Aggregation kinetics of heated whey protein-stabilised emulsions: effect of low-molecular weight emulsifiers

Soy Protein Isolate-Phosphatidylcholine Nanoemulsions Prepared Using High-Pressure Homogenization

The nanoemulsions of soy protein isolate-phosphatidylcholine (SPI-PC) with different emulsion conditions were studied. Homogenization pressure and homogenization cycle times were varied, along with SPI and PC concentration. Evaluations included turbidity, particle size, ζ-potential, particle distribution index, and turbiscan stability index (TSI). The nanoemulsions had the best stability when SPI was at 1.5%, PC was at 0.22%, the homogenization pressure was 100 MPa and homogenization was performed 4 times. The average particle size of the SPI-PC nanoemulsions was 217 nm, the TSI was 3.02 and the emulsification yield was 93.4% of nanoemulsions.

Improved Bioavailability of Encapsulated Bioactive Nutrients Delivered through Monoglyceride-Structured O/W Emulsions

Effects of monoglyceride (MG) on the properties of WPI-stabilized emulsions and the bioavailability of encapsulated β-carotene were investigated. MG-structured emulsions showed reduced surface charge, higher viscosity, and better creaming stability than an emulsion without MG. Exposure of emulsions to GIT digestion led to significant changes in droplet size and interfacial properties. In vitro bioavailability of β-carotene in 1% MG (63.9%) and 2% MG (77.1%) structured emulsions were higher than that in emulsion without MG (53.4%) (p < 0.05). All MG emulsions demonstrated a better cellular uptake of β-carotene by Caco-2 cells than the emulsion without MG (p < 0.05). A significant increase in the cellular uptake of β-carotene with increasing MG content was observed, increasing from 0.109 μg/well for the 0.5% MG emulsion and up to 0.138 μg/well for 2% MG emulsion. The findings in this study confirm the potential of the MG-structured emulsions as novel carriers for lipophilic nutrients with improved stability and bioavailability.

Properties of chitosan-microencapsulated orange oil prepared by spray-drying and its stability to detergents

Fragrance encapsulated in small particles of <20 μm diameter is preferred for use in textiles. This study demonstrated that the proper combination of surfactants could produce small and heat-stable emulsion droplets with chitosan that could be spray-dried to produce microcapsules. The microcapsules were able to be deposited onto cotton using water or detergents. It was found that stable emulsion was obtained when Tween 40 and Span 20 were used as compound emulsifiers with the ratio of 4:1 (w/w). The optimum conditions were 1% (w/w) chitosan in acetic acid with the compound emulsifiers of 3-7% (w/w) in the oil, and the inlet temperature for spray-drying was 150 °C. The encapsulation efficiency for orange oil was >90% with a 1:2 (w/w) ratio of oil to chitosan. Microcapsules had a mean diameter of <20 μm and regular particle morphology. The orange oil in the microcapsules was well retained in cotton fabrics after washing in normal detergent solution. The process and products are low in cost, nontoxic, biocompatible, and biodegradable.

Edible films and coatings from whey proteins: a review on formulation, and on mechanical and bioactive properties

The latest decade has witnessed joint efforts by the packaging and the food industries to reduce the amount of residues and wastes associated with food consumption. The recent increase in environmental awareness has also contributed toward development of edible packaging materials. Viable edible films and coatings have been successfully produced from whey proteins; their ability to serve other functions, viz. carrier of antimicrobials, antioxidants, or other nutraceuticals, without significantly compromising the desirable primary barrier and mechanical properties as packaging films, will add value for eventual commercial applications. These points are tackled in this review, in a critical manner. The supply of whey protein-based films and coatings, formulated to specifically address end-user needs, is also considered.

Fluorescence spectroscopy as a tool for monitoring solubility and aggregation behavior of β-lactoglobulin after heat treatment

Denaturation and aggregation of whey proteins are of interest to the food and pharmaceutical industry due to the importance of final structure in functionality, impact on food texture, and the chemical stability of the final product. In this study, we demonstrate the potential of fluorescence spectrometry combined with multivariate chemometric methods for quantifying solubility and aggregation behavior of beta-lactoglobulin (beta-LG); a major whey protein and a frequent food ingredient. Heat-induced aggregation of beta-LG was studied under different conditions including pH, temperature and heating durations. Results showed very good agreement between the fluorescence-based predictions and measurements obtained by HPLC and gravimetric analysis regardless of the conditions. Standard normal variate (SNV), a signal preprocessing and filtering tool, was found to enhance the predictive accuracy and robustness of the fluorescence-based model.

Thermodynamic and functional properties of legumin (11S globulin from Vicia faba) in the presence of small-molecule surfactants: effect of temperature and pH

We report on the effect of a set of water-dispersible small-molecule surfactants (the main and the longest-hydrocarbon components of which are a citric acid ester of monostearate, a sodium salt of stearol-lactoyl lactic acid, and a polyglycerol ester of stearic acid) on molecular, thermodynamic, and functional properties of the major storage protein of broad beans (Vicia faba) legumin in different molecular states (native, heated, and acid-denatured). The interaction between legumin and the surfactants has been characterized by a combination of thermodynamic methods, namely, mixing calorimetry and multiangle laser static and dynamic light scattering. It was found that hydrogen bonds, electrostatic interactions, and hydrophobic contacts provided a basis for the interactions between the surfactants and both the native and the denatured protein in aqueous medium. Intensive association of the protein molecules in a bulk aqueous medium in the presence of the surfactants was revealed by static and dynamic laser light scattering. In consequence of this, both the surface activity and the gel-forming ability of legumin increased markedly, which has been shown by tensiometry, estimation of protein foaming capacity, and steady-state viscometry. A likely molecular mechanism underlying the effects of small-molecule surfactants on legumin structure-forming properties at the interface and in a bulk aqueous medium is discussed.

Heat-induced destabilization of oil-in-water emulsions formed from hydrolyzed whey protein

The emulsifying ability, heat stability, and coalescence stability of oil-in-water emulsions prepared with whey protein of varied degrees of hydrolysis (DH), and at varied protein contents, was studied. Whey protein hydrolysates (WPH) with a DH of 4% and 10% had poorer emulsifying ability than non-hydrolyzed whey protein concentrate (WPC), but were more heat stable. Increasing DH between 10 and 27% improved emulsifying ability and further improved the heat stability of the emulsion droplets. Increasing DH from 27 to 35% led to a big decrease in both emulsifying ability and heat stability. The quiescent coalescence stability of WPH emulsions was relatively good up to a DH of 27%. Above DH 27% emulsions become highly unstable. It appears that two mechanisms of instability are at work here. At low DH heat-induced denaturation and aggregation occur. In the DH range of 4-20% heat stability increases as protein globular structure is disrupted. At a DH greater than 27% we see a change from a hydrolysis-induced increase in heat-stability to coalescence instability, with a resultant large increase in emulsion breakdown during heating.