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Amanda Minnaar - One of the best experts on this subject based on the ideXlab platform.
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effects of gamma irradiation on cotyledon cell separation and pectin solubilisation in hard to cook Cowpeas
Journal of the Science of Food and Agriculture, 2018Co-Authors: Talknice Z. Jombo, Amanda Minnaar, John R. N. TaylorAbstract:Cowpeas stored under high temperature and humidity develop the hard-to-cook defect (HTC). This defect greatly increases cooking times and energy costs. To better understand the mechanisms involved in the HTC defect development, the effects of gamma-irradiation on cotyledon cellular structure and pectin solubility in two cowpea cultivars with different susceptibility to HTC defect were investigated.; Results: Gamma-irradiation decreased cotyledon cell wall thickness, increased cell size, and intercellular spaces in both cowpea cultivars and reduced cooking time of the less HTC susceptible cultivar. However, it did not reverse the HTC defect in the susceptible cultivar. Gamma-irradiation also increased the levels of cold water- and hot water-soluble pectin. The irradiation effects were thus mainly due to hydrolysis of pectin fractions in the cell walls. However, chelator-soluble pectin (CSP) solubility was not affected.; Conclusion: As the cell wall changes brought about by gamma-irradiation were associated with pectin solubilisation, this supports the phytate-phytase-pectin theory as a major cause of the HTC defect. However, the non-reversal of the defect in HTC susceptible Cowpeas and the absence of an effect on CSP indicate that other mechanisms are involved in HTC defect development in Cowpeas, possibly the formation of alkali-soluble, ester bonded pectins. © 2017 Society of Chemical Industry.; © 2017 Society of Chemical Industry.
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novel in situ evaluation of the role minerals play in the development of the hard to cook htc defect of Cowpeas and its effect on the in vitro mineral bioaccessibility
Food Chemistry, 2015Co-Authors: Johanita Kruger, Roya Minnisndimba, C Mtshali, Amanda MinnaarAbstract:Abstract Cowpea is a nutritionally important drought-resistant legume in sub-Saharan Africa. It is, however, underutilised, in part due to the hard-to-cook (HTC) defect caused by adverse storage conditions resulting in seeds not softening during cooking. This study introduced a novel evaluation of the potential role that minerals play in the development of the HTC defect. The mineral distribution in the cotyledons of normal and HTC Cowpeas were analysed by Proton Induced X-ray Emission (PIXE) spectrometry. The phytate, tannin and total phenolic contents were analysed together with in vitro mineral bioaccessibility. In HTC Cowpeas, Ca and Mg were more concentrated in the cell wall-middle lamella area of the parenchyma cells. This, together with the reduction in phytate content, confirmed the ‘phytase–phytate–mineral’ hypothesis as a mechanism for development of the HTC defect. Despite the phytate reduction in stored Cowpeas, the HTC defect decreased the bioaccessibility of Ca, Fe and Zn in Cowpeas.
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phenolic composition and inhibitory effect against oxidative dna damage of cooked Cowpeas as affected by simulated in vitro gastrointestinal digestion
Food Chemistry, 2013Co-Authors: Alice M Nderitu, Amanda Minnaar, Linda Dykes, Joseph M Awika, Kwaku G DuoduAbstract:Cowpeas contain phenolic compounds with potential health benefits. The effect of simulated gastrointestinal digestion on phenolic composition of cooked Cowpeas and the ability of the digests to inhibit radical-induced DNA damage was determined. A red and a cream-coloured cowpea type were used. The phenolic composition of acetone extracts and enzyme digests of cooked Cowpeas was determined using UPLC-MS. Compounds such as p-hydroxybenzoic acid, p-coumaric acid, coumaroylaldaric acid and feruloylaldaric acid were present in the acetone extracts of the cooked Cowpeas but were not detected in the enzyme digests. Glycosides of quercetin and myricetin decreased upon in vitro gastrointestinal digestion of cooked Cowpeas whereas flavan-3-ols were hardly present except catechin glucoside. The enzyme digest of the red cowpea type was about thrice as effective as that of the cream cowpea type in protecting DNA from oxidative damage. The observation that enzyme digests of cooked Cowpeas inhibited radical-induced DNA damage suggests that cowpea phenolics retain some radical scavenging activity after gastrointestinal digestion.
