Electrospinning is a potential way for preparing edible plant protein-based nanofibers with porous surface using safflower seed meal

Food microstructure design has become an important research area in artificial food manufacturing. The fibrous structure is one of the most critical elements since it is the fundamental building blocks constructing the structure of several important food matrices. However, at present, edible fibers at nanoscale are seldomly successfully manufactured due to technical difficulties when only food-grade materials are allowed to be used. In the current study, edible nanofiber consisting of a single component of safflower seed meal protein (SMP) was prepared based on a three-step protocol consisting of electrostatic spinning, protein-cinnamaldehyde cross-linking, and subsequent immersion in the citric acid buffer to remove none-protein components. Addition of pullulan (PUL) to SMP during electrospinning facilitated fibrous structure formation. Results of SEM demonstrated that SMP: PUL = 5:5 with combined ratio 20% (w/v) in water is the upper limit to obtain well-structured composite nanofiber with no addition of Tween 80. In the second step, protein-cinnamaldehyde cross-linking was implemented to stabilize the structure of SMP. In the last step, citric acid buffer with pH4.6 was used to remove pullulan residues and thereafter nanofibers with porous surfaces composed of only SMP were successfully obtained. Our results showed that SMP single-component nanofibers had high thermal stability and good water-holding capacity, and thus suggesting that electrospinning can be a potentially innovative strategy to manufacture food fibrous microstructures especially at nanoscale.