Investigating the in-vitro and in-vivo flavour release from 21 fresh-cut apples

• 21 different apple cultivars have been investigated for flavour release profiles.
• PTR-ToF-MS is used to measure the in-vivo and in-vitro release of apple flavour.
• Selected in-vivo parameters describe the texture-flavour release relationship.
• Dynamics of flavour release is described by Tmax in relation to in-vivo release.
• Juiciness in apples induces more swallowing which may increase flavour perception.

In-vitro and in-vivo flavour release from 21 different apple cultivars was studied using proton transfer reaction time-of-flight mass spectrometry (PTR-ToF-MS) with a focus on the relationship between texture and volatile organic compound (VOC) emission. Generally, firm-juicy cultivars had a shorter time to first swallow (Tswal) and a higher number of swallows (Nswal), while softer-mealy cultivars had a longer Tswal and a lower Nswal. Firm-juicy cultivars containing high VOC concentrations had a short time to maximum intensity (Tmax) owing to a shorter Tswal and a higher Nswal as juice was released during mastication. Swallowing increased VOC flow through the nasal cavity. These results differ from previous flavour release studies with gel/gel-like model systems as juiciness/release of fluids is not a factor in such matrices. The current study, therefore, highlights the benefits of using in-vivo analysis to gain a better understanding of flavour release in real food products.