Rice bran-based hydrolyzed vegetable protein for modulating fermentation and sensory properties of reduced-salt kimchi

Kimchi is a traditional Korean fermented vegetable food in which salt plays important roles in fermentation, texture development, microbial stability, and flavor. Reducing salt content may therefore alter both fermentation behavior and sensory quality. This study evaluated rice bran-based hydrolyzed vegetable protein (HVP) as a flavor-modulating ingredient in reduced-salt kimchi. Five formulations were prepared: conventional kimchi containing 2.0% sea salt (CN), reduced-salt kimchi containing 1.0% sea salt (LN), and 1.0% sea salt kimchi supplemented with 0.5% HVP (LN-1), L-arginine (LN-2), or monosodium glutamate (LN-3). Samples were fermented at 20 °C for 2 days followed by 10 °C for 8 days. Sodium content, physicochemical properties, microbial populations, DPPH radical scavenging activity, free amino acid composition, and sensory characteristics were determined. Sodium content was 504.45 mg/100 g in CN and 388.14 mg/100 g in LN, while the supplemented formulations contained 324.06–335.50 mg/100 g. HVP-treated kimchi exhibited an acidification pattern closer to that of conventional kimchi than the unsupplemented reduced-salt control. Arginine and glutamic acid were the major free amino acids in HVP. Sensory evaluation showed that HVP supplementation enhanced perceived saltiness while maintaining desirable texture and overall liking. In contrast, L-arginine increased saltiness but was accompanied by greater bitterness and mushiness. These results indicate that rice bran-based HVP may help preserve the sensory characteristics of traditional kimchi under reduced-salt conditions while providing a value-added use for rice bran.