Differences in water and biopolymer dynamics in Australian native fruits and the connection with drought-tolerance...

Australian native fruits are unique in water-binding and agricultural properties. Optimal preservation for sustainable nutrient delivery is not well understood but essential for increased consumption. Water influences microbial and structural stability, so the anomalous behaviour of water in native fruits requires investigation. Dynamics of hydrocolloid-associated water in the native fruits finger lime, muntrie, riberry, and Kakadu plum, as well as apple, was studied with neutron spectroscopy. Native fruit matrix water featured self-diffusion constants slower than apple by up to 61 %, demonstrating strong monolayer water binding, which was also correlated with drought-tolerance markers. Free water self-diffusion was up to 24 % faster than apple and even 13 % faster than pure water, which in turn was related with diffusion-accelerating minerals e.g. potassium. Stronger water binding in native fruits may be due to more small starch polymers and fewer cellulose polymers. This work advances the sustainable processing of more climate-resilient crops.