Using different physical treatments to modify the structure and improve the technofunctional properties of clementine by-products

Clementine by-products are an important source of dietary fiber, which has different technofunctional properties depending on its chemical composition and structure. These properties can be modified through different treatments. In this work, the impact of treatments such as hot air drying (HAD), homogenization (HOM), freeze drying (FD), and extrusion (EXT) was evaluated on the structure and technofunctional properties of clementine by-products’ powders, to promote their use as ingredients in food development as a way of valorization. The structure of by-products was studied using microscopy (Light Microscopy and Field Emission Scanning Electron Microscopy) and vibrational spectroscopic (FTIR and FT-Raman) techniques. The technofunctional properties, water and oil holding capacities, water solubility, swelling capacity, and emulsifying capacity, as well as particle size were evaluated. HOM and EXT showed a more stratified and porous structure than HAD and FD. FTIR and FT-Raman showed that the by-products mainly comprised pectin and cellulose. Regarding technofunctional properties, HOM powders had high water retention and swelling capacities, and good emulsifying capacity even when using high amounts of oil in an emulsion (75 %). FD powders showed the highest oil retention capacity and EXT powders the highest water solubility.