Some Nutritional and Physical Properties of Different Zambian Market Classes of Bambara Groundnut (Vigna subterranea)

Abstract

Selected nutritional and physical properties of the two commonly cultivated Zambian market classes of Bambara groundnut (red and brown) were investigated to establish their end-user traits. Nutritional (essential amino acids, proximate and mineral compositions) and physical (hydration capacity, hydration index, swelling capacity, swelling index and 100 seed mass) properties were investigated using established standard methods. All the essential amino acids were present in both the red and brown Bambara groundnuts. The highest amount was recorded for leucine (9.7 g/100g protein) in the brown Bambara groundnut and least for methionine (1.2 g/100g protein) in the red market class. All the essential amino acids except methionine in the brown Bambara groundnut market class were above the recommended WHO/FAO provisional requirements for children (2 – 5 years) and adults. The crude protein values ranged from 14.62-18.55 g/100g, total ash (4.21 – 4.29 g/100g), crude fibre (2.79 – 5.33 g/100g), fat (6.28 – 6.54 g/100g), moisture (8.95 – 9.13 g/100g) and carbohydrate (59.23 – 60.34 g/100g). Potassium was found to be the most concentrated mineral in both market classes, followed by phosphorous, magnesium and calcium, while lead, mercury and arsenic were not detected. The swelling capacity, swelling index, hydration capacity, and hydration index of the two market classes of Bambara groundnuts were not significantly different, whereas their 100 seed mass was significantly different, with the brown recording the highest.

Managing the hard-to-cook (HTC) phenomenon in bambara groundnut (Vigna subterranea (L.) Verdc.) processing for resource limited communities in Zimbabwe

“…Flavonoids found in raw bambara groundnut were naringenin, quercetin, myricetin and kaempferol as shown in Table 4.5. Epicatechin was the most abundant flavonoid found, whilst catechin was not detected, contrary to the findings of Nyau [229], who reported the occurrence of catechin in raw red bambara groundnut. Catechin was only detected after cooking in deionised water and NaHCO3, agreeing with Nyau, Prakash [231].…”

“…High polyphenol content is suggested to interfere with digestion and absorption of nutrients [249]. The found TPC of raw seeds i.e., 100-110 mg/100 g DW (Table 5.3) agrees with 109-138 mg/100 g found by Nyau [229], but lower than 217 mg/100g DW reported by Yagoub and Abdalla [250]. Red variety products had a significantly higher TPC (p = 0.000) than brown variety.…”

“…Red variety products had a significantly higher TPC (p = 0.000) than brown variety. Boiling increased TPC of both varieties as already found also by Nyau [229]. However, the increase after boiling is contrary to the findings of Siddhuraju and Becker [251].…”

“…As for the identification of rutin, a peak appeared and the mass under the peak was found to be [M-H] + 611 and with a molecular weight of 610. Comparison with Nyau [229] indicated that this compound could be quercetin-3-O-rutinoside (rutin) as was found in red bambara groundnuts in their study. However, after spiking with the rutin standard, it was confirmed that this compound was not rutin.…”

“…Gallic acid decreased after cooking with NaHCO3, whilst an increase was observed after cooking in deionised water. Nyau [229] reported the occurrence of t-ferulic, p-coumaric and salicylic acid in red bambara groundnut. The differences in phenolic acids present could be due to differences in variety and analytical methods.…”