Sensory exploration of the freshness sensation in plain yoghurts and yoghurt-like products

• We investigate the freshness sensation of fermented milks.
• Qualitative, static and dynamic quantitative methodologies were compared.
• Holistic consumer and analytical dynamic results were consistent.
• A temporal ordering of the freshness sensation sensory drivers was established.

The term “freshness sensation” is used by consumers for characterizing some plain yoghurts and yoghurt-like products. This study consisted in an investigation of this sensation aiming at determining its underlying sensory attributes. First, two focus groups of consumers were conducted to open up the framework. A set of plain yoghurts and yoghurt-like products, both commercial and experimental, was then subjected to sensory analysis. The samples were sorted by means of a free sorting task, and further scored for the intensity of their freshness sensation and their liking, by 72 untrained consumers. Temporal Dominance of Sensations (TDS) measurements were performed by a trained sensory panel on the same products. The holistic notations of the freshness sensation and TDS results were finally combined using an internal mapping methodology. Freshness sensation and liking were highly correlated. However, a product with a low liking score was evaluated as giving an intense freshness sensation. A strong consensus of untrained subjects was observed on the fermented milk with the lowest freshness sensation intensity. Fermented milks with the highest freshness sensation intensity were the ones with the highest fat content. The main characteristics of the freshness sensation in yoghurts and yoghurt-like products were a sensation of decrease in the mouth temperature, followed by a fluid texture together with a cream flavor. A thick texture followed by the sensations of acidity and astringency clearly appeared to decrease the freshness sensation of the products. The key sensory attributes of the freshness sensation were highlighted by classical sensory approaches (free sorting task, freshness sensation scoring and focus groups). Their temporal order was determined by the TDS methodology. This could be valuable for formulating fresher products.