Selected Cassava Varieties Research Articles

Effectiveness of Levilactobacillus brevis fermentation on antinutrients and protein quality of leaves of selected cassava varieties

This study aimed to determine the effect of fermentation using an isolated Levilactobacillus brevis strain on the antinutrients and the protein quality of cassava leaves. Cassava leaves from tajirika and kibandameno variety which are considered bitter and sweet varieties, respectively, were fermented using the probiotic isolate and spontaneous fermentation was used as a control. The antinutrients of interest were cyanide and phytic acid whereas the protein quality of the leaves was analyzed in terms of the total crude protein and in-vitro digestibility. These were analyzed using standard procedures namely; picrate paper method for cyanide, spectrophotometry for phytic acid, Kjedahl method for the crude protein, and trypsin and pepsin enzymes simulation for the actual human digestion process for the in vitro protein digestibility. The data obtained was analyzed using the SPSS software and means separated at p < 0.05. The results obtained showed a decrease in the level of both the cyanide and phytic acid as the fermentation time increased. The cyanide levels were reduced by >37% with the L. brevis isolate for both cassava varieties which was higher than 20–33% for the spontaneous fermentation (control). The crude protein in both the varieties ranged between 28% and 32% and improved up to 43% on fermentation. Upon digestion of the cassava leaves, the in vitro protein digestibility improved from 63% up to 94%. The findings of this study therefore indicates that the Levilactobacillus brevis isolate can reduce cyanide and phytic acid as well as improve the protein quality by increasing the crude protein content and enhancing the digestibility of protein in cassava leaves of kibandameno and tajirika varieties, hence can be used to detoxify cassava leaves and for food formulation.

Comparison of Cyanide Levels in Selected Cassava Varieties Cultivated in Lurambi Constituency, Kakamega County Using the Picric Acid Method

Comparison of Cyanide Levels in Selected Cassava Varieties Cultivated in Lurambi Constituency, Kakamega County Using the Picric Acid Method

Effect of some selected soil properties, moisture content, yield and consumptive water use on two Cassava (TMS 0581 and TME 419) varieties

The increasing demand of Cassava for our dietary needs and shortage experienced going by the burgeoning global population is a cause for concern that require urgent attention. The study therefore considered the effect of some selected soil properties, nutrients, moisture content, yield and consumptive water use (CWU) on two selected Cassava varieties TMS 0581 and TME 419 respectively. The design was a Randomized Complete Block Design (RCBD) of four treatments and three replicates. Treatment A had fertigation, B used poultry manure, C employed NPK, 15-15-15 while D with no treatment was used as control. Soil properties such as Bulk Density (BD), Particle Density (PD), soil classification and nutrients such as Cation Exchange Capacity (CEC), Organic Matter (OM), Nitrogen (N), Potassium (K) and others were determined using standard procedures. Penman-Monteith (PM) model was used in estimating reference evapotranspiration (ETr) while its product with crop coefficient (Kc) produced crop evapotranspiration (ETc). Moisture content was measured at depths 10, 20 and 30 cm respectively while water use efficiency (WUE), irrigation water applied and tuber yield were also determined. The findings of this study showed that all the soil properties were within permissible levels to encourage optimum agronomic development of Cassava plant and the class was entirely a loamy soil which permits well-developed roottuber configuration. Tuber yields varied from 21.96 Kg to 25.13 Kg for TMS 0581 variety while TME 419 had 17.04 Kg to 31.63 Kg in all the treatments. Deficiencies were observed in some of the nutrients which were replenished with the introduction of the fertilizers among the plots. Moisture content at 30 cm depth is suggestive of adequate water availability sufficient enough to encourage proper tuber development for optimum yield while fertigation technique was adjudged the best as it improved Cassava Tuberization and WUE in all the treatments considered.

Assessing the Degeneration of Cassava Under High-Virus Inoculum Conditions in Coastal Tanzania.

