Colloidal Gas Aphrons separation to obtain polyphenol rich fractions from artichoke agro-industrial discards

Abstract

Artichoke agro-industrial discards have proved an excellent source of polyphenolic compounds with high antioxidant capacity, which can be extracted at mild conditions. The aim of this study was to further separate these bioactive molecules from an ethanolic extract by using Colloidal Gas Aphrons (CGAs) generated from a cationic surfactant, Cetyl trimethylammonium bromide, CTAB (1 mM) and a nonionic one, Tween 20 (10 mM). Total proteins, total sugars, total phenolic content (TPC), antioxidant capacity (AOC) and polyphenolic profile were determined in the crude extracts and CGA fractions. Highest recovery was obtained with the nonionic Tween 20 at CGA to feed volumetric ratio 5 (RE%= 64) whereas the cationic CTAB proved more efficient (RE%= 58) at the highest ratio studied here (ratio 11). Antioxidant capacity followed the same trend as the recovery of polyphenols and highest enrichment in antioxidant activity for each of the 2 surfactants (1.5 for Tween 20 and 1.4 for CTAB) was obtained at those conditions that led to maximum recovery. Highest selectivity was obtained with CTAB. The interactions between the negatively charged polyphenols and the positively charged cationic surfactant drove the separation, whereas with Tween 20 hydrophobic interactions were predominant, and at the studied concentrations (10 mM) the separation of polyphenols within the micelles might also compete with the CGA separation. Polyphenolic profile of feed and CGAs fractions comprised mainly mono and dicaffeoylquinic acids and a small proportion of flavones. In most of the cases no enrichment of any particular polyphenol compound was observed from the initial extract to CGAs samples generated with Tween 20 and CTAB. However, at ratio 5 and with Tween, CGAs were enriched in dicaffeoylquinic acid. Future research should focus on studying further the activities and stability of these surfactant rich fractions in order to assess if the surfactant could offer any advantage to the formulation of these polyphenols.

Exploring different strategies of separation of antioxidant compounds from winery by-products via surfactant-assisted processes for process intensification and integration

“…Nevertheless, the trends of TPC and TAC observed in Fig. 6 are in good agreement with the findings of Noriega et al (2018), who detected a gradual enrichment of the aphron phase with phenolics extracted from artichoke wastes when increasing the volumetric ratio, independently of the surfactant agent utilized for CGAs generation (Tween20, CTAB).…”

“…The characteristic structure of CGAs confers them several important features, namely high foam stability, easy phase separation, and capability to absorb particles/molecules to the encapsulating shell, which could be properly tuned by varying the type of surfactant implied for their production (Fuda and Jauregi, 2006;Jauregi and Varley, 1998;Jauregi and Dermiki, 2010;Spigno et al, 2015). Within this frame, different scientists have previously reported the successful application of CGAs for the efficient recovery of proteins from whey (Amiri and Valsaraj, 2004;Jarudilokkul et al, 2004), cellulose from paper mill wastewaters (Hashim and Sen Gupta, 1997), oil from water (Corpuz et al, 2019), and antioxidants from artichoke bracts/stems (Noriega et al, 2018).…”

Protein Hydrolysate from Pterygoplichthys disjunctivus, Armoured Catfish, with High Antioxidant Activity

“…The mild conditions in which maximum activity were achieved was another advantage of HT compared to PF and PAL enzymes; this is illustrated in Figure 5, where maximum antioxidant activities for each enzyme and conditions are shown for the ABTS method. Overall, the antioxidant activity based on the ABTS method was superior to that reported for other fish hydrolysates, e.g., 48 μmol/g hydrolysate from the unicorn leatherjacket, DH 40% [19] and was comparable to the value reported for plant-derived extracts, e.g., artichoke extract, 92 μmol/g [20]; blackcurrant extract, 156–196 μmol/g (results from our group, not published); and grape marc extract, 193–485 μmol/g [21].…”

Enrichment of Quercetin from Winemaking Residual Diatomaceous Earth via a Tailor-Made Imprinted Adsorbent

“…In addition, an emerging separation technique based on colloidal gas aphrons was also employed to separate phenolic compounds from sugars and proteins [ 19 , 20 ]. This technique relies on a fast-stirred surfactant solution generating microbubbles able to adsorb molecules due to charge attraction [ 19 , 20 ].…”

“…In addition, an emerging separation technique based on colloidal gas aphrons was also employed to separate phenolic compounds from sugars and proteins [ 19 , 20 ]. This technique relies on a fast-stirred surfactant solution generating microbubbles able to adsorb molecules due to charge attraction [ 19 , 20 ]. Additionally, the enrichment of polyphenols from olive oil wastewater was attempted using ionic and non-ionic resins showing an enrichment factor of twofold for the non-ionic resins [ 21 ].…”