Impact of non-thermal modifications on the physicochemical properties and functionality of litchi pomace dietary fibre

Pomace is frequently underestimated as a complex by-product. High pressure homogenisation (HPH), enzymatic hydrolysis (EH) and high hydrostatic pressure (HHP) modifications are applied to improve the functional properties of litchi pomace insoluble dietary fibre (LPDF). The relationships between physicochemical properties and structural alterations and digestibility of LPDF are studied. The results showed that HPH, EH and HHP changed the LPDF's microstructure, causing it to develop more porous structures. Meanwhile, HPH modification exhibited a remarkable effect on LPDF's water holding (15.6 g/g), water swelling (26.1 mL/g) and oil retention (5.4 g/g) capabilities, resulting in the change of the complexity of the neutral sugar side chain. Notably, the highest total phenol content (3.4 GAE mg/g) and antioxidant activities (DPPH 153.6, ABTS 188.9, FRAP 195.1 μmol Trolox/g) were also observed in LPDF modified with HPH. Moreover, the diversity of structural features and high affinity of modified LPDFs are conducive to its functional properties, i.e., inhibition of starch digestion. The remarkable potential of LPDF modified with HPH was attributed to the beneficial effects of dietary fibre on human health. As a result, litchi pomace could be a useful and effective source of functional fibres. The incorporation of litchi pomace into the human diet is still underexplored but is a promising alternative.