Epsilon Archive for Student Projects

Abstract

Whole wheat flour is rich in nutrients for humans, but its utilization is challenged due to the presence of anti-nutritional factors and limited techno-functional properties. Bioprocess treatments such as germination and sourdough fermentation are promising techniques to mitigate these limitations. While many studies on individual germination and fermentation are present, the number of combined studies is limited, and especially, research on germinated wheat as a sourdough is lacking. This research was aimed at filling this gap by developing a germinated whole wheat-based sourdough and investigating the combined effect of germination and lactic acid fermentation on the techno-functional properties of whole wheat flour. Wheat grains were germinated, subsequently fermented (sourdough type III) with Lactobacillus plantarum, Weissella cibaria, or their combination, or spontaneous fermentation, and then freeze-dried. The obtained freeze dried sourdough flours were compared with non-germinated and germinated whole wheat flour as controls. Mixed-culture of L. plantarum and W. cibaria sourdough exhibited a more effective fermentation kinetics in terms of total titratable acidity (27.15 mL 0.1 M NaOH/10 g of dough), total soluble solids (34.33 ºBrix), lactic acid bacteria count (2.22×1013 CFU/g of dough) and total viable count (7.05×106 CFU/g of dough) among other sourdough systems indicating its metabolic efficiency. The integrated bioprocesses of germination and fermentation enhanced some functional properties of whole wheat flour. The water absorption index and swelling power of germinated-fermented flour increased by approximately 2.1–2.2 times and 2.3-2.5 times, respectively, compared to non-germinated whole wheat flour. In contrast, the non-germinated whole wheat flour exhibited highest oil absorption capacity (2.43 g/g), emulsion activity (53%), and foaming capacity (20%),which were reduced in the germinated-fermented samples. Bulk density decreased by approximately 1.3 times in all germinated-fermented flour samples compared to non-germinated wheat flour. The color analysis showed that the mixed-culture sourdough exhibited a 1.2-fold increase in browning index and 1.3-fold increase in yellowness compared with non-germinated whole wheat flour. Nutritional and bioactive properties were determined by total phenolic content and antioxidant activity through the Folin-Ciocalteu and ferric reducing antioxidant power assay, respectively. Germinated-fermented flour presented the best improvement, with 2.1 and 1.5 times greater total phenolic content compared to non-germinated and germinated wheat flour, respectively, and 1.8 and 1.4 times greater antioxidant capacity, respectively. These enhancements point toward synergistic effects of fermentation and germination of whole wheat flour on phenolic release and antioxidant activity. Collectively, the findings reflect that germination in combination with lactic acid fermentation of whole wheat flour remarkably elevates the nutritional, functional, and antioxidant properties. The germinated-fermented sourdough flours developed here are a rich functional food ingredients with scope for applications in cereal-based product developments.