmesat et al, 2008).…”

Section: Other Natural Antioxidantsmentioning

confidence: 99%

Action and fate of natural and synthetic antioxidants during frying

Marmesat¹,

Morales²,

Velasco³

et al. 2010

Grasas y Aceites

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RESUMENAcción y destino de los antioxidantes naturales y sintéticos durante el proceso de fritura.La acción de antioxidantes para retrasar la oxidación en grasas y aceites es bien conocida aunque la mayor parte de la información está relacionada con su actividad a temperatura ambiente durante el almacenamiento o a las temperaturas moderadas de los ensayos de oxidación acelerada. Sin embargo, su efectividad a la temperatura elevada de procesos como la fritura es más compleja debido a la existencia de reacciones oxidativas y térmicas que tienen lugar simultáneamente. En esta revisión, se resumen los estudios principales que definen la acción de los antioxidantes naturales y sintéticos durante el proceso de fritura. Se ha dividido en dos partes que resumen la acción y los compuestos de degradación de los antioxidantes naturales, es decir, tocoferoles y otros compuestos fenólicos presentes en aceites de oliva, sésamo y salvado de arroz, y de los principales antioxidantes sintéticos como BHA, BHT y TBHQ. PALABRAS CLAVE: Antioxidantes sintéticos -BHA -BHT -Compuestos fenólicos -Fritura -TBHQ -Tocoferoles. SUMMARY Action and fate of natural and synthetic antioxidants during frying.The action of antioxidants to delay lipid oxidation in fats and oils is well known although most of the information is related to their effects at room temperature during storage or at the moderate temperatures of the accelerated tests to measure oil stability. However, oxidation at the high temperatures of food processes like frying, is more complex because the availability of air is unknown and both oxidative and thermal reactions are simultaneously involved. In this review, the main studies defining the action of natural and synthetic antioxidants at frying temperatures are summarized. This review has been divided into two main parts concerning the information on natural antioxidants, i.e. tocopherols and other phenolic compounds present in specific oils like olive, sesame and rice bran oils, and on synthetic antioxidants, i.e. BHA, BHT and TBHQ.

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Microwave Heating Effects on Relative Stabilities of Tocopherols in Oils

Cited by 44 publications

References 29 publications

Oxidative changes of vegetable oils during microwave heating

Oxidative changes of vegetable oils during microwave heating

Effect of roasting on tocopherols of gourd seeds (<i>Cucurbita pepo</i>)

Action and fate of natural and synthetic antioxidants during frying

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