Unlocking the functional potential of asparagus fibre via a novel wet ball milling strategy

• Wet ball milling enhanced fibre functionality without achieving the smallest particle size. • Dry milling fractured fibres by raising the glass transition temperature through drying. • Fibre elongation, rather than particle size, governed techno-functional performance. • EDTA pre-treatment effectively reduced discolouration during wet ball milling. • Wet ball milling offers an energy-efficient route to valorise asparagus fibre by-products. This study investigated ball milling as a method to transform white asparagus pomace into functionalised fibre. The effects of ball milling conditions (i.e., temperature: 0°C, −20 °C or −40 °C; water content: pre-dried 9 % or wet 74 %) on the properties of obtained asparagus fibre were evaluated. Ball milling of wet pomace at 0 °C significantly improved water-holding capacity, viscosity, emulsifying stability, and enzymatic digestibility of asparagus fibre, despite not producing the smallest particles. In contrast, ball milling of pre-dried pomace led to the greatest size reduction but resulted in poor functionality of asparagus fibre due to the collapse of the dry fibrous structure that is in the glassy state. Fibre morphological analyses using confocal laser scanning microscopy and optical imaging indicated that changes in particle morphology/microstructure contributed more to the improved functionality than particle size reduction. Nevertheless, milling of wet pomace resulted in asparagus fibre with a dark colour which is likely to be attributed to polyphenol–iron interactions. Pre-treating asparagus pomace using ethylenediaminetetraacetic acid (EDTA) solution effectively reduced the discoloration after milling. These findings highlight that careful control of water content and temperature during ball milling, combined with appropriate pre-treatment, enables an energy-efficient strategy to produce high-functionalized fibre ingredients from fibre-rich plant by-products like asparagus pomace.