Mitigation of cyanide formation in Jiangxiangxing Baijiu brewing sorghum during grain hydration: Effects of abscisic acid and γ-irradiation

Cyanide converts to carcinogenic ethyl carbamate upon reaction with ethanol in distilled spirits, raising safety concerns in using cyanogenic crops for fermentation and distillation. Thus, control of cyanide in cyanogenic sorghum-based liquors, such as baijiu, represents a scientific and industrial challenge. This study introduced a novel enzymatic–alkaline method to quantify total cyanide in sorghum used for baijiu brewing. Results showed that dhurrin is the primary source of cyanide in sorghum. Additionally, dhurrin is produced during grain hydration, as it mimics germination conditions. High levels of dhurrin were detected in intact hydrated kernels, whereas crushing limited dhurrin synthesis. Two additional interventions, abscisic acid (ABA) spraying and γ-irradiation, were evaluated to test their ability to reduce dhurrin production during sorghum hydration. Both methods reduced total cyanide levels by approximately 80%. Importantly, neither approach compromised starch structure or nutritional value. However, ABA was more effective at preserving starch crystallinity and structural stability, whereas γ-irradiation offered advantages in speed and simplicity. Graphical Abstract: • Control of sorghum hydration reduces cyanide and ethyl carbamate risk in baijiu. • Dhurrin in intact sorghum kernels is the main precursor of cyanide. • An enzymatic–alkaline headspace GC–MS method quantifies total cyanide in sorghum. • ABA spraying and γ-irradiation each reduce total cyanide by about 80%. • Both treatments preserve starch structure and show promise for industrial use.