Effect of Infrared and Conventional Drying Methods on Physicochemical Characteristics of Stored White Rice

Abstract

26The objective of this study was to investigate the effect of infrared (IR) drying 27 followed by tempering and natural cooling on the change of physicochemical 28 characteristics of white rice during up to 10 months of storage. The physicochemical 29 characteristics of IR dried rice were also compared with that of conventionally dried rice. 30It took only 58 s to heat the rough rice from room temperature to 60 °C using IR and 2.17 31 percentage points of moisture was removed. After 4 months of storage, the increments of 32 yellowness index, water uptake and volume expansion ratio of the rice dried with IR were 33 73.8%, 63.9% and 55.3% of that dried with ambient air drying methods, respectively. IR 34 drying slightly decreased the gelatinization temperature, enthalpy and viscosities, reduced 35 the changes in microstructure and maintained cooking characteristics during storage. 36 Therefore, IR drying process is recommended to maintain the quality of white rice during 37 storage. 38 39

Infrared radiation drying of parboiled rice: Influence of temperature and grain bed depth in quality aspects

“…The protein complexation limits the leaching of solids during cooking and increases hardness after cooking (Derycke et al, ). These conditions combined undesired changes in milling and color parameters along with increased grain hardness, which is also an undesired sensory attribute (Ding, Khir, Pan, Zhang, et al, ).…”

“…The protein complexation limits the leaching of solids during cooking and increases hardness after cooking (Derycke et al, 2005). These conditions combined undesired changes in milling and color parameters along with increased grain hardness, which is also an undesired sensory attribute (Ding, Khir, Pan, Zhang, et al, 2015). Bualuang et al (2012) studied the drying of parboiled rice with IR (1,000 to 1,500 W) and hot air with a temperature range of 60 to 100 C. These authors reported an increase in the hardness of the rice grains according to the increase of the drying temperature.…”

“…The majority of the studies found in the literature with IR drying and heating treatments were carried out in medium grain rice (Bualuang et al, 2012;Das, Das, & Bal, 2004;Das, Das, & Bal, 2009;Ding, Khir, Pan, Zhang, et al, 2015;Ding, Khir, Pan, Zhao, et al, 2015;Ding et al, 2018;Khir, Pan, Salim, Hartsough, & Mohamedc, 2011;Pan et al, 2008;Wang, Khir, Pan, & Yuan, 2017) and little information is found for long grain rice (Likitrattanaporn & Noomhorm, 2011;Zhou et al, 2018).…”

Effects of infrared radiation drying and heat pump drying combined with tempering on the quality of long‐grain paddy rice

“…The taste properties of milled rice can be indicated by TPA indices. Hardness is one of the most representative sensory properties of rice; a lower hardness is important for the sensory experience of consuming rice (Ding et al, 2015). As seen in Table 1, the drying method and the intermittent ratio (d) both had significant effects on the hardness of cooked paddy rice (P < 0.05).…”

“…HP dryers are economical and efficient and have been proven to ensure product quality, especially for food and agriculture products (Goh et al, 2011). Infrared (IR) drying also provides significant advantages over conventional drying methods, including reductions in drying time and quality losses, uniform drying, an absence of solute migration in food material, a compact size of the equipment and significant energy savings (Khir et al, 2011;Ding et al, 2015).…”