Optimized Ultrasound-Assisted Extraction of Carminic Acid from Dactylopius opuntiae

Dactylopius opuntiae is a major pest of prickly pear crops and has therefore been extensively studied with the aim of controlling its proliferation. However, it has largely been disregarded as a potential natural red pigment source, despite producing carminic acid (CA), as does Dactylopius coccus, albeit in lower amounts. CA, an anthraquinone compound, is highly valued for its strong coloring capacity and commercial relevance in the food, cosmetic, and pharmaceutical industries. Conventional CA extraction methods are often constrained by long processing times and limited environmental sustainability. In this context, ultrasound-assisted extraction (UAE) has emerged as an efficient and eco-friendly alternative, offering improved extraction yields. This study aimed to optimize the UAE of CA from D. opuntiae and maximize extract yield. A Box–Behnken experimental design was applied, testing temperatures of 20, 40, and 60 °C; extraction times of 3, 6, and 9 min; and ultrasound amplitudes of 20, 30, and 40%. The highest CA concentration (14.76 ± 0.32%) was obtained at 60 °C, 3 min of sonication, and 20% amplitude, representing a 7.45% increase compared with the conventional method. These findings demonstrate that UAE enables higher CA yields in significantly shorter processing times, providing a sustainable strategy to transform D. opuntiae from an agricultural pest into a valuable natural pigment source.