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By changing consumers' tendency to use low-fat healthy food products, reducing oil content in fried foods by maintaining sensory quality is inevitable. In this study, ultrasound pretreatment at two frequencies of 20 and 40 kHz for 15 minutes as well as osmotic dehydration pretreatment using 2 and 4% salt solution concentration for 3 hours applied on the potato pieces and then deep-fat frying was performed at 150, 170 and 190°C for 60, 120, 180 and 240 seconds. The effect of the pretreatments on oil uptake and sensory characteristics were analyzed. To optimize and improve process equipment and frying conditions, oil uptake in potato pieces pretreated with ultrasound and osmotic dehydration was also investigated. Oil uptake in the fried potato pieces was significantly decreased (P<0.05) using osmotic dehydration pretreatment. The use of ultrasound together with osmotic dehydration, led to further reduction in oil uptake compared to the other samples. Proposed experimental models in this study fitted well with experimental data. In addition, osmotic dehydration and its combination with ultrasound pretreatment improved sensory characteristics of the fried potato slices. [ABSTRACT FROM AUTHOR]

The effect of carboxymethyl cellulose (CMC) coating on the mass exchanges during the osmotic dehydration of apples and its effect on the quality of final product were studied. Coating semi-rings of apple with CMC solution (1%) was found to prevent solute uptake and to reduce salt diffusion coefficient from 4.35 × 10-10 m²/s to 2.86 × 10-10 m²/s. However, coating did not significantly affect the diffusivity of water. The effective diffusivity of salt and consequently solids gain were found to be depended on the concentration of CMC solution in the range of 0-1%. Increasing the concentration of CMC further from 1% had no effect on the mass exchanges during the osmotic process. Maximum performance ratio, defined as water loss/solids gain, and the lowest solids diffusion was observed for coated samples (with 1% CMC solution) treated with an osmotic solution containing glucose syrup (50%) and NaCl (2%). [ABSTRACT FROM AUTHOR]