Dioscorea Dumentorum Research Articles

ANALYSIS OF CALCIUM AND PHOSPHORUS (CALCIUM-PHOSPHOROUS RATIO) BY SPECTROPHOTOMETRIC TECHINQUES OF SOME COMMONLY EATEN ROOTS/TUBERS SPECIES IN NIGERIA

Some commonly eaten species of roots/tubers namely: Capsium annum (red and white species), Manihot utilisima, Dioscorea dumentorum and Colocassi sagiltifolium were analyzed to compare their calcium-phosphorus ratio by method of APHA, (2018) and AOAC (2005) respectively. The results showed much higher proportions of phosphorus than calcium as against 1 to1 or 1.5 to 1.0 ratios which are the ideal dietary calcium-to-phosphorus ratio. The results suggest that calcium be seriously supplemented and or complemented in these commonly eaten food staples since excess phosphorus tends to suppress the transformation of vitamin D into calcitriol, one of the routes by which the body maintains calcium levels. This will go a long way in reducing conditions of porous, brittle and fracture prone bones that lead to bone diseases which are rampant in our society today.

Synthesis of oxidized Dioscorea dumentorum starch nanoparticles for the adsorption of lead(II) and cadmium(II) ions from wastewater

The search for efficient adsorbents for the treatment of wastewater has led to the exploration of derivatized starches. Here, Dioscorea dumentorum starch was isolated, oxidized and acid-hydrolyzed in a dual-modification approach. The native starch (NTS) and the resulting oxidized starch nanoparticles (Oxy-SNPs) were characterized by FTIR, SEM, XRD and TGA, and then applied in removing Pb2+ and Cd2+ ions from simulated wastewater. Investigation of the functional properties of the starches as well as their characterization confirmed the success of the modification and the suitability of the Oxy-SNPs as adsorbent for metal-ions removal. Adsorption of Pb2+ and Cd2+ ions increased with augmentation of initial metal-ions concentration. Metal removal peaked and flattened after 90 min. Freundlich isotherm gave a superior fitting of experimental data above the Langmuir and Dubinin-Radushkevich (D-R) isotherms, indicating energetically heterogeneous Oxy-SNPs surface. Kinetic data followed the pseudo-second-order model with R2 values of 0.9934 and 0.9989 for Pb2+ and Cd2+ ions, respectively, signifying that the valency forces caused sharing or exchange of electrons during the interactions. Thermodynamic parameter showed that the processes were feasible, exothermic and occurred with decrease disorderliness. Energy values calculated from D-R model (35.36 kJ/mol for Pb2+; 28.87 kJ/mol for Cd2+), the good fitting of Elovich model and the magnitude of ΔHº being <29 kJ/mol all suggest chemical adsorption.

Current Status of Yam (Dioscorea Sp) Genetic Resources-Case Study of Selected Locations in South-West Nigeria

Yam is an important tuber crop in Nigeria. Some locations in South west Nigeria (Oyo State, Ondo State, Osun State, and Ogun State) were surveyed to find out the existence and the abundance of diversity of white guinea yam (Dioscorea rotundata). It was discovered that there are also diversity in other species of landrace yams (Dioscorea cayenensis, Dioscorea alata, Dioscorea dumentorum). One unidentified species of yam was found in Ondo State. This species also exist in Osun State. Some of the yam diversities are endangered. Genetic erosion of these yam diversities is imminent because of the decline of the traditional farmers growing these diversities; also because of modern commercial farms that tend to mono-cropping of improved variety and also because of problem of storage of yams and especially ex-situ conservation of yam genetic resources of yam in Nigeria.

