Improving Shrimp Preservation Quality Through Edible Coatings Based on Starch Modified with Aqueous Plant Extracts

The problems of food waste and packaging waste production currently force us to search for new solutions that are safe for people and the environment. Applying edible coatings directly onto food offers a sustainable method of maintaining shrimp freshness, eliminating the need for artificial preservatives and avoiding the high energy demands of conventional chemical or physical preservation techniques. In this study, starch materials modified with natural extracts from plants with proven health-promoting and antibacterial properties—rooibos and garlic—were obtained and tested. The structure, hydrophilicity, water vapor permeability, and thermal and mechanical properties of the obtained starch films were determined. The study further revealed that Escherichia coli was absent in all shrimp samples coated with starch-based films following seven days of refrigerated storage, in contrast to uncoated samples. For Staphylococcus aureus , coatings with rooibos extract resulted in a significant reduction in bacterial counts. Coatings with garlic extract showed a marginally reduced antibacterial effect. The effect of the coatings on the overall numbers of lactic acid bacteria and aerobic mesophilic bacteria was evaluated as well. Coatings enriched with rooibos were more effective in the early days of storage, while garlic-based coatings exhibited a less intense but more enduring antimicrobial effect.