Structure of whey protein emulsion gels containing capsaicinoids: Impact on in-mouth breakdown behaviour and sensory perception

• Published in: Food hydrocolloids Vol. 92; pp. 19 - 29
• Main Authors: Luo, Nan, Ye, Aiqian, Wolber, Frances M., Singh, Harjinder
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.07.2019
• Subjects: Capsaicinoid; capsaicinoids; droplet size; droplets; Emulsion gel; emulsions; gels; hardness; hydrocolloids; ionic strength; Mastication; mouth; Mouth burn; oils; particle size; rheological properties; Rheology; saltiness; sensation; Sensory perception; sodium chloride; whey protein; Mouth burn; Mastication; Capsaicinoid; Emulsion gel; Sensory perception; Rheology
• ISSN: 0268-005X; 1873-7137
• DOI: 10.1016/j.foodhyd.2019.01.019

This work investigated the sensory perception of whey protein emulsion gels containing capsaicinoids, in relation to their structure and in-mouth breakdown behaviour. The gel structure was modified by varying the oil droplet size and the ionic strength. Eighteen human subjects were used to investigate oral processing behaviour and sensory perception. The gels were classified into three groups according to their rheological properties: semi-solid gel (10 mM NaCl with d4,3 of ∼0.17 μm); soft and elastic gels (10 mM NaCl with d4,3 of ∼4, 1 and 0.5 μm); hard and brittle gels (100 mM NaCl with d4,3 of ∼4, 1, 0.5 and 0.17 μm). A power-law relationship between gel hardness and masticated bolus particle size was established: Y=25.38X−0.29, with R2 = 0.69, indicating that greater hardness led to smaller bolus particle size. A power-law relationship between mouth burn perception and bolus particle size was also established: Y=119.5X−0.25, with R2 = 0.76, indicating that mouth burn perception was positively related to the degree of fragmentation. A higher degree of fragmentation led to greater surface exposure during mastication and, therefore, a greater possibility of capsaicinoid molecules being released. Moreover, an increase in gel hardness led to a lower diffusion rate of capsaicinoid molecules through the gelled particles and, therefore, to lower mouth burn perception. The effects of oil droplet release after mastication and saltiness perception were less important than the degree of fragmentation and gel hardness. [Display omitted] •The mouth burn perception of capsaicinoids in emulsion gels was investigated.•The masticated bolus particle size depends on gel hardness.•Smaller masticated bolus particle size leads to greater mouth burn perception.•Mouth burn perception correlates negatively with food hardness.•Modifying food structure can tailor food breakdown behaviour and sensory perception.