In vitro investigation of the influence of nano-cellulose on starch and milk digestion and mineral adsorption

Three types of nanocellulose, namely nano-fibrilated cellulose (NFC, also called cellulose nano-fibrils (CNF)), TEMPO (2,2,6,6-tetramethylpiperidine-1-oxyl radical) oxidized cellulose nano-fibrils (TEMPO-CNF), and nano-crystalline cellulose (NCC, also called cellulose nano-crystals (CNC)), were studied in terms of their effects on in vitro milk digestion and mineral adsorption. The effects of anionic NC (TEMPO-CNF and CNC) on in vitro starch digestion and glucose diffusion were also investigated. Results show that TEMPO-CNF and CNC at high concentrations caused significant reductions in glucose diffusion, especially at 0.36% (w/w) TEMPO-CNF and 2–4% (w/w) CNC. In addition, CNF and TEMPO-CNF at 0.30% (w/w) significantly reduced the amount of free fatty acid produced during intestinal digestion of milk fat. CNC at a concentration of 0.3% (w/w) delayed diffusion of free amino nitrogen during intestinal digestion of milk protein. All three types of NC adsorbed significant amount of Fe, and CNC adsorbed significant amount of Zn, while no significant adsorption was observed on other minerals (Ca, Mg, Zn, Cu and Ag). Results from this study suggest that all three types of NC, when incorporated in food or supplements as zero-calorie fiber, may affect food digestion and nutrient absorption.