Enhancing the aroma of white whole sorghum flour using supercritical carbon dioxide

Abstract

Removal of undesired odor-active compounds from sorghum flour is vital for the widespread production of sorghum-based foods. This study investigated the use of supercritical carbon dioxide (SCCO2) for the extraction of volatile compounds (VCs) from white sorghum flour. The extraction temperature (33.18–66.81 °C), pressure (8.18–41.82 MPa), and time (1.32–4.68 h) were optimized for the removal of 11 VCs (decane, undecane, tetradecane, dodecane, hexanal, nonanal, hexanol, dodecanol, limonene, styrene, and butylated hydroxytoluene) from whole white sorghum flour using a central composite response surface design. The maximum VC removal (∼89%) was obtained at 60 °C and 15 MPa with 2 h extraction time. SCCO2 extraction at higher pressures (> 15 MPa) or lower temperatures (<60 °C) did not improve the VC removal. After SCCO2 treatment, water absorption index, oil absorption capacity, and swelling power increased, whereas moisture/lipid contents, water solubility index, and particle size reduced significantly (p<0.05). The lightness of the sorghum flour treated with SCCO2 increased significantly compared to untreated sorghum flour, while the yellowness decreased after SCCO2 extraction (p<0.05). Overall, this study developed a novel green approach to enhancing the aroma of sorghum flour, which has a high potential for scale-up, and generating sorghum flours with more neutral flavors for numerous food applications.

Keywords

• Supercritical carbon dioxide
• Sorghum flour
• Response surface methodology
• Volatile compounds
• Aroma
• Functional properties