Shelf Life Estimation of Preconditioned Brown or Unpolished Rice (Oryza sativa) and its Storage Effect in Microwave Puffing

Microwave puffing of prepacked preconditioned brown rice can provide a hygienic, fresh, and nutritious puffed rice as compared to conventional puffed rice. Pre-puffing conditioning (salt infusion) makes brown rice more hygroscopic; therefore, long storage of preconditioned brown rice reduces the puffing quality. This study was conducted to estimate the shelf life of prepacked conditioned brown rice in a wrapped paper envelope with low-density polythene for its microwave puffing. Preconditioning of brown rice was carried out at optimized conditions, i.e., parboiling pressure (303 kPa) and time (14 min), preconditioning temperature (76.7°C), salt content (3.5% (w/w)), and pre-puffing moisture content (11.6% (wb)). These packets were stored at 38±2°C temperature and 90% relative humidity. Moisture sorption characteristics can be well described by Henderson's model. The shelf life of preconditioned brown rice was estimated 36 days by its puffing quality characteristic and found that moisture content of preconditioned brown rice reaches 15.27% (wb).