Characterization of yellow root cassava and food products: investigation of cyanide and β-carotene concentrations

Antioxidant, starch-digesting enzymes inhibitory, and pasting properties of elite yellow-fleshed cassava genotypes

Biofortification of cassava roots has improved its health benefits by raising the quantity and bioavailability of bioactive compounds, particularly carotenoids. This study analyzed the bioactive constituents (carotenoids, tannins, total phenolics, and flavonoids), antioxidant, starch-digesting enzymes (α-amylase and α-glucosidase) inhibitory and pasting properties of flours of 18 elite yellow-fleshed cassava genotypes grown at the International Institute of Tropical Agriculture, Ibadan, using standard laboratory methods. Generally, the concentrations of the bioactive constituents (9-cis-β-carotene, 13-cis-β-carotene, all trans-β-carotene, total β-carotene, total carotenoids, tannins, total phenolics, and total flavonoids) of the different cassava genotypes varied. The antioxidant activity varied significantly among the different cassava genotypes, with IITA-TMS-IBA183001 having the highest reducing power (2.59 GAE mg/g) and most potent DPPH· scavenging ability (SC50: 14.56 mg/mL). However, the starch-hydrolysing enzymes (alpha-amylase and alpha-glucosidase) inhibitory and the pasting properties of the different genotypes were generally comparable. Total carotenoids content significantly correlated with the DPPH· SC50 (r = −0.495), while total phenolics content correlated with ABTS·+(r = 0.839) and DPPH· SC50 (r = −0.870). Also, tannins content significantly correlated with ABTS·+ (r = 0.553), while total flavonoids content was significantly correlated with α-amylase IC50 (r = −0.532). These findings suggest the potential of flours of the 18 elite yellow-fleshed cassava genotypes to serve as important dietary sources of antioxidants and starch-hydrolysing enzyme inhibitors, which may be beneficial in oxidative stress and postprandial hyperglycaemic conditions.

Evaluation of Leaf Mineral, Flavonoid, and Total Phenolic Content in Spider Plant Germplasm

Spider plant (Cleome gynandra L.) is an important leafy vegetable that grows naturally in many parts of the world. The leaves are highly nutritious and are used mainly for human consumption. The mineral content and phenolic compounds of 17 genotypes (local and exotic) of spider plant and four standards (swiss chard, jute mallow, cowpea, and pumpkin) were investigated. Leaf samples were harvested from plants raised at Thohoyandou, South Africa. Exotic genotypes were superior to local genotypes for most of the minerals. Swiss chard possessed significantly high levels of some minerals such as iron and manganese in comparison with exotic spider plant genotypes. The calcium content in the local (‘MP-B-3-CG’) and exotic (‘GPS’) genotypes was >30.0% and >60.0% higher than in swiss chard, respectively. Total phenolics among spider plant genotypes ranged from 9.86 to 12.21 mg GAE/g DW and were superior to pumpkin. In addition, the spider plant genotypes varied significantly in the antioxidant capacity as estimated by the 2,2 diphenyl-1-picrylhydrazyl method and ferric-reducing antioxidant power. The main flavonoid in the leaves of spider plant genotypes was quercetin-3-rutinoside. Crotonoside (glycoside) was detected in all the spider plant genotypes and swiss chard. A positive correlation was observed between total phenolic content and each of the three flavonoids. The PCA biplot associated exotic genotypes (‘ML-SF-29′, ‘PS’, ‘TZ-1’, and ‘GPS’) and local genotypes (‘ML-3-KK’, ‘ML-13-SDM’, and ‘ML-12-TMP’) with high Al, Fe, Zn, N, and TPC. Cluster analysis indicated high “distant groups” between exotic and local genotypes of spider plant. These results indicated that some of the local germplasm of spider plant was largely inferior to the exotic germplasm in terms of their mineral composition but contained considerable quantities of quercetin-3-rutinoside, particularly in the local genotypes ‘MP-B-2-CG’ and ‘MP-B-1-CG’. There is a need for genetic improvement of the local germplasm in some of the minerals particularly to benefit the end-users.