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Yam
Kinds of Yam Terms modified by Yam Selected AbstractsTEXTURE PROFILE ANALYSIS APPLIED TO POUNDED YAMJOURNAL OF TEXTURE STUDIES, Issue 3 2007BOLANLE OTEGBAYO ABSTRACT Textural quality of pounded yam made from tubers of Dioscorea rotundata Poir. and Dioscorea alata L. that were freshly harvested or stored for 4 months were evaluated using texture profile analysis. Significant correlations were obtained between the values for texture attributes evaluated using sensory texture profile analysis and those from instrumental texture profile analysis (ITPA). This implies that ITPA had the ability to measure the textural quality of pounded yam in a way similar to a trained sensory panel and could be used as an objective method to evaluate the textural quality of pounded yam. PRACTICAL APPLICATIONS Because texture profile analysis (TPA) has been successfully used to study the textural quality of pounded yam, a glutinous dough, it can be used in the food industry to study the texture attributes of pounded yam or similar doughlike products. It can also be used to screen yam varieties for textural quality for subsequent utilization. [source] SENSORY TEXTURE PROFILING AND DEVELOPMENT OF STANDARD RATING SCALES FOR POUNDED YAMJOURNAL OF TEXTURE STUDIES, Issue 5-6 2005BOLANLE OTEGBAYO ABSTRACT This study evaluated sensory texture profile analysis (STPA) as an objective method for characterizing the texture attributes of "pounded yam," a popular dish in West Africa made by peeling yam, boiling, pounding and kneading it into a glutinous dough. Panelists were carefully selected and trained to assess the texture attributes of pounded yam. Standard rating scales were developed from local foods that are common in Nigeria, and the foods were used as descriptors to exemplify the texture attributes being assessed. Reproducible and consistent results were obtained. It is thus concluded that STPA can be used as an objective method for evaluating the texture attributes of pounded yam. [source] The performance of QoS-aware IP multicast routing protocols,NETWORKS: AN INTERNATIONAL JOURNAL, Issue 2 2003Chih-Jen Tseng Abstract Research in the area of QoS-aware dynamic multicast routing protocols has been very active in recent years. Protocols based on dynamic Steiner tree strategies, such as YAM and QoSMIC, have been consistently shown to outperform those based on shortest path heuristics, such as PIM and DVMRP. However, these protocols all suffer from the problem of poor scalability for one or more of the following reasons: high control overhead, insufficient robustness with the adoption of a centralized group manager, and excessively long join latency. In addition, these protocols perform well only when group members are either densely populated or sparsely populated, but, unfortunately, not both. In this paper, we propose a protocol, named DSDMR, which can adapt its strategy based on sensed group member densities. Underlying DSDMR is an adaptive two-direction join mechanism that tries to find good attaching points for new group members either from the source or from the new joining member depending on member densities. We evaluate our scheme using extensive simulations and found that DSDMR can build multicast trees with costs close to the best greedy strategy, very low control overhead, and very short join latency across a wide member density spectrum. Furthermore, its success ratio is only slightly lower than is the best greedy strategy in finding feasible routes subject to both bandwidth and end-to-end delay constraints. © 2003 Wiley Periodicals, Inc. [source] Qualities and antioxidant properties of bread as affected by the incorporation of yam flour in the formulationINTERNATIONAL JOURNAL OF FOOD SCIENCE & TECHNOLOGY, Issue 2 2004Chin-Lin Hsu Summary Yams (the tubers of Dioscorea spp.) are widely consumed but are also regarded as a medicinal food in China. Traditional Chinese herbal medicines using yams are only available on a seasonal basis, as yams quickly deteriorate during winter storage. Yam (Dioscorea purpurea, a major variety of yams in Taiwan) was freeze-dried and ground to obtain yam flour. Bread was made by replacing up to 25% of wheat flour with yam flour. Although the loaf volume decreased with the addition of yam flour, the results showed that up to 20% of yam flour could be included in bread formulation without altering the sensory acceptance of the blended bread. The incorporation of yam flour in bread markedly increased the antioxidant capacity of the bread as tested by both DPPH free radical scavenging and total antioxidation tests. Breads containing yam flour can broaden the utilization of yams and may be regarded as possible health-promoting foods. [source] Effect of Yam (Dioscorea alata Compared to Dioscorea japonica) on Gastrointestinal Function and Antioxidant Activity in MiceJOURNAL OF FOOD SCIENCE, Issue 7 2006Cheng-Chin Hsu ABSTRACT:, Effects of Chinese yam (Dioscorea alata) and Japanese yam (Dioscorea japonica) on gastrointestinal