Properties and health benefits of a novel resistant starch

Resistant starch (RS) is known for its use to prevent hyper- and hypo-glycemic responses of diabetic patients and for intervention of diabetes and obesity. A novel RS was developed by complexing high-amylose cornstarch VII (HA7) with fatty acids (FA). The HA7-FA complex contained up to 72% RS when analyzed using AOAC Method 991.43 for total dietary fibers. The objective of this study was to understand the properties and health benefits of this novel RS for applications in health food products. Scanning electron microscopic (SEM) images showed that the HA7-FA complex had granular structures similar to the control native starch. X-ray diffractograms confirmed the presence of a starch-lipid complex. The HA7-FA complex had a higher onset gelatinization temperature and lower swelling power and solubility than the control native starch. RS residues were collected after the starch was digested with thermostable alpha-amylase at 100°C. SEM images of the RS residues of the HA7-FA complex showed granular structures. Human feeding studies of the RS product were conducted with twenty healthy male subjects ingesting bread made from the RS. The RS bread was made by substituting 75% of the bread flour with the HA7-FA complex and wheat gluten to give the same proportions of starch and protein contents as the control bread. Blood samples were collected every 15 min from 15 min before ingestion to 2 h after ingestion of the control and RS bread. The total plasma glucose response and the total plasma insulin response of the human subjects fed with RS bread were reduced by 51% and 58%, respectively, comparing with those fed with the control bread. In conclusion, the HA7-FA complex contained up to 72% RS, and this starch could be baked into bread. When fed to human, there were more than 50% reductions in glucose and insulin responses