Fisetin yeast-based bio-capsules via osmoporation: effects of process variables on the encapsulation efficiency and internalized fisetin content

Abstract

Osmoporation is an innovative method that can be used with food-grade yeast cells of Saccharomyces cerevisiae as natural encapsulating matrices. This technique overcomes barriers that difficult encapsulation and enables the internalization of fragile bioactive molecules such as fisetin into yeasts. In the present study, we assessed the effects of concentration, osmotic pressure, and temperature on the encapsulation efficiency (EE) and internalized fisetin content (IF). Two different quantification strategies were investigated: direct extraction (DE) without cell washing or freeze-drying steps and indirect extraction (IE) performed after washings with ethanol and freeze-drying. Our results showed that osmoporation improved EE (33 %) and IF (1.199 mg). The best experimental conditions were found by using DE. High-resolution images showed that the yeast cell envelope was preserved during osmoporation at 30 MPa and 84 % of yeast cells remained viable after treatment. Washing cells with organic solvent led to decreased EE (0.65 %) and IF (0.023 mg). This was probably due to either damages caused to yeast cell envelope or fisetin dragged out of cell. Overall, the results demonstrated the adequacy and relevant biotechnological potential of yeasts as encapsulating matrices for hydrophobic compounds. This fresh biotechnological approach has proven to be a promising tool for the production of bioactive-rich food products.

Ultrasound-assisted encapsulation of curcumin and fisetin into Saccharomyces cerevisiae cells: a multistage batch process protocol

“…2019) and fisetin (0·729 mg; Câmara Jr. et al . 2016) were reached when higher bioactive concentrations in a range of 1–3 and 0·32–3·68 mg ml −1 were used, respectively. Moreover, a comparison between our current results and those obtained by the multistage osmoporation technique of Medeiros et al .…”

“…2019) and fisetin (Câmara Jr. et al . 2016) led to EE levels of 34·2 and 33·3%, respectively. Previously, 85·8% of fisetin were entrapped by poly‐lactic acid nanoparticles (Feng et al .…”

“…For example, Young et al (2017) demonstrated enhanced EEs of curcumin and fisetin, from 35Á9 and 34Á4% by mere impregnation to 64Á0 and 66Á6% via vacuum infusion, respectively. Osmoporation-assisted encapsulation of curcumin (de Medeiros et al 2019) and fisetin (Câmara Jr. et al 2016) led to EE levels of 34Á2 and 33Á3%, respectively. Previously, 85Á8% of fisetin were entrapped by poly-lactic acid nanoparticles (Feng et al 2019), while a formulation of inulin, maltodextrin and tamarind gum encapsulated 82Á5 and 89Á4% of curcumin via spray drying and freeze drying, respectively (Guo et al 2020).…”

“…A similar trend was observed via osmoporation bioprocess. Improved EYs of curcumin (50Á5%; de Medeiros et al 2019) and fisetin (0Á729 mg ;Câmara Jr. et al 2016) were reached when higher bioactive concentrations in a range of 1-3 and 0Á32-3Á68 mg ml −1 were used, respectively. Moreover, a comparison between our current results and those obtained by the multistage osmoporation technique of Medeiros et al (2018) demonstrates the benefits of adding non-loaded yeasts between each stage.…”

“…2, it seems that the increment of ESs will reduce the total loaded content of the biocapsules, then, a reasonable balance between EE and EY is essential to find an adequate amount of ESs to maximize the efficiency of the encapsulation process. Previous reports have shown that encapsulation processes with increasing yeast densities usually led to poorly enriched final encapsulated products (Paramera et al 2011;Câmara Jr. et al 2016;de Medeiros et al 2019;Rubio et al 2021). Therefore, greater EYs may be achieved by batching the process into successive stages using less concentrated nonloaded yeast suspensions in each one of these ESs.…”