functions including intestinal microflora and intestinal enzymes' activities, as well as antioxidant protection against lipopolysaccharide (LPS)-induced oxidative damage, in Balb/cA mice were examined. In part I, mice were fed yam-supplemented diet for 4 or 8 wk, and killed with carbon dioxide. In part II, mice were fed yam-supplemented diet for 4 wk, and followed by intraperitoneal LPS treatment (i.p. 4 mg/kg bodyweight). The intake of Chinese yam and Japanese yam significantly changed intestinal microflora, in which the colony numbers of Bifidobacterium and Lactobacillus were increased and the colony numbers of Clostridium perfringens were decreased (P < 0.05). The intake of both Chinese and Japanese yams also significantly elevated the activity of leucine aminopeptidase and lipase (P < 0.05), and the activities of sucrase and maltase were increased only in 20% yam-treated groups (P < 0.05). The preintake of yam significantly alleviated subsequent LPS-induced oxidative injury by decreasing lipid oxidation level and fibronectin production and elevating superoxide dismutase activity (P < 0.05). Both Chinese and Japanese yams contained dietary fibers, polyphenols, and flavonoids, which may contribute to the observed gastrointestinal function and antioxidant protection. These results suggest that both Chinese yam and Japanese yam were beneficial for intestinal health and oxidation prevention. [source] Screening of Water Yam (Dioscorea alata L.) Genotypes for Reactions to Viruses in NigeriaJOURNAL OF PHYTOPATHOLOGY, Issue 11-12 2006B. O. Odu Abstract Studies were made to identify sources of resistance to yam viruses in Dioscorea alata. Forty genotypes of D. alata were evaluated in both the field and in the screenhouse for reactions to the yam viruses: Yam mosaic virus (YMV), genus Potyvirus; Dioscorea alata virus (DAV), genus Potyvirus; Cucumber mosaic virus (CMV), genus Cucumovirus; and Dioscorea alata bacilliform virus (DaBV), genus Badnavirus. The D. alata genotypes were planted in the field and subsequently scored for virus symptom severity. All the genotypes were also planted in an insect-proofed screenhouse, and challenged mechanically and by vectors for susceptibility to each of the viruses. Analysis of variance (anova) of the symptom severity scores showed that the genotypes responded differently (P < 0.01) to virus disease in the field. Field evaluation also showed that TDa 291 (a landrace genotype from Puerto Rico), TDa 87/01091, TDa 96-4, TDa 95-163 and TDa 289 from Nigeria, and TDa 95-25 (a landrace genotype from Ghana), had a low virus disease symptom rating. Overall screening results showed that two D. alata genotypes (TDa 289 and TDa 291) are good sources of resistance to YMV, DAV and CMV, and that they are tolerant to DaBV. [source] Vegetative Compatibility Among Isolates of Colletotrichum gloeosporioides from Yam (Dioscorea spp.) in NigeriaJOURNAL OF PHYTOPATHOLOGY, Issue 1 2004M. M. Abang Abstract Isolates of Colletotrichum gloeosporioides obtained from yam-based cropping systems in Nigeria, previously characterized on the basis of morphology, virulence and rDNA internal transcribed spacer (ITS) sequence variation were further compared for vegetative compatibility (VC). Chlorate-resistant nitrate non-utilizing (nit) mutants were generated from the isolates and used in complementation (heterokaryon) tests. Tests of VC between complementary mutants from different isolates indicated the presence of several genotypes within a single field, suggesting limited clonal spread. In some cases, isolates obtained from the same lesion were observed to belong to different vegetative compatibility groups (VCGs). No compatibility was observed between isolates of the highly virulent slow-growing grey (SGG), the moderately virulent fast-growing salmon (FGS) and the avirulent/weakly virulent fast-growing grey (FGG) strains. Forty-one C. gloeosporioides isolates belonged to 28 VCGs, giving a genotype diversity estimate of 0.68. This diversity confirmed the high variability of the pathogen population as revealed by previous characterization studies, however, a correlation between VCGs and isolate groupings based on morphology and virulence was not found. The finding that an isolate from weed was compatible with yam isolates indicated that transfer of important traits, such as virulence, may take place between isolates from yam and non-yam hosts. The VCG diversity revealed by this study suggests that in addition to asexual reproduction, sexual reproduction may play an important role in the epidemiology of anthracnose on yam. [source] Qualities and antioxidant properties of bread as affected by the incorporation of yam flour in the formulationINTERNATIONAL JOURNAL OF FOOD SCIENCE & TECHNOLOGY, Issue 2 2004Chin-Lin Hsu Summary Yams (the tubers of Dioscorea spp.) are widely consumed but are also regarded as a medicinal food in China. Traditional Chinese herbal medicines using yams are only available on a seasonal basis, as yams quickly deteriorate during winter storage. Yam (Dioscorea