In the present work, methanolic extracts from thyme and dittany plants were prepared and characterized in terms of their polyphenolic content through analytical and spectrophotometric techniques. Rosmarinic acid, thymol and carvacrol were found to be the main components of the extracts, which were further biologically assessed for their antioxidant, anti-tyrosinase, anti-lipase and antibacterial activity against Gram-negative and Gram-positive bacteria. As found, thyme extracts exhibited superior antioxidant activity (SC₅₀ at 33.9 μg mL⁻¹), while dittany extracts inhibited the microbial growth to a great extent against Bacillus subtilis strain (MIC at 0.5 mg mL⁻¹) and E. coli strain (MIC at 2 mg mL⁻¹). Furthermore, the thyme extract was proven to strongly inhibit the activity of lipase from Candida rugosa (IC₅₀ at 63.9 μg mL⁻¹), comparable to the standard inhibitor orlistat, while its inhibitory effect against mushroom tyrosinase was weak. On the other hand, the dittany extract presented an inhibitory effect against the tested lipase (IC₅₀ over 500 μg mL⁻¹) and an activation effect against tyrosinase (at concentrations > 500 μg mL⁻¹). Additionally, molecular docking studies of the main compounds of the extracts showed that rosmarinic acid plays a crucial role on the inhibitory activity of the extracts against lipase, while thymol has a stronger effect on inhibiting tyrosinase. Furthermore, both extracts were employed in the preparation of gelatin-deep eutectic solvent (DES) hydrogels that were further studied for their antioxidant and antibacterial activity. The results showed that the incorporation of the extracts offered antibacterial properties to the biopolymer-based hydrogels and enhanced the antioxidant activity of gelatin up to 85%.

Soft spread cheese is highly perishable, and conventional packaging offers limited protection against surface spoilage. Here, we present a sustainable, multifunctional solution: edible films made from whey protein concentrate (WPC), a valuable by-product of the cheese industry, incorporated with the probiotic Lactobacillus acidophilus LA5 (LA5). The objective of this study was to evaluate these films as active coatings for soft cheese, specifically assessing their physicochemical properties, probiotic viability during storage and simulated gastric transit, and their impact on cheese microbial stability and sensory quality over 60 days. Applied as active coatings on soft cheese stored at 4 °C for 60 days, these films were evaluated for their physicochemical properties, probiotic viability, microbial stability, and sensory acceptance. The incorporation of LA5 did not significantly alter film thickness (control: 0.20 ± 0.03 mm; test: 0.18 ± 0.02 mm), moisture content (control: 33.42 ± 0.54%; test: 32.34 ± 1.28%), or water solubility (control: 21.44 ± 1.14%; test: 22.89 ± 0.75%) (p > 0.05). However, mechanical properties were markedly modified: tensile strength decreased from 35.42 ± 5.38 MPa (control) to 6.04 ± 0.55 MPa (test), while elongation at break increased from 4.87 ± 0.93% to 68.23 ± 3.46% (p < 0.05), indicating a transition from rigidity to flexibility upon probiotic incorporation. The probiotic strain exhibited exceptional resilience, retaining 100% viability during simulated gastric exposure at both day 0 and day 30 of storage. During cheese storage, LA5 counts in test film-coated samples remained above the recommended therapeutic threshold (10⁶ cfu/g), starting at 7.44 ± 0.15 log(cfu/g) on day 0 and maintaining 6.56 ± 0.20 log(cfu/g) after 60 days. Critically, yeast and mold spoilage were delayed in probiotic-coated cheese, with detectable growth appearing only at day 60 (1.64 ± 1.34 log(cfu/g)), whereas uncoated cheese showed spoilage as early as day 28 (1.33 ± 1.62 log(cfu/g)). Sensory evaluation revealed no significant differences (p > 0.05) between the coated and uncoated samples for color, appearance, texture, flavor, or overall acceptability. By valorizing a dairy by-product into an active, probiotic-loaded edible film, this approach offers a sustainable, waste-reducing strategy that enhances cheese preservation while delivering added functional value—bridging the gap between food packaging and nutrition. Sensory evaluation (n = 8, preliminary) indicated no significant differences between coated and uncoated samples, but these results require confirmation with a larger, validated panel.