Chemical versus thermal anti-browning of fresh-cut potato slices: Effects on structure, water state, and physicochemical attributes under freeze–thaw stress

Fresh-cut potato slices are highly susceptible to enzymatic browning and textural degradation during freeze–thaw cycling, limiting their commercial viability. This study compared two pre-freezing anti-browning strategies (chemical immersion in 1% ascorbic acid + 0.5% CaCl₂ (AACC, 30 min) and high-humidity hot-air impingement blanching (HHAIB; 105 °C, 50% RH, 14 m s⁻¹, 4 min)) on the browning enzyme activity, physicochemical parameters, and starch structural attributes of fresh-cut potato slices with and without a single freeze–thaw cycle. HHAIB inactivated 99.6% of polyphenol oxidase activity (96.5% retained after freeze–thaw) and maintained higher lightness (L* = 77.4), lower browning index (BI = 12.1), and lower color difference (ΔE = 5.97) than non-treated (L* = 54.7; BI = 48.9; ΔE = 33.4) and AACC-treated (BI = 54.2) samples. Freeze–thaw reduced hardness by > 87% in non-treated and AACC-treated samples; HHAIB retained superior springiness (0.76), higher rehydration ratio (4.09 g g –1 DW), lower drip loss (16.1% vs. 24.5–26.1%), and the lowest malondialdehyde content (0.155 µmol kg –1 FW). HHAIB reduced the free water relaxation peak (T 23 ) from 672.60 ms (non-treated) to 145.80 ms and elevated the immobilized water fraction (A 22 = 14.00%); BL + Fr–Th retained the lowest T 23 among frozen treatments (179.45 ms). HHAIB exhibited the lowest relative crystallinity (17.97%), reflecting additive gelatinization and ice-crystal-mediated granule damage. These findings establish HHAIB blanching as a superior pre-freezing method that reduces enzymatic browning, preserves texture and water-holding capacity, and limits membrane damage in fresh-cut potato, outperforming chemical anti-browning under freeze–thaw conditions.