Preparation of Hydrogels Composed of Bioactive Compounds from Aqueous Phase of Artichoke Obtained by MHG Technique

Abstract

This work deals with the valorisation of artichoke industrial wastes from natural and blanched processed samples to prepare innovative functional gelling matrices. For this purpose, the recovery of bioactive liquid phases using microwave hydrodiffusion and gravity (MHG) in a broad range of irradiation powers and the corresponding phytochemical and colour characterisations were conducted. Liquid phases with the highest bioactive compounds were used to formulate functional hydrogels. These gelled systems were mechanically characterised. Phytochemical analyses indicated that the highest bioactive features were identified for liquors collected from both natural and blanched samples MHG-treated at 500 W. The blanching pre-treatment favoured the bioactive compound recovery, without notable differences in terms of colour properties. In general, no significant differences (p > 0.05) were observed in energy consumption when MHG treatments for natural and blanched artichoke extractions were compared. In all selected cases, typical gel spectra were observed for bioactive liquid phases gelled using both alginate and gelatine. Softening of the gelled matrices was identified in the presence of bioactive extracts. Texture profile analyses for natural and blanched artichoke samples were consistent with the results obtained by rheology. Phytochemical and colour analyses indicated that frozen storage was an adequate method to preserve the bioactive properties of the samples for at least 3 years.