Influence of ultrasound and osmotic dehydration pretreatments on drying and quality properties of persimmon fruit.


Munzur University, Faculty of Engineering, Food Engineering Department, Tunceli, Turkey. Electronic address: [Email]


In this study, the effect of the ultrasound and osmotic dehydration pretreatments before the convective drying of the persimmon fruit was assessed via their drying behavior and quality properties. Ultrasound-assisted osmotic dehydration (30 °C, 45 °Brix) was performed at 35 kHz for 10, 20, and 30 min. Afterward, samples were placed first in 45 then in 70 °Brix sucrose solutions; the solutions were next shaken at 100 rpm. The control group without ultrasound treatment dehydrated osmotically. The samples were dried in a tray drier at a temperature of 60 °C and an air velocity of 1.5 m/s. Ultrasound-assisted osmotic drying treatments increased water loss and sugar gain; moreover, the osmotic dehydration time was shorter than in the untreated group. The ultrasound-assisted osmotic dehydration demonstrated a significantly decreased drying time, increased drying rates, and a 21% increase in effective water diffusivity by 30 min. The ultrasound pretreated osmotic dehydration prior to hot air-drying decreased the total required drying time. The ultrasound-assisted osmotic dehydration affected the rehydration rate and total phenolic content significantly and there was no significant difference between the color change (ΔE, ΔC, and Hue°) of the ultrasound treatment (30 min) group and the untreated group.


Drying,Osmotic dehydration,Persimmon fruit,Quality,Ultrasound pretreatment,

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