Functional properties of three native starches and their modified derivatives

Starches were isolated from cocoyam (Xanthosoma sagittifollium), white yam (Dioscorea rotundata) and bitter yam (Dioscorea dumentorum). Starch modification was carried out using acetic anhydride and phthalic anhydride. The native and modified starches were characterized using Fourier Transformed Infra-red Spectroscopy (FTIR) for identification of the functional groups. Functional properties such as water absorption capacities, oil absorption capacity, swelling power, solubility, gelation temperature, least gelation capacity, amylose content and pH were determined using standard procedures. Acetylation increased the water absorption capacity, oil absorption capacity, swelling power, amylose content, and solubility of the starches while phthalation decreased water absorption capacity, oil absorption capacity, swelling power, and solubility of the starches. Native cocoyam starch has the highest gelation temperature (85 °C) while Acetylated bitter yam has the lowest gelation temperature (74 °C). The pH of the native and modified starches was within the range of 4.14 − 6.55. Phthalation and acetylation increased the bulk density of the starches. Native cocoyam, white yam, and bitter yam starches had the lowest gelation concentration (6%). Modification of native starches will improve the usage of starch in food and non-food applications.

Mycoflora of postharvest rots of bitter yam &lt;i&gt;Dioscorea dumentorum&lt;/i&gt; Pax in Nsukka agro ecological zone, Nigeria

This study was done to recover fungi associated with postharvest rotting of bitter yam, Dioscorea dumentorum tubers in Nsukka Agroecological Zone, Nigeria. Tubers showing signs of rot were picked from farmers in four randomly selected towns in the zone. The towns included, Nsukka, Orba, Ibagwa and Obollo-Afor. Five (5) samples each were picked from three (3) randomly selected farmers. Samples were packaged in sterile polythene bags, labeled accordingly and moved to the laboratory for studies. The fungal isolates were identified using both cultural and molecular techniques. Results showed that mycoflora of rotted bitter yams in the Zone were, Aspergillus flavus, Aspergillus niger, Lasiodiplodia pseudotheobromae, Galactomyces candidum and Rhizopus delemar. The percentage frequencies of occurrence of the fungal organisms ranged from 14.03% to 26% with A. niger recording the highest (26%) while A. flavus recorded the least (14.03%). Pathogenicity tests revealed that the fungi produced rots (diameter) ranging from 1.70 cm to 2.40 cm with R. delemar recording the highest rot diameter (2.40 cm) while A. niger produced the least (1.70 cm)Keywords: Bitter yam, mycoflora, postharvest, fungal organisms, Nsukka, rots

Physicochemical, functional and antinutritional properties of starches from Caladium bicolor and Dioscorea dumentorum

Starch samples from the wild species of cocoyam (Caladium bicolor (Aiton) Vent.) and three leaf yam (Dioscorea dumentorum (Kunth) Pax.) found abundantly in the south and eastern regions of Nigeria, were characterized for their physicochemical, functional and antinutrient properties. C. bicolor had higher amylose (17.68%), carbohydrate (83.57%) and ash (2.85%) than D. dumentorum. Moisture, crude lipid, protein and fibre ranged between 7.56 to 10.29%, 0.12 to 0.15%, 0.11 to 0.13%, and 2.85 to 3.39%, respectively. The starches exhibited promising functional properties with D. dumentorum having higher dispersibility (64.85%), solubility (73.99%) and oil absorption capacity (2.15 g/g). Onset (To), midpoint (Tm), and conclusion (Tc) gelatinization temperatures ranged between 63 to 79 °C. Peak, breakdown and setback viscosity were higher in D. dumentorum than C. bicolor. Moisture sorption behavior indicated increased hygroscopy with exposure time. The starches had high antinutrient levels, with D. dumentorum having higher levels of HCN and oxalates. In addition, infrared (IR) spectra of both starches were similar. Taken together, these properties suggest the suitability of these starches for non-food applications due to their high antinutrient contents.

Physio-chemical properties of sugar syrup produced from two varieties of yam (Dioscorea dumetorum and Dioscorea alata) using exogenous enzymes

