Abstract

This study assessed the effect of malted soybean flour addition on the chemical composition of acha-based biscuits. Acha flour was substituted with malted and unmalted soybean flours at four inclusion levels (100:0%, 95:5%, 85:15%, and 75:25%), with 100% wheat flour as a control. The samples were analyzed using standard methods. The results obtained showed that there were significant differences (P<0.05) in the proximate composition of the samples. The moisture content of the biscuit samples ranged from 2.44-3.95%, indicating that the biscuit is a low-moisture food product. The samples were also high in ash, protein and fat which ranged from 1.18-2.39%, 8.09-12.88% and 18.71-22.22%, respectively, while the carbohydrate content ranged from 59.67 to 68.16%. As soybean flour inclusion increased, significant increases (p < 0.05) were observed in ash, protein, fat, crude fiber, and mineral contents (iron, potassium, phosphorus, magnesium) were observed in the biscuits. Antioxidant properties, including DPPH, FRAP, and ABTS, increased significantly (p < 0.05) with higher soybean flour addition. In the biscuit samples produced from Acha-malted soybean blends, DPPH increased from 68.79 to 72.84 mg/mL, FRAP (1.90 to 2.93 µmol Fe²⁺/g), and ABTS (48.02 to 75.70 µmol TE/g). Similarly, biscuit samples produced from Acha-unmalted soybean flour blends showed significant increases (p < 0.05) in DPPH (71.31 to 75.71 mg/mL), FRAP (0.38 to 2.15 µmol Fe²⁺/g), and ABTS (44.56 to 76.38 µmol TE/g). Protein digestibility improved significantly (p < 0.05) from 140.13% to 178.11%, while starch digestibility improved from 19.62% to 27.79%, with increasing soybean flour inclusion. Amino acid profiles also showed significant improvements (p < 0.05), with higher levels of methionine (2.15 g/100g), aspartic acid (8.92 g/100g), and glutamic acid (10.12 g/100g) in the biscuit sample produced from 95% Acha and 5% unmalted soybean flour substitutions.