SUSTAINABLE VALORIZATION OF COCOA ALMOND SHELL (CAS) THROUGH GREEN SYNTHESIS OF SILVER NANOPARTICLES WITH POTENTIAL ANTIMICROBIAL APPLICATIONS

Téllez-Monzón L.A.; Félix L.L.; Ogata-Gutiérrez K.; Nolazco-Cama D.M.; Lima F.R.A.; Carranza-Oropeza M.V.; Visitación-Figueroa L. · Ecologia Aplicada (2026) · DOI: 10.21704/rea.v24i2.2382

Resumen

The growing emphasis on sustainability is driving the valorization of agro-industrial waste. Perú, as the world's eighth-largest cocoa producer (Theobroma cacao), generates significant quantities of cocoa almond shell (CAS), a byproduct rich in polyphenols and fiber. This research proposes a circular economy strategy through the green synthesis of silver nanoparticles (AgNp) with antibacterial capacity. Three antioxidant compound extraction methods were evaluated, identifying ultrasound combined with Soxhlet (ULSH) as the most efficient (achieving an antioxidant capacity of 88.85 μmol-TE/g), outperforming microwave and reflux methods due to its superior mass transfer efficacy and preservation of bioactive compounds. The ULSH extract was used for AgNp synthesis under optimized conditions (pH 10.5; 20 °C; 60 min), yielding spherical and crystalline nanoparticles with an average size of 7.1 nanometers (nm) and a zeta potential of-33.34 mV, indicating high colloidal stability. The formation of metallic silver was corroborated by X-ray diffraction (2 Theta ≈ 38.1°, 43.8°, 64.4°, and 77.5°) and FTIR spectroscopy. The synthesized AgNPs demonstrated significant antimicrobial activity against foodborne pathogens, with inhibition zones of 1.86 mm for Staphylococcus aureus and 1.15 mm for Salmonella spp. These results highlight the potential of CAC as a raw material for nanobiotechnology applications, providing a dual solution: sustainable valorization of agro-industrial waste and the development of eco-friendly antimicrobials. © Departamento Académico de Biología, Universidad Nacional Agraria La Molina, Lima – Perú.

Instituciones: Universidad Nacional Mayor de San Marcos; Universidad Nacional Agraria La Molina