Physio-chemical properties of sugar syrup produced from two varieties of yam (Dioscorea dumetorum and Dioscorea alata) using exogenous enzymes were studied. Starch and flour samples of two yam varieties (Dioscorea dumetorum and Dioscorea alata) were converted into sugar syrup by enzyme hydrolysis using exogenous enzymes. The sprouted and unsprouted tubers were processed into dried starch by washing, peeling, and milling; stirring, settling for about 6 hours; the supernatant was decanted and the sediment which contained the starch was filtered with muslin cloth and oven-dried at 70oC for 30minutes to produce the dry starch. The sprouted and unsprouted tubers were also processed into fine flour by drying, milling and sieving with a 0.8 mm sieve. Alpha and Beta amylase enzymes were used in the syrup production. Physiochemical analysis was carried out on the syrup and results obtained were subjected to statistical analysis using analysis of variance (One-way ANOVA). The results obtained show that the pH values ranged from 4.45 to 5.65 while the moisture content values ranged from 67.42 to 72.25%; the dextrose equivalent results for the samples were 26.68, 26.47, 29.64, 27.13, 29.56, 26.34, 30.15 and 24.79% for the un-sprouted Dioscorea dumentorum flour (UD), sprouted Dioscorea dumetorum flour (SD), un-sprouted Dioscorea alata flour (UA), sprouted Dioscorea alata flour (SA), un-sprouted Dioscorea dumetorum starch (UDS), sprouted Dioscorea dumetorum starch (SDS), un-sprouted Dioscorea alata starch (UAS) and sprouted Dioscorea alata starch (SAS) respectively. This indicates that sample UAS had the highest level of hydrolysis. For the sugar syrups; sample SD had the highest viscosity value (950.05cp) while sample UA had the lowest value (835.10cp). The specific gravity of the sugar syrup samples ranged from 1.16 to 1.29 with sample SDS having the highest value and sample UD having the lowest value. Result from the analysis on sugar concentration (disaccharides) showed that the highest maltose concentration was recorded in sample SDS (57.27%) and the lowest was obtained in sample UA (51.65%). The glucose concentration of the sugar syrup samples ranged from 1.55 to 2.05%; sample SA recorded the lowest value of 1.55% while UAS recorded the highest value of 2.05%. The maltotriose, raffinose and starchyose concentrations of the sugar syrup samples ranged from 7.39 to 7.76%, 0.12 to 023% and 0.93 to 1.15% respectively. Results of this work suggest that sugar syrup can be made from underutilized yam species.

Species Composition of a Degraded Watershed in Amawbia, Anambra State, Nigeria

This work was carried out in a period that spans the rainy and dry seasons of 2010 – 2011. In times past, Anambra State was rich in chains of productive watershed, saturated with luxuriant plant species. This however is now history owing to steadily increasing, degradatory anthropogenic influences. Ignorance and crass indifference on the indispensability of plant resources to man’s survival in tropical Africa has also resulted in very poor biodiversity of our watersheds. Amawbia watershed is not an exception. With the assistance of a field taxonomist and relevant texts, tree, climber, shrub, grass and forb species were firstly identified and recorded for sampled sites (sites A – E). Unlike productive watersheds, the dominant species encountered in this watershed were grasses and forbs. Dominant individual plants include: <i>Heivea brasiliensis, Senna siamea, Napoleana imperialis, Dactyledenia barteri, Pentaclethra macrophyla,</i> (Trees); <i>Gongronema latifolium, Dioscorea dumentorum, Telfeiria occidentalis, Smilax anceps, Cissus aralioides</i> (Climbers); <i>Olax viridis, Mimosa invisa, Bambusa vulgaris, Vernonia amygdalina, Sarcocephalum laxiflora</i> (Shrubs); <i>Zea mays, Panicum maxima, Imperata cylindrica, Sporobolus pyramidalis, Andropogon tectorum</i> (Grass); <i>Amaranthus viridis, Ageratum conyzoides, Sida acuta, Gomphrena celosoides, Ocimum basilicum</i> (Forbs). Most of these species are not very important in terms of economic relevance.

