Sensory Texture and Mechanical Properties of Stranded and Particulate Whey Protein Emulsion Gels

Abstract

The influence of gel structure type and amount of lipid on texture of whey protein isolate (WPI) gels was evaluated by descriptive sensory analysis and determination of fracture and water-holding properties. A series of 16 gels of varying structure (particulate or stranded) and lipid composition (0% to 20%) were developed at a constant protein concentration (12% w/v). Stranded gels had higher values for fracture strain, strain hardening, and held-water. Particulate and stranded gels were similar in fracture stress. Eighteen sensory texture attributes were used to evaluate gels throughout the mastication process that was separated by the following phases: prefracture, 1st bite, chew-down, and preswallowing. The 1st bite property of firmness and preswallowing properties of number of chews and time to swallow were the only sensory properties associated with lipid content. Fracture stress was correlated with these properties. The remaining 15 texture terms were primarily determined by gel structure type. It appears that gel structure type determines the primary texture properties of WPI emulsion gels. An increase in lipid content increases gel firmness and amount of chews required; however, it did not change the primary texture sensation.

Designing Food Structure to Control Stability, Digestion, Release and Absorption of Lipophilic Food Components

“…10,11 digestive enzymes, interacts with the surfaces of the tongue, mouth, and throat, experiences a complex flow profile, and may be physically broken down into smaller pieces by chewing. [15][16][17][18][19][20][21] The nature and extent of the changes of the lipid phase of a food in the mouth and throat depends on the original composition and properties of the lipid phase, its structural organization within the food, and the nature of the food matrix. 22 Typically, a food or beverage only spends a relatively short time (5 to 20 s) in the mouth before being swallowed.…”

Oral processing of emulsion systems from a colloidal perspective

“…NaCl and CaCl2) reduced the surface charge of the emulsion droplets and caused calcium bridging between the droplets; this resulted in an increase in the strength of the protein emulsion gel and made the structure of the gel change from homogeneous at the micro scale to porous in both heat-set and cold-set whey protein emulsion gels. 62,76,77 A prior heating of the protein solution to denature the protein that stabilizes the emulsion or of the protein-stabilized emulsion to denature the surface protein can enhance the acid-induced gelation of whey-protein-stabilized emulsions. 62,64,65,77 …”

Food Biophysics of Protein Gels: A Challenge of Nano and Macroscopic Proportions

“…In very general terms, particulate gels were more similar to Mozzarella and Monterey Jack cheeses, and the finestranded gels were similar to agar gels [74] (Barrangou et al unpublished data). A superscript letter indicates that the term was evaluated in the investigations of (a) Gwartney et al, [73] (b) Brown et al, [74] or (c) Barrangou et al (unpublished data). *Definition for terms used in Gwartney et al [73].…”

“…A comparison of fine-stranded and particulate whey protein isolate gels was made under gelling condition where gels had similar fracture stress (11-12 kPa) but different fracture strain [73]. All gels were at pH 7.0 and contained 12% protein and 25 mM NaCl.…”

“…The first step in descriptive analysis is to develop a set of terms that describe the texture. The terms listed in Table 1 were developed and used for analysis of whey protein isolate gels [73], agar gels (Barrangou et al unpublished data) and two cheeses (Mozzarella and Monterey Jack) [74]. The general sequence for evaluating gel texture once placed in the mouth is: surface properties, first bite, chew down and residual [72].…”