Optimization of fluidized bed preconditioning for microwave puffed rice using integrated artificial neural network and genetic algorithm approach

Abstract

Preconditioning of rice is heat curing of salt infused moist parboiled rice prior to microwave puffing process. The sudden expansion of moisture present in the interstices of the starch granules caused by microwave heating of the preconditioned rice results in highly expanded smooth‐surface puffed rice. The expansion ratio (ER) and percentage of puffing (PP) of the microwave puffed rice preconditioned under different conditions were varied between 5.16–7.51 and 84.32–93.12%, respectively. Optimum temperature, air velocity, and salt concentration for fluidized bed preconditioning obtained by using integrated artificial neural network and genetic algorithm approach were estimated to be 70°C, 2.9 m s−1, and 4%, respectively. The predicted values of ER and PP at optimum combination of independent variables were 7.5 and 92.82%, respectively. Scanning electron microscopy revealed that preconditioning transformed the compact polyhedral structure of starch granules to fused mass with interlocking and overlapping structure. Practical applications Preconditioning with fluidized bed drying of salt infused rice would be feasible as a substitute with traditional direct heat curing process with saving of time, labor, and energy. This study would enhance understanding of the effects of preconditioning process on the mechanisms of puffing. Artificial neural network and genetic algorithm integrated optimization can be applied for prediction and control of mechanization of the preconditioning and puffing process. Preconditioned rice can be puffed directly by using a microwave oven that will make the puffing process convenient to consumers.

Puffed rice: A materialistic understanding of rice puffing and its associated changes in physicochemical and nutritional characteristics

“…(2012) obtained a hardness (60 N) at a moisture content of 10.5-11% (Mohapatra et al, 2012), which is in line with the results of Dash and Das (2019a). Considerable alterations in hardness had been observed both after the parboiling and puffing process.…”

“…It decreases with an increase in moisture content (Dash & Das, 2019a;Siriamornpun et al, 2008). To establish this, researchers had made some attempts and ended up with seemingly contradictory results like a grain with moisture content of 10.5% had a hardness of 60 N (Dash & Das, 2019a) while a 12.5% moisture containing rice showed a grain having hardness of 86-160 N (Joshi et al, 2014). This contradiction has possibly risen due to the differences in rice variety that has been used in the mentioned study.…”

“…Mahanti, Chakraborty, and Babu (2019) performed pressure parboiling with cold soaking and subsequent steaming and drying. In a recent study, Dash and Das (2019a) optimized the parboiled rice salt preconditioning process using a fluidized bed dryer and used microwave puffing. Maximum expansion of the grain (7.5) was achieved at 850 W microwave power (Dash & Das, 2019a • Silica contamination from sand (for sand-bed puffing) (Chandrasekhar & Chattopadhyay, 1991) Hot sand-bed (200-300 C, 10-11 s)…”

“…Soaking at 70 C, steaming at 1 atm, drying and milling (Joshi et al, 2014) Hot • Costly equipment (Dash & Das, 2019a) et al, 2019) each involving a separate set of processing equipment.…”

Modeling and optimization of microwave puffing of rice using artificial neural network and genetic algorithm

“…Traditionally puffing of cereal grains was done by sand roasting method (Bhat Upadya, Bhat, Shenoy, & Salimath, 2010;Dutta & Mahanta, 2014;Dutta, Mahanta, Singh, Das, & Rahman, 2016), where the sand was heated by husk or wood-chipped fire furnace. Traditional methods of puffing create severe environmental hazards along with a risk of adherence of sand with the rice (Chinnaswamy & Bhattacharya, 1983;Hoke, Houšová, & Houška, 2005). Additionally, puffing can be achieved using specific techniques such as hot oil frying (Hoke et al, 2005), gun puffing (Hoke et al, 2005), and the hot air puffing method (Nath, Chattopadhyay, & Majumdar, 2007;Sweley, Rose, & Jackson, 2013;Ushakumari, Rastogi, & Malleshi, 2007;Virot & Ponomarenko, 2015;Zapotoczny, Markowski, Majewska, Ratajski, & Konopko, 2006).…”