Antioxidant activity and DNA protection against oxidative damage of bambara groundnut seeds (Vigna subterranea (L.) Verdc.) as affected by processing methods

This research investigated the effects of processing by dry heating, boiling, and steaming on the antioxidant activity and DNA protection against oxidative damage of bambara groundnut seeds (Vigna subterranea (L.) Verdc.). Comparing raw and processed samples of bambara groundnut seeds, dry heating caused a significant (P < 0.05) reduction of ferric-reducing antioxidant power (FRAP), metal chelating activity, DPPH^? and ABTS^?+ radical scavenging activity. The boiling process did not cause a significant difference in FRAP and metal chelating activity and caused smaller losses in DPPH^? and ABTS^?+ radical scavenging activity than the dry heating and steaming processes. The steaming process caused a significant (P < 0.05) reduction of FRAP, DPPH^? and ABTS^?+ radical scavenging activity. For DNA protection against oxidative damage, boiled and steamed bambara groundnut seed samples were more effective with a lower minimum concentration (50 µg/mL) than raw and dry heated samples. These results indicated that the boiling process caused smaller losses antioxidant activity than dry heating and steaming. Therefore, boiling was recommended as processing method for bambara groundnut seeds to preserve antioxidant components and antioxidant activity.     

Effect of Processing on Certain Antinutrients in Bambara Groundnut (Vigna subterranea) Cotyledons

Cotyledons of two Nigerian varieties of bambara groundnut were analysed for trypsin inhibitor activity (TIA) and polyphenols after whole beans had, in each case, been cold-soaked, hot-soaked, cold-soaked/germinated and dehulled. Another portion of beans was fermented after they had been cold-soaked, dehulled and boiled for 10 min (pretreatment), simulating the ‘dawadawa’ process. Germination made dehulling of the beans very easy, as the hulls broke open during the process, but was not very effective in reducing the polyphenol levels (9%, average loss) and TIA (17%, average loss). The combined pretreatment/fermentation process reduced the polyphenol level and TIA by 24% and 40%, respectively (average losses). Hot-soaking considerably improved the dehulling properties of the beans over cold-soaking and was more effective in reducing the TIA level in the cotyledons (31%, average loss) than cold-soaking (12%, average loss). Polyphenol losses by the two conditioning methods were similar (9%, average). Generally, losses in polyphenols and TIA could be attributed to leaching and inactivation respectively during the processes involved. The results show that a combination of two or more simple processing methods could be used to improve the food value of bambara groundnut. © 1997 SCI.     

Growth,Nodulation and Yield of Bambara Groundnut (Vigna subterranea (L) Verdc) on Selected Nigerian Soils

To compare their performances in terms of growth, nodulation and yield, six bambara groundnut lines collected from Benue, Bauchi, Enugu and Sokoto states of Nigeria were grown on five different Nigerian soils: alfisol, entisol, inceptisol, ultisol and vertisol. Data obtained showed that the soil reaction did not impair the nodulating capacity of the genotypes except at very low pH values. Best performances in terms of growth and yield were observed in vertisol. Nodulation, growth and yield were consistently depressed in entisol and inceptisol. The ease of penetration of the different soils measured at field capacity, during pegging, was an important factor in the cultivation of bambara groundnut. There were strong evidences of differential pod and seed yields per plant by the genotypes on the different soils. © 1997 SCI.     

Effects of bambara groundnut (Vigna subterranea) variety and processing on the quality and consumer appeal for its products

Five landraces of bambara groundnut ( Vigna subterranea ) from northern Ghana were assessed for their physical characteristics, chemical composition and the effects of variety and processing on quality and consumer appeal for use in food products. The cultivars had distinct colour differences ranging from cream through brown, maroon to black, with variations in the seed sizes and seed coat thicknesses. Significant ( P  <   0.05) differences were observed in some of the chemical components of the different varieties of bambara. Protein and fat contents ranged from 19.3% to 27.1% and 4.8% to 7.0%, respectively, while ash content was not significantly ( P  >   0.05) different among the cultivars. Tannin content ranged between 4.5 mg CE g⁻¹ sample for the cream-coloured and 14.9 mg CE g⁻¹ sample for the black variety. Dehulling increased the protein content, reduced tannin content by up to 92% and improved the colour of bambara products, while heat treatment enhanced their taste, aroma and overall acceptability.     

