Modelling the stability of maltodextrin-encapsulated grape skin phenolics used as a new ingredient in apple puree.

Highly soluble maltodextrin-encapsulated grape skin phenolics comprising anthocyanins and less hydrophilic flavonoids were added as an ingredient to apple puree. Upon formulation, heat treatments were applied to achieve 3-14 decimal reductions (D) of the target microorganism (Alicyclobacillus acidoterrestris). A storage study was performed at 15-35°C for 1month. Monomeric anthocyanins were retained at 100% after the 3 D treatment, while anthocyanin retention decreased to 72% with increasing heating intensity until 14 D. During storage, the concentration of monomeric anthocyanins decreased following first-order kinetics (k25°C=34.4d(-1), activation energy=51.0kJ/mol). The flavanols were more stable than the monomeric anthocyanins. The hydroxycinnamic acid, dihydrochalcone and flavonol contents did not change. The fortified puree had a two-fold higher reducing capacity with respect to apple puree. Overall, this ingredient could meet the industrial demand for sustainable colouring agents and health promoting compounds.