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This paper aims to investigate how awareness influences the adoption of positive selection (PS) technology among smallholder yam farmers in West Africa. PS has the potential of increasing yield and reducing disease incidence and severity in yam production.

This paper applies the average treatment effect (ATE) methodology to estimate the rates of awareness and adoption of the PS technology and associated factors using data from 678 smallholder seed yam farmers in Ghana and Nigeria.

The results indicate that the actual adoption rates of PS technology are 58 and 55%, while the potential adoption rates are estimated at 89.5 and 79.3% for Ghana and Nigeria, respectively, if the PS technology was fully disseminated. This leads to adoption gaps of 31.7 and 24.8%, respectively, for Ghana and Nigeria stemming from incomplete awareness of the PS among the population of yam growing farmers. The PS adoption is high among the educated young farmers who are members of farmer based organizations and participate in demonstrations.

Promotional efforts for enhancing awareness and adoption of PS should target educated youth willing to participate in field demonstrations and should focus on scaling up of PS technology to ensure quality farmer saved seed yams and enhance yam productivity in West Africa.

The introduction of PS in seed yam production is quite recent also its introduction to seed yam farmers in West Africa. Subsequently, a better understanding of what the adoption status would be should everyone in the population of yam farmers are aware of PS is vital for policy, research and development.

The purpose of this paper is to develop poundmix for reconstitution, such as pounded yam, from yam, cocoyam and breadfruit blends and to evaluate their nutritional compositions.

Pregelatinized flours of yam, cocoyam and breadfruit were prepared separately. Three coded samples of 30, 40 and 50 per cent composite blends of poundmix were formulated. The proximate composition, starch, vitamin C and mineral elements contents of the poundmix were determined and the results were subjected to statistical analysis.

The protein contents of poundmix samples were 5.6, 6.1 and 6.2 per cent for 30, 40 and 50 per cent composites, respectively, which is an increase from that of whole yam (4.8 per cent). Significant difference also existed between the starch content of the poundmix and that of the whole yam flour (p<0.05). However, there is no significant difference in the overall acceptability of the poundmix samples and that of the whole yam flour at p<0.05.

The paper's findings show that supplementing poundo yam at 40 per cent composite level has the best nutritional composition and organoleptic scores and so it is recommended for both household and industrial practice.

A refined singles yam torsional model was built based on a previously developed singles yam model⁽¹⁾. The initial yam density distribution was found to be a very important yam parameter governing the torsional property of singles yams. Detailed study of the differential volumetric changes within the yam has shown that jamming of the structure is the key factor initiating longitudinal tensile and compressive strains in the fibres. The yam model was summarised in the form of a system of non-linear equations and the solution finding algorithm was presented.

The purpose of this paper is to develop poundmix for reconstitution as pounded yam, from yam, cocoyam, breadfruit and plantain and to evaluate their physico‐chemical and sensory properties.

Instant flour of the components was prepared separately and 30‐50 per cent composite blends of poundmix were formulated. The physico‐chemical, and sensory properties of the poundmix were determined and the results were subjected to appropriate statistical analysis.

The swelling capacities of the poundmix are 3.14±0.03, 3.13±0.04, 3.81±0.01 per cent for 30, 40 and 50 per cent composite levels, respectively, as against 2.27±0.04 per cent for yam flour. Whole yam flour compared well with the composites in terms of peak temperatures with the 40 per cent composite flour having the highest pasting temperature 93°C and 50 per cent composite with the lowest (72°C). However, the higher the composite level the lower the peak viscosity as 390, 260, 210, and 190 BU were recorded for 0, 30, 40 and 50 per cent composites, respectively (F=3.18, p<0.05).

These findings showed that supplementing poundo yam at 40 per cent composite level should be practiced as it gives the best physico‐chemical properties and sensory score.

The aim of the study is to compare the effect of steaming method and time on the physico‐chemical properties of underutilized Dioscorea dumetorum with three more commonly consumed Dioscorea rotundata, Dioscorea cayenensis and Dioscorea alata.

Raw and pre‐gelatinized flour were produced from the yam species. Pre‐gelatinization was done by steaming diced cubes in autoclave at 68,950 Nm‐2 for 5 min and in Barlett steamer at 98±2°C for 10, 20 and 30 min. Flour samples were analyzed for amylose content, swelling index, consistency, solubility, water absorption capacity, and iodine affinity for starch.

The physico‐chemical properties of the flours were affected by both species and steaming time. Pre‐gelatinization of the tuber reduced amylose content in all the yam species, which reduced further with increase in steaming time. Except for amylose content and iodine affinity for starch, D. dumetorum compared with D. rotundata and D. cayenensis in the parameters that were measured. Samples autoclaved for 5 min had value similar to those steamed in Barlett steamer for 10 and 20 min for all the parameters that were measured, except consistency.

It is very important to encourage the cultivation and utilization of D. dumetorum because of the high yield and nutritional composition to enhance the nutritional and financial well‐being of the populace.

Pre‐gelatinization is important as pre‐treatment for yam tubers. Underutilized D. dumetorum could be useful in ingredient formulation for product development, especially as a thickening agent.

This study aims to examine the effect of lesser yam-based cookies on glucagon-like peptide-1 (GLP-1), blood glucose and lipid profile in overweight and obese individuals.

This was an experimental study on overweight or obese adults aged 21-50 years old. The intervention was done by giving 87g of cookies made with lesser yam flour in combination with wheat flour (80 and 20 per cent, respectively) for six weeks. Anthropometric measures, fasting plasma glucose, lipid and GLP-1 were measured before and after the intervention.

