A preliminary study on the synthesis of resistant starch type III (RS - 3) from banana flour

Abstract

Resistant starch (RS) is a functional food regarded as prebiotic beneficial to human health. ~3 is specifically a type of RS synthesised from retrograded starch. In this research, a preliminary study has been conducted to explore the potentiality of producing ~3 from starchy banana flour of Indonesian variety (pisang ambon). In particular, the effect of several process parameters on the RS content and functional properties of the products has been investigated. Synthesis of RS-3 was carried out using 1-5 cycles of subsequent autoclaving (121 °C, 15 psi, 15 minutes) and cooling (4 0C, 24 hours) processes, after initial pregelatinisation of starch flour suspension (20'Ya-wlv, at 70°C and 20 minutes). The resulting gelatinous mass was subsequently dried, pulverised and sieved to obtain fine RS-3 powder. The experimental result shows that RS content of the products (13.98'Ya-18.35%) was significantly higher compared to banana flour (4.57%). Solubility of RS-3 products was significantly higher, while their swelling power was slightly lower than banana flour. The result suggests that autoclaving-cooling process is a promising method to improve RS content and functional properties of banana flour.