Development of an SO2 indicator label applied to shrimp

Sulfiting agents are added to crustaceans products to prolong their shelf life. However, depending on the concentration, these agents can be toxic to consumers due to the presence of SO2. In this context, a colorimetric indicator label based on starch and iodine was developed to detect SO2 in shrimp, showing whether the product is safe or not for consumers. The incorporation of iodine into the starch matrix resulted in labels with a smooth and homogeneous surface, and reduced water solubility from 9.26% to around 0.12%. In both in vitro and shrimp paste test, a visual detection response was observed in the label containing 0.02% of iodine when evaluated in the presence of 100 to 160 ppm of SO2, with Delta E* values greater than 5 (can be identifiable by the human eye). Therefore, the elaborated label showed potential as an economical and simple method to detect SO2 concentration in shrimp-based foods.