High pressure intensification of cassava resistant starch (RS3) yields

•A solvent free environment is used to produce resistant starch.•RS3 yields can be increased significantly by employing high pressure annealing.•Resistant starch formation times are shorter under high pressure conditions.

Cassava starch, typically, has resistant starch type 3 (RS3) content of 2.4%. This paper shows that the RS3 yields can be substantially enhanced by debranching cassava starch using pullulanase followed by high pressure or cyclic high-pressure annealing. RS3 yield of 41.3% was obtained when annealing was carried out at 400 MPa/60 °C for 15 min, whereas it took nearly 8 h to obtain the same yield under conventional atmospheric annealing at 60 °C. The yield of RS3 could be further significantly increased by annealing under 400 MPa/60 °C pressure for 15 min followed by resting at atmospheric pressure for 3 h 45 min, and repeating this cycle for up to six times. Microstructural surface analysis of the product under a scanning electron microscope showed an increasingly rigid density of the crystalline structure formed, confirming higher RS3 content.