Adsorption and desorption of eggplant peel anthocyanins on a synthetic layered silicate

• Published in: Journal of food engineering 2019-12, Vol.262, p.162-169
• Main Authors: Capello, Cristiane, Leandro, Gabriel Coelho, Maduro Campos, Carlos Eduardo, Hotza, Dachamir, Mattar Carciofi, Bruno Augusto, Valencia, Germán Ayala
• Format: Article
• Language: English
• Subjects: Eggplant residue; Food pigment; Food residue valorization; Layered silicates; Natural pigments
• ISSN: 0260-8774; 1873-5770
• DOI: 10.1016/j.jfoodeng.2019.06.010

This work reports for the first-time the adsorption of anthocyanins (ACN) on the surface of laponite® (Lap), as well the physicochemical characterization of ACN-Lap powders after the adsorption process. ACN were extracted from eggplant peel by using an acidified water solution. The adsorption/desorption tests were carried out at different temperature and pH values. The best adsorption conditions were at 20 °C and pH 1.0. The adsorption mechanism of ACN on Lap was better explained by Langmuir and pseudo-first-order kinetic models, therefore, the ACN adsorption on Lap can be classified as monolayer adsorption, influenced by physical interactions. Lap has a high ratio of adsorption/desorption. After adsorption, the ACN-Lap powder presents an amorphous structure with a purple color, which changes with pH modification. Lap can be used to valorize food residues rich in ACN such as eggplant peel. The ACN-Lap powder has potential application as dye or pigment in the food industry. •Laponite can be used for separating anthocyanins.•Laponite had good adsorption/desorption capacities of anthocyanins.•Langmuir and pseudo-first-order kinetic models described adequately the adsorption process.•Anthocyanin-laponite powder can be used as pH sensing.