Design of reduced-fat food emulsions: Manipulating microstructure and rheology through controlled aggregation of colloidal particles and biopolymers

Abstract

The objective of this study was to develop model reduced-calorie food emulsions with desirable textural and optical properties based on controlled aggregation of food-grade colloidal particles and biopolymers. The model food emulsion consisted of fat droplets (5wt.%), starch granules (4wt.%), and xanthan gum (0 to 0.02wt.%) under acidic conditions (pH3). The fat droplets were stabilized by a protein-based emulsifier (whey protein isolate). Fat droplet aggregation was induced by adding anionic xanthan gum to promote bridging flocculation of the cationic protein-coated fat droplets. Thermal processing (95°C) did not have a major impact on fat droplet aggregation, but it did promote starch granule swelling. The structural organization of the fat droplets could be regulated by altering xanthan levels. Relatively small droplet aggregates were formed at low xanthan concentrations that coated the starch granule surfaces. Conversely, large irregular shaped droplet aggregates were formed throughout the system at higher xanthan levels. The rheological and optical properties of the model emulsions could therefore be controlled by altering fat droplet organization. Addition of low levels of xanthan significantly increased the viscosity, yield stress, and complex modulus of the model food emulsions. However, high levels of xanthan led to the formation of large visible aggregates that would negatively impact on sensory quality. This study has important implications for the development of cost-effective and clean-label reduced-fat products with desirable quality attributes, such as dressings and sauces.

A review of the rheological properties of dilute and concentrated food emulsions

“…In food emulsions, electrostatic interactions are the most common attractive interaction between the hydrocolloid and droplet surfaces. For instance, the addition of charged polysaccharides to emulsions containing oppositely charged droplets has been shown to promote bridging flocculation, which leads to an increase in emulsion viscosity (Simo, Mao, Tokle, Decker, & McClements, ; Tippetts & Martini, ; Vingerhoeds, Silletti, de Groot, Schipper, & van Aken, ; Wu & McClements, ). Hydrophobic attraction : Under certain conditions, the surfaces of emulsifier‐coated oil droplets may gain some nonpolar character. As a result, there is an increase in the hydrophobic attraction between them, which can promote droplet aggregation.…”

“…Rheological measurements can also be used to monitor changes in the structural organization and interactions of the droplet in emulsions. For instance, measuring changes in the viscosity or elastic modulus of an emulsion when system conditions are changed in a specified way can be used to follow changes in emulsion properties (Zhu, Chen, McClements, Zou, & Liu, , ), such as droplet flocculation, continuous phase gelation, or gravitational separation (Wang & Heuzey, ; Wijaya, Van der Meeren, Wijaya, & Patel, ; Wu & McClements, ). This type of measurement can also be used to monitor the degradation of emulsions during preparation or storage.…”

Food structure design to modulate bioaccessibility of carotenoids from brazilian native fruits after screening of eleven non-conventional tropical fruits

“…The surfactant aggregates with celullose (figure 6) and probably pectin observed are gel-like structures and have some rheologic effects, like an increase in viscosity and microemulsion stability. Other works showed microemulsions interactions with polyshacarides (xanthan gum and locust bean gum) with microscopy photos that have an organization of the microstructure that is similar to the one we observed in our products (agregation, flocculation and gel-like structures), and similar rheological effects (Chung, Degner & McClements, 2013;Wu & McClements 2015). Therefore, we may conclude that the obtained microstructure is mostly an effect of surfactant-fibers interactions, which have a great importance in the final functional properties, since carotenoid-rich microcapsules need to be spread and free to be attacked by digestive enzymes for carotenoid accessibility.…”

Effects of the Addition of Spray‐Dried Whey on the Stability of Fat‐Reduced Mayonnaise‐Type Emulsions During Storage

“…The addition of whey to food matrices can be beneficial for the diet because whey contains essential amino acids and remarkable amounts of Ca, K, and P (Çakır‐Fuller, ; El‐Salam et al, ). Moreover, the addition of whey to a food product may partially replace the addition of fats (Liu, Tian, Stieger, van der Linden, & van de Velde, ; Wu & McClements, ). Dried and concentrated whey powders are commonly used for fortifications and contain 11–14.5% and 35–80% w/w of protein, respectively, depending on the processing method (Chegini & Taheri, ; El‐Salam et al, ).…”

“…Dried and concentrated whey powders are commonly used for fortifications and contain 11–14.5% and 35–80% w/w of protein, respectively, depending on the processing method (Chegini & Taheri, ; El‐Salam et al, ). However, the replacement of fat in reduced‐calorie food products can cause undesirable changes of the physical and sensory properties (Liu et al, ; Wu & McClements, ), affecting the consumer preference. For this reason, a specific study of the stabilization of reduced‐calorie emulsions is needed in the new formulated products.…”