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.