Innovative pH sensors developed from ultrafine fibers containing açaí (Euterpe oleracea) extract.

This work describes the development of ultrafine fibers with açaí (Euterpe oleracea Mart.) extract (AE) for use as pH sensors with potential applications in the food industry. The fibers were produced by electrospinning with polymeric solutions composed of 7% (w v-1) polycaprolactone, 2% (w v-1) polyethylene oxide and 3% (w v-1) AE solubilized in chloroform and methanol (3:1). The mean diameter of the fibers was 1635 ± 277 nm, with hydrophilic characteristics (contact angle < 90°), a melting point of 58 °C and a maximum degradation temperature of 408 °C. The total color difference (ΔΕ) of the colorimetric response was greater than 5, corresponding to the human ability for color differentiation. This new material can be used as a pH sensor for foods such as pork and fish to ensure quality and safety for the consumer, who can visually check the condition of the products.