ABSTRACT:The main physiology and biochemistry metabolism including amino acids composition and gamma-aminobutyric acid (GABA) content of sorghum during 3-day germination period was investigated. Respiratory rate increased during germination. Protease activity, free amino acid and reducing sugar content increased with germination time. While moisture, protein, fat and starch content decreased, significantly. Meanwhile, amino acid composition redistributed and the relative content of essential amino acids increased except for leucine and valine. In addition, some nonessential amino acids content such as proline, glycine and histidine was largely enhanced by germination. GABA content increased about 3 folds after germination. Furthermore, combining tannin (the main antinutritional factor) was converted to be free and solvable. These results greatly suggest that germinated sorghum could be a functional food rich in GABA and other health-promoting nutrients.

Germination is of importance to improving nutritional attributes of cereal grains for human consumption. The effect of germination time on major nutrient compositions and functional properties of sorghum flour was investigated in this study. Grains of Butanua, a new Sudanese sorghum cultivar, were germinated for 0, 1, 2, and 3 days to analyze their chemical and functional properties. The contents of starch, protein, oil, foaming stability, bulk density, and least gelation concentration of sorghum flour decreased, whereas oil absorption capacity, foaming capacity, and emulsion capacity and stability enhanced with an increase in germination time. Improved functional properties of sorghum flour by germination of the grains not only make it useful and suitable for various food processing formulations, but also improve the food product quality. This new finding will beneficially help develop innovative technologies, design new types of functional foods, and promote both sorghum production and relevant food processing industry in the future.

This study aimed to estimate the γ‐aminobutyric acid (GABA) content and glutamate decarboxylase activity (GAD) in germinated sorghum grain as affected by different concentrations of NaCl, pyridoxal 5‐phosphate (PLP), and CaCl2. In general, the obtained results revealed that the addition of low doses of NaCl (40 mmol/L), PLP (90 mmol/L), and CaCl2 (0.5 mmol/L) to the germination culture significantly (p < .05) enhanced the GABA content and subsequently improved the GAD activity in sorghum grains. Moreover, CaCl2 played a dominant role in the extent of enzymolysis, followed by NaCl and PLP. Regarding the GABA content, the optimal concentration of the NaCl, PLP, and CaCl2 was estimated as 41.07 mmol/L, 82.62 μmol/L, and 0.40 mmol/L, respectively. Under this optimal culture medium, the maximum GABA content was 0.336 mg/g. In conclusion, the findings of this work would provide a scientific basis for the industrialized production of GABA‐enriched sorghum foods.