Effects of Germination Process and Drying Temperature on Gamma-Aminobutyric Acid (GABA) and Starch Digestibility of Germinated Brown Rice

Abstract

In this work, germination method, germination time, and drying temperature were investigated for their effects on gamma-aminobutyric acid (GABA) and starch digestibility. The germination method and germination time influenced the GABA and dietary fiber contents as well as starch and glucose, but both factors did not provide a faster hydrolysis of starch for germinated brown rice because of the dietary fiber. When the germinated samples were dried by a hot-air fluidized bed dryer at 130 or 150°C, the GABA content was not decreased and the amylose-lipid complexes occurred. Dissociation temperature of the complexes was given in a range of 100–117°C, which was lower than that of complexes in the non-germinated paddy. Thus, the amylose-lipid complexes in the germinated samples obtained at high temperature lost some crystalline structure when cooked by the boiling method. The corresponding rate of starch hydrolysis or glycemic index of the germinated samples changed insignificantly from that of the shade-dried germinated sample or non-germinated brown rice which was dried in shade.

Keywords:

• Fluidized-bed drying
• GABA rice
• Germination
• Glycemic index

Notes

Different superscripts in the same column mean that the mean values are significantly different at p < 0.05.

Different superscripts in the same column mean that the mean values are significantly different at p < 0.05.

ND = not detected.

ND: not detected, N/A: not available.

Different superscripts in the same column mean that the mean values are significantly different at p < 0.05.