Extraction of high-value compounds from Theobroma grandiflorum (cupuassu) seed shells using pressurized liquid extraction with NADES: a green chemistry approach

The species of Theobroma grandiflorum, commonly known as cupuassu, is widely used in the production of various cosmetic and food products. However, cupuassu seed shell (CSS), a major agro-industrial residue generated during the processing of its seeds, remains largely underexplored. In this study, a dual-extraction strategy was developed to valorize CSS using green chemistry principles, emphasizing waste recovery, reduced solvent consumption, and lower environmental impact. This methodology was applied to the extraction of theobromine, a methylxanthine of growing interest in the development of nutraceuticals and functional foods. In the first step, lipids were extracted using the energized dispersive guided extraction (EDGE) system, an automated and sustainable alternative to conventional methods. Fatty acids analysis revealed an oil profile like that of commercial cupuassu seed oil, reinforcing the potential of CSS oil as a functional ingredient in food, pharmaceutical, or cosmetic applications. In the second step, defatted CSS solid residue was subjected to theobromine extraction using the same EDGE system, this time employing a natural deep eutectic solvent (NADES) composed of choline chloride and glycerol (1:3). Extraction conditions were optimized using a BBD (Box-Behnken Design), with the best results achieved at 150 °C, 15 min, and 80% NADES, yielding 0.62 mg g^-1 in dry basis (d.b.) of theobromine. This study demonstrates a sustainable and efficient approach to convert a low-value byproduct into high-value bio-based compounds, highlighting the versatility of the EDGE system and reinforcing the principles of a circular economy and green analytical chemistry.