Effect of ultrasonic pretreatment on textural properties and sensory attributes of cooked faba beans.

ABSTRACT

Drying process extends the shelf-life of fresh faba beans and makes them available all year round. Dried and cooked faba beans are used to make a variety of traditional food products. Ultrasonic pretreatment, as a modern food processing technology, can shorten the drying time of fresh legumes and improve the quality and sensory properties of products. So, the present study aimed to analyze the impact of the ultrasonic treatment process (0, 5, 10, and 15 min, 40  kHz, and 150 W) on the mass transfer rate, drying time, and effective moisture diffusivity (Deff) of fresh faba beans. Also, the effect of ultrasonic treatment on textural properties and sensory attributes of cooked faba beans was studied. By using the ultrasonic process, the rate of water extraction from fresh faba beans, and thus their dehydration rate, can be increased. With increasing the duration of ultrasonic pretreatment from 0 to 15 min, the drying time of fresh faba beans decreased from 250 min to 150 min (p < 0.05). The Deff was calculated by Fick's second law, and it significantly increased from 0.70 × 10-9 m2 s-1 to 1.05 × 10-9 m2 s-1 when the sonication duration was extended from 0 to 15 min (p < 0.05). The Page model best fitted the drying kinetic of fresh faba beans with a coefficient of determination (r) > 0.9968, and the sum of squared error (SSE) and root mean squared error (RMSE) were also closer to zero compared to other models. The rehydration ratio of dried faba beans (after cooking) significantly increased from 308.4 % to 327.1 % with the extension of processing time from 0 to 15 min (p < 0.05). The maximum and minimum crust hardness and texture firmness values were for the untreated and sonicated samples for 15 min, respectively. The sonication increased the sensory acceptance of the cooked faba beans and the highest appearance, odor, texture, flavor, and overall acceptance were for the 10 min sonicated faba beans.