2.7. Sensory Evaluation: Quantitative Descriptive Sensory Analysis (QDA)

A trained sensory panel (n = 10–12), with a minimum of two years’ experience, developed consensus descriptive vocabularies of the sensory attributes (appearance, aroma, taste/flavour, mouthfeel and aftereffects) over three training sessions for cakes and three for biscuits, using reference standards to assist in defining attributes where required (Supplementary Table S1). For cake, approximately 25 g of each sample (30 × 30 × 60 mm), with crust removed, were presented to panellists at each tasting on a 3-digit coded ceramic grey plate. For biscuits, approximately 3.5 g of each sample (half of a biscuit, 50 × 35 mm), were presented at each tasting to panellists on a 3-digit coded ceramic grey plate. During duplicate quantification, samples were presented in a balanced monadic sequential order and sample attributes were scored by panellists individually on visual analogue scales (scaled 0–100) using Compusense cloud software (Compusense Inc., Guelph, ON, Canada). In order to minimize carryover effects, a 1 min interval was allowed between each sample. In addition, panellists were provided with filtered water and asked to cleanse their palate between tastings. Panellists received the agreed list of attributes, including definitions, to aid them during sample evaluation. Unstructured lines scales were used except for sweetness where a structured scale was used with 5 reference anchors. The reference anchors were 5 aqueous sucrose solutions of increasing sweetness (2, 3, 4, 5 and 6% w/v) for which the anchor positions had been agreed by the panel (anchor point 1 [low] = 0, 2 = 25, 3 = 50, 4 = 75 and 5 [strong] = 100)). These standards were given to the panellists at the beginning of the test for refamiliarisation when panellists were instructed to score the sweetness on the structured line scale. All assessments were carried out in isolated sensory booths under artificial daylight and with the room temperature controlled at 23 °C.