Impact of high hydrostatic pressure and thermal processing on the quality of kimchi juice

Kimchi, a traditional Korean side dish comprising fermented vegetables, has gained increasing attention owing to its flavor and health benefits. However, the effect of preservation methods on the quality parameters of kimchi juice remains unknown. This study aimed to assess the impact of high hydrostatic pressure (HHP) and thermal processing (TP) on kimchi juice quality, focusing on microbial viability, pH, color, bioactive compounds, and volatile profiles. Both HHP and TP treatments effectively reduced microbial counts, with TP at 100°C achieving complete bacterial inhibition. Minimal pH changes were observed; however, TP led to a substantial reduction in lightness (L*), causing the juice to appear darker. Antioxidant analysis revealed a significant reduction in ferric-reducing antioxidant power and phenolic content following TP, while HHP retained these bioactive compounds more effectively. Additionally, HHP preserved the essential sulfur-containing volatile compounds, whereas TP caused a marked decline in these flavor components. Overall, this study demonstrates that HHP is more effective than TP in maintaining the sensory and nutritional qualities of kimchi juice while ensuring microbial safety. Our findings support HHP as a promising preservation method for industrial applications of kimchi juice, with potential for broader application across other fermented products.