purpurea, a major variety of yams in Taiwan) was freeze-dried and ground to obtain yam flour. Bread was made by replacing up to 25% of wheat flour with yam flour. Although the loaf volume decreased with the addition of yam flour, the results showed that up to 20% of yam flour could be included in bread formulation without altering the sensory acceptance of the blended bread. The incorporation of yam flour in bread markedly increased the antioxidant capacity of the bread as tested by both DPPH free radical scavenging and total antioxidation tests. Breads containing yam flour can broaden the utilization of yams and may be regarded as possible health-promoting foods. [source] Antioxidative activity of water extracts from the yam (Dioscorea opposita Thunb.) tuber mucilage tororoEUROPEAN JOURNAL OF LIPID SCIENCE AND TECHNOLOGY, Issue 6 2006Takeshi Nagai Abstract A water extract as a viscous solution was obtained from the yam Dioscorea opposita tuber mucilage tororo, and its functional properties were demonstrated. The protein content was about 280,,g/mL extract, and the main protein bands with an MW of ,33,kDa without 2-mercaptoethanol (2-ME) and ,31,kDa with 2-ME were detected by SDS-PAGE. The water extract possessed high antioxidative activity and scavenging activities against superoxide anion and hydroxyl radicals. However, it showed no inhibitory activity against angiotensin,I-converting enzyme. The yam tuber contains relatively high contents of vitamins, different micro- and macroelements, enzymes, and dietary fibers. The yam D.,opposita tuber will be increasingly regarded as a health-promoting food. [source] Globalization vs. localization: global food challenges and local solutionsINTERNATIONAL JOURNAL OF CONSUMER STUDIES, Issue 3 2010Quaye Wilhelmina Abstract The objective of this study was to examine the effect of global,local interactions on food production and consumption in Ghana, and identify possible local solutions. Primary data were collected using a combination of quantitative-qualitative methods, which included focus group discussions and one-on-one interviews. Approximately 450 household heads were randomly selected and interviewed between August 2007 and August 2008 in Eastern, Central, Upper East and Northern Regions of Ghana. Findings revealed increasing consumption of foreign rice as opposed to decreasing consumption of local rice and other staples like millet, sorghum and yam because of global,local interactions. However, opportunities exist to re-localize production-consumption patterns through the use of ,glocal foods' like improved ,koose and waakye'. Referencing the situation in Ghana, the study recommends improved production and processing practices backed with appropriate technologies that reflect changing consumption dynamics in order to take full advantage of opportunities created as a result of global,local interactions. [source] Anti-Fenton reaction activity of three taxa of water yam (Dioscorea alata L.)INTERNATIONAL JOURNAL OF FOOD SCIENCE & TECHNOLOGY, Issue 9 2007Tsu-Shing Wang Summary In the present study, we compared the anti-Fenton reaction activity of three taxa of water yam (Dioscorea alata L.): DS2, TN2 and PSY [D. alata L. var. purpurea (Roxb.) M. Pouch]. Anti-Fenton reaction activity was evaluated by measuring the damage inflicted on calf thymus DNA by copper ions combined with hydrogen peroxide with the use of an ethidium bromide binding assay and agarose gel electrophoresis. We found that extracts of tuber pulp from all three taxa of yam had significant anti-Fenton reaction activity. The protection pattern of the three tuber pulp extracts was similar to that of EDTA, a typical divalent metal ion chelator, which displayed a significant protection lag-phase. With the use of thin-layer chromatography, we found that a common, major ansialdehyde-sulphuric acid stained spot (possibly a polysaccharide mucilage) with an Rf of 0.09 may be the most likely contributor to the anti-Fenton reaction activities of the yam tuber extracts investigated. The present study identifies the mechanism of the health benefit of the Dioscorea family. The copper-chelating and absorbing capability of yam tuber pulp extracts may be useful in functional screening. [source] Effect of storage on the gel-forming properties of yam-containing surimi gelsINTERNATIONAL JOURNAL OF FOOD SCIENCE & TECHNOLOGY, Issue 5 2007Yun-Chin Chung Summary The breaking forces, deformations and water-holding capacities of pollock surimi gels (PSG) containing 20% fresh Tainung No. 1 (TNG1) yam (Dioscorea alata) stored at room temperature, 17 and 10 °C, were determined for 12 weeks to evaluate the feasibility of using fresh yam as a healthy ingredient and an alternative source for starch in surimi seafoods. The results showed that the texture properties of TNG1-PSG decreased during storage regardless of the storage temperatures, except for an insignificant change found in the water-holding capacity at 10 °C. Most changes in the texture properties occurred within 1 week, thus the use of fresh TNG1 