Evaluation of the nutritional, functional, and glycemic properties of commercially available white, finger millet, and multigrain breads in sri lanka

Abstract

With the ongoing increase in metabolic syndrome cases worldwide and the importance of carbohydrate quality for glycemic control, assessing the nutritional and functional qualities of commonly consumed staple foods is of great importance. This study assessed the nutritional composition, glycemic index (GI), functional properties and overall loaf suitability of three commercially available bread types: white, finger millet and multigrain bread for managing metabolic syndrome. While the nutritional parameters were measured using standard AOAC methods, the Folin–Ciocalteu reagent method and the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assay were used to analyse the total phenolic content (TPC) and antioxidant activity of breads, respectively. Eighteen non diabetic, healthy participants with an average BMI of 21.2±1.7 kg/m2 underwent GI studies in accordance with ISO 26642:2010 protocols. The studies were conducted after a 10-12-hour fast, measuring the blood sugar response over 2 hours from the time of consumption of bread samples containing 50 g of available carbohydrates. The results indicated that the three breads differed significantly (P < 0.05) in specific nutritional properties, including fat, protein, and dietary fiber. White bread, prepared from refined wheat flour, showed the lowest fat (2.40±0.14%) and ash content (1.30±0.14%) along with the highest protein content (8.10±0.14%). Conversely, finger millet bread and multigrain bread contained 7.20±0.14% and 5.40±0.00% protein and 3.20±0.14% and 4.80±0.14% fat, respectively. No significant difference (P > 0.05) was observed in dietary fiber content between multigrain bread (3.40±0.14%) and finger millet bread (3.10±0.14%); however, both were significantly higher (P<0.05) than white bread (2.10±0.14%). The antioxidant activities were 0.13±0.04%, 10.09±0.10% and 7.76±0.46% for white, finger millet and multigrain bread, respectively. The TPC was 3.05±0.39 mg GAE/g for white bread, 3.53±0.05 mg GAE/g for finger millet bread and 4.41±0.00mg GAE/g for multigrain bread, indicating that it was significantly higher (P<0.05) in multigrain bread. Glycemic Index for white, finger millet and multigrain bread were 63.93±8.14 (medium-GI), 53.50±4.81 (low-GI) and 45.78±4.14 (low-GI), respectively. In conclusion, these findings suggest that finger millet and multigrain breads have the potential to serve as healthier bread options for glycemic control and metabolic health in the general population, owing to their lower glycemic impact and higher antioxidant and phenolic content.