The results presented indicated that the proposed cooking method is useful to control final oil content of fried carrot slices, so indirectly limiting the daily calorie intake by consumers without spectacular losses in quality attributes. © 2016 Society of Chemical Industry.

Main objective of the current study was to reduce the fat content of fried carrot slices by applying a microwave assisted drying (MAD) step before frying. The effects of MAD and deep-fat-frying conditions on moisture and oil contents, breaking force, and color parameters of predried and fried carrot slices were investigated. The results of data analysis using response surface methodology showed that there was a significant correlation between investigated responses and process variables (P 0.05). Based on the optimal conditions (12% for weight loss, 1408C for frying temperature, and 227 s for frying time), more than 18% reduction in fat content of fried carrot slices was achieved by MAD applied before frying. SEM analysis was performed to determine the relationship between fat absorption and structural changes under effects of conditions of the proposed MAD and frying. PRACTICAL APPLICATIONSDeep-fat-frying is one of the most common cooking methods for foods. There are plenty number of studies devoted to manufacturing of fried foods with reduced fat content, since concerns about high fat content rise for food manufacturers from an economic point of view and also for the consumers from the health angle. The information presented in this work will be useful in manufacturing of fried carrot slices of acceptable quality attributes by optimizing the MAD and frying processes. The result is very useful for manufacturer and consumers in considering different processing variables and responses at the same time, which have been commonly studied with single factor experiment in literature and none of them has included MAD combined frying for cooking of carrot slices in terms of fat content and quality assurance.

Oil absorption is partially associated to the initial moisture content of frying material, thus controlling the moisture level could result in decreased oil absorption during frying with accompanying changes in other physical properties. As a result, in the current study, in order to figure out the changes in moisture and oil contents of fried carrot slices, the effects of process parameters of ultrasound (U/S) assisted pre-drying was examined. As process conditions of U/S, power levels of 30%, 50%, and 70%, temperature levels of 30 and 50 °C, and time periods of 5, 10 and 15 min were studied. Additionally texture and color preferences were studied. Any reduction in oil absorption was achieved by U/S-predrying, whereas it was observed that there was an increase in brightness (L*) value of carrot slices as well as generally a decrease in a* values compared to the control group (directly deep-fat-fried 4mm-carrot slices at 160°C for 120 seconds). Effect of temperature was found to be significant over a* and L* values for all power levels. Additionally, no statistically significant change was observed for the textural properties with applied ultrasound power levels.