Development of a sweet potato starch-based coating and its effect on quality attributes of shrimp during refrigerated storage

- Shrimp was coated with sweet potato starch-based coating with or without thyme essential oil.
- Coating reduced lipid oxidation, loss in freshness and melanosis.
- Coating with thyme essential oil resulted in higher bacterial population reduction.

Shrimp is enjoyed for the uniqueness of its flavor and texture. However, shrimp has limited shelf-life due to biochemical, microbiological or physical changes during postmortem storage. In this study, edible coatings from sweet potato starch (SPS) and variable levels of thyme essential oil (TEO) (0, 2, 4 and 6 g/100 g) were developed to maintain the quality of shrimp during refrigerated storage. Application of SPS-based coating resulted in lower pH (p < 0.05). Coated samples activated with TEO had lower counts of bacteria and lipid oxidation (p < 0.05) toward the end of storage. Textural and color properties of coated shrimp were generally more acceptable. Sensory scores indicated no significant changes in all samples during storage. The results of this study suggest that the TEO incorporation at 4 g/100 g into SPS- based coating could be useful in extending the shelf life of shrimp meat during refrigerated storage.