Kafirin microparticle encapsulated sorghum condensed tannins exhibit potential as an anti-hyperglycaemic agent in a small animal model

In vitro analysis has indicated that sorghum condensed tannins (SCT) survive simulated gastric digestion and inhibit digestive amylases when encapsulated in sorghum kafirin protein microparticles (SCT-KEMS). This study investigated SCT-KEMS as a potential anti-hyperglycaemic nutraceutical agent in vivo. Oral starch tolerance tests were performed on healthy rats. SCT-KEMS prevented a blood glucose spike and decreased the maximum blood glucose level by 11.8% compared to the water control, the same reduction as the acarbose standard. Neither SCT-KEMS nor acarbose elevated serum insulin levels. Further, the rats took the SCT-KEMS willingly, unlike the case with the unencapsulated SCTs. SCT-KEMS are potentially effective nutraceuticals for the management of hyperglycaemia because of the high affinity of SCT for the proline-rich kafirin and kafirin's slow digestibility, which enables SCT bitterness to be masked and delivered to the small intestine to inhibit carbohydrate hydrolysis, thus reducing glycaemic response.