Cassava brown streak disease (CBSD), caused by cassava brown streak ipomoviruses (CBSIs), has become the most debilitating biotic stress to cassava production in East and Central Africa. Lack of CBSD-resistant varieties has necessitated the search for alternative control measures. Most smallholder farmers reuse stems from previous crops for planting in the new season. Recycling planting material in this way can lead to “degeneration” owing to the compounding effects of disease. In this study, degeneration was defined as the increase in CBSD incidence and reduction in marketable root yield over time. An experiment was established to study the rates of degeneration in selected cassava varieties Chereko, KBH2002_135, Kipusa, Kizimbani, and Mkuranga1 and cultivars Kiroba and Kikombe under high-CBSD inoculum conditions in Bagamoyo, Tanzania from 2013 to 2017. The experiment was replicated across two seasons: the first planted during the long rains (Masika) between March and June and the second planted during the short rains (Vuli) between October and December. Mean abundance of the whitefly vector (Bemisia tabaci) was much greater during the Vuli season (>19 insects per plant) than the Masika season (<2 insects per plant). CBSD shoot symptoms occurred naturally and were observed only on Kikombe, Kiroba, and Kipusa. New materials had overall lower CBSD shoot incidences (1.5%) compared with recycled materials (6.9%) in Masika, although no significant differences were obvious in Vuli. However, Masika (8.7%) had an overall lower CBSD shoot incidence than Vuli (16.5%) in the varieties that had shoot symptoms. CBSD root incidences were higher in Vuli (10.3%) thanMasika (4.4%), and root yields in Masika (29.4 t/ha) were significantly greater than those in Vuli (22.5 t/ha). The highest percentage of roots rendered unusable owing to CBSD was observed in Vuli. There was significantly higher unusable root incidence in recycled materials (3.7%) than in new materials (1.4%) in Masika but not in Vuli. Overall root yield was similar between recycled and new materials in either season. Significant reductions in root yield over the course of the experiment were observed both in Masika and Vuli, whereas changes in marketable yield were significant only in Masika. Differences in the response of varieties to degeneration led to the identification of four degeneration patterns, namely “strong,” “moderate,” “mild,” and “delayed” degeneration. The strongest effects of degeneration were most obvious in the susceptible cultivar (Kikombe), which also had the lowest marketable yield in either season. Seasonal differences were a key driver of degeneration, because its effects were much greater in Vuli than Masika. To the best of our knowledge, this work reports the first study of degeneration caused by cassava viruses.

Crossability among Five Cassava (Manihot Esculenta CRANTZ) Varieties

Controlled crosses were carried out to determine crossability among five selected cassava varieties in terms of seed set per cross and influence of maternal inheritance on seed set in cassava. The experiment was carried out at the Teaching and Research Farm of the Department of Agronomy, University of Ibadan Oyo State, Nigeria. Three yellow root varieties (IITA-TMS-I011412, IITA-TMS-I011368 and IITA-TMS-I070539) selected for their high β-carotene content and two white root varieties (IITA-TMS-I30752 and COB-7-25) selected for their high dry matter content and acceptable plant architecture among subsistence farmers were crossed in a reciprocal diallel design with no selfing. Fourteen hybrid populations were developed and data obtained were analyzed using T-Test and simple linear correlation. The result showed that genotype and maternal inheritance influenced seed setting in cassava. The cross IITA-TMS-I011368 x IITA-TMS-I011412 gave the highest seed set percentage (57.1) and the two parents were the best female and male parents, respectively. This was followed by IITA-TMS-I30752 x IITA-TMS-I011412 (39.8%), IITA-TMS-I011368 x IITA-TMS-I070539 (26.5%), IITA-TMS-I070539 x IITA-TMS-I011412 (24.9%) and IITA-TMS-I30752 x IITA-TMS-I011368 (24.1%). Reciprocal differences were observed for crosses between IITA-TMS-I30752 and IITA-TMS-I011412; IITA-TMS-I011412 and IITA-TMS-I011368; IITA-TMS-I011412 and COB-7-25 which suggests that seed setting in cassava is influenced by cytoplasmic genes which are transmitted exclusively by the maternal parent. The best female and male parents (IITA-TMS-I011368 and IITA-TMS-I011412) in terms of percentage seed set in this study are good candidates as parents to generate large populationsin breeding for high carotene content in cassava.

