Effect of Soaking and Gaseous Phase Sprout Processing on The GABA Content of Pre-Germinated Brown Rice

Abstract

‘Pre-germinated brown rice’ soaking in water at constant temperature begins to sprout to about 0.5 ~1mm in length. Such sprouting increases the .-aminobutyric acid (GABA) content in brown rice. GABA reportedly has several physiological functions, such as hypotensive effects, diuretic effects, and tranquilizer effects. In this research, the effect of soaking and sprout processing method on the GABA content in brown rice that has a large germ (e.g., Haiminori rice) was studied to establish a processing method that can be used to accumulate high concentrations of GABA. Brown rice was soaked in 35 . water for 0.5, 1, 2, 3, 4, and 5 hours. Gaseous phase sprout processing was then done at the same temperature until the total time (soaking and sprout processing) was 24 hours, Moisture content and the amount of two types of free amino acids (GABA and glutamic acid) were measured. GABA concentration was the highest in the sample soaked for 3 hours and processed for 21 hours. Therefore, change in free amino acid content after 3-hour soaking and sprout processing time was studied, The highest GABA concentration (42.2mg /100g) occurred after 22 hours of processing. This concentration was higher than that for samples that only underwent soaking (37.6mg / 100g).