Antioxidant efficacy and in silico toxicity prediction of free and spray-dried extracts of green Arabica and Robusta coffee fruits and their application in edible oil

Abstract

Extracts of green coffee fruits (GCFEs), either of the Arabica or Robusta variety, obtained by percolation with a 68% (w/w) aqueous ethanol solution using a 0.9:10 (w/w) solid-to-solvent ratio, were tested in this study as antioxidant additives to delay sunflower oil oxidation. In addition, safety of the major secondary metabolites of the extracts was investigated by in silico modeling. For this purpose, GCFEs were spray dried either as such or microencapsulated with a 1:1 (w/w) maltodextrin and gum Arabic mixture as wall material. The encapsulation efficiencies of Arabica and Robusta GCFEs were as high as 96.9 ± 0.04 and 97.36 ± 0.03% and the chlorogenic acid retentions 59.61 ± 1.3 and 73.72 ± 2.49%, respectively. The HPLC-DAD analysis revealed higher contents of total chlorogenic acids and caffeine but a lower content of trigonelline in the Robusta GCFE compared with the Arabica one. The ACD/I-Lab, AdmetSAR, and pKCSM computational tools allowed excluding, for GCFEs major compounds, any toxicological potential in terms of Ames toxicity, carcinogenicity, hERG inhibition, hepatotoxicity, reproductive toxicity and skin sensitization. Foodstuff application of GCFE powders demonstrated that microencapsulated GCFEs were more effective in delaying sunflower oil oxidation than free GCFEs and butylated hydroxytoluene as a synthetic antioxidant. These results suggest the use of microencapsulated GCFE as a source of natural antioxidants to stabilize food products, especially unsaturated vegetable oils.