immediately after harvest is required for producing TNG1-PSG with good texture properties. Frozen storage of TNG-PSG was also undertaken at ,20 °C for 6 months. After 6-months of storage, the breaking force and water-holding capacity of TNG1-PSG decreased by about 22% and 19%, respectively. [source] EFFECTS OF THERMAL AND ELECTROTHERMAL PRETREATMENTS ON HOT AIR DRYING RATE OF VEGETABLE TISSUEJOURNAL OF FOOD PROCESS ENGINEERING, Issue 4 2000WEI-CHI WANG ABSTRACT Cylindrical samples of carrot, potato and yam were dried in a hot-air dehydrator after preheating to 50C or 80C by three different heating methods (conventional, microwave and ohmic). The results showed that enhancement of drying rate increased with pretreatment temperature. Ohmic pretreatment increased the drying rate more than conventional and microwave heating. Desorption isotherms showed that in the low aw range, desorption data of preheated and raw materials were similar. However, the isotherms of preheated samples shifted when aw was high, which indicated that thermal pretreatments altered the structure, and apparently, the water distribution within these materials. For all samples, ohmic pretreatment showed stronger influences on isotherms than microwave heating, while the pretreatment effect of conventional heating was only observed for potato tissue. [source] EFFECT OF YAM VARIETY ON THE PASTING PROPERTIES AND SENSORY ATTRIBUTES OF TRADITIONAL DRY-YAM AND ITS PRODUCTSJOURNAL OF FOOD QUALITY, Issue 3 2008J.M. BABAJIDE ABSTRACT Six varieties of yam were processed into traditional dry-yam slices. The pasting properties and sensory attributes of dry-yam samples, flour and paste from the flour were investigated. Significant differences (P , 0.05) were observed in the pasting properties of flour from different yam varieties. "Ijedo," the commonly used variety, had the highest peak, trough and final viscosities. There was no significant difference in the viscosities of "Efuru" (206.04 rapid viscosity analyzer), "Ise-Osi" (242.75 rapid viscosity unit [RVU]) and "Abuja" (241.25 RVU) varieties. Samples of dry yam made from "Efuru,""Ise-Osi" and "Abuja" yams were not significantly different (P > 0.05) from "Ijedo" in terms of instrumental color measurement, as their degree of brownness (100 , L*) were 21.53, 19.21, 20.87 and 22.42, respectively. There was no significant difference (P > 0.05) in color, taste and moldability of the paste made from "Efuru,""Ise-Osi,""Ijedo" and "Abuja" yams. There was no significant difference (P > 0.05) between the hardness of dry yams made from "Ise-Osi,""Ijedo" and "Abuja." There were positive correlations between the yam paste moldability, peak, trough and final viscosities for the different yam varieties. "Ise-Osi,""Efuru" and "Abuja" varieties were found to be suitable for dry-yam processing in terms of sensory property and pasting of dry-yam slices and their products, which were not significantly different from those of "Ijedo" variety , the commonly used yam. PRACTICAL APPLICATIONS The study revealed that dry-yam processors and potential dry-yam processors in Nigeria can use other white yam varieties, such as "Abuja,""Ise-Osi" and "Efuru," apart from "Ijedo" variety , the commonly used yam variety. These yam varieties were also acceptable in terms of the sensory and pasting properties of dry-yam slices and their products. Thus, the general knowledge that white yams are good for dry-yam processing has been scientifically verified. [source] Antioxidative Ability, Dioscorin Stability, and the Quality of Yam Chips from Various Yam Species as Affected by Processing MethodJOURNAL OF FOOD SCIENCE, Issue 2 2009Y.-M. Liu ABSTRACT:, The antioxidative ability, stability of storage protein dioscorin, and the quality of fried yam chips from different cultivars of Chinese yams influenced by various processing treatments were investigated. Total phenolic content and DPPH free radical scavenging effect were found to be the highest in Mingchien (MC) and the lowest in Keelung (KL) yam. Following processing, freeze-dried yams of all varieties showed the least decrease in total phenolic compounds and DPPH radical scavenging effect, while boiling caused the greatest decrease in both. Fresh yams of all varieties contained the highest dioscorin contents comparing with their counterparts. Boiling and deep-frying caused severe protein denaturation resulting in loss of dioscorin solubility after purification. Freeze-drying resulted in increase in protein surface hydrophobicity (So); nonetheless, it attained higher total phenol content, antioxidative capacity, and dioscorin stability of yams compared with other processing treatments. The peroxide values of all yam chips increased during the initial stage, then declined with advanced storage. Fracturability of all yam chips gradually decreased, due to the absorption of moisture, with increasing storage time. [source] Effect of Yam (Dioscorea alata Compared to Dioscorea japonica) on Gastrointestinal Function and Antioxidant Activity in MiceJOURNAL OF FOOD SCIENCE, Issue 7 