Pickering stabilization of thymol through green emulsification using soluble fraction of almond gum – Whey protein isolate nano-complexes

Abstract

In this study, the soluble fraction of almond gum (SFAG) as a sustainable biopolymer source and whey protein isolate (WPI) were used for self-assembly preparation of SFAG-WPI nano-complexes through electrostatic interaction. The SFAG was characterized using 1 H and 13 C NMR. The influence of total biopolymer concentration (0.2-0.4 %w/v) and ratios (1:3-3:1) as well as of the pH (2-6) on the formation of complexes was established by visual, light scattering, surface charge, and spectrometric observations. The outcomes proved the formation of negatively charged soluble complexes in the range of pH 4-5 and insoluble complexes at pH values 3 to 4. The soluble coacervate particles at pH 4.5 and total concentration of 0.4 %w/v were selected to induce Pickering stabilization of thymol. The static light scattering with microscopy studies (CLSM and Cryo-SEM) showed the formation of thymol oil-in-water emulsions by adsorption of nano-complexes on the surface of the droplets. Thymol emulsions stabilized using complexes had no size variation under storage (40 days) with an opaque and homogenous appearance. On the other hand, the emulsions containing solely WPI at pH 4.5 showed a substantial droplet size increase with severe creaming. Droplet size analysis together with coalescence and flocculation indices presented that coalescence was mainly responsible for droplet size coarsening of the emulsions stabilized by native WPI at pH 4.5. Overall, our outcomes indicated the improvement of WPI in the stabilization of emulsions through complexation.

Stability and functionality of xanthan gum–shellac nanoparticles for the encapsulation of cinnamon bark extract

“…A nano-particulate carrier of bioactive compounds targeting the colon has to survive the harsh acidic conditions of the stomach; otherwise, the distribution, release, and bioavailability of the compound can be uncontrolled (Jafari & McClements, 2017;Park, Saravanakumar, Kim, & Kwon, 2010). Natural polymers have been widely acknowledged to have many functions in foods, including as a stabilising agent (Manuhara, Praseptiangga, Muhammad, & Maimuni, 2016;Muhammad et al, 2019;Praseptiangga, Giovani, Manuhara, & Muhammad, 2017;Sedaghat Doost et al, 2019b). Xanthan gum, a non-toxic biopolymer produced by Xanthomonas campestris through fermentation, has been widely used as a thickening and stabilising agent in various products, including emulsion systems and micro particles.…”

A review on nuclear overhauser enhancement (NOE) and rotating-frame overhauser effect (ROE) NMR techniques in food science: Basic principles and applications

“…Likewise, in another work, Jahed et al (2014) showed that this technique was capable to confirm the formation of complexes between the host and guest molecules; the complex ofcyclodextrin and curcumin was evaluated via NOE cross peaks (Figure 4 Recently, there has been a great demand for consumption of food products containing natural ingredients, including essential oils (EOs). The latter are hydrophobic volatile compounds that are increasingly attracting interest due to their antimicrobial and antioxidant properties (Sedaghat Doost et al, 2018b, Sedaghat Doost et al, 2019.…”

Self-assembled proteins for food applications: A review

“…In recent years, there is a growing demand from consumers for healthier and more convenient food products. With this in mind, edible polymers such as carbohydrates, lipids and proteins have been used in the food industry as emulsifiers, thickeners, food packaging and coatings, among others (Gutiérrez, 2018a;Sedaghat Doost et al, 2019).…”

“…Another option to modify the physicochemical properties of proteins is by self-assembly of protein structures with themselves or with others proteins, polysaccharides and active compounds (e.g. organic acids, flavonoids, phenolic compounds, among others), thus improving and creating novel structures with new functionalities which are not available by other means (Sedaghat Doost et al, 2019).…”

“…In the last years, several research studies have been focused on the development of additives, coatings, emulsions, films, functional foods, hydrogels, micelles/vesicles and particles based on the self-assembly of proteins (Belbekhouche, Bousserrhine, Alphonse, & Carbonnier, 2019;Diarrassouba et al, 2015;Li, He, et al, 2019;Mantovani, Fattori, Michelon, & Cunha, 2016;Murmu & Mishra, 2017;Sedaghat Doost et al, 2019;Tsai & Weng, 2019;Visentini, Perez, & Santiago, 2019). These architectures have been formed by changing environmental conditions, such as ionic strength, mechanical force, pH, temperature and ion types.…”