Structure,composition and functional properties of storage proteins extracted from bambara groundnut (Vigna subterranea) landraces

Bambara groundnut is a protein‐rich traditional legume. In this study, storage proteins were isolated from three bambara landraces. Bambara protein revealed four major protein bands: one broad band at 55 kDa, two medium bands at 62 kDa and 80 kDa and a high molecular weight (HMW) protein at 141 kDa. The vicilin (7S) subunits with molecular weight of 55 kDa and 62 kDa were major fractions in bambara storage proteins. Bambara proteins showed two endothermic peaks ranging from 64 to 69 °C and 76 to 90 °C, respectively. Bambara protein isolates had well‐defined tertiary and secondary structures, respectively, at pH 3.0, and this well‐defined structure decreased slightly at higher pH values. The isolates revealed a strong secondary structure dominated by α‐helical conformation. Foaming capacities of bambara proteins were dependent on pH with maximum percentage FC observed at pH 3.0, while the emulsion activity increased with increasing pH for all the isolates. Vicilin (7S) fraction seems to be the major storage protein fraction of bambara. Bambara proteins could serve as excellent ingredients for the formulation of food foams and emulsions.     

Studies on the nutritive characteristics and fracture resistance to compressive loading of selected bambara groundnut lines

Extensive laboratory experiments were conducted to determine the nutritive characteristics and fracture resistance to compressive loading of some bambara groundnut lines. Data obtained showed percentage carbohydrate, protein and oil contents of 52.60, 17.52 and 6.66 respectively for dehulled bambara groundnut seeds as against lower percentage values of 48.60, 16.99 and 6.20 obtained from the analysis of whole seeds of BgB-Br. Investigations on the mechanical properties revealed that the force needed to rupture the seeds was influenced by moisture content and loading position of the seeds. The force was found to decrease from 262 to 100 N with increase in moisture content, while the deformation increased from 1.9 to 4.5 mm with increase in moisture content. Maximum toughness occurred at different moistures which represent the moisture levels for absorbing compressive energy which are important for resisting mechanical damage during handling of the bambara groundnut lines. © 1999 Society of Chemical Industry     

Triple bag hermetic technology for post-harvest preservation of Bambara groundnut (Vigna subterranea (L.) Verdc.)

Experiments were conducted to evaluate the performance of hermetic triple bagging using Purdue Improved Crop Storage (PICS) bags for storage of Bambara groundnut (Vigna subterranea (L.) Verdc.). One set of experiments used grain heavily infested by Callosobruchus maculatus (F.) while a second set began with a low level infestation. Each experiment consisted of V. subterranea grain kept in four replicate 50 kg PICS bags or two replicate woven bags as controls. Two to five days after the beginning of the experiments, oxygen level inside the bags averaged about 21% (v/v) in the controls but decreased significantly in PICS bags, reaching 10% (v/v) with the heavily infested grain but falling only slightly in the lightly infested grain. After 7 months of storage, (i) the number of C. maculatus adults found between and within the grains, (ii) the 100 seed weight, (iii) the number of seed with holes, and (iv) the percentage germination of grain stored in PICS bags did not differ from what had been measured on the day that the experiment was set up. In woven bags, by contrast, there was a massive increase in C. maculatus numbers with means of 309 and 251 adults per 500 g in heavily and lightly infested grain, respectively. Grain weight losses in the woven bag controls ranged from 8 to 19% and the percentage of C. maculatus emergence holes per 100 seed increased from 51 to 135%.     