Proximate Composition, Colour Characteristics, Index of Oiliness and Estimated Glycemic Index of Deep-fried Bitter Yam (Dioscorea dumentorum) Chips

Proximate Composition, Colour Characteristics, Index of Oiliness and Estimated Glycemic Index of Deep-fried Bitter Yam (Dioscorea dumentorum) Chips

Role of Fungal Rots in Post-harvest Storage Losses in Some Nigerian Varieties of Dioscorea Species

Aims: To study storage rots in yam varieties cultivated in South East Nigeria and to determine under conditions of experimental storage, the influence of fungal rot on their post harvest storage losses. Place and Duration of Study: Laboratories, Department of Applied Microbiology & Brewing, Nnamdi Azikiwe University, Awka, Nigeria between January 2012 and July 2013. Methodology: Five yam varieties; Dioscorea dumentorum, two varieties each of D. alata and D. rotundata, obtained immediately after harvest were stored in an experimental barn (30oC and 95% RH) and examined at intervals for storage rots. Fungal causative agents of rots were isolated and identified using the partial ITS rDNA sequencing analysis and a BLAST search using the GenBank sequence database. Post harvest storage losses in terms of weight loss and reduction of shelf life among the varieties were determined. Results: All varieties of yams studied suffered fungal rots, predominantly, dry rots during storage. Seven distinct fungal isolates, which caused these rots, were fully characterized. The species were Aspergillus tamari, Fusarium solani, Lasiodiplodia theobromae, Aspergillus niger, Mucor circinelloides, Aspergillus flavus and Aspergillus sp. In all the yams, storage rots reduced shelf life and aggravated weight loss. Post harvest storage losses varied among the different varieties of yams. Conclusion: The varieties of yams studied suffer rots from various fungi, which are similar Original Research Article British Microbiology Research Journal, 4(3): 343-350, 2014 344 to those reported in other parts of the world. Severity of post harvest losses resulting from fungal rots varies among different varieties of yams. This should be taken into consideration in the development of storage techniques.

Proximate Composition, Physiological Changes during Storage, and Shelf Life of Some Nigerian Varieties of Yams (Dioscorea species)

Aims: The objectives of this work were to study the influence of proximate composition and physiological changes during storage, on the shelf life some Dioscorea sp. This is needed to complement knowledge of the influence of extrinsic factors of the storage environment in improving the shelf life, a key attribute of yam quality. Place and Duration of Study: Department of Applied Microbiology & Brewing, Nnamdi Azikiwe University, Awka, Nigeria between January 2012 and July 2013. Methods: AOAC and sensory methods were used to determine proximate composition and shelf life respectively, while physiological changes during storage were monitored by moisture and pH measurements. Results: Moisture content of yams ranged from 61 70%; protein, 0.48 – 1%; fat, 0.39 – 1.67% and carbohydrates, 24 – 32%. These contents varied among the yams at the varietal level. Ash ranged from 1.33 – 2.17% and crude fibre, 2.83 – 4.33% and were largely similar in all varieties. During storage, different varieties of yams maintained different contents of moisture (%) but all shared similar characteristics in respiratory activity. Methanolic extracts from the peels of some Dioscorea dumentorum and D. Original Research Article Frank and Kingsley; JSRR, Article no. JSRR.2014.003 554 rotundata varieties inhibited the growth of Aspergillus sp. The shelf life of the yams ranged from low 27 weeks in D. alata to a high of 40 weeks in D. rotundata. Moisture content (P = 0.1) was negatively correlated while fat (P = .05) and carbohydrate contents were positively correlated with shelf life of yams. Conclusion: The chemical composition of yams plays a role in the determination of their shelf lives. A better understanding of this relationship will help in efforts to increase yam production through the reduction of post harvest losses.

Effect of Enrichment of Trifoliate Yam Flour with Pumpkin Seeds Flour on the Pasting Characteristics and the Acceptability of its Product

Trifoliate yam (Dioscorea dumentorum) is an underutilized yam species which is highly nutritious, but cannot be stored for a long period like other yams because it hardens a few days to harvest. This makes it unavailable all year round. There is therefore the need for processing of the yam to stable flour. Trifoliate yam flour was produced and enriched with pumpkin (Telfaria occidentalis) seed flour at three substitution levels (10%, 15% and 20%) and processed into chin-chin, this product was compared with the chin-chin made from Irish potato (Solanumtuberosum) flour. The flour was analysed for physico-chemical, functional and pasting properties. The product made from the flour (chin-chin) was tested for proximate composition and sensory evaluation to determine its acceptability. Results showed that enrichment of trifoliate yam flour with pumpkin seed flour increased the pH of the flour from 5.95 at 10% substitution to 6.03 at 15% substitution level, while the protein content also increased from 14.23% (10% substitution) to 16.53% (20% substitution). There was also an increase in fat content at the same substitution level. Peak viscosity of the flour decreased from 344.17RVU (10% substitution) to 269.25 (20% substitution). The overall acceptability showed that 10% substitution level had the highest rating and there was no significant difference in the chin-chin made from the enriched flour at the different substitution levels (P>0.05).