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effect of micronisation of pre conditioned Cowpeas on cooking time and sensory properties of cooked Cowpeas
Journal of the Science of Food and Agriculture, 2013Co-Authors: Eugenie Kayitesi, Kwaku G Duodu, Amanda Minnaar, Henriette L De KockAbstract:BACKGROUND: Cowpea is mostly utilised as cooked whole seeds. This is often achieved only after boiling for up to 2 h, resulting in high energy consumption and a long time for food preparation. Micronisation of pre-conditioned Cowpeas reduces their cooking time. Micronisation changes the physicochemical properties of cowpea seeds, which may affect the sensory properties of cooked Cowpeas. Consumer acceptance and utilisation of micronised Cowpeas depend on their sensory properties. Micronised and unmicronised samples of Blackeye, Bechuana white, Glenda and Dr Saunders Cowpeas were subjected to cooking time, descriptive sensory and colour analyses. RESULTS: Micronisation significantly reduced cowpea cooking time by 28–49%. There were significant (P < 0.05) increases in roasted aroma and flavour, mushy texture and splitting in all micronised samples. Bechuana white was more mushy and split than others. There were significant decreases in firmness, mealiness and coarseness after micronisation for all cowpea types. Micronised Cowpeas were darker (lower L* values) than unmicronised cooked Cowpeas. Darkening was more evident in light-coloured than dark-coloured Cowpeas. CONCLUSION: Micronisation reduces cowpea cooking time but also affects sensory properties of Cowpeas such as introducing roasted flavours that may not be familiar to consumers. This might have an influence on consumer acceptance of micronised Cowpeas. © 2012 Society of Chemical Industry
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Effect of micronisation of pre‐conditioned Cowpeas on cooking time and sensory properties of cooked Cowpeas
Journal of the Science of Food and Agriculture, 2012Co-Authors: Eugenie Kayitesi, Kwaku G Duodu, Amanda Minnaar, Henriette L De KockAbstract:BACKGROUND: Cowpea is mostly utilised as cooked whole seeds. This is often achieved only after boiling for up to 2 h, resulting in high energy consumption and a long time for food preparation. Micronisation of pre-conditioned Cowpeas reduces their cooking time. Micronisation changes the physicochemical properties of cowpea seeds, which may affect the sensory properties of cooked Cowpeas. Consumer acceptance and utilisation of micronised Cowpeas depend on their sensory properties. Micronised and unmicronised samples of Blackeye, Bechuana white, Glenda and Dr Saunders Cowpeas were subjected to cooking time, descriptive sensory and colour analyses. RESULTS: Micronisation significantly reduced cowpea cooking time by 28–49%. There were significant (P < 0.05) increases in roasted aroma and flavour, mushy texture and splitting in all micronised samples. Bechuana white was more mushy and split than others. There were significant decreases in firmness, mealiness and coarseness after micronisation for all cowpea types. Micronised Cowpeas were darker (lower L* values) than unmicronised cooked Cowpeas. Darkening was more evident in light-coloured than dark-coloured Cowpeas. CONCLUSION: Micronisation reduces cowpea cooking time but also affects sensory properties of Cowpeas such as introducing roasted flavours that may not be familiar to consumers. This might have an influence on consumer acceptance of micronised Cowpeas. © 2012 Society of Chemical Industry
Kwaku G Duodu - One of the best experts on this subject based on the ideXlab platform.
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phenolic composition and inhibitory effect against oxidative dna damage of cooked Cowpeas as affected by simulated in vitro gastrointestinal digestion
Food Chemistry, 2013Co-Authors: Alice M Nderitu, Amanda Minnaar, Linda Dykes, Joseph M Awika, Kwaku G DuoduAbstract:Cowpeas contain phenolic compounds with potential health benefits. The effect of simulated gastrointestinal digestion on phenolic composition of cooked Cowpeas and the ability of the digests to inhibit radical-induced DNA damage was determined. A red and a cream-coloured cowpea type were used. The phenolic composition of acetone extracts and enzyme digests of cooked Cowpeas was determined using UPLC-MS. Compounds such as p-hydroxybenzoic acid, p-coumaric acid, coumaroylaldaric acid and feruloylaldaric acid were present in the acetone extracts of the cooked Cowpeas but were not detected in the enzyme digests. Glycosides of quercetin and myricetin decreased upon in vitro gastrointestinal digestion of cooked Cowpeas whereas flavan-3-ols were hardly present except catechin glucoside. The enzyme digest of the red cowpea type was about thrice as effective as that of the cream cowpea type in protecting DNA from oxidative damage. The observation that enzyme digests of cooked Cowpeas inhibited radical-induced DNA damage suggests that cowpea phenolics retain some radical scavenging activity after gastrointestinal digestion.