2006Cheng-Chin Hsu ABSTRACT:, Effects of Chinese yam (Dioscorea alata) and Japanese yam (Dioscorea japonica) on gastrointestinal functions including intestinal microflora and intestinal enzymes' activities, as well as antioxidant protection against lipopolysaccharide (LPS)-induced oxidative damage, in Balb/cA mice were examined. In part I, mice were fed yam-supplemented diet for 4 or 8 wk, and killed with carbon dioxide. In part II, mice were fed yam-supplemented diet for 4 wk, and followed by intraperitoneal LPS treatment (i.p. 4 mg/kg bodyweight). The intake of Chinese yam and Japanese yam significantly changed intestinal microflora, in which the colony numbers of Bifidobacterium and Lactobacillus were increased and the colony numbers of Clostridium perfringens were decreased (P < 0.05). The intake of both Chinese and Japanese yams also significantly elevated the activity of leucine aminopeptidase and lipase (P < 0.05), and the activities of sucrase and maltase were increased only in 20% yam-treated groups (P < 0.05). The preintake of yam significantly alleviated subsequent LPS-induced oxidative injury by decreasing lipid oxidation level and fibronectin production and elevating superoxide dismutase activity (P < 0.05). Both Chinese and Japanese yams contained dietary fibers, polyphenols, and flavonoids, which may contribute to the observed gastrointestinal function and antioxidant protection. These results suggest that both Chinese yam and Japanese yam were beneficial for intestinal health and oxidation prevention. [source] Field Studies on Cross-protection against Japanese yam mosaic virus in Chinese yam (Dioscorea opposita) with an Attenuated Strain of the VirusJOURNAL OF PHYTOPATHOLOGY, Issue 2 2008H. Kajihara Abstract An attenuated strain of Japanese yam mosaic virus (JYMV), designated T-3, was evaluated for its cross-protection efficacy against virulent (native) strains of JYMV in Chinese yam (Dioscorea opposita) grown in farmers' fields in Japan. Native strains of JYMV were detected by a polymerase chain reaction-based assay in all the Chinese yam plants grown from virus-free tubers in the first growing season in the fields. In contrast, the virus was detected in only one of fifty plants grown from tubers preinoculated with T-3 during the experiments for 6 years, suggesting that T-3 consistently cross-protected against native JYMV in Chinese yam in the field. Chinese yam plants preinoculated with T-3 produced significantly greater yield of tubers per plant compared with non-inoculated plants. [source] Two Genetically Distinct Populations of Colletotrichum gloeosporioides Penz.JOURNAL OF PHYTOPATHOLOGY, Issue 3 2005Causing Anthracnose Disease of Yam (Dioscorea spp.) Abstract Variation within Colletotrichum gloeosporioides, the causal agent of yam anthracnose disease, is still poorly defined and this hinders breeding for resistance. Two morphotypes of C. gloeosporioides, designated slow-growing grey (SGG) and fast-growing salmon (FGS), are associated with anthracnose disease of yam in Nigeria. The morphotypes are distinguishable based on colony and conidial morphology, growth rate, virulence, as well as vegetative compatibility, but molecular differentiation of SGG and FGS strains is needed to facilitate epidemiological studies. Denaturing gradient gel electrophoresis (DGGE) of polymerase chain reaction (PCR)-amplified small subunit (18S) rDNA fragments, and microsatellite-primed PCR (MP-PCR) genomic fingerprinting were employed to provide a basis for molecular differentiation of the morphotypes. DGGE analysis revealed patterns that clearly differentiated isolates of the aggressive defoliating SGG from the moderately virulent non-defoliating FGS strains. Genetic analysis based on 52 MP-PCR markers revealed highly significant differentiation between the SGG and FGS populations on yam (GST = 0.22; Nei's genetic identity = 0.85; , = 0.28, P < 0.001), indicating that the SGG and FGS morphotypes represent genetically differentiated populations. The results of the molecular typing using DGGE and MP-PCR analyses were consistent with the disease phenotype caused by the two morphotypes. Consequently, these molecular techniques might be used, at least partly, to replace time-consuming virulence studies on yam. [source] Vegetative Compatibility Among Isolates of Colletotrichum gloeosporioides from Yam (Dioscorea spp.) in NigeriaJOURNAL OF PHYTOPATHOLOGY, Issue 1 2004M. M. Abang Abstract Isolates of Colletotrichum gloeosporioides obtained from yam-based cropping systems in Nigeria, previously characterized on the basis of morphology, virulence and rDNA internal transcribed spacer (ITS) sequence variation were further compared for vegetative compatibility (VC). Chlorate-resistant nitrate non-utilizing (nit) mutants were generated from the isolates and used in complementation (heterokaryon) tests. Tests of VC between complementary mutants from different isolates indicated the presence of several genotypes within a single field, suggesting limited clonal spread. In some cases, isolates obtained