Nutritional and Antinutritional Potentials of Sorghum: A Comparative Study among Different Sorghum Landraces of Tigray, Northern Ethiopia

Abstract

Sorghum is one of the staple food crops in Tigray, northern Ethiopia. Despite this, limited research attention was given to the nutritional and antinutritional profiling of sorghum. Thus, this research was initiated to profile and evaluate the variabilities in protein, starch, minerals, flavonoid, tannin, and antioxidant activities among sorghum landraces of Tigray, northern Ethiopia. Protein and starch were analyzed using an infrared spectrophotometer, whereas mineral elements were estimated using an atomic absorption spectrophotometer. Antioxidant activity was analyzed using DPPH (2,2-diphenyl-1-picrylhydrazyl) free radical scavenging, ferric-reducing antioxidant power, and phosphomolybdenum assays. The result revealed significant variation among the landraces for all the evaluated parameters. Protein and starch contents ranged from 6.21 to 18% and 33.42 to 78.30%, respectively. Wider variations were observed for Fe (32–101), Zn (16.9–42.98), Cu (1.48–5.25), Mn (9.21–20.23), and Cr (0–1.5) as measured in mg/100 g. The variabilities were high for total flavonoid (0–665 mg CE/g) and tannin (0.18–7.5 mgCE/100 g). DPPH (EC50 = 29.09–818.37 µg/mL), ferric reducing antioxidant power (17.85–334.81 mgAAE/g), and total antioxidant activity (1.71–63.88 mgBHTE/g) were also highly variable among the samples. The relationship between seed color and phenolics, as well as antioxidant activities, are discussed. Multivariate analysis revealed that the landraces were clustered into four distinct groups. The rich genetic diversity in the nutritional and antinutritional attributes may be an opportunity for breeding for grain quality improvements of sorghum that, in turn, helps in addressing malnutrition.