Abstract
Buckwheat is a pseudo-cereal with chemical, functional and application comparable to wheat but possesses higher antinutrient contents, which limit their digestibility and broader utilisation. The study investigated the effects of germination and nixtamalisation on the quality characteristics of buckwheat flour. Germination and nixtamalisation processes were carried out using limewater and potassium hydroxide. Whole, germinated buckwheat flour (GBW), organically nixtamalised buckwheat flour and synthetically nixtamalised buckwheat flour (SNBW) were produced and analysed for nutritional composition (proximate and mineral contents), antinutrients (phytate, oxalate, tannin and saponin) and antioxidant properties (phenol, flavonoids, ferric-reducing antioxidant power and total antioxidant), physicochemical and functional properties (water absorption capacity [WAC], oil absorption capacity (OAC), swelling capacity (SC) and bulk density (BD), and data were analysed using ANOVA at α (0.05). Germination and nixtamalisation processes significantly increased the moisture content (5.67%-8.67%; p < 0.05, ash (1.67%-4.30%; p value p < 0.05), crude protein (11.43%-14.91%; p < 0.05), fibre (10.20%-13.20%) and fat (5.0%-15.0%) but reduced the carbohydrate (61.52%-50.43%) of buckwheat flour. Protein digestibility of buckwheat flour was significantly improved (65.11%-78.14%). Similar trends were observed for the mineral content and antioxidant properties of the treated flours. The antinutritional properties of flour samples were reduced by both germination and nixtamalisation. Germinated buckwheat showed higher lightness (L), redness (a) and light intensity (E) compared with nixtamalised ones. Germination and nixtamalisation significantly influenced the pH, WAC, OAC, SC, solubility and bulk density of the buckwheat flour, which ranged between (4.94-8.91), (74.67-190.33 mL/g), (72.00-84.00 mL/g), (6.28-9.87 mL/g), (15.67-52.67 mL/g) and (0.8-0.85 g/mL), respectively. The application of germination and nixtamalisation processes significantly improves the protein digestibility, mineral content, and acidity of buckwheat flour as compared to whole buckwheat. Thus, these methods of processing have been proven to further enhance the qualitative attributes of buckwheat flour, promoting its expanded application in the food sector.