ORCID

Abstract

The present study investigated the effect of steeping solution containing a thiol- and amino-functionalization of hydrolyzed brewers' spent yeast hydrolysate (HBSY) on the enzymatic and nutritional profile of germinated barley. Thiol- and amino-functionalized HBSY (GSN) resulted in significantly elevated activities of α-amylase (35.5 U/g), β-amylase (41.2 U/g), protease (29.9 U/g), cysteine protease (12.6 U/g), lipase (4.8 U/g), and phytase (3.4 U/g) compared to control samples germinated in water (GW) (α-amylase: 23.5 U/g; β-amylase: 12.4 U/g; protease: 8.4 U/g; cysteine protease: 2.6 U/g; lipase: 2.1 U/g; phytase: 1.06 U/g). Higher cysteine protease activity was associated with increased β-amylase activity, consistent with a higher maltose concentration in GSN (2.92 g/L) than in the control (1.81 g/L). Comparative electrophoretic patterns and the branch-chain length distribution of amylopectin indicated that GSN is reflected more strongly in protease- and amylase-mediated hydrolysis, respectively. Steeping with GSN during a 96-h germination period produced nearly twice the γ-aminobutyric acid (GABA) content (2381.30 μg/g) compared with water steeping (1132.00 μg/g). Fortification with GSN resulted in significantly elevated levels of folic acid, niacin, riboflavin, γ-tocopherol, and minerals.

Keywords

Amination, Barley germination, Brewer's spent yeast, Nutritional profile, Thiolation, Γ-Aminobutyric

Publication Date

2026-01-01

Publication Title

Food Chemistry: X

Volume

36

Deposit Date

2026-05-13

Funding

Authors express their appreciation to Sarah Kӧnig, Elham Noroozian and Dr. Natalia Svedlund for their kind assistance. The authors thank Georg Forster Research Fellowship for providing funds.

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