Formation and Stabilization of W1/O/W2 Emulsions with Gelled Lipid Phases

Water-in-oil-in-water (W1/O/W2) emulsions are emulsion-based systems where the dispersed phase is an emulsion itself, offering great potential for the encapsulation of hydrophilic bioactive compounds. However, their formation and stabilization is still a challenge mainly due to water migration, which could be reduced by lipid phase gelation. This study aimed to assess the impact of lipid phase state being liquid or gelled using glyceryl stearate (GS) at 1% (w/w) as well as the hydrophilic emulsifier (T80: Tween 80 or lecithin) and the oil type (MCT:medium chain triglyceride or corn oil (CO) as long chain triglyceride) on the formation and stabilization of chlorophyllin W1/O/W2 emulsions. Their colloidal stability against temperature and light exposure conditions was evaluated. Gelling both lipid phases (MCT and CO) rendered smaller W1 droplets during the first emulsification step, followed by formation of W1/O/W2 emulsions with smaller W1/O droplet size and more stable against clarification. The stability of W1/O/W2 emulsions was sensitive to a temperature increase, which might be related to the lower gelling degree of the lipid phase at higher temperatures. This study provides valuable insight for the formation and stabilization of W1/O/W2 emulsions with gelled lipid phases as delivery systems of hydrophilic bioactive compounds under common food storage conditions.This study was funded by the Ministerio de Economía y Competitividad throughout the project AGL2018-65975-R (Fondo Europeo de Desarrollo Regional (FEDER) and Ministerio de Economía y Competitividad)

Lipid digestibility and polyphenols bioaccessibility of oil-in-water emulsions containing avocado peel and seed extracts as affected by the presence of low methoxyl pectin

In this study, the digestibility of oil-in-water (O/W) emulsions using low methoxyl pectin (LMP) as surfactant and in combination with avocado peel (AP) or seed (AS) extracts was assessed, in terms of its free fatty acid (FFA) release and the phenolic compound (PC) bioaccessibility. With this purpose, AP and AS were characterized by UPLC-ESI-MS/MS before their incorporation into O/W emulsions stabilized using LMP. In that sense, AP extract had a higher content of PCs (6836.32 ± 64.66 mg/100 g of extract) compared to AS extract (1514.62 ± 578.33 mg/100 g of extract). Both extracts enhanced LMP’s emulsifying properties, leading to narrower distributions and smaller particle sizes compared to those without extracts. Similarly, when both LMP and the extracts were present in the emulsions the FFA release significantly increased. Regarding bioaccessibility, the PCs from the AS extracts had a higher bioaccessibility than those from the AP extracts, regardless of the presence of LMP. However, the presence of LMP reduced the bioaccessibility of flavonoids from emulsions containing either AP or AS extracts. These results provide new insights regarding the use of PC extracts from avocado peel and seed residues, and the effect of LMP on emulsion digestibility, and its influence on flavonoids bioaccessibility.This study was supported by the Ministry of Economy and Competitiveness, Spain throughout the projects AGL2015-65975-R (MINECO/FEDER, UE) and RTI2018-094268-B-C21 (MINECO/FEDER, UE). Gustavo R. Velderrain-Rodríguez (CVU 426539) also thank to the CONACyT for the postdoctoral gran

Edible films from essential-oil-loaded nanoemulsions: physicochemical characterization and antimicrobial properties

Edible films including active ingredients can be used as an alternative to preserve food products. Essential oils (EOs) exhibit antimicrobial activity against pathogenic microorganisms but their low water solubility limits the application in foods. To improve water dispersion and protect EOs from degradation, nano-sized emulsions emerge as a viable alternative. Nanoemulsions containing EOs and polysaccharides could be used to form edible films with functional properties. This study was focused on the evaluation of physical, mechanical and antimicrobial properties of alginate-based edible films formed from nanoemulsions of EOs. Nanoemulsions containing thyme (TH-EO), lemongrass (LG-EO) or sage (SG-EO) oil as dispersed phase and sodium alginate solution as continuous phase were prepared. The average droplet size of nanoemulsions was reduced after the microfluidization treatment exhibiting multimodal size distributions. The zeta-potentials of nanoemulsions were between 41 mV and 70 mV depending on the type of EO used. The lowest whiteness index was found in SG-EO nanoemulsions, whereas those containing TH-EO showed the highest value. Films formed from SG-EO nanoemulsions exhibited higher transparency, water vapor resistance and flexibility than films formed from TH-EO or LG-EO. Edible films containing TH-EO were those with the strongest antimicrobial effect against inoculated Escherichia coli, achieving up to 4.71 Log reductions after 12 h. Results obtained in the present work evidence the suitability of using nanoemulsions with active ingredients for the formation of edible films, with different physical and functional properties. (C) 2015 Elsevier Ltd. All rights reservedThis research was supported by the Ministerio de Ciencia e Innovación (Spain) throughout projects ALG2009-11475 and ALG2012-35635. Author Acevedo-Fani also thanks to the University of Lleida for the pre-doctoral grant. Author Martín-Belloso acknowledges to the Institució Catalana de Recerca I Estudis Avançats (ICREA) for the Academia 2008 Award