Effectiveness of Traditional Processing Techniques in Reducing Cyanide Levels in Selected Cassava Varieties in Zombo District, Uganda

The root tubers of cassava (Manihot esculenta Crantz) contain varying amounts of cyanogenic glucosides which liberate toxic hydrogen cyanide with the resultant effect of poisoning especially the highly cyanogenic cultivars. These include some of the local and improved cassava varieties grown in Zombo district, Uganda among others. Therefore, this study explored the effectiveness of some traditional processing techniques used singly and in combination to reduce cyanide levels in highly toxic root tubers of selected local (Nyar-anderiano, Nyar-papoga, Nyar-udota, Nyar-pamitu, Bisimwenge, Nyar-matia) and improved (NASE 3, NASE 9, NASE 14, NASE 19, TME 14 and TME 204) cassava varieties grown in Zombo District, Uganda. The processed and the fresh cassava tubers were analysed for Hydrogen cyanide (HCN) by the standard titration method. The results indicated that heap fermentation followed by sun-drying reduced the cyanide levels in all the selected improved varieties to WHO safe levels for consumption (below 10mg/kg) in the dried chips. Mixed processing methods combining soaking, fermentation and sun-drying reduced the cyanide concentrations in the local varieties (Nyar-udota, Nyar-anderiano) and improved variety (NASE 19) to World Health Organisation (WHO) safe levels. None of the processing techniques used singly reduced the HCN levels in the root tubers of the selected cassava varieties to safe levels. Hence mixed strategies combining several traditional cassava processing techniques should be adopted to detoxify the selected cassava varieties of cyanogens. The local cassava varieties (Bisimwenge, Nya-matia, Nya-pamitu, Nya-papoga) would require modifications of the combined traditional processing techniques or other more complex processes to detoxify them of HCN before human consumption.

English

Application of enzyme preparations has shown great potential in aiding extraction procedures. However, the focus has mostly been on single crop varieties, thereby limiting knowledge on the effects of enzyme technology to those (single) varieties studied. The present work compared the effects of various dosages of crude pectolytic enzymes from Saccharomyces cerevisiae (ATCC 52712) on yield and extraction rates of starch from the roots of five indigenous cassava varieties (Nkabom, Afisiafi, Doku duade, Bankye hemaa and Esam bankye). The study aimed to establish whether varietal differences (with respect to response of variety to the technology) existed and to establish which variety is best suited for the technology. Generally, application of the crude pectolytic enzymes with activity of about 4.91 U significantly (P<0.05) increased starch yield and recovery rates in all selected cassava varieties. However, optimization of both yield and recovery rate was dependent on an interplay of variety, enzyme dosage and holding time for enzyme action. An enzyme dosage of 0.02% was found as significant (P<0.05) for peak of starch yield in the Esam bankye and Nkabom varieties at 0.5 and 1 h holding time in the Afisiafi variety; 0.025% enzyme dosage at 0.5 h holding time was the optimum treatment combination for starch yield in both Bankye hemaa and Doku duade varieties. The study therefore showed that although application of pectolytic enzymes for starch extraction enhances yield, the technology is affected by varietal differences. Given the heavy dependence of most Ghanaian industries on starch, the technology if made available would greatly boost the productivity of these sectors at relatively lower cost. Key words: Cassava varieties, crude pectinase, pectolytic enzyme dosage, polygalacturonase, submerged fermentation.

Chemical Composition of Chips from Selected Cassava Varieties in Makurdi, Benue State

Chemical Composition of Chips from Selected Cassava Varieties in Makurdi, Benue State