Hard-to-cook phenomenon in bambara groundnut (Vigna subterranea (L.) Verdc.) processing: Options to improve its role in providing food security

Indigenous legume crops are pivotal in providing proteins and food security to sub-Saharan African rural communities, but most of these crops are underutilized because of the so-called hard-to-cook (HTC) phenomenon in combination with inadequate processing techniques. This review studies the case of bambara groundnut, which is third in importance after groundnut and cowpea and especially adapted to semi-arid areas. Published data on the HTC phenomenon implicate microstructural and compositional changes as factors leading to its development. Useful and sustainable techniques to process HTC legumes in developing countries include cooking with alkaline salts, milling, roasting, fermentation, and malting. Improvement of these processing techniques in relation to nutrient bioaccessibility, safety, and consumer acceptance of the products is urgently needed. Recommendations are to lessen the problems of food security in sub-Saharan African countries through, amongst other means, the optimization of bambara groundnut processing methods.     

Physicochemical and Functional Properties of Insoluble Dietary Fiber Isolated from Bambara Groundnut (Vigna subterranea [L.] Verdc.)

Bambara groundnut (BGN) is a widely cultivated legume with a rich nutritional profile, yet despite its many benefits it still remains underutilized. To highlight its potential value, 4 BGN varieties—brown, red, black eye, and brown eye were subjected to sequential enzymatic treatments followed by centrifugation to obtain the insoluble dietary fiber (IDF) fraction. The IDFs were vacuum‐dried and evaluated for color, hydration properties, fat absorption, polyphenolic compounds, neutral sugars, and uronic acids. An optimized white bread formulation was also determined using brown BGN‐IDF in an optimal (IV) mixture design. Three mixture components constrained at lower and upper limits (water: 57% to 60%, yeast: 2.3% to 5.3%, and BGN‐IDF: 7% to 10%) were evaluated for their effects on responses of specific loaf volume, gumminess, chewiness, and resilience of the loaves. All BGN‐IDFs differed significantly (P ≤ 0.05) across all color parameters. Polyphenols were significantly (P ≤ 0.05) highest in red and brown BGN‐IDFs. Arabinose/galactose (31.04% to 37.12%), xylose (16.53% to 27.30%), and mannose (14.48% to 22.24%) were the major sugars identified. Swelling capacity was significantly (P ≤ 0.05) highest for brown eye BGN‐IDF (7.72 ± 0.49 mL/g). Water retention capacity ranged from 1.63 to 2.01 g water/g dry weight. Fat absorption for red BGN‐IDF differed significantly (P ≤ 0.05). Furthermore, the best optimal white bread formulation enriched with brown BGN‐IDF was established with numerical optimization at 59.5% water, 4.3% yeast, and 8.5% BGN‐IDF. Overall positive physicochemical and functional properties were observed for BGN‐IDFs, and it was shown that an optimal white bread enriched with BGN‐IDF could be produced.     

Physical,nutritional and antioxidant properties of Zimbabwean bambara groundnut and effects of processing methods on their chemical properties

This study examined the physical, nutritional and antioxidant properties of popular Zimbabwean bambara groundnut landraces and the effects of different processing methods on their chemical properties. The physical, nutritional and antioxidant properties of grains of the bambara landraces differed significantly with grain type, and the processing methods investigated had varying effects on the chemical properties of the grains. Bambara had significantly lower protein content than the reference common bean. Protein and carbohydrate content of the grains increased upon dehulling, while tannin (approx. 36%), total phenolic content (approx. 83%) and antioxidant activities (approx. 18%) decreased. Roasting alone seemed to have little or no effect on the nutrient content of the grains, while sifting significantly reduced the phenolic content and antioxidant activity of all the dehulled and roasted samples. The results indicate that roasting bambara grains would be a suitable method as it is relatively more conservative of nutrients and antioxidants than the other methods investigated.     

