Effect of hot air assisted infrared drying on drying characteristics and quality of rice bran pellets

Sahachart Sansak,Jiraporn Sripinyowanich Jongyingcharoen,C Hamontree

doi:10.1051/matecconf/201819203040

Sahachart Sansak, Jiraporn Sripinyowanich Jongyingcharoen + Show 1 more

Open Access

https://doi.org/10.1051/matecconf/201819203040

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Abstract

The objective of this study was to determine drying characteristics and quality of rice bran pellet subjected to hot air assisted infrared (HA-IR) drying at different levels of infrared (IR) intensity (750 – 3750 W/m2) and air temperature (40 – 80°C). The rice bran pellets were dried from 0.18 to 0.08 g water/g dry matter. The maximum drying rate (DR) and drying time were in the ranges of 0.0030 – 0.0165 g water/g dry matter·min and 8 – 54 min, respectively. Higher IR intensity and air temperature resulted in greater maximum DR and shorter drying time. The same trend was also observed for the effective moisture diffusivity (Deff) values which were between 0.3103×10-7 and 2.7603×10-7 m2/s. As compared to the commercial reference sample of dried rice bran pellets, the products of this study had higher oil content and lower FFA content. The oil content was affected by IR intensity only while the FFA content was affected both by IR intensity and air temperature. HA-IR drying could improve drying characteristics of the rice bran pellets and produce better quality of the dried products.

Highlights

Rice bran is a by-product obtained during the process of rice milling
Conventional drying method used for rice bran pellets is hot air drying, which takes long time and needs high temperature
The greater effect of the IR intensity over the air temperature was observed by Ponkham [5] for hot air assisted infrared (HA-IR) drying of ring shaped-pineapple at 1000-5000 W/m2 and 40-60 C

Summary

Introduction

Rice bran is a by-product obtained during the process of rice milling. It is 8 – 10% of the whole grain weight and generally used for rice bran oil production. In the industrial level of rice bran oil production, the rice bran is subjected to steam cooking and extruding to be rice bran pellets. During this step, enzymatic degradation is delayed and porous structure of the rice bran is formed. The pellets are high in moisture content, at risk of lipid oxidation, and unsuitable for oil extraction. The pellets must be dried prior to oil extraction. Conventional drying method used for rice bran pellets is hot air drying, which takes long time and needs high temperature

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