Bio macromolecular stabilization of Lacticaseibacillus paracasei and Lactiplantibacillus plantarum : A comparative study of cryoprotection, shelf stability, and metabolic recovery

This research investigated the preservation and functionality of two probiotic strains Lacticaseibacillus paracasei ( L . paracasei ) and Lactiplantibacillus plantarum ( L . plantarum ), subjected to freeze‐drying with five cryoprotectants (skim milk powder, sorbitol, inulin, sucrose, and mannitol). Strains were identified via 16S rRNA sequencing, and their survival and storage stability were assessed at −20°C and 4°C for 56 days. Skim milk powder conferred the highest post‐lyophilization viability for L . paracasei (97.54%), whereas sorbitol was most effective for L . plantarum (95.82%). Both strains retained over 80% viability after simulated gastrointestinal digestion, confirming their digestive resilience. Nutritional analysis (HPLC and FTIR) verified ascorbic acid retention, whereas post‐rehydration assays demonstrated robust metabolic activity, including growth (OD 600 > 1.4), lactic acid production (>1.6 g/L), and acidification to pH ∼4.0. These findings highlight the importance of strain‐specific cryoprotectants in maintaining probiotic viability and functionality, supporting their potential application in functional foods with improved shelf life and nutritional value.