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effect of micronisation of pre conditioned Cowpeas on cooking time and sensory properties of cooked Cowpeas
Journal of the Science of Food and Agriculture, 2013Co-Authors: Eugenie Kayitesi, Kwaku G Duodu, Amanda Minnaar, Henriette L De KockAbstract:BACKGROUND: Cowpea is mostly utilised as cooked whole seeds. This is often achieved only after boiling for up to 2 h, resulting in high energy consumption and a long time for food preparation. Micronisation of pre-conditioned Cowpeas reduces their cooking time. Micronisation changes the physicochemical properties of cowpea seeds, which may affect the sensory properties of cooked Cowpeas. Consumer acceptance and utilisation of micronised Cowpeas depend on their sensory properties. Micronised and unmicronised samples of Blackeye, Bechuana white, Glenda and Dr Saunders Cowpeas were subjected to cooking time, descriptive sensory and colour analyses. RESULTS: Micronisation significantly reduced cowpea cooking time by 28–49%. There were significant (P < 0.05) increases in roasted aroma and flavour, mushy texture and splitting in all micronised samples. Bechuana white was more mushy and split than others. There were significant decreases in firmness, mealiness and coarseness after micronisation for all cowpea types. Micronised Cowpeas were darker (lower L* values) than unmicronised cooked Cowpeas. Darkening was more evident in light-coloured than dark-coloured Cowpeas. CONCLUSION: Micronisation reduces cowpea cooking time but also affects sensory properties of Cowpeas such as introducing roasted flavours that may not be familiar to consumers. This might have an influence on consumer acceptance of micronised Cowpeas. © 2012 Society of Chemical Industry
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Effect of micronisation of pre‐conditioned Cowpeas on cooking time and sensory properties of cooked Cowpeas
Journal of the Science of Food and Agriculture, 2012Co-Authors: Eugenie Kayitesi, Kwaku G Duodu, Amanda Minnaar, Henriette L De KockAbstract:BACKGROUND: Cowpea is mostly utilised as cooked whole seeds. This is often achieved only after boiling for up to 2 h, resulting in high energy consumption and a long time for food preparation. Micronisation of pre-conditioned Cowpeas reduces their cooking time. Micronisation changes the physicochemical properties of cowpea seeds, which may affect the sensory properties of cooked Cowpeas. Consumer acceptance and utilisation of micronised Cowpeas depend on their sensory properties. Micronised and unmicronised samples of Blackeye, Bechuana white, Glenda and Dr Saunders Cowpeas were subjected to cooking time, descriptive sensory and colour analyses. RESULTS: Micronisation significantly reduced cowpea cooking time by 28–49%. There were significant (P < 0.05) increases in roasted aroma and flavour, mushy texture and splitting in all micronised samples. Bechuana white was more mushy and split than others. There were significant decreases in firmness, mealiness and coarseness after micronisation for all cowpea types. Micronised Cowpeas were darker (lower L* values) than unmicronised cooked Cowpeas. Darkening was more evident in light-coloured than dark-coloured Cowpeas. CONCLUSION: Micronisation reduces cowpea cooking time but also affects sensory properties of Cowpeas such as introducing roasted flavours that may not be familiar to consumers. This might have an influence on consumer acceptance of micronised Cowpeas. © 2012 Society of Chemical Industry
Hesham M Elzun - One of the best experts on this subject based on the ideXlab platform.
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persistence and residual activity of an organophosphate pirimiphos methyl and three igrs hexaflumuron teflubenzuron and pyriproxyfen against the cowpea weevil callosobruchus maculatus coleoptera bruchidae
Pest Management Science, 2004Co-Authors: Gamal E Aboelghar, Anwar E Elsheikh, Ferial M Elsayed, Hamdi M Elmaghraby, Hesham M ElzunAbstract:Three insect growth regulators (IGR), the chitin synthesis inhibitors (CSI) teflubenzuron and hexaflumuron and the juvenile hormone mimic (JHM) pyriproxyfen, as well as the organophosphate (OP) pirimiphos-methyl, were evaluated for their activity against the cowpea weevil, Callosobruchus maculatus (F), in cowpea seeds stored for up to 8 months post-treatment. The initial activity data showed that, based on LC50 level, teflubenzuron had strong ovicidal activity (LC50 = 0.056 mg kg−1) followed by pirimiphos-methyl (1.82 mg kg−1) and pyriproxyfen (91.9 mg kg−1). The residual activity data showed that none of the IGRs tested had strong activity when applied at 200 mg kg−1 in reducing the oviposition rates of C maculatus at various storage intervals up to 8 months post-treatment. However, teflubenzuron reduced adult emergence (F1 progeny), achieving control ranging from 96.2% at 1 month to 94.3% at 8 months. Hexaflumuron showed a similar trend in its residual activity, ranging between 93.8% control at 1 month to 88.2% control at 8 months post-treatment. However, pyriproxyfen was more active than the CSIs tested and caused complete suppression (100% control) of adult emergence at all storage intervals. Unlike the IGRs tested, pirimiphos-methyl applied at 25 mg kg−1 was more effective in reducing oviposition rates of C maculatus up to 8 months post-treatment. A strong reduction of adult emergence was also observed at various bimonthly intervals (98.6% control at 1 month to 91.6% control at 8 months post-treatment). The persistence of hexaflumuron and pirimiphos-methyl in cowpea seeds was also studied over a period of 8 months. The loss of hexaflumuron residue in treated Cowpeas (200 mg kg−1) was very slow during the first month post-treatment (4.43%). At the end of 8 months, the residue level had declined significantly to 46.4% of the initial applied rate. The loss of pirimiphos-methyl residue in treated Cowpeas (25 mg kg−1) was relatively high during the first month post-treatment (36.7%) and increased to 81.6% after 8 months. Copyright © 2003 Society of Chemical Industry
K Mcwatters - One of the best experts on this subject based on the ideXlab platform.
