Traditional Food of India
2.5.Popped rice
Popped rice is a ready-to-eat product obtained from the sudden expansion of paddy. The traditional product is popular in several places in India. Other names of popped rice are khoi and aralu. The product is cost-effective and possesses a long shelf-life of 6 months or higher. Like popcorn, the extent of volumetric expansion may cross ten times.
Popped rice is bright white in colour and possesses a soft and floppy texture that can melt in the mouth (Figure 2.5.1). Popped rice is also used as a base material to prepare other traditional products like popped rice bars/cakes/balls/crispies wherein a binder like sugar/jaggery (unrefined dried cane sugar juice) solution is often employed. Further, hot concentrated sugar/jaggery is used to soak popped rice for a short duration to develop non-sticky individual pieces of sweet popped rice which is locally called murki (Figure 2.5.2). Rice balls prepared with sugar/jaggery-soaked popped rice are called khoichur and moa (Figure 2.5.3). The latter products are available during the winter season when jhola gur or nolen gur is obtained as syrup from date palm trees followed by heat concentration.
Raw materials
The starting material for producing popped rice is rough rice or paddy.
Method of preparation
After partial soaking of paddy to attain a moisture content of about 15%, the semi-wet paddy is equilibrated for a short time followed by sand roasting (Figure 2.5.4). The inedible husk and sand are finally separated by sieving and rubbing in the next step. Caution is required for the complete removal of inedible husk from popped rice. The added moisture can generate enough steam during the roasting process. The outer husk acts as a barrier for holding the generated steam before popping. Finally, the steam pressure raises enough to suddenly crack open the husk; the gelatinisation of starch also helps expansion.
Technical data
- The process and the extent of expansion depend on the variety of paddy, moisture content at the time of popping, the starch content of the grain, and the time-temperature combination employed for popping.
- A limitation of this process is the presence of un-popped grains in addition to being a batch process. High amylose paddy variety (IR-36 containing 26.7% amylose and 8.1% protein) was sprinkled with water followed by partial drying and equilibration to have a moisture content of 14-15%. Microwave treatment was provided to obtain popped rice.
- The compact structure of the grain sample is important to withstand the pressure before undergoing a sudden expansion. The time of heating was indicated to be a more important factor on the extent of popping compared to the power level of the microwave. The maximum popping percentage of 64% was obtained at a grain moisture content of 14% and an energy level of 80 kJ.
Machinery
Soaking, mixing, and sieving units, and a sand roasting facility and packaging machines are needed.
Requirements
- Identifying the suitable varieties of paddy for preparing popped grains is needed.
- A continuous process may be developed where the extent of popped grains is close to 100%.
- Standardisation of the processes to prepare ready-to-eat popped rice-based products.
Further reading
Bhattacharya, K.R. and Ali, S.Z. (2015). An introduction to rice-grain technology. Woodhead Publishing India Pvt. Ltd (CRC Press), New Delhi, India, pp 186-188.
Bhattacharya, S. (2022). Snack foods: Processing and Technology. Academic Press (Elsevier), London, UK.
Swarnakara, A.K., Kalpana Devi, M. and Das, S. K. (2014). Popping characteristics of paddy using microwave energy and optimization of process parameters. International Journal of Food Studies 3, 45–59.
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