from the same lesion were observed to belong to different vegetative compatibility groups (VCGs). No compatibility was observed between isolates of the highly virulent slow-growing grey (SGG), the moderately virulent fast-growing salmon (FGS) and the avirulent/weakly virulent fast-growing grey (FGG) strains. Forty-one C. gloeosporioides isolates belonged to 28 VCGs, giving a genotype diversity estimate of 0.68. This diversity confirmed the high variability of the pathogen population as revealed by previous characterization studies, however, a correlation between VCGs and isolate groupings based on morphology and virulence was not found. The finding that an isolate from weed was compatible with yam isolates indicated that transfer of important traits, such as virulence, may take place between isolates from yam and non-yam hosts. The VCG diversity revealed by this study suggests that in addition to asexual reproduction, sexual reproduction may play an important role in the epidemiology of anthracnose on yam. [source] TEXTURE PROFILE ANALYSIS APPLIED TO POUNDED YAMJOURNAL OF TEXTURE STUDIES, Issue 3 2007BOLANLE OTEGBAYO ABSTRACT Textural quality of pounded yam made from tubers of Dioscorea rotundata Poir. and Dioscorea alata L. that were freshly harvested or stored for 4 months were evaluated using texture profile analysis. Significant correlations were obtained between the values for texture attributes evaluated using sensory texture profile analysis and those from instrumental texture profile analysis (ITPA). This implies that ITPA had the ability to measure the textural quality of pounded yam in a way similar to a trained sensory panel and could be used as an objective method to evaluate the textural quality of pounded yam. PRACTICAL APPLICATIONS Because texture profile analysis (TPA) has been successfully used to study the textural quality of pounded yam, a glutinous dough, it can be used in the food industry to study the texture attributes of pounded yam or similar doughlike products. It can also be used to screen yam varieties for textural quality for subsequent utilization. [source] SENSORY TEXTURE PROFILING AND DEVELOPMENT OF STANDARD RATING SCALES FOR POUNDED YAMJOURNAL OF TEXTURE STUDIES, Issue 5-6 2005BOLANLE OTEGBAYO ABSTRACT This study evaluated sensory texture profile analysis (STPA) as an objective method for characterizing the texture attributes of "pounded yam," a popular dish in West Africa made by peeling yam, boiling, pounding and kneading it into a glutinous dough. Panelists were carefully selected and trained to assess the texture attributes of pounded yam. Standard rating scales were developed from local foods that are common in Nigeria, and the foods were used as descriptors to exemplify the texture attributes being assessed. Reproducible and consistent results were obtained. It is thus concluded that STPA can be used as an objective method for evaluating the texture attributes of pounded yam. [source] Characterizing diversity in composition and pasting properties of tuber flour in yam germplasm (Dioscorea spp.) from Southern EthiopiaJOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 10 2008Muluneh Tamiru Abstract BACKGROUND: Studies on composition and functional properties in germplasm collections are important in determining their diversity and suitability for food and non-food applications. The diversity in 65 yam accessions collected from Southern Ethiopia and belonging largely to a yet unknown species and to Dioscorea bulbifera L. (aerial yam) was analyzed based on protein, starch and amylose contents, and pasting properties of tuber flour, applying descriptive and multivariate statistics. RESULT: Starch content varied from 65.2% to 76.6% dry matter, while the protein content range was 6.4,13.4% dry matter. Amylose represented between 7.1% and 30.6% of the starch fraction, and was negatively correlated (P < 0.01) with starch content. UPGMA clustering and principal component analysis clearly distinguished aerial yam from those accessions with underground tubers. The first four principal components accounted for 78% of the total variability, and were highly correlated with pasting parameters. CONCLUSION: The extent of diversity detected among accessions studied showed scope for improving the crop through selection of landraces with desirable characteristics. Similar investigations on tubers grown under different environmental conditions and additional data on physicochemical properties of isolated starch will be useful in evaluating the potential of yam for food and non-food applications. Copyright © 2008 Society of Chemical Industry [source] Variability in starch physicochemical and functional properties of yam (Dioscorea sp) cultivated in Ivory CoastJOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 15 2004N'Guessan Georges Amani Abstract An Erratum has been published for this article in Journal Of the Science of Food and Agriculture 85(5), 889 (2005). Native starches were extracted from 21 cultivars of four yam species representative of the