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Hot air puffing is the simplest, hazard- and contamination-free, and quickest method, wherein grains are suddenly exposed to a high temperature short time (HTST) process to get puffed. In this study, the continuous hot air puffing system was developed, comprising of grain feeder, heating chamber, puffing chamber, cyclone separator, and recirculation pipe. The experiments were conducted using Central Composite Rotatable Design (CCRD), on pre-processed rice (cv. MTU 1010), with one pre-heating pass of 11.50 s at 150 °C. The results showed that the puffed rice can be produced optimally at a pre-fixed whirling air velocity of 4.75 (± 0.25) m/s, puffing air temperature of 260 °C and with a feed rate of 6500 g/h, resulting in final moisture content (% db), expansion ratio, puffing percentage (%), whiteness index, hardness (kg) and crispness (+ve peaks) as 3.71, 5.68, 95.87, 69.82, 32.12 and 89.81, respectively. Further study on increased time of preheating upto 46 s (4 passes) at 150 °C keeping all other puffing parameters unchanged, showed that final moisture content (% db), expansion ratio, puffing percentage (%), and whiteness index were further improved like final moisture content reduced upto 2.68% db and expansion ratio, puffing percentage, whiteness index increased upto 7.35, 99.58% and 87.76, respectively. Thus, the rice puffing using a continuous hot air puffing system can be accomplished using 4 pre-heating passes (accumulative retention heating time of 46 s) at 150 °C, puffed using a hot air puffing system with whirling velocity of 4.75 m/s at a puffing temperature and feed rate of 260 °C and 6500 g/h. [ABSTRACT FROM AUTHOR]

The thermodynamic parameters (▵ G°, ▵H° and ▵S°) for adsorption of acrylic acid on CaO2 nanoparticle were estimated in the temperature range of 300.15 - 313.15 K, which helps to evaluate the feasibility of adsorption process, nature of adsorption process and affinity of adsorbent toward solute molecule. A dynamic adsorption study in a fixed-bed column was performed using CaO2 nanoparticle for the recovery of acrylic acid from aqueous stream. The breakthrough curves of adsorption system were obtained for different process variables, such as initial acrylic acid concentration (2882-7206 mg L-1), flow rate (5-9 mL min-1) and bed height (10-20 cm). The bed-depth service time model, Thomas model, Yoon-Nelson model and deactivation kinetic model were applied to the experimental data to predict the column performance. The data were in good agreement with the deactivation kinetic model. The presented results may be useful for the design of adsorption system using nanoparticles, which can be further extended to other systems. [ABSTRACT FROM AUTHOR]