ASSESSMENT OF STARCH DIGESTIBILITY AND HYPOGLYCEMIC EFFECT OF ORANGE PEEL ENRICHED UNRIPE PLANTAIN-WHEAT NOODLES IN DIABETIC RATS

Abstract

Developing medicinal food items for diabetics has become imperative in a bid to relieve them of the ordeal of a very narrow diet choice, taking into consideration that such food items should not only be tasteful, but should also be able to manage the disease. This project sought to assess the glycemic indices, antioxidant properties and effect of orange peel fortified unripe-plantain wheat noodles on the blood glucose levels, antioxidant status and activities of enzymes relevant to carbohydrate metabolism (α-amylase and α-glucosidase) in streptozotocin induced diabetic rats. Composite mixtures of the unripe plantain-flour (UPF) and wheat flour (WF) were prepared at various percentages (90% WF, 0% UPF: 85% WF, 5% UPF: 75% WF, 15% UPF: 65% WF and 25% UPF: 55% WF and 35% UPF) and mixed with 10% orange peel powder for the production of the different noodle samples. The noodles were analyzed for their organoleptic properties, amylose, amylopectin, starch and sugar contents. The total phenol and flavonoid contents as well as the radicals [1,1-diphenyl-2 picrylhydrazyl (DPPH), hydroxyl (OH) and nitric oxide (NO)] scavenging abilities, ferric reducing antioxidant power (FRAP) and Fe2+ chelating abilities were assessed. Thereafter, the effects of the noodles on plasma glucose level, pancreatic α-amylase and intestinal α-glucosidase activities in streptozotocin - induced diabetic rats were determined. W55-UP35 had the highest total phenol and flavonoid contents, as well as the strongest antioxidant properties. The glycemic indices of the noodles ranged from 35 (W55-UP35) to 58 (W90), while the amylose / amylopectin ratio ranged from 0.30 (W55-UP35) to 0.24 (W90). The orange peel enriched noodles also significantly reduced blood glucose levels, enhanced antioxidant status and inhibited α-amylase and α-glucosidase activities in diabetic rats. Orange peel enriched unripe-plantain-wheat noodles could serve as a healthy food choice for diabetics.