Textural characterisation of wheat–oat breads using a combination of quantitative descriptive analysis and partial napping profiling techniques

The aim of this study was to determine the textural sensory profile of wheat breads developed using oat flour at different substitution levels (10%, 30%, and 50%) and particle sizes (<224, 250–280, 280–500, 500–600 μm). A trained descriptive panel evaluated the wheat–oat breads using quantitative descriptive analysis (QDA) (n = 8) and partial napping (PN) (n = 12) sensory techniques. The QDA results showed that the textural properties of the breads were significantly affected by oat flour at different substitution and particle size levels (P < 0.001). The attributes crumb ‘denseness’ and ‘stickiness’ discriminated most frequently across samples, while crumb ‘chewiness’ and ‘dryness’ discriminated the least. Principal component analysis (PCA) illustrated that in PC1 (59%) crumb ‘denseness’ was positively correlated with crumb ‘hardness’ and ‘graininess’, while ‘stickiness’ was negatively correlated with crumb ‘graininess’. The application of clustering techniques on QDA data showed that breads with 10% oat flour were differentiated based on particle size; however, as the substitution level of oat flour increased, the substitution level of oat flour used in formulations exceeded the effect of particle size. In terms of PN, panellists identified four distinct groups of wheat–oat breads, indicating that wheat breads with 10% oat flour and <224 μm, 280–500 μm and whole oat flour had similar textural properties to the control wheat bread sample. The texture of wheat breads substituted with 50% oat flour were very different to the control. The results of this study suggest that in addition to the effect of substitution level, fractionation of oat flour may have application in the production of wheat bread formulations with different textural profiles. The findings also emphasise the importance of considering clustering techniques when evaluating complex samples for new product development applications.