Modulating fat digestion and encapsulating β-carotene in emulsions stabilized by nanocellulose

Abstract

This research aimed to study the influence of the addition of nanocellulose, either nanocrystalline cellulose (NCC) or nanofibrillated cellulose (NFC), on the properties and stability of 10% oil-in-water (O/W) emulsion encapsulating β-carotene and in vitro fat digestibility, including free fatty acid released, β-carotene bioaccessibility and stability. Tween 20 was selected to be used as an emulsifier whereas either NCC or NFC was used as a stabilizer at 0.05%(w/w), 0.10%(w/w), and 0.20%(w/w). Increase in NCC and NFC concentration caused the increase in oil droplet diameter, viscosity, zeta-potential, and creaming stability. NFC exhibited more pronounce effect on the properties and stability of the emulsions than NCC. Encapsulation efficiency of the emulsions containing nanocellulose (99.65% to 99.88%) were significantly (p<0.05) higher than that of the control (98.60%). Moreover, NFC at concentration higher than 0.05%(w/w) also promoted the highest stability of β-carotene in the emulsions after storage at room temperature for eight weeks. For in vitro fat digestion, NFC addition at concentration higher than 0.05%(w/w) decreased the initial digestion rate and final digestion extent as well as increased stability of β-carotene during digestion. Conversely, NCC addition to the emulsions, especially at 0.20% (w/w) increased the bioaccessibility of β-carotene. Overall, both NCC and NFC can be used as a novel natural stabilizer for the design of colloidal delivery systems for bioactive compounds. The nanocellulose type and concentration selection depends on the main purpose of food product development.