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Effect of milling and preparation method on the physical properties and quality of moin-moin (steamed paste).
Journal of food science, 2007Co-Authors: M Jarrard, K Mcwatters, Y.c. Hung, R D PhillipsAbstract:Moin-moin is steamed cowpea paste native to Nigeria. This product is classified as a protein/starch gel with the dominate portion of the gel network consisting of cowpea starch. Moin-moin was prepared from starting materials (cowpea meal and cowpea flour) and compared to moin-moin prepared from dry, whole, undecorticated cowpea seeds. Texture profile measurements showed that moin-moin made from cowpea flour (small particle size) formed a firmer structure when compared to moin-moin made from either cowpea meal or whole, dry cowpea seeds. Starting materials with smaller particle sizes and longer cooking times produced stickier moin-moin. The cowpea solids to water ratio was shown to affect the firmness of moin-moin, where a 3.75:1 ratio of solids to water produced a firmer product than other concentrations. Generally, color was unaffected across treatment regimens as identified by an expert sensory panel, although instrumental color measurements showed significant differences for hue angle and chroma. This study demonstrated that the particle size of this food ingredient contributes significantly to its functionality in food formulations.
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physical and sensory characteristics of sugar cookies containing mixtures of wheat fonio digitaria exilis and cowpea vigna unguiculata flours
International Journal of Food Science and Technology, 2003Co-Authors: K Mcwatters, A V A Resurreccion, Jean B Ouedraogo, Yenc Hung, Dixon R PhillipsAbstract:Summary White fonio (Digitaria exilis) and California blackeye cowpea (Vigna unguiculata) flours were used in sugar cookie preparation. Formulations were: (1) 100% wheat, (2) 50% wheat/50% fonio, (3) 50% wheat/50% cowpea, (4) 33% wheat/33% fonio/33% cowpea, (5) 25% wheat/75% fonio, (6) 25% wheat/50% fonio/25% cowpea, (7) 75% fonio/25% cowpea and (8) 50% fonio/50% cowpea. The 100% wheat cookies had the greatest spread ratio (5.86) and the 75% wheat/25% cowpea the least (4.39). The 50% fonio/50% cowpea cookies required the most force (720.3 N) to shear and the 50% wheat/50% fonio the least (399.4 N). The 100% wheat and the 50% wheat/50% cowpea cookies had the lightest colour and the 25% wheat/75% fonio the darkest. Sensory panel assessments of appearance, colour and texture were not affected by component flours. Cookies containing 100% wheat or 50% wheat /50% fonio received the highest hedonic ratings for flavour (7.1 and 6.7, respectively) and overall acceptability (6.9 and 6.5, respectively). All other formulations were unacceptable.
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evaluating the role of cell wall material and soluble protein in the functionality of cowpea vigna unguiculata pastes
Journal of Food Science, 2002Co-Authors: P Kethireddipalli, R D Phillips, Y.c. Hung, K McwattersAbstract:Wet-milling of soaked, decorticated Cowpeas generated large amounts of coarse cell wall material (CWM) and soluble protein (SP). CWM with high water-holding and swelling capacities contributed to excellent paste hydration and flow properties; high SP and paste viscosity resulted in superior foaming characteristics. In hydrated cowpea meal, the presence of coarse cellular material adversely affected paste hydration and flow characteristics; low SP and viscosity resulted in poor foaming. Wet-milling of hydrated meal improved viscosity and functionality. Intense dry-milling increased SP but adversely affected paste viscosity and functionality. La pâte de dolique est utilisee dans la preparation de l'Akara, consomme en Afrique. Les effets des proteines solubles et des parois cellulaires sur la capacite de retention d'eau et les proprietes de gonflement et d'hydratation de la pâte de dolique sont observes.Cette pâte est obtenue soit a partir de la mouture par voie humide des grains trempes, soit par hydratation de la farine, soit par mouture a sec.