Studies on bambara groundnut flour performance in Okpa preparation

Bambara groundnut flours of different particle sizes were prepared after bean seeds had been cold‐soaked and/or germinated, dried, milled and sieved. The flours were used to prepare okpa (local dish prepared by steaming mashed bambara groundnut) and their sensory properties determined. Viscosity of the flour pastes, before steaming, were also determined. Results showed that bambara groundnut flours from both germinated and cold‐soaked beans could be used in preparing good quality okpa and, therefore, remove all the problems involved in preparing the raw beans for okpa‐making as is done traditionally. Particle size appeared to play a major role in obtaining good okpa; therefore flours intended for okpa preparation should be such that 66, 86 and 96%, respectively, of cold‐soaked bean flour or 58, 78 and 91%, respectively, of germinated bean flour, after 1, 3 and 5 milling passes, should be in the particle range 1.5–4.5 × 10^?4 m. Slightly higher amounts of the coarse (6.0 × 10^?4 m) particles are needed in the germinated bean flours to compensate for the breakdown of starch and proteins, the gelling agents in bambara groundnut. Copyright © 2004 Society of Chemical Industry     

Effect of annealing on the functionality of Bambara groundnut (Vigna subterranea) starch–palmitic acid complex

Bambara groundnut is an underutilised African leguminous crop. This study investigated the effect of annealing on the complexing ability and functionality of Bambara groundnut starch with palmitic acid. Corn starch was included as the reference. Annealing created cracks and pores on the surface of Bambara groundnut and corn starches, respectively. Bambara groundnut starch had significantly higher amylose content, higher peak and final viscosities than corn starch. The peak viscosities of native Bambara groundnut and corn starches significantly reduced with palmitic acid addition. Greater reduction in peak viscosities was observed when the annealed starches were complexed with palmitic acid, suggesting that more palmitic acid was complexed after annealing. This was confirmed by XRD peaks and melting enthalpies. Pasting of native Bambara groundnut and corn starches with palmitic acid resulted in the formation of type I V‐amylose complexes, while type II complexes were formed from annealed starches pasted with palmitic acid.     

Influence of extraction methods on functional properties of protein concentrates prepared from South African bambara groundnut landraces

Functional properties of protein concentrates prepared from three bambara groundnut landraces using acid precipitation and salt solubilisation methods were evaluated. The protein content of bambara grains (26–27%) was similar for the three landraces. The acid precipitation gave a much higher yield of protein concentrates (52%), which were also high in protein (79%) compared to the salt solubilisation method (yield: 25%, protein content: 57%). Functional properties of proteins were more influenced by the methods of preparation rather than the landraces. Protein concentrate prepared by salt solubilisation method showed higher emulsifying (63–66%), foaming (53–57%), water (1.4–2.0 mg mL^?1) and oil absorption properties (2.2–2.6 mg mL^?1) than the acid‐precipitated concentrates (53–57%, 63–66%, 2.0–2.7 mg mL^?1, 1.4–1.7 mg mL^?1). The foaming capacity and stability of all the protein concentrates decreased with increasing pH from 3 to 8. Salt solubilisation may be the most appropriate method for the enhanced functionality and utilisation of bambara groundnuts’ protein concentrates.     

Properties of some protein fractions from bambara groundnut [Voandzeia subterranea (L.) Thouars]

Eight cultivars of bambara groundnut [Voandzeia subterranea (L.) Thouars] were examined for their protein, non-protein nitrogen, starch, reducing sugar, tannin and trypsin inhibitor contents. Protein (N × 5.71), starch and reducing sugar contents showed little inter-cultivar variation giving mean values of 18.7, 42.1 and 1.26 g 100 g^?1 whole seed, respectively. Tannin contents ranged from 0.36 to 0.94 g 100 g^?1 whole seed and trypsin inhibitory activity from 6.75 to 15.44 units mg^?1. The majority of the protein nitrogen present was extractable in water or dilute salt solution. Trypsin inhibitory activity was directly correlated with the quantity of protein nitrogen extracted from each of the cultivars, which in turn, was found to be inversely related to their tannin contents. This latter effect was modified by both the pH and the molarity of the extractant used.     