Cyanogenic Potential of Selected Cassava Varieties in Zombo District, Uganda

Both improved and local cassava varieties are widely grown and also, consumed in Zombo district as well as West Nile Sub region and Uganda as a whole. However, all cassava varieties contain cyanogenic glycosides which are toxic, although the amounts in each cultivar may vary considerably. Consumption of such toxins in sufficient quantities poses a health risk since they can cause acute cyanide poisoning and death in humans and animals. As such, information concerning the cyanogenic glycosides content in cassava cultivars is indispensable in averting health risks linked with cassava consumption. In this study, the cyanogenic content of the most common local cassava varieties (Bisimwenge, Nyar-anderiano, Nya-matia, Nya-pamitu, Nya-papoga and Nyar-udota) grown in Zombo district and six improved cassava varieties (NASE 3, NASE 9, NASE 14, NASE 19, TME 14 and TME 204) were investigated. Generally, the improved cassava varieties revealed lower levels (mean value was 108.75 mg/kg) of cyanogens than the local varieties (mean value was 201.65 mg/kg). The concentrations of the cyanogen in all the cultivars investigated were far above the FAO/WHO recommended value (<10 mg/kg). Hence, adequate detoxification and reduced frequency of consumption of these cassava cultivars are necessary in order to limit the ingestion of toxic levels of cyanide.

Composition of arbuscular mycorrhizal fungi associated with cassava (&lt;i&gt;Manihot esculenta&lt;/i&gt; Crantz) cultivars as influenced by chemical fertilization and tillage in Cameroon

Objectives: Arbuscular mycorrhizal fungi (AMF) form root symbiotic relationships with higher plants, but their abundance and symbiotic effectiveness may be influenced by agricultural practices. This study investigated the effect of N-K fertilization and tillage on soil’s AMF composition and root colonization of some selected cassava varieties in Eastern and Southern Cameroon.Methodology and results: Three cassava varieties were grown in Eastern Cameroon in tilled and non-tilled plots. In Southern Cameroon, five varieties were grown in non-tilled plots, with half of them receiving NPK (10-10-20) fertilization. Collected soil and root samples were analyzed to quantify and describe the AMF communities. AMF root colonization was 35% regardless to the variety and farming system in Eastern region, while it reached 45% in Southern Cameroon. Root colonization varied among varieties within and between locations. Fertilized plots displayed lesser microbial density than non-fertilized plots and the tillage highly reduced the root colonization as well as the density of spores.Conclusions and application of findings: In Eastern and Southern parts of Cameroon, the identified AMF communities in a symbiotic relationship with cassava were ascribed to the three genera Glomus, Gigaspora and Acaulospora. Among these three genera, Glomus was predominant in all the sites; indicating its wide geographical distribution in Cameroon and affinity with cassava. Species of the genus Glomus may therefore be used during mycorrhizal inoculations of cassava. However, AMF root colonization varies in relation to the variety type and the environment; with the southern region of Cameroon showing the higher colonization levels. This study revealed that to obtain higher AMF spores densities in soil and maximize root colonization, cultivation systems with a lesser soil disturbance and fertilization is recommendable in cassava cultivation.Keywords: Arbuscular mycorrhiza funji (AMF), Cameroon, Cassava cultivation, Chemical fertilization, Tillage

Production and evaluation of Ighu from selected cassava varieties using a motorized shredder-a response surface analysis.

Cassava varieties, TME419, TMS30572, and TMS98/0505, were planted and harvested at 3-month intervals of 10, 13, and 16 months, respectively. A central composite response surface design was used to study the effects of the variables cassava variety, harvesting time, and shredding aperture on selected physicochemical properties of Ighu samples. Regression models showed that the experimental variables had significant (P ≤ 0.05) effects on the hydrogen cyanide, moisture content, thickness, and width of dry Ighu. Minimum values obtainable for the physicochemical properties were 8.1195 mg/kg (10-month, 3-mm shredding aperture from TMS98/0505), 7.58% (13-month, 3-mm shredding aperture from TME419), 0.19 mm (13-month, 3-mm shredding aperture and from TMS30572), and 0.99 mm (16-month, 3-mm shredding aperture from TME419) for hydrogen cyanide, moisture content, thickness, and width, respectively. In addition, Ighu produced from 3-mm shredding aperture (TMS30572) at 10-month harvest was the most preferred of all the samples.

