Modelling of electrohydrodynamic drying kinetics for carrot at varying electrode distance.

This study was conducted to analyze the drying kinetics of carrot slices in electrohydrodynamic (EHD) dryer at different electrode distances. Higher drying rate was observed up to about 70% (w.b.) moisture content, which has been noted as first falling rate period. The time taken to dry the carrot slices to the safe moisture content of 2.5% (wb) was about 9, 8.5 and 6.8 h at a distance of 7, 5 and 3 cm respectively. Five empirical models, Page Model, Newton model, Henderson and Pabis model, logarithmic model and two term model, were tested for the best fit. The drying rate constant (k) increased in all the empirical models as the distance between the electrode decreased. For 7 cm electrode distance, the Page model fitted best whereas the Logarithmic model was found to be the best fit for 5 and 3 cm electrode distance. There is no significant difference found in shrinkage of dried carrot slices at different electrode distance. Rehydration ratio increased as the distance between electrodes decreased. Moisture diffusivity increased as the distance between the electrode decreased. No significant difference in colour, ß-carotene and sensory attributes were found between fresh and EHD dried carrot slices at 3 cm electrode distance. Specific energy consumption was significantly influenced by the electrode distance.

Defatted flaxseed meal incorporated corn-rice flour blend based extruded product by response surface methodology.

Considering the evidence of flaxseed and its defatted flaxseed meal (DFM) for human health benefits, response surface methodology (RSM) based on three level four factor central composite rotatable design (CCRD) was employed for the development of DFM incorporated corn - rice flour blend based extruded snack. The effect of DFM fortification (7.5-20 %), moisture content of feed (14-20 %, wb), extruder barrel temperature (115-135 °C) and screw speed (300-330 RPM) on expansion ratio (ER), breaking strength (BS), overall acceptability (OAA) score and water solubility index (WSI) of extrudates were investigated using central composite rotatable design (CCRD). Significant regression models explained the effect of considered variables on all responses. DFM incorporation level was found to be most significant independent variable affecting on extrudates characteristics followed by extruder barrel temperature and then screw rpm. Feed moisture content did not affect extrudates characteristics. As DFM level increased (7.5 % to 20 %), ER and OAA value decreased. However, BS and WSI values were found to increase with increase in DFM level. Based on the defined criteria for numerical optimization, the combination for the production of DFM incorporated extruded snack with desired sensory attributes was achieved by incorporating 10 % DFM (replacing rice flour in flour blend) and by keeping 20 % moisture content, 312 screw rpm and 125 °C barrel temperature.