Molecular Mechanism for Improving Emulsification Efficiency of Soy Glycinin by Glycation with Soy Soluble Polysaccharide

Abstract

Glycation with carbohydrates has been considered to be an effective strategy to improve the emulsifying properties of plant storage globulins, but the knowledge is inconsistent and even contradictory. This work reported that the glycation with soy soluble polysaccharide (SSPS) progressively improved the emulsification efficiency of soy glycinin (SG) in a degree-of-glycation (DG)-dependent manner. The glycation occurred in both the acidic (A) and basic (B) polypeptides to a similar extent. The physicochemical and structural properties of glycated SG samples with different DG values of 0−35% were characterized. The emulsifying properties of unglycated and glycated SG were performed on the emulsions at an oil fraction of 0.3 and a protein concentration in the aqueous phase, produced using microfluidization as the emusification process. The glycation with increasing the DG led to a progressive decrease in solubility and surface hydrophobicity but remarkably increased the magnitude of ζ-potential. Dynamic latter scattering and spectroscopic results showed that the glycation resulted in a gradual dissociation of the 11S-form SG at the quaternary level (into different [AB] subunits), in a DG-dependent way, while their tertiary ([AB] subunits) and secondary structure were slightly affected. Besides the emulsification efficiency, the glycation progressively accelerated the droplet flocculation and facilitated the adsorption of the proteins at the interface and formation of bridged emulsions. The results demonstrated that the improvement of the emulsification efficiency of SG by the glycation with SSPS was largely attributed to the enhanced conformation flexibility at the [AB] subunit level as well as facilitated formation of bridged emulsions. It was also confirmed that once the glycated SG adsorbed at the interface, it would readily dissociated into subunits; the dissociated [AB] subunits exhibited an outstanding Pickering stabilization. The findings would be of importance for providing new knowledge about the molecular mechanism for the modification of emulsifying properties of oligomeric globulins by the glycation with polysaccharides.

Pea protein microgel particles as Pickering stabilisers of oil-in-water emulsions: Responsiveness to pH and ionic strength

“…whey protein microgels (Destribats, et al, 2014;Sarkar, et al, 2016b) and lactoferrin nanoparticles or nanogels (David-Birman, et al, 2013;Gal, et al, 2013;Meshulam, et al, 2014;Sarkar, et al, 2018), those involving particles obtained from plant proteins are fairly recent and are attracting significant research attention. For example, Liu and co-authors (Liu, et al, 2017;Liu, et al, 2013;Liu, et al, 2014;Liu, et al, 2016;Peng, et al, 2020;Peng, et al, 2018;Zhu, et al, 2017) investigated the ability of soy protein nanoparticles aggregates (SPN) (~ 100 nm, created via heat-treatment at 95 o C for 15 min) to act as Pickering stabilizers. On the other hand, Chen, et al (2014) prepared heat denatured soy protein nanogel particles at various pH values (pH 2.0-7.0) and added ions (0-200 mM NaCl).…”

Exploration of the Stabilization Mechanism and Curcumin Bioaccessibility of Emulsions Stabilized by Whey Protein Hydrolysates after Succinylation and Glycation in Different Orders

“…The far-UV CD spectra and secondary structure distribution of WPH, W-S-L, and W-L-S are presented in Figure . The spectrum of WPH, exhibiting a remarkable negative band at ∼200 nm and a peripheral shoulder band at ∼230 nm, revealed the fact that the secondary structure of WPH was mainly composed of β-sheet (37.6 ± 0.14%) and random coil (43.7 ± 0.29%) . A significant hypsochromic shift in the spectrum of W-S-L and W-L-S indicated that the structure of WPH was changed after modification.…”

“…The spectrum of WPH, exhibiting a remarkable negative band at ∼200 nm and a peripheral shoulder band at ∼230 nm, revealed the fact that the secondary structure of WPH was mainly composed of β-sheet (37.6 ± 0.14%) and random coil (43.7 ± 0.29%). 17 A significant hypsochromic shift in the spectrum of W-S-L and W-L-S indicated that the structure of WPH was changed after modification. As shown in the inset of Figure 2, the contents of α-helix, β-sheet, β-turn, and random coil were 7.1%, 11.9%, 34.8%, and 46.2% for W-S-L and 6.4%, 18.4%, 30.4%, and 44.8% for W-L-S, respectively, which indicated that the order of the two modification methods resulted in a different effect on the secondary structure of WPH because of the various degrees of reaction with LD and SA for modified WPH after succinylation and glycation in different orders.…”

Emulsifying and emulsion stabilizing properties of soy protein hydrolysates, covalently bonded to polysaccharides: The impact of enzyme choice and the degree of hydrolysis

“…However, they exhibit poor emulsifying capability compared to milk derived proteins such as casein or whey protein, due to their large molecular weight, compact globular structure and limited solubility (Dickinson, 2019;Tang, 2017). Recent progress on achieving emulsifiers from SPI and SPI derived materials has mainly focused on Pickering-type aggregated protein emulsifiers or microgel particles (Chen, Chen, Ren, & Zhao, 2011a;Dickinson, 2019;Guo, et al, 2016;Hao, Peng, & Tang, 2020;Luo, Liu, & Tang, 2013;Matsumiya & Murray, 2016;Peng, Xu, Liu, & Tang, 2018;Tang, 2017). These reported emulsions are not stabilised by molecularly adsorbed protein layers (i.e.…”