Response of Selected Cassava Varieties to the Incidence and Severity of Cassava Brown Streak Disease in Tanzania

Cassava brown streak virus disease (CBSD) has been a serious and most damaging disease in cassava crop throughout the East, Central and Southern part of Africa. Several cassava varieties invariably respond to the disease, but the effect of the disease on affected varieties was not known. The current study was conducted to assess the ability of some farmer-preferred CBSD-affected varieties to withstand the disease. Field experiments were conducted at Kibaha Agricultural Research station from 2006 to 2008. The inherent variety characteristics influenced the incidence and severity levels of CBSD in the test plants. Leaf and stem CBSD incidences and severities, root weight and number of whiteflies (vectors) were significantly (P<0.001) related to the individual variety. Varieties Albert, Cheupe, Kibaha and Nachinyaya were seriously affected. The CBSD incidences and severities in these varieties increased with plant age, with highest disease records starting at nine to twelve months after planting. Dual infections of CBSD and CMD were recorded in four (Cheupe, Kibaha, Namikonga and Nachinyaya) of the five test varieties. Namikonga was proven to be resistant to CBSD. The correlation analysis suggested a significantly positive relationship between the perceived disease vector, Bemisia tabaci and the incidence and severities of CBSD and CMD. It was concluded that different varieties responds differently to CBSD and the disease severity increases with plant age.

Kinetics of thermal softening of cassava tubers and rheological modeling of the starch

Cassava or tapioca (Manihot esculenta Crantz) tubers having high amount of carbohydrate are utilized after boiling or processing into starch and flour. Textural properties of raw and cooked tubers depend on variety, maturity, growing environment, physico-chemical and starch properties. Starch is used in food preparations as gelling and thickening agent, stabilizer and texture modifier. This study aims at analyzing and modeling the textural, dynamic rheological and gelatinization properties of selected cassava varieties. The thermal softening behavior was analyzed by linear regression and fractional conversion techniques, rheological properties of the gelated starch by Maxwell and power law models. The varieties were classified based on their physico-chemical, texture profile, rheological and gelatinization properties by multivariate analysis. The textural, rheological and gelatinization properties were significantly affected by the varieties (p < 0.05). Thermal softening of tubers was modeled by dual mechanism first order kinetic model with rate constant values ranging from 0.081 to 0.105min(-1). Linear regression models with extremely good fit were obtained to explain the relationship between the degree of cooking and relative firmness. The dynamic spectra of the gelated starch showed the characteristics of concentrated biopolymer dispersion and described using Maxwell and power law model. The results showed that textural, rheological and gelatinization properties varied considerably among the varieties and besides the physico-chemical properties, interaction between them and structural make up of the tuber parenchyma had a great influence on cooking quality and rheological properties.

&lt;i&gt;Abacha&lt;/i&gt; making qualities of selected cassava varieties

‘Abacha’ of three different thickness, 0.8, 1.0 and 1.6mm was prepared from four varieties of cassava, 91/02324, 97/4779, 98/2101 and NR 87184. The varietal effects on the length of the ‘abacha’ per thickness as well as the yield were analyzed. The HCN, the proximate composition, length of the ‘abacha’ shreds and sensory qualities were evaluated. The effect of drying methods on the quality of ‘abacha’ wasalso determined. Results showed that the proximate composition of ‘abacha’ from the varieties ranged 8.32-8.46% for moisture, 2.38-3.87% ash, 0.54-0.82% fibre, 0.44-0.87% fat, 1.42-1.75% protein, 83.88-85.15% for carbohydrate and 325.39-333.12KJ/100g energy content. Variety 97/4779 had the highest yield. The sun dried‘abacha’ had lower HCN content (8.44-10.00%) than the freshly made ‘abacha’ (15.25-15.95%). For long term consumption of fresh ‘abacha’, the soaking time should be extended beyond 12hrs before washing to prevent HCN toxicity. Sensory evaluation results showed that sun-dried‘abacha’ sample was preferred to oven dried samples. Variety 91/02324 having 0.8mm thickness was preferred in terms of appearance and mouth-feel while 98/2101 of 0.8mm thickness was preferred in taste and general acceptability.

Characterisation of starch from selected cassava varieties and their possible use for pasta production

Characterisation of starch from selected cassava varieties and their possible use for pasta production