Three types of nanocellulose (NC), namely cellulose nano-fibrils (CNF), TEMPO-oxidized CNF and cellulose nanocrystals (CNC), were studied in terms of their effects on in vitro digestion of whey protein isolate (WPI). The behavior of NC itself during digestion was monitored by particle size, confocal microscopy imaging, viscosity, and zeta potential. 1% CNF and 4% CNC significantly retarded free amino nitrogen (FAN) diffusion (23% and 50% respectively) mainly due to high viscosity. 4% CNC also significantly reduced %FAN release during intestinal digestion. Anionic NC (TEMPO-CNF and CNC) bound with WPI causing less protein aggregation at the gastric phase as well as reductions in mean particle size and/or viscosity of digesta. However, cellulose and CNF did not bind with WPI. The findings from this study lay a foundation for future applications of nanocellulose in the food industry as rheology modifiers and development of functional foods for delaying gastric emptying and promoting satiety.
Keywords: Cellulose nano-fibrils; Cellulose nanocrystals; Fluorescence; TEMPO-oxidized cellulose nano-fibrils; Viscosity.
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