The model may well have future applications on defining complex relationships between food structure, texture, sensory perception, satiety and nutrient availability.
Previous studies have highlighted the challenges faced in evaluating the role of food structure on texture and health due to variations in macronutrients, total calories and sample volume.
The knowledge of food structure has become something of ongoing issue, particularly in light of the industry’s efforts in reformulating popular products to reduce high levels of sugar, fat and salt.
In addition, the emergence of specific market segments such as the elderly, vegan, and gluten-free has accelerated the need to develop textures that consumers are familiar with whilst meeting nutritional requirements.
Texture tests
The model featured in the study differs from previous studies as a range of textures that are representative of conventional food products were included.
Here, a team assembled from researchers at North Carolina State University, created a set of isocaloric, macronutrient-matched model foods with varying textures.
Six distinct food textures were produced by varying the extent and combination type of 11% whey protein isolate (WPI) solutions.
Textures were grouped into fluid-like (fluid, thin and thick semisolids) and solid-like (three soft solid gels), based on rheological and sensory properties.
Six female subjects, aged between 43 and 58 years, began evaluating both WPI model foods and commercial foods (tap water, heavy cream, chocolate syrup, maple syrup, molasses, chocolate pudding and Mozzarella cheese) as a reference.
Criteria used at the stages of pre-consumption, first chew, chew down and post swallow were assessed using a 0-15 point scale from none (0) to high (15).
The team found correlations with increasing mechanical stiffness of the food with increasing cohesiveness (a measurement of the degree to which breakdown particles stick together) in fluid-like textures and a decreasing cohesiveness in solid textures.
In other words, more chewing was required for the foods that were stiffer in structure. Additional findings identified solid textures were broken down with the molars while fluid-like textures were manipulated by tongue and jaw movements.
Food consumption control
“For this model food system, the movement from fluid-like to solid-like occurred when oral processing required fracture and formation of particles,” the study commented.
“This model food system can be used for future investigations into the effects of food structure and texture on parameters of food consumption, including the regulation of food intake via physiological and psychological satiation and satiety, and nutrient bioavailability.”
Measures of sensory hardness and firmness have previously been observed with mechanical fracture properties of food that contain protein and/or polysaccharide gels.
While only minor textural differences existed among the soft solid gels in this study, trends in compressibility, particle size and cohesiveness were consistent with those observed between stranded and increasingly coarser gels.
Source: Journal of Texture Studies
Published online ahead of print, doi:10.1111/jtxs.12182
“An Iso-Protein Model Food System for Evaluating Food Texture Effects.”
Authors: Caroline Campbell et al.