The impact of drying and storage in the semi-dry state on the texturizing potential of partially pectin-depleted tomato cell wall material functionalised by high-pressure homogenisation

The current study assesses the impact of air -drying at 22 C-degrees after water -alcohol exchange (and potentially also of the preceding freezing step) and storage in the semi -dry state on the texturizing potential of cell wall material (CWM) functionalised by high-pressure homogenisation (HPH). Reconstitution of the suspension was performed using overnight stirring only or combined with high -intensity mixing. Partially pectin -depleted CWM of tomato was used as study material, as both the network forming capacity (evaluated by the storage modulus of the suspension, G') and water binding capacity (WBC) could be largely improved by HPH at 20 MPa. The functionalisation of the CWM was followed by the drying step and storage of the dried CWM at different relative humidities at 30 C-degrees. Drying, even after water -alcohol exchange, resulted already in an extensive decrease (approximately 60%) in the G' of the suspension when reconstituted. When the dried material was regenerated using high -intensity mixing reverting the aggregation induced by drying, the decrease in G' was 50% and 33%, with and without preceding freezing, respectively. The impact of drying on the WBC was limited and a higher WBC was observed after high -intensity mixing. Based on the glass transition line of the alcohol -insoluble residue of tomato, it was anticipated that only some of the CWM systems were in the rubbery state during storage. A decrease in the G' during storage was only observed at the two highest relative humidities studied and only upon reconstitution using high -intensity mixing. Overall, the major impact on the functionality was linked with the drying phase.