Modelling and optimisation of apple pomace powder hydrothermal treatment parameters using response surface...

Agri-food waste management focuses on recycling and valorising by-products, such as fruit and vegetable residues, to create functional compounds and materials that support zero-waste strategies. Apple pomace powder has shown great potential in enhancing the nutritional and textural qualities of foods, with its properties strongly influenced by processing methods such as drying, extrusion and hydrothermal treatment.

The study aimed to investigate the effect of hydrothermal treatment parameters on selected technological and functional properties of dried apple pomace powder based on the properties of pulps obtained after its hydration. Response surface methodology was employed to optimise time and temperature at the levels of 1-10 min and 60-90 °C, respectively. The obtained results showed that elevated temperature and longer duration of the process favourably influenced the water holding capacity of apple pomace powder, which was in the range of 6.44-7.92 g_water g_d.m. ^-1. The texture-forming potential of apple pomace powder was also improved, as observed in an increase in firmness and consistency, as well as adhesiveness and index of viscosity. However, higher temperatures negatively affected the polyphenol content and antioxidant activity of the obtained pulps. Pulps obtained after hydrothermal treatment were characterised by a smaller average particle size, which could favourably affect functional properties of the pomace, and better perception and acceptance of a product.

Hydrothermal treatment effectively enhanced the techno-functional properties of apple pomace powder, improving water holding capacity, texture and particle size, thus supporting its use in food applications. Higher temperatures reduced bioactive compounds: optimisation identified 71.8 °C for 10 min as the best balance between functionality and bioactive retention. These results provide a clear pathway for valorising apple pomace in functional foods and advancing sustainable, zero-waste strategies. © 2025 Society of Chemical Industry.