Time-salinity interactions shapes flavor-precursor formation and quality evolution in naturally fermented of Phyllostachys praecox shoots

This study investigated the impact of brine salinity on acidification kinetics, quality, and flavor precursor formation during the natural fermentation of Phyllostachys praecox shoots. A time-resolved fermentation was conducted at 0 %, 1 %, 2 %, and 3 % NaCl (w/w), integrating measurements of pH, titratable acidity, color, texture, electronic nose (E-nose) responses, and untargeted LC-MS/MS metabolomic profiles. Salinities of 1–2 % NaCl accelerated acidification (pH decreased from 5.92 to 3.41–3.68 by day 3) stabilized texture, and promoted the accumulation of oxylipins, N-lactoyl amino acids, phenolic derivatives, and amino acid-derived taste precursors, as evidenced by texture analysis, E-nose profiles, and metabolomic shifts. In contrast, 3 % NaCl delayed acidification yet prolonged the metabolic remodeling window. Nitrite levels remained low in all salted groups (≤2.63 mg/kg), well below the national safety threshold. The salt-free control (0 % NaCl) showed unstable acidification, the highest nitrite peak, rapid texture loss, and a metabolome distinct from salted fermentations, indicating compromised product quality. Time-salinity interactions primarily affected amino acid degradation, glycerophospholipid remodeling, and phenylpropanoid biosynthesis, thereby shaping flavor-precursor pools and defining 1–2 % NaCl as a practical salinity window that balances processing speed, safety, and flavor development in fermented bamboo shoots. • Salinity shapes metabolite dynamics and acidification kinetics in bamboo shoot fermentation. • 1–2 % NaCl accelerates acidification (pH decreased from 5.92 to 3.41–3.68 by day 3) and enriches oxylipins, N-lactoyl amino acids, and phenolic derivatives. • 3 % NaCl slowed acidification but prolonged metabolic remodeling. • Salt-gated metabolic hubs link amino-acid, lipid, and phenylpropanoid pathways to quality outcomes. • Salinity modulates nitrite degradation and texture softening dynamics during fermentation.