B. K. Kumbhar

Optimization of Fluidized Bed Drying Process of Green Peas Using Response Surface Methodology

The fluidized bed drying process of green peas was optimized using the response surface methodology for the process variables: drying air temperature (60–100°C), tempering time (0–60 min), pretreatment, and mass per unit area (6.3–9.5 g/cm2). The green peas were pretreated by pricking, hot water blanching, or chemical blanching. Product quality parameters such as rehydration ratio, color, texture, and appearance were determined and analyzed. Second-order polynomial equations, containing all the process variables, were used to model the measured process and product qualities. Rehydration ratio was influenced mostly by pretreatment followed by tempering time, temperature, and mass per unit area. Pretreatment and mass per unit area significantly affected color and texture. Higher levels of temperature and lower levels of tempering time and mass per unit area increased the rehydration ratio. The optimum process conditions were derived by using the contour plots on the rehydration ratio and sensory scores generated by the second-order polynomials. Optimum conditions of 79.4°C drying air temperature, 35.8-min tempering time, pretreatment of the once pricked peas with chemical blanching in a solution of 2.5% NaCl and 0.1% NaHCO3, and mass per unit area of 6.8 g/cm2 were recommended for the fluidized bed drying of green peas. At these conditions the rehydration ratio was 3.49.

Textural profile analysis of paneer dried with low pressure superheated steam

Paneer is highly perishable at ambient conditions and its shelf-life is very low. At high temperature, it develops a sour smell, and bitter taste. Drying can be one of the methods to increase shelf-life. Drying experiments were conducted at 62, 72 and 82°C and 10, 14 and 18 kPa absolute pressures with superheated steam. The product quality was judged by instrumental texture profile. Hardness, adhesiveness, gumminess and chewiness increased with increase in temperature and decreased with increase in pressure. Springiness and cohesiveness, however, decreased with increase in temperature and pressure. Textural properties of fresh and rehydrated paneer indicated large variation on hardness, adhesiveness and resilience whereas springiness, cohesiveness and chewiness had marginal variation as compared to fresh paneer.

Mass transfer kinetics model of osmotic dehydration of carrots

A model based on mass balance was developed and validated to predict the mass transfer kinetics during osmotic dehydration of carrot slices. Carrot slices, 5 mm thick, were dipped in solutions of salt (three different concentrations: 5%, 10%, and 15%) along with 50°B sugar and 0.1% sodium metabisulphite at 30°C temperature for 10, 20, 30, 40, 50, 60, 90, 120, 150, and 180 min. A sample to solution ratio of 1:5 and a constant agitation of 150 rpm were used. The moisture loss from and solids gain by carrots increased non-linearly with the duration of osmosis at all salt concentrations, and both were higher in the initial period of osmosis than the later period. Further, both increased with increasing salt concentration. The proposed model was able to predict osmosis mass transfer data up to the equilibrium point using data for relatively short period of osmosis.

Colour Characteristics and Overall Acceptability of Fibre Enriched Biscuits: A Response Surface Approach

The effects of baking time and baking temperature on colour (L*a*b*), colour difference (?E) and overall acceptability (OAA) of biscuits made from different blends of refined wheat flour (RWF) and millet was investigated using a three factor central composite rotatable design (CCRD). ANOVA for response surface model demonstrated that the data could fit the three polynomial models adequately. All the models were found to be statistically sound to predict the responses. The colour values and OAA were significantly influenced by the processing variables at different levels of significance. The blend ratio, percent RWF, was found to have an overwhelming effect on all the colour values and OAA. It was predicted that the optimum product colour characteristics in terms of L*(29.45), a*(-105.01), b*(-92.7), ?E (11.9) and OAA (6.3) were obtained at blend ratio, 70 percent RWF; baking time, 5.6 min; and baking temperature, 171.7°C.