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

Abstract

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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