Biological activity in traditional Alaska pollack sikhae during low temperature fermentation

Biological activity was examined on Alaska pollack sikhae produced with 4 treatments (by irradiating at 5 or 10 kGy, or by adding either 0.1 or 0.3% of chitooligosaccharide), compared with control (2‐step fermentation only) during fermentation at ‐2°C. The extracts (500 ppm level) of sikhae had antimicrobial activities against 4 different strains of food poisoning bacteria such as Staphy. aureus, B. subtilis, B. cereus, and L. monocytogenes. Antioxidative activity (EDA50, 11.55 mg/mL) in control group increased with time up to 60 days of fermentation but decreased thereafter, while those levels in other products were kept within 10.60–18.30 mg/mL ranges during fermentation. Inhibitory activity of angiotensin‐I converting enzyme (ACE) (IC50, 1.51–2.89 mg/mL) in all products was observed during fermentation except at 0 day. Inhibitory activity of xanthine oxidase (XO) (IC50, 0.65–0.87 mg/mL) in all products also increased with time up to 30 days of fermentation. Without irradiating or adding of chitooligosaccharide, Alaska pollack sikhae showing biological activities was enough by 2‐step fermentation and storage at ‐2°C only.