Layer-by-Layer Coating Approach Based on Sodium Alginate, Sage Seed Gum, and Savory Oil: Shelf-Life Extension of Fresh Cheese

This research aimed to develop a new bi-layer edible coating using sodium alginate (SA, internal layer) and sage seed gum (SSG, external layer) to extend the shelf-life of fresh cheese. Satureja khuzestanica Jamzad essential oil (SEO) with high carvacrol content (91.33%) was incorporated into SA coating as an active agent. Four fresh cheese groups were prepared, including uncoated and coated samples with SA-SSG, SA-SSG with 0.5% SEO, and SA-SSG with 1% SEO. Cheeses were characterized in microbiological, physicochemical, and sensory aspects during 15 days of storage at 4 ± 1 °C. Cheese samples with bi-layer coatings exhibited ca. 51.2–61.8% lower weight loss at the storage end than the uncoated group. SEO-containing coating caused a substantial reduction in inoculated Listeria monocytogenes and total mesophilic count after 24 h of coating (0.65–1.4 log CFU/g). Bi-layer coating reduced the lightness and whiteness index while increasing the yellowness of the cheese compared to the uncoated. The lipid oxidation rate increased significantly for uncoated and SA-SSG groups; however, SEO-containing coating effectively prevented it. The hardness and chewiness values of the coated cheeses were considerably lower than the uncoated ( p < 0.05). Although SEO-containing coating decreased the odor and flavor scores, the overall preference of all samples was acceptable until the end of storage. Our findings suggest a potential utility of the layer-by-layer coatings approach to maintain the quality acceptance of fresh foodstuffs. Graphical Abstract