Inactivation of Soybean Lipoxygenase by Microwave Heating: Effect of Moisture Content and Exposure Time

Wang, S.H.; Toledo, Maria Cecília de Figueiredo

doi:10.1111/j.1365-2621.1987.tb14078.x

Cited by 30 publications

(13 citation statements)

References 16 publications

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“…The same conclusion was obtained for soybeans (Esaka et al, 1986). Wang and Toledo (1987) reported that LOX in microwave-heated high-moisture soybean samples was completely inactivated. The temperature of the soybeans was ∼100°C.…”

Section: Effect Of Microwave Heat On Lox Activitysupporting

confidence: 80%

Prevention of Oxidative Rancidity in Rice Bran during Storage

Ramezanzadeh

Rao

Windhauser

et al. 1999

J. Agric. Food Chem.

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The effect of microwave heat on lipoxygenase (LOX) activity in rice bran under various storage conditions was examined. Raw rice bran from the long-grain variety Lemont was adjusted to 21% moisture content and heated in a microwave oven at 850 W for 3 min. Raw and microwave-heated rice bran samples were packed in zipper-top bags or vacuum packs and stored at room temperature (25 degrees C) or in the refrigerator (4-5 degrees C) for 16 weeks. Samples were analyzed for LOX activity at 4-week intervals. LOX activity did not significantly change from its initial value at week 0 for zipper-top and vacuum-packed samples while stored at 4-5 degrees C for 12 weeks, but decreased at week 16. Vacuum packing did not show a significant impact on LOX activity during 16 weeks of storage. Microwave-heated samples stored in the refrigerator did not show significant change in LOX activity for up to 12 weeks but showed a significant (p < 0. 05) decrease at 16 weeks. Results showed that oxidative rancidity of rice bran could be prevented by microwave heating the samples, packing in zipper-top bags, and storing at 4-5 degrees C for up to 16 weeks.

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Section: Effect Of Microwave Heat On Lox Activitysupporting

confidence: 80%

Prevention of Oxidative Rancidity in Rice Bran during Storage

Ramezanzadeh

Rao

Windhauser

et al. 1999

J. Agric. Food Chem.

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“…A similar phenomenon was observed by Wang and Toledo (1987) in heated soybeans with microwaves and by Chiou and Tsai (1989) in toasted peanut kernels. This delay can be explained by the rate of water evaporation.…”

Section: Chemical Composition Of Raw Almondssupporting

confidence: 75%

Physico-chemical and sensory property changes in almonds of Desmayo Largueta variety during toasting / Cambios en las propiedades físico-químicas y sensoriales de almendras de la variedad Desmayo Largueta durante el tostado

Gou

Dı́az

Guerrero

et al. 2000

Food sci. technol. int.

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Almonds modify their properties during toasting due to the high temperatures reached. The aim of this study was to evaluate the physico-chemical and sensory property changes in shelled almonds, Desmayo Largueta variety harvested in Tarragona (Spain) and toasted at 200 and 220°C. Internal temperature and moisture content were determined in almonds during toasting, and fatty acid composition, the index of acidity, the peroxide value and the TBA test in almond oil. Sensory analysis of almonds with different toasted intensity was performed. Rancidity was also evaluated by sensory analysis after a year of storage. There was a delay in the internal temperature increase of the almonds between 120 and 130 °C, which coincided with the period of maximum rate of water evaporation. There was no significant variation in the fatty acid composition of the almond oil during toasting. The peroxide value of almond oil had a slight increase from 6 min at 220°C and from 8 min at 200°C, reaching a maximum at 10 min. Rancidity after a year of storage increased up to 8 min and then decreased. The maximum crispiness was obtained at the end of the period of a maximum rate of water evaporation: between 6 and 8 min of toasting at 220 °C and between 8 and 10 min of toasting at 200°C. Over-toasting produced an antioxidant effect in the product, but decreased sweetness and increased bitterness and grittiness. Durante el tostado de las almendras se alcanzan altas temperaturas que modifican sus propiedades. El objetivo de este estudio fue evaluar los cambios fisico-quimicos y sensoriales que se producen en una muestra de almendras de la variedad Desmayo Largueta procedente de Tarragona (España) durante el tostado a temperaturas de 200 y 220°C. Durante el tostado se determinó la temperatura interna y el contenido de humedad de las almendras, así como la composición de los ácidos grasos, el indice de acidez, el valor de peróxidos y el indice TBA del aceite de almendra. Se realizó un análisis sensorial de las almendras con diferente intensidad de tostado. También se evaluó sensorialmente la rancidez después de un año. Se observó un retraso en el incremento de la temperatura interna de las almendras entre los 120 y 130 °C del tostado que coincidió con el periodo de máxima velocidad de evaporación. No se detectó una variación significativa en la composición en ácidos grasos del aceite durante el tostado. El valor de peróxidos aumentó ligeramente a partir de los 6 min a 220 °C y de los 8 min a 200 °C y alcanzó el máximo a los 10 min. La rancidez después de un año aumentó con el tiempo de tostado hasta los 8 min, a partir de los cuales disminuyó. El máximo crujiente se obtuvo al final del periodo de máxima velocidad de evaporación: entre los 6 y 8 min de tostado a 220°C y entre los 8 y 10 min de...

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“…This is because, unlike lipase, lipoxygenase exhibits very little activity at moisture contents typically found during storage (Wang and Toledo, 1987), and because whole wheat flour contains high levels of protective antioxidants (Adom et al, 2005).…”

Section: Oxidative Ranciditymentioning

confidence: 99%