yam population of Ivory Coast. They were first characterized for their proximate composition, starch physico-chemical properties (amylose content, particle size distribution, crystallinity, thermal properties and intrinsic viscosity). Some functional properties (swelling, solubility and pasting behaviour and paste clarity) were then determined. Analysis of variance and principal component analysis showed that three homogenous groups could be distinguished, mainly based on starch physico-chemical properties. The first group contained all yam starches of the D alata and the D cayenensis-rotundata complex species. It was characterized by a large diameter grain (approximately 25 µm), a high amylose content (around 25% db), a high intrinsic viscosity (mean of 190 cm3 g,1), and a high apparent viscosity and clarity of the paste. The second group contained the D esculenta varieties, characterized by a small granule size (diameter 6 µm), a low intrinsic viscosity (121 cm3 g,1), a high gelatinization enthalpy change (19 J g,1) and a low paste viscosity. The D dumetorum sample differed from the D esculenta group by having a pure A-type crystalline form and an opaque paste. A multiple regression showed that the volume fraction of the dispersed phase and native granule size (or amylose content) could account for close to 80% of the variability of paste apparent viscosity. Gel clarity appeared mainly linked to granule size, small granules from D dumetorum and D esculenta giving the most opaque gels. Copyright © 2004 Society of Chemical Industry [source] Effect of section of yam (Dioscorea cayenensis) tuber used in minisett on the biochemical properties of the resultant tuberJOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 13 2002Andrew O Wheatley Abstract The effect of the section of yam (Dioscorea cayenensis) tuber used as planting material in minisett on the biochemical properties of the resultant tuber was studied. The biochemical parameters invertase (EC 3.2.1.26), acid phosphatase (EC 3.1.3.2), peroxidase (EC1.11.1.7), polyphenol oxidase (EC 1.10.3.1), total sugars and starch were evaluated in tubers resulting from field-grown and tissue culture-derived setts of the cultivars Roundleaf and Blackwiss yellow yams. No significant differences were observed between tubers resulting from field-grown and tissue culture-derived setts relative to the parameters studied. Invertase activity was found to be highest in tubers from middle-derived setts, while tail-derived setts had the lowest activity for both cultivars. Middle-derived tubers were also found to have significantly higher levels of acid phosphatase activity and starch content. However, middle-derived tubers had the lowest level of total sugars. Polyphenol oxidase and peroxidase were also found to be significantly higher in tubers from middle-derived setts. These results suggest a higher rate of active starch formation in tubers from middle-derived setts. © 2002 Society of Chemical Industry [source] Development of DNA microsatellite markers in tropical yam (Dioscorea sp.)MOLECULAR ECOLOGY RESOURCES, Issue 1 2006S. TOSTAIN Abstract We developed new simple sequence repeat (SSR) markers in different species of yam (Dioscorea sp.). A microsatellite-enriched bank was created from Dioscorea alata, Dioscorea abyssinica and Dioscorea praehensilis. Sixteen polymorphic loci were characterized. Several of these markers are transferable to species of other Dioscorea sections. [source] Effect of a novel botanical agent Drynol Cibotin on human osteoblast cells and implications for osteoporosis: promotion of cell growth, calcium uptake and collagen productionPHYTOTHERAPY RESEARCH, Issue S2 2010Barbara Wegiel Abstract Osteoporosis is a widespread problem afflicting millions of people. Drynol Cibotinis is a newly developed proprietary botanical combination of eight botanicals including Angelica sinensis, Glycine max, Wild yam, Ligustrum lucidum, Astragalus membranaceus, Cuscuta chinensis, Psoraleae corylifoliae, and Drynaria fortune. Each of the botanicals has been used in traditional Chinese medicine to treat osteoporosis. The effect of Drynol Cibotinis, with the specific combination of these anti-osteoporosis botanicals for promoting bone growth, was examined in this study. The effects of Drynol Cibotin on cell growth, apoptosis, cell spreading, calcium uptake and production of bone matrix proteins Collagen I and Laminin B2 on human osteoblast cells were assessed by BrdU incorporation, TUNEL assay, cell staining, intracellular Ca2+ measurement and Western blot analysis. The results showed that Drynol Cibotin significantly increased cell proliferation and inhibited apoptosis in osteoblasts (P < 0.01). In addition, Drynol Cibotin was found to promote cell spreading and greatly increase calcium uptake both instantaneously and in the long term (P < 0.01). Furthermore, Drynol Cibotin significantly increased production of two key extracellular matrix proteins in bone cells: Collagen I and Laminin B2. These results indicate that Drynol Cibotin alone or in