Reducing Visual Differences in Whole Grain Bread Prepared with Hard Red and Hard White Wheat: Application for Sensory Studies

Abstract

Consumer taste preference can be influenced by visual preference. To eliminate the influence of visual preference in the sensory evaluation of whole grain wheat, a reproducible method to eliminate color differences between Whole Grain breads prepared from hard white wheat (HWW) and hard red wheat (HRW) was evaluated. Response surface methodology (RSM) was used to match the color of HWW to HRW with the addition of commercially available dye solutions: McCormick black (red #40, yellow #5, blue #1), red (red #40, red #3, yellow #6), and yellow (yellow #5). Bread color was assessed by L*, a*, and b* color parameters according to the CIELAB international system of color measurement. Four replicates of the control and dye treated breads were analyzed. Initial color values for HRW were L* = 56.8 ± 0.40; a* = 8.04 ± 0.44; b* = 21.34 ± 0.46. RSM was used to predict dye addition levels to match color between HWW and HRW. With the addition of black (0.457 µL/mL), red (0.574 µL/mL), and yellow (1.165 µL/mL) dye to HWW, breads could be produced with L*, a*, and b* values of no statistical difference to the HRW (P < 0.05). A timed storage trail demonstrated the need to standardize the time between bread production and feeding studies. Visual bias can hinder assessment of wheat varieties in sensory studies. A reproducible method of dying wheat was developed that can be used to reduce this bias in sensory studies. Practical Applications The ability to control color variability is a critical tool in determining perceived quality in sensory analysis of breads. In this study, a method to reduce or eliminate visual bias between breads made from different varieties of wheat was developed. This method is applicable to any foods where dye could be added to reduce or eliminate color bias in sensory studies.

Understanding whole‐wheat flour and its effect in breads: A review

“…Obviously, differences in the color of breads made from both types of WWFs are easily detectable, as is the taste (Grafenauer et al., 2020). In fact, to reduce the influence of bran color in sensory studies, the use of dyes has been proposed (Smith, Ramsay, Roe, Ferrante, & Brooks, 2019). Some bitterness is detected in breads made with red varieties and a sweeter taste in those made with white varieties (McGuire & O'Palka, 1995; Talbert et al., 2013; Watts et al., 2012).…”

Review of the Sensory and Physico-Chemical Properties of Red and White Wheat: Which Makes the Best Whole Grain?

“…Manufacturing grain products, particularly whole grain products, can be complicated by higher levels of these volatile and potentially bitter phenolic compounds mostly derived from the bran [6]. However, it is thought that white wheat is less bitter than red wheat, and may have broader acceptance [2], particularly among children who tend to be more sensitive to bitter tastes [7]. An advantage for wheat is its versatility within food products, yet for more than 20 years, preference for white wheat over red wheat in grain-based foods has been debated.…”

“…Sensory attributes include colour, odour, texture and flavour [14], and testing is important to determine taste preference among consumers. It is understood that children and adults differ in terms of their food choice preferences [7,19] and although the sensory characteristics are important, food choices are complex and learning [20], past behaviour, habit and hedonic factors all play a role [21]. The subjective nature of sensory testing and the production of reliable and reproducible outcomes has been questioned [21].…”

Tortilla chips made with white sorghum and corn: Comparison of sensory and physicochemical characteristics with corn‐made commercial products

“…This negative effect generated by color was also observed in tortilla chips made from sorghum, which were no different to rice chips in terms of brittleness or friability, but which obtained lower values of acceptability (Quintero‐Fuentes et al., 1999). Appearance, especially color, can greatly influence acceptance, and in certain studies, it has been used to mask products in order to try to obtain the preferred response on acceptance by participants without the use of visual effects (Smith, Ramsay, Ferrante, & Brooks, 2019).…”