The Interaction between Zein and Lecithin in Ethanol-Water Solution and Characterization of Zein–Lecithin Composite Colloidal Nanoparticles

Abstract

Lecithin, a naturally small molecular surfactant, which is widely used in the food industry, can delay aging, enhance memory, prevent and treat diabetes. The interaction between zein and soy lecithin with different mass ratios (20:1, 10:1, 5:1, 3:1, 2:1, 1:1 and 1:2) in ethanol-water solution and characterisation of zein and lecithin composite colloidal nanoparticles prepared by antisolvent co-precipitation method were investigated. The mean size of zein-lecithin composite colloidal nanoparticles was firstly increased with the rise of lecithin concentration and then siginificantly decreased. The nanoparticles at the zein to lecithin mass ratio of 5:1 had the largest particle size (263 nm), indicating that zein and lecithin formed composite colloidal nanoparticles, which might aggregate due to the enhanced interaction at a higher proportion of lecithin. Continuing to increase lecithin concentration, the zein-lecithin nanoparticles possibly formed a reverse micelle-like or a vesicle-like structure with zein in the core, which prevented the formation of nanoparticle aggregates and decreased the size of composite nanoparticles. The presence of lecithin significantly reduced the ζ-potential of zein-lecithin composite colloidal nanoparticles. The interaction between zein and lecithin enhanced the intensity of the fluorescence emission of zein in ethanol-water solution. The secondary structure of zein was also changed by the addition of lecithin. Differential scanning calorimetry thermograms revealed that the thermal stability of zein-lecithin nanoparticles was enhanced with the rise of lecithin level. The composite nanoparticles were relatively stable to elevated ionic strengths. Possible interaction mechanism between zein and lecithin was proposed. These findings would help further understand the theory of the interaction between the alcohol soluble protein and the natural small molecular surfactant. The composite colloidal nanoparticles formed in this study can broaden the application of zein and be suitable for incorporating water-insoluble bioactive components in functional food and beverage products.

Preparation and Characterization of Whey Protein Isolate–DIM Nanoparticles

“…By comparing the spectrum of WPI with encapsulated DIM, peaks of Amid I were shifted from 1640 cm −1 to 1647, 1666, and 1667 cm −1 , with different ratios of DIM in WPI, indicating the presence of an electrostatic interaction between WPI and DIM rather than the chemical reactions. Therefore, it is concluded that the interaction of WPI and DIM is based on electrostatic forces [49]. An increase in the intensity of Amid I and Amid II also suggests the binding of DIM to β-lactoglobulin; similar results were revealed by Wang et al [30].…”

“…Hydrogen bonding and hydrophobic interaction maybe the main forces related to the interaction of whey protein and hydrophobic substances [30]. Several characteristic peaks due to C–H stretching of the aliphatic group were observed at 2970, 2983, 2970, and 2980 cm −1 in the spectra of microencapsulated DIM with different ratios [14,49]. Amid I and Amid II bands are considered as the backbone of whey protein isolate, confirming the presence of α-lactalbumin and β-lactoglobulin, which are the main constituents of whey protein isolate.…”

Sodium deoxycholate-decorated zein nanoparticles for a stable colloidal drug delivery system

“…35 For this reason, the influence of the temperature on the various zein nanoparticles was investigated. The surfactant-free formulation showed a considerable increase of size and polydispersity index when it was heated, while the zeta potential analysis provided negative values (Table 3).…”

Zein Nanoparticles and Strategies to Improve Colloidal Stability: A Mini-Review

“…In the case of ionic strength and pH, these nanoparticles have been shown to be highly liable to aggregation at a low concentration of sodium chloride (NaCl), and to be unstable at pH above 5. The salt added to formulations increases the ionic strength, with consequent increases in van der Waals interactions and hydrophobic effects among the protein chains, favoring aggregation and precipitation of the proteins (Dai et al, 2016 ). Similar findings have been reported in other studies (Patel et al, 2010 ).…”