Saponins from Chenopodium quinoa Willd. as natural surfactants for cleaners from used cooking oil: physical extraction, afrosymmetric quantification and evaluation

Abstract

This study evaluated the use of saponins from Chenopodium quinoa Willd. to formulate natural cleaners from used cooking oil (UCO). The objective was to extract saponins from three quinoa varieties (Real, Sajama Blanca, and Blanca de Juli), quantify them using the standard afrosymetric method, and evaluate the stability and pH of the cleaners made with UCO. The saponins were obtained by physical extraction (scarification with 600-grit sandpaper), achieving yields of 9.2–11.8 mg of extract/g of quinoa. Saponin quantification was performed using the afrosymetric method, estimating contents of 2.4852% for Blanca de Juli, 0.0953% for Real, and 0.0060% for Sajama Blanca, which allowed for the selection of Real and Blanca de Juli for formulation. The UCO was purified by washing with water, decantation, filtration with cotton/activated carbon, and deodorization with dried mandarin peels. Formulations with and without oil were prepared, and pH and stability were evaluated. The cleaners showed no phase separation after two weeks, exhibited good consistency, and the pH ranged from 4.36 to 5.92, amenable to adjustment with a mild buffer. Overall, the results confirm the technical feasibility of using quinoa saponins as natural surfactants to valorize ACU in cleaning formulations.