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akara making characteristics of five u s varieties of Cowpeas vigna unguiculata
Journal of Food Quality, 2001Co-Authors: K Mcwatters, Y.c. Hung, C Y T Hung, Manjeet S Chinnan, R D PhillipsAbstract:Akara-making characteristics of five U.S. varieties of cowpea were determined, using a small-scale method developed based on 50 g dry seed starting material. Blackeye, crowder, pinkeye, white acre and a new breeding line (white-eye) Cowpeas were evaluated at three paste moisture contents (63, 65, 67%). Blackeye Cowpeas at 65% paste moisture served as the control. Ranges for color characteristics were: lightness (L * ), 59.8 to 68.3 (control = 61.9); chroma (intensity), 34.6 to 41.4 (control=38.3); hue angle (light brown), 72. 7 to 78. 6 (control = 74.9); total color difference, 12.8 to 14.9 (control= 14.0). Akara ball hardness ranged from 9.7 to 18.9 N (control= 14.2). Ranges for other texture characteristics were: elasticity, 1.79 to 3.18 mm (control=2.35); cohesiveness (ratio), 0.20 to 0.34 (control=0.23); gumminess, 2.45 to 4.61 N (control=3.23); and chewiness, 4. 39 to 14.2 J x 10 -3 (control=7.59). Each variety produced four to five balls per batch with weights ranging from 17.54 to 21.24 g (control=21.06 g). Paste with overall handling characteristics (ease of dispensing, ease of ball formation) and akara-making quality (shape of ball, appearance of ball surface) the most like the control was the white-eye, while crowder was the least like the control.
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physical and sensory characteristics of akara fried cowpea paste made from whole and decorticated Cowpeas vigna unguiculata
Lwt - Food Science and Technology, 1993Co-Authors: K Mcwatters, A V A Resurreccion, Stanley M Fletcher, A V Peisher, E L AndressAbstract:Abstract The preparation of akara, a popular West African food made from whipped cowpea paste, traditionally involves decortication (seed coat removal). Decortication may not be necessary for consumers who are unfamiliar with product characteristics. Akara was prepared from meal processed from whole or decorticated seeds. Paste from whole seeds was more viscous and dense than decorticated and produced fewer balls per batch. Akara from whole seeds required significantly more force to shear-compress and had a darker, duller color than akara from decorticated seeds. Akara from both processes contained 22% protein, which was more than twice that of fried cornmeal hush puppies and French fried potatoes. Sensory quality was evaluated by 128 Georgia teenagers. Appearance and color ratings were significantly higher for the decorticated product; there was no difference in flavor, mouthfeel or overall quality ratings due to decortication.
K. Waldron - One of the best experts on this subject based on the ideXlab platform.
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Use of two varieties of hard-to-cook beans (Phaseolus vulgaris) and Cowpeas (Vigna unguiculata) in the processing of koki (a steamed legume product)
Plant Foods for Human Nutrition, 1999Co-Authors: C.m.f. Mbofung, N. Rigby, K. WaldronAbstract:Koki is a nutritious cowpea-based food product usually processed by steam cooking whipped cowpea (Vigna unguiculata) paste mixed with spices and palm oil. A study was carried out to investigate the effect of the partial replacement of Cowpeas (CP) with hard-to-cook (HTC) beans on the chemical, nutritional and sensory characteristics of koki. Towards this objective, two varieties of beans – Phaseolus vulgaris (red kidney beans – RKB and mottled brown beans – MBB), each with the HTC defect, were separately incorporated into cowpea paste in the following Bean:CP ratios 0:100, 20:80, 30:70, 40:60, 50:50, 60:40 and processed into koki. Incorporation of dry HTC beans into Cowpeas in the making of koki affected the bulking properties of the uncooked paste, the nutrient composition, essential amino acid content, antinutritional factors, digestibility as well as the sensory attributes of cooked koki. Sensory tests showed that a highly acceptable, nutritious and digestible koki can be processed from Cowpeas partially replaced with dry HTC bean paste up to levels of about 40–50% depending on the variety of dry bean used.