combination with amino acids and vitamins may have prophylactic potentials in osteoporosis. Copyright © 2009 John Wiley & Sons, Ltd. [source] Resistance in water yam (Dioscorea alata) cultivars in the French West Indies to anthracnose disease based on tissue culture-derived whole-plant assayPLANT PATHOLOGY, Issue 5 2006T. J. Onyeka Reactions of 60 water yam (Dioscorea alata) cultivars to three isolates of the yam anthracnose fungal pathogen (Colletotrichum gloeosporioides) were evaluated using tissue culture-derived whole-plant assay. Three disease parameters: single score on a scale of 0,6 at the seventh day after inoculation (SD7); area under the disease progress curve (AUDPC); and disease progress rate (Rd) were compared, and cultivars were classified into disease-response groups using a rank-sum method based on AUDPC scores for the two most virulent isolates. A wide range of variation in resistance of the D. alata cultivars, and significant effects of pathogen isolate and isolate,cultivar interactions, were observed for all disease parameters. The three disease parameters were positively correlated; however, four cultivars showed great dispersions from the regression lines for comparisons of SD7 with the multiple assessments based AUDPC and Rd. The 60 cultivars were separated into resistant (n = 12), moderately resistant (n = 19), moderately susceptible (n = 18) and susceptible (n = 11) groups. The potential of the tissue culture-derived whole-plant assay to resistance breeding programmes and further understanding of the yam anthracnose pathosystem is discussed. [source] First report of Dasheen mosaic virus in elephant foot yam in IndiaPLANT PATHOLOGY, Issue 6 2001NEW DISEASE REPORT No abstract is available for this article. [source] In vitro micro-tuber initiation and dormancy in yamANNALS OF APPLIED BIOLOGY, Issue 2 2010E.I. Hamadina Dormancy is a mechanism that regulates the timing of sprouting (germination) of affected plant parts as well as ensures that the food quality of edible parts is maintained in storage until the following growing season. In yam, however, little is known about the control of tuber initiation or tuber dormancy. The objective of this study was to determine the effects of selected plant growth regulators (PGRs) on tuber initiation and dormancy, using an in vitro system. In two replicated experiments, 2-chloroethylphosphonic acid (ethephon, an ethylene source), abscisic acid (ABA) and gibberellin (GA3) , and their inhibitors silver nitrate, fluridone and 2-chloroethyl-trimethylammonium chloride, respectively , were added at two concentrations to the culture medium prior to explant culture. Dates of micro-tuber initiation and sprouting (end of dormancy) and tuber number were recorded. In the control (no PGR) in Experiment 1, micro-tubers were initiated at the base of the stem after 176 days and sprouted 235 days later, that is 411 days after culturing. Most PGR treatments had only small effects (±30 days) on the duration of dormancy and the time of micro-tuber initiation. However, in GA3 micro-tuber initiation occurred after 76 days, about 100 days earlier than in the control, whereas fluridone affected the position of micro-tubers and duration of dormancy. With fluridone treatments, tubers were found at the base of the stem (normal position) and on lower and upper nodes. Lower node tubers sprouted within 225 days of culturing compared with about 420 days after culturing at other nodal positions and in other PGR treatments. These data suggest an important role for ABA and gibberellic acid in yam micro-tuber initiation and the induction of dormancy. [source] Survey of the incidence and distribution of viruses infecting yam (Dioscorea spp.) in Ghana and TogoANNALS OF APPLIED BIOLOGY, Issue 2 2010A.O. Eni Yam leaves were collected during surveys of major yam producing agro-ecological zones (AEZs) in Ghana (n = 628) and Togo (n = 218) respectively, in 2005. Leaf tissues were tested for Cucumber mosaic virus (CMV), Dioscorea mottle virus (DMoV), Yam mild mosaic virus (YMMV), Yam mosaic virus (YMV) and badnaviruses by enzyme-linked immunosorbent assay (ELISA), immunocapture-polymerase chain reaction (IC-PCR) and/or IC-reverse transcription-PCR (IC-RT-PCR). Eighty-one percent (370/459) and 78.9% (127/161) of symptomatic leaf samples from Ghana and Togo, respectively and 56.2% (95/169) and 57.9% (33/57) of non-symptomatic leaf samples, reacted positive to CMV, YMMV, YMV and/or badnaviruses, but DMoV was not detected. The highest incidence of YMV and badnaviruses was observed in the forest,savannah transition and Guinea savannah AEZ respectively in Ghana. In Togo, incidence of badnaviruses across the four AEZ ranged from 50 to 57.9%; however, Savane Derivée Seche AEZ had the highest incidence of badnaviruses (57.9%), YMV (34.2%) and CMV (7.9%). Mixed infection of badnaviruses and YMMV was the most frequent (105 of 276 mixed infections) in the two countries and Dioscorea alata was more heavily infected than D. rotundata in both countries. [source] | ||||||||||||||||