Vegetable milk processing and rehydration characteristics of bambara groundnut [Voandzeia subterranea (L.) thouars]

Eight cultivars of bambara groundnut [Voandzeia subterranea (L.) Thouars] were studied to determine their rehydration characteristics. Seeds from all cultivars approximately doubled their weight after 36 h and were then easily dehulled. Losses of nutrients to the soak water during this period were small. Mature seeds from one cultivar were evaluated for suitability as a base for a vegetable milk. Homogenisation of whole seed flour in water together with coconut or soya bean oils yielded an emulsion containing 20 g protein (Nx 5.71) and 30 ml oil litre-¹. Good emulsion stability was maintained after pasteurisation. Curds, similar to those traditionally prepared from soya beans, were easily prepared from bambara groundnut milk. The bland, creamy-white product which was high in protein had a trypsin-inhibitor content very much lower than that of the untreated vegetable milk.     

Production of maize–bambara groundnut complementary foods fortified pre‐fermentation with processed foods rich in calcium,iron, zinc and provitamin A

BACKGROUND: Maize–bambara groundnut complementary foods are deficient in calcium, iron, zinc and vitamin A. Food‐to‐food fortification could be cheaper, safer and more easily adopted by local communities compared to the use of chemically pure compounds and vitamins to enrich such foods. RESULTS: Maize–bambara groundnut complementary foods fortified for iron, zinc, calcium and vitamin A by blending with a multi‐mix (1.41:1:2.25, w/w) of processed roselle calyces, cattle bones, and red palm oil in a 1:2.1 (w/w) ratio showed significant increases in calcium, iron, zinc and vitamin A contents of 3.26–4.225, 0.083–0.134 and 0.015–0.017 g kg^?1 and 4855.3–7493.7 µgRE kg^?1, respectively. CONCLUSION: The maize–bambara groundnut foods had calcium, iron, zinc and vitamin A contents that satisfy the proposed nutrient requirements for infants. Only the maize–bambara groundnut and maize–bambara groundnut malt fermented by backslopping [(MB)_b and (MB_m)_b] containing red palm oil emulsified with Brachystegia eurycoma had calcium contents significantly (P < 0.05) higher than Nutrend, a complementary food produced by Nestle (Nigeria) PLC. These products are from raw materials produced in commercial quantities by rural farmers using household level technologies which the rural and urban poor can more easily access in order to reduce micronutrient malnutrition. Copyright © 2010 Society of Chemical Industry     

米曲霉固态发酵大豆粕制备大豆肽研究

对米曲霉固态发酵大豆粕生产大豆肽条件进行研究,结果表明,最适发酵原料(由大豆粕和麸皮组成)中大豆粕含量为93%。发酵温度35℃,初始pH为6.8,发酵时间102 h;在此条件下,发酵得到大豆肽转化率达62.77%。     

干酪乳杆菌(HN-2)固态发酵培养基的优化

该研究选择一株具有水质净化能力的干酪乳杆菌(Lactobacillus casei HN-2),以麸皮及米糠为主要基质对其开展了固态发酵研究。通过部分因子析因试验设计及响应面分析,获得了最佳的固体培养基组合,包括:麸皮6.87g、米糠9.84g、葡萄糖0.26g、大豆蛋白胨0.10g、MgSO4.7H2O 0.05g、CaCO30.25g、K2HPO4.3H2O 0.10g。当初始湿度为65%、初始pH值为6.0时,在37℃经过48h的固态发酵,干酪乳杆菌HN-2的菌体密度最大可达2.47×1010cfu/g。     

固体发酵制备毛霉蛋白酶的研究

该文研究了毛霉M2产蛋白酶的若干影响因素，包括培养基的成分以及发酵条件等。结果表明：在麸皮与水的合适比例为1：0.8；在基本培养基上添加一定浓度的碳源、氮源及无机盐有利于蛋白酶的合成；菌体较为合适的产酶条件为温度28℃，pH6．0，发酵时间36h。