The Yield Improvement of Resistant Starches from Africa Locust (Parkia biglobosa): The Influence of Heat-moisture, Autoclaving-cooling and Cross-linking Treatments

Native paprika starch was treated by heat-moisture treatment (HMT), autoclaving-cooling (Aut-cd) with and without anhydride acetic acid/adipic acid (Aut-acid) and sodium trimetaphosphate/sodium (STMP/STPP) tripolyphosphate cross-linking to produce Resistant Starch (RS). The resistant starch yield, crystalline structure, as well as other physicochemical properties of the modified starch was investigated. The yield of resistant starch was 36.33 and 50.16%, by HMT and Aut-col, respectively, whereas 48.56 and 50.16%, respectively were obtained by Aut-acid and STMP/STPP. The scanning electron microscopy images clearly illustrated that the granular structure of native parkia starch was disrupted and a continuous network with irregular shape was formed after HMT and autoclaving-cooling cycles. The subsequent chemical cross-linking appeared to make the network structure more compact and dense. X-ray diffraction patterns showed that B- and V types coexisted in all the modified parkia starches and the DSC results also showed that the formation of amylose double helices could contribute to the changes in the X-ray diffraction patterns. The RS-rich powder presented crystalline due to the process of heat moisture and autoclaving-cooling cycles with cross-linking treatment induced starch retrogradation. The procedure proposed might be used for production of a RS-rich powder from parkia starch with high resistant starch level and functional properties.