A comparative study of effects of storage on basic nutritional composition of two major edible &lt;i&gt;Dioscorea dumentorum&lt;/i&gt; varieties

The proximate analysis comprising the carbohydrate, crude protein, crude fibre, ash and moisture contents, and the minerals analysis of two major edible varieties of Dioscorea dumentorum (Esuru), commonly consumed inEkiti State, Nigeria were estimated after a period of storage using standard chemical methods. The crude protein percentage for stored yellow and white varieties are 3.13 and 2.50 respectively. This is contrary to that of fresh varieties whose crude protein percentages for the yellow and white varieties are 8.24 and 5.44 respectively. The results reveal a significant decrease in protein content in stored Discorea dumentorum varieties compared with previous work on fresh varieties. The crude fat content for the stored yellow and white varieties are 6.07 and 6.88% respectively, while the ash content and the crude fibre contents for the stored yellow and white varieties are 2.80, 2.53 and 1.73 and 1.79% respectively. The carbohydrate contents of the two varieties are 26.97 and 21.33% in the same order. The presence of important minerals like iron, magnesium, phosphorus, calcium, and zinc at a very high level showed that bitter yam would find some useful application in the food and pharmaceutical industries.

Calcium, zinc and phytate interrelationships in some foods of major consumption in Nigeria

The calcium (Ca), zinc (Zn) and phytate (Phy) contents of 35 Nigerian foods were determined. Levels (mg/100 g) of Ca were 29–45 (legumes), 17–49 (cereals), 17–187 (spices) and 38–155 (tuber/roots) while the Zn levels were 0.55–2.00 (legumes), 0.67–1.84 (cereals), 0.34–4.92 (spices) and 1.35–7.07 (tubers/roots). Phytate levels were 14–344 (legumes), 112–287 (cereals), 35–184 (spices) and 0.0–1070 (tubers/roots). It was found that fermentation reduced Phy levels in Parkia filicoidea , Sorghum bicolor and Manihot esculenta while Phy level was increased in fermented Zea mays . The Phy:Zn molar ratios calculated for many legumes, cereals, tubers/roots and one spice analysed were greater than 20:1. Corresponding Ca:Phy molar ratios were generally low in legumes (except for Sphenostylis stenocarpa , 54:1), cereals and tubers/roots but generally high in spices (except Irvingia gabonensis , 2:1). Dioscorea rotundata , Dioscorea dumentorum and Manihot esculenta have respective molar ratios of Ca:Phy 1.8, 2.5 and 1.4 while the respective [ca] [Phy]/[Zn] molar ratios were 0.50, 0.54 and 0.62. These results suggest that the bioavailability of zinc in the Nigerian diet may be low due to the high phytate content of the staple foods.

Dihydrostilbene phytoalexins from Dioscorea bulbifera and D. dumentorum

Analysis of the ethyl acetate extract of the buibil of Dioscorea bulbifera and the tuber of Dioscorea dumentorum infected with Botryodiplodia theobromae gave demethylbatatasin IV and a new dihydrostilbene, 3,5,4′-trihydroxybibenzyl (dihydroresveratrol) respectively, as their major phytoalexins.

Disease-induced changes in carotenoid content of edible yams (Dioscorea spp.) infected by Botryodiplodia theobromae and Aspergillus niger

When pieces of Dioscorea dumentorum, Dioscorea alata and Dioscorea cayenensis were inoculated with suspensions of Botryodiplodia theobromae and Aspergillus niger and incubated at room temperature, the quantities of carotenes and xanthophylls were decreased by infection. The quantities of carotenes and xanthophylls were highest in D. dumentorum followed by D. cayenensis; D. alata had the lowest amounts.