Physicochemical and Structural Properties of Freeze-Dried Lacto-Fermented Peach Snacks

The snack market is shifting toward healthier options, leading to a growing interest in organic snacks. Dried fruits are particularly popular due to their long shelf life and convenience. Freeze-drying helps preserve both the taste and nutrients of these fruits. Among them, peaches are noteworthy for their antioxidant and anti-inflammatory properties. The research assessed the impact of lactic fermentation using Lactiplantibacillus plantarum (P_LP) and Fructilactobacillus fructivorans (P_FF), followed by freeze-drying, on the physicochemical, structural, and sensory properties of peach slices. Fermentation increased acidity (>22 mg/kg), decreased sugars (up to 43.5%), and raised salt content (to ~0.5%), effectively altering the fruit’s chemical profile. Dry matter content decreased by 6.0% (P_LP) and 7.2% (P_FF), while water activity remained low (0.13–0.15). Color parameters changed notably: L* values decreased, and a* values increased, with total color differences (ΔE) exceeding 15. Structural changes included higher porosity (to 71.4% in P_LP and 72.8% in P_FF) and reduced hardness from 50.1 N (control) to 35.7 N (P_LP) and 28.2 N (P_FF), which may benefit processing. Water sorption isotherms suggested improved stability under elevated humidity. However, sensory analysis showed lower consumer acceptance of the fermented samples due to reduced sweetness, crunchiness, and overall palatability, along with undesirable flavors from F. fructivorans. While lactic fermentation holds the potential for creating fruit snacks with better functional value, further optimization is needed to enhance sensory appeal and market potential.