Effect of Glycerol Pretreatment on the Recovery of Antioxidant from Rice Husk

Chong, Wan Sin (2018) Effect of Glycerol Pretreatment on the Recovery of Antioxidant from Rice Husk. Final Year Project (Bachelor), Tunku Abdul Rahman University College.

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Abstract

Rice husk is a type of residual agricultural biomass generate from rice milling process. This study was carried out to investigate the effect of different pretreatment methods on the efficiency of antioxidant extraction from rice husk and to determine chemical and antioxidant properties of rice husk extract. Initially, the rice husk was pretreated with 100 mL of aqueous glycerol, acidified aqueous glycerol and alkali aqueous glycerol respectively at 70ᴼC, 105ᴼC and 130ᴼC for 1 hour. The pretreated rice husk was separated from the liquor. Total phenolic compound (TPC) and antioxidant activity of the liquor were determined, followed by lignin removal. The results highlighted that liquor of the acidified aqueous glycerol pretreatment at 130ᴼC had the highest TPC (71.533 ± 0.153 mg/g RH) prior to lignin removal. The acidified aqueous glycerol pretreatment at 130ᴼC was further investigated 2 and 3 hour. The results obtained revealed that the 2- and 3-hour pretreatment had lower TPC (24.167 ± 0.289 mg/g RH and 14.867 ± 0.153 mg/g RH for 2- and 3-hours, respectively) than the 1-hour pretreatment. Therefore, in order to facilitate high TPC extraction, acidified aqueos glycerol pretreatment at 130oC for 1 hour has been selected as the best pretreatment method for rice husk in this study. Moreover, SEM analysis had shown that the lignin treated by acidified aqueous glycerol at 130ᴼC stick back to the surface of rice husk. This proved that the acidified aqueous glycerol had the highest TPC compared with other pretreatment methods.