Optimization of pressure parboiling conditions and pre-conditioned moisture content of brown rice (unpolished rice) for microwave puffing and its comparison with hot sand bed puffing

Abstract

Brown rice puffing (unpolished rice) gives a more nutritious product compared to traditional puffed polished rice and reduces the cost of the product significantly, even though, the rice bran layer resists expansion during puffing. In the present study, brown rice was puffed in a microwave and hot-sand-bed after its pressure parboiling. Pressure parboiling parameters, steam pressure (196, 294, 392, 490 kPa) and steaming time (5, 10, 15 min), along with pre-conditioned moisture content (8, 10, 12 % wb) were studied and optimized for puffing characteristics (puffing percentage, expansion ratio, whiteness index, bulk density and hardness). All the experiments were carried out using a full factorial design. Statistical analysis showed there was a significant effect of processing variables on puffing characteristics. Optimized steam pressure, steaming time and pre-conditioned moisture content for microwave puffing were found to be 303.6 kPa, 14.25 min and 11.6% (wb) respectively, and for hot-sand-bed puffing to be 260.7 kPa, 15 min and 8% (wb) respectively.

A review on processes, mechanisms, and quality influencing parameters for puffing and popping of grains

“…Rapid and volumetric heating of the food by microwave can build up high steam pressure and escape from the grain vigorously (Dash & Das, 2019a) and consequently upon the grain expands. Several works on microwave popping and puffing of cereals, that is, sorghum, corn, paddy, and rice, are worth mentioning here (Joshi, Mohapatra, Joshi, & Sutar, 2014; Maisont & Narkrugsa, 2010; Mishra, Joshi, Mohapatra, & Babu, 2015; Mom et al, 2020; Singh & Singh, 1999; Swarnakar et al, 2020). Microwavable ready‐to‐eat foods are becoming popular because of their convenience, cost, and availability in retail markets (Lin & Anantheswaran, 1988; Singh & Singh, 1999).…”

“…They soaked brown or unpolished rice and cooked this soaked brown rice for 15 min at a steam pressure of 103 kPa. Recently, attention has been given to puffing brown again (Mir, Bosco, Shah, & Mir, 2016; Mir, Bosco, Shah, Mir, & Sunooj, 2016; Swarnakar et al, 2019, 2020).…”

“…Puffing and popping whole grains with bran provides a good option for preserving a vital component (dietary fiber) along with minerals and vitamins in it (Mir, Bosco, Shah, & Mir, 2016; Puangjinda et al, 2016). Therefore, a puffed or popped product with bran is a better nutritious item than the product obtained with polished grains (Swarnakar et al, 2019, 2020).…”

“…The RF heating showed an insignificant effect on popping. In recent years, microwave heating has been studied in the production of expanded cereals in a wide range of cereal products such as rice (Mohapatra & Das, 2011; Mom et al, 2020; Swarnakar et al, 2020), corn (An et al, 2020; Singh & Singh, 1999), sorghum (Mishra, Joshi, Mohapatra, & Babu, 2015) and many more, their performance evaluations, product qualities, and theoretical modeling and simulations have been carried out (Gulati & Datta, 2016; Mohapatra, 2010). This article gives insight into the development of popping and puffing processes, mechanisms, and processing parameters responsible for the quality of expanded grain products in different methods through reported studies.…”

Antioxidants Effect of Two Aminomethyl Derivatives of 2-Methoxyphenol on Thermal and Storage Oxidative Stability of Coconut Oil

“…35 Swarnakar et al, 2020 stated that an increase in the moisture content of rice from 8% to 12% decreased the expansion ratio on puffing. 36 In case moisture content is high, high temperature is essential for puffing to cause more expansion as inferred from the positive coefficient of interaction term AC. As the salt concentration increased, expansion ratio decreased (Fig.…”