Germinated wheat: Phytochemical composition and mixing characteristics

Authors: Ohm, Jae-Bom; LEE, CHIWON - North Dakota State University; CHO, KYONGSHIN - North Dakota State University

Submitted to: Cereal Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/4/2016
Publication Date: 11/1/2016
Publication URL: http://handle.nal.usda.gov/10113/5581428
Citation: Ohm, J.-B., Lee, C.W., Cho, K. 2016. Germinated wheat: Phytochemical composition and mixing characteristics. Cereal Chemistry. 93(6):612-617.

Interpretive Summary: Germinated grain recently attracts interest due to its beneficial effect on human health. Germinated wheat flour samples of a hard red wheat cultivar were prepared after germination of three and five days and investigated for phytochemical composition, mixing quality, and effect on human cancer cells. Germination decreased molecular size of proteins in wheat and caused degradation of bread-making quality. As proteins were degraded by germination, great surge of free amino acids was observed for germinated wheat samples. Free amino acids such as glutamine, serine, threonine, and tyrosine which did not appear in non-germinated sample were found in germinated wheat. Gamma-amino butyric acid that is known to affect several neurological disorders, relieving anxiety in humans was also detected in germinated wheat. Germinated wheat had significantly higher total phenolic compound concentration and antioxidant activity than non-germinated wheat. The concentrations of those components increased as wheat seeds were left to germinate longer. We also tested influence of a germinated wheat flour sample on human breast cancer cell growth. Specifically, the flour sample prepared after germination of three days was tested against two isolated lines of human breast cancer cells and found effective in suppressing growth of the cancer cells. These results indicated that germinated wheat flour could be used as a supplementary food to benefit human health although it might have poor bread-making property.

Technical Abstract: Germinated grain recently attracts interest due to its beneficial effect on human health. In this research, whole wheat flour samples obtained after three days and five days of germination were analyzed for biochemical components, mixing quality, and effects on human breast cancer cells. Germination caused severe initial degradation of SDS insoluble polymeric proteins, which was accompanied by deterioration of mixing quality. Proteolysis during germination resulted in a significant increase of free amino acid concentration. Specifically, free asparagine which is a precursor to form carcinogenic acrylamide during high temperature processing increased significantly after five days of germination. Gamma-aminobutyric acid, of which concentration was undetectable in non-germinated grain, also increased substantially during germination. Levels of phenolic concentration and antioxidant activity were elevated exponentially during germination and high correlation appeared between them. In an in-vitro study, germinated wheat flour (GWF) showed an inhibitory effect on proliferation of two human breast cancer cell lines, the estrogen-receptor-positive and estrogen- receptor-negative cancer cell lines. Flow cytometry indicated that GWF induced up-regulation of apoptosis for the cancer cell lines. These findings indicate that GWF is a valuable ingredient for functional foods with increased levels of the phytochemical components that are beneficial to human health and digestion.