There were no changes in anthropometric measurements and glucose level after the intervention (p > 0.05). However, plasma low density lipoprotein (LDL) and total cholesterol decreased after the intervention (p = 0.033 and p = 0.035, respectively). Although fasting GLP-1 level (p = 0.121) was unchanged, we found that the slight changes in GLP-1 concentration was associated with changes in LDL and total cholesterol (p = 0.002 and p = 0.001, respectively).

The lesser yam-based cookies reduced fasting plasma LDL and total cholesterol, but not glucose level after six weeks of intervention. Additionally, reduction of LDL and total cholesterol level was negatively associated with the changes in GLP-1 level.

The aim of the paper is to evaluate the microbiological and physico‐chemical characteristics of fermented pounded yam, a unique and popular food of the Igbominas of Nigeria.

Fresh pounded yam was prepared in the laboratory by a modification of the traditional method, and then fermented for varying periods of time (0‐96hrs), also essentially by the traditional method. Analysis was carried out on the products following documented and established procedures.

Data obtained indicated noticeable increases in the populations of all the groups of microorganisms investigated with increases in fermentation time, except coliforms which declined in population after 24 hours. Heating of the samples after each fermentation interval resulted in significant reductions in microbial populations such that coliforms could not even be detected after 24 hours of fermentation. Lactic acid production, an indication of flavour development, and pH drop were highest at 48 hours of fermentation. The samples also became softer with increases in fermentation period. The heated samples were considered safe microbiologically, since they contained neither coliforms nor faecal coliforms.

The consumption of fermented pounded yam is encouraged since it is safe microbiologically and develops a desired flavour, while further research should be carried out on the nutritional benefits.

The findings here suggested that adequate heating after fermentation is necessary to eliminate any potential microbial contamination, and for full flavour development.

The results of this research contribute to the knowledge of fermented foods, especially those that are indigenous to Nigeria and West Africa.

The importance of staple yam hairiness as a key factor affecting the properties of yams and fabrics is well known. Accurate measurement of yam hairiness is essential for quality control. This series of papers reports findings of the author's most recent studies on the subject of yam hairiness. In Part 1, the fallacy of hairiness testing using commercial hairiness meters is examined, with particular reference to the effect of testing speed on yam hairiness results. In Part 2, several novel ways of reducing yam hairiness are described.

This study aims to investigate the levels of some anti‐nutritional factors and minerals and the effect of boiling or roasting on selected commonly consumed Caribbean tuber crops.

Three commonly consumed tuber crops in the Caribbean namely: Yellow yam (Dioscorea cayenensis), Cocoyam (Xanthosoma sp.) and Sweet potato (Ipomea batatas) were harvested from farmers’ field in the Parish of Manchester, Jamaica and assessed in their boiled, raw and roasted forms for levels of some anti‐nutritional factors and minerals.

Zinc and iron levels were highest in raw Yellow yam, while the highest levels of calcium were observed in Sweet potato. The phytic acid to zinc molar ratio was higher than 15 in all the tuber crops in their raw and roasted forms. Boiling reduced this ratio to below 15 for Yellow yam and Cocoyam but still remained above 15 for Sweet potato. Cyanoglucoside level was highest in raw Sweet potato followed by Yellow yam and Cocoyam. Boiling or roasting reduced the levels of cyanoglucosides. Roasting greatly lowered the level of trypsin inhibitor activity compared to boiling. The highest level of trypsin inhibitor activity was recorded in the raw tubers, and slight reductions were observed upon processing.

Trypsin inhibitor was more stable to heat treatment compared to similar tubers grown in Africa. It may be beneficial to isolate and characterize trypsin inhibitor in these Caribbean tuber crops for utilization in nutraceutics.

This study shows that the two traditional processing methods were effective in lowering the levels of anti‐nutritional factors.

The purpose of this paper is to evaluate the effect of dehulling/soaking on the chemical, functional and anti‐nutritional contents of three varieties of beans. This research work involved comparative study of the underutilized bean species with the commonly consumed beans in Nigeria.

Three species of legumes were used for this study. The cowpea seeds were divided into two parts. One part was milled and packaged for raw flour while the other part was dehulled and soaked for 30 min, dried in the oven, milled and packed. For the pigeon pea and African yam beans, the raw beans were milled and packaged while part of the seeds was steamed for 5 min and the coats were removed. The dehulled beans were soaked for 30 min, dried in the oven, milled and packaged. Chemical, functional and anti‐nutritional content were determined on the samples.

Fat content ranged from 0.95 to 1.98 per cent. Ash and crude fibre ranged from 1.98 to 6.13 and 2.41 to 7.90 per cent, respectively. Raw cowpea had the highest calcium content (3.86 per cent) while pigeon pea had higher value in magnesium content (2.01 per cent). Raw African yam beans had the highest iron content (23.44 per cent). Bulk density, swelling index and water‐absorption capacity ranged from 0.53 to 0.92 g/cm³, 2.3 to 5.9 and 0.9 to 2.8 ml H₂O/g, respectively. African yam bean had higher values in oxalate, phytate and tannin contents while cowpea had higher saponin content. Raw flour of pigeon pea had higher value in trypsin inhibitor.

This work enables us to make use of the underutilized beans. These beans were higher in nutrients than the cowpea used. Processing of these beans will make them useful for human nutrition without imposing any health problem to the consumer. They could also be converted to flour and used in formulating food such as weaning food.