Root starches enriched with proteins and phenolics from Pachyrhizus ahipa roots as gluten‐free ingredients for baked goods

Ahipa is a gluten-free starchy root, bearing phenolics and a protein content of ~9% db. Ahipa proteins are hydrosoluble, thus they are lost during starch extraction. The aim of this work was to recover ahipa proteins by isoelectric point (pI) precipitation to enrich ahipa and cassava starches. Both enriched starches had protein contents of ~2%, and their ATR-FTIR spectra revealed bands characteristic of ahipa proteins. Enriched starches also contained phenolics in concentrations of 18-20 μg GAE/g. Enrichment lowered the whiteness index, but it remained higher than 90. Protein-enrichment did not modify gelatinization onset and peak temperatures but reduced the gelatinization enthalpy of ahipa starch. Enriched starches produced less-rigid buns than the native ones, with smaller and more homogeneously distributed alveoli in the crumb which resulted darker than the crust. Starch slurries acidified to the pI of ahipa proteins led to novel gluten-free ingredients by an easy, low cost processFil: Malgor, Martina. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Centro de Investigación y Desarrollo en Criotecnología de Alimentos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigación y Desarrollo en Criotecnología de Alimentos. Universidad Nacional de la Plata. Facultad de Ciencias Exactas. Centro de Investigación y Desarrollo en Criotecnología de Alimentos; ArgentinaFil: Viña, Sonia Zulma. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Centro de Investigación y Desarrollo en Criotecnología de Alimentos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigación y Desarrollo en Criotecnología de Alimentos. Universidad Nacional de la Plata. Facultad de Ciencias Exactas. Centro de Investigación y Desarrollo en Criotecnología de Alimentos; ArgentinaFil: Dini, Cecilia. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Centro de Investigación y Desarrollo en Criotecnología de Alimentos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigación y Desarrollo en Criotecnología de Alimentos. Universidad Nacional de la Plata. Facultad de Ciencias Exactas. Centro de Investigación y Desarrollo en Criotecnología de Alimentos; Argentin

Farmer’s Knowledge on Selection and Conservation of Cassava (Manihot esculenta) Genetic Resources in Tanzania.

Farmers have traditionally depended on their knowledge to cultivate diverse set of crop population for their subsistence. This practice has contributed to high genetic diversity found in farmers’ fields. Occurrence of natural disasters has threaten survival of crop populations and diversity, and thus causing food shortage. Breeding efforts have been targeted to develop crop varieties which can tolerate these natural disasters but there has been poor adoption by farmers. There is a need to understand social and biological factors which farmer base on during selection and maintenance of their genetic resources. There is limited information for researcher’s understanding of factors that farmers considered for landraces selection and conservation. In a view of the above mentioned problems a study was conducted using PRA tools to gather information on conservation of cassava genetic resources. The study found that farmer’s decision on what landrace to plant was what has shaped the diversity. Farmer’s decision comprised of diverse factors from food security, market forces and culinary attributes. The study found that seed (stem cuttings) flow occurs as farmers exchange or buy from local market. These exchanges occur within and outside the village. Most of cassava landraces were indigenous to the place and have been grown for more than 40 years, and only 8.4% were newly introduced. There was considerably loss of landraces due to disease, pest and drought outbreaks. Landrace selection decision was made by both men and women and these decisions on the other hand influenced the diversity of cassava landraces found in farmer’s field. Cultivars like Kiroba, Kibandameno and Msenene were found in every farmer’s field in those particular areas but other cassava landraces differed considerably from one field to another. It is concluded that farmer’s knowledge is useful in conservation of cassava genetic resources for improved livelihood. Therefore farmer’s knowledge should be incorporated in research intervention packages to be able to address specific needs of farmers in a particular area and fasten the adoption process. Keyword: Farmer’s knowledge; Genetic resources; Kiroba, Farmer’s decision making

Effect of genotype and genotype by environment interaction on total cyanide content, fresh root, and starch yield in farmer-preferred cassava landraces in Tanzania

High starch yield is the most important trait for commercialized cassava starch production. Furthermore, cyanide present in cassava roots poses a health challenge in the use of cassava for food. Cassava genotypes have varying maturity periods that are also environmental dependent. This study aimed at identifying suitable cultivars and optimum time of harvest to maximize starch production across three environments. The study found significant difference between genotypes, locations, harvest period, and all the interactions (P ≤ 0.001) for all traits analyzed. Kiroba recorded high starch yields of 17.4, 12.7, and 8.2 t ha−1 at Chambezi, Amani, and Magadu, respectively. Kilusungu recorded highest cyanide content of 300–400 ppm across all locations but Kiroba recorded highest values of 800 ppm, 15 months after planting at Chambezi. Genotype by environment (GGE) biplot analysis revealed that Kiroba was a superior cultivar in terms of starch yield. Kilusungu recorded highest cyanide content and average starch yield, therefore suitable for use in starch production. The study confirmed effect of genotype and genotype by environment interaction, Kiroba cultivar was superior in terms of starch yield and maximum starch yield was obtained at 9 months after planting. Nyamkagile and Kibandameno had the lowest cyanide content across all environments

The role of exogenous and endogenous proteases in processing of sorghum

SIGLEAvailable from British Library Document Supply Centre- DSC:DX172539 / BLDSC - British Library Document Supply CentreGBUnited Kingdo

Improving sweet potato processing and storage performance throug slicing, drying and packaging

Tanzania Journal of Agricultural Sciences 2003, Vol 6(1) : 19:27Sweet potato is an important food security crop in, many parts of Tanzania. Despite this potential, research into its post-harvest handling for maximum utilisation hass been low. The objective of this study was therefore, to assess slicing performance of a fabricated hand operated slicing machine against the traditional knife slicing by hand in the production of michemhe. It also assessed how slice thickness, the drying surfaces, and packaging of the slices influenced quality during storage. The slicing machine was set to produce slices of 4.8 12 and 16 mm thickness. Together with the traditionally obtained slices the samples were dried on three surfaces (perforated surface, thatched roof and on the ground) for three days. Dry samples were then packaged in polypropylene bags, perforated polyethylene bags and sealed plastic containers and stored for nine months with observation carried in three months intervals. The investigations included moisture content, fungal count and mycotoxin detection discoloration and insect infestation aa quality attributes. Results showed that the slicer throughput ranged between 16 and 46 kg/h of fresh peeled roots in the thickness range of 4-16 mm, against 17 kg/h for traditionally sliced (75 mm) sweet potatoes. During drying, weight of slices decreased exponentially with time. In terms of drying effectiveness, the three drying surfaces used displayed almost the same final mean moisture content in the lower slice thickness range (4-8 mm). With increased slice thickness to 12 and 16 mm: the perforated surface was the most effective (10. 63-18. 03%) followed by the ground floor- (15.67-18.65%) and thatched roof the least (16.5-19.36%) Quality of dried michembe decreased with storage time and the best performance was obtained in polypropylene bags for the nine months storage. Packaging in sealed plastic containers produced the worst results. Quality was also influenced by the drying surfaces used with ground floor resulting in poor product and perforated surface the best. Increasing the slice thickness affected the quality of the dry product except in the range of 4 to 8 mm. Slicing of the roots to 4-8 mm drying on perforated surface and packging in polypropylene bags for room temperature storage of up to six months produced michembe of acceptaple quality. Use of improved slicing machines including mechanically powered machines requires further investigation. Studies on more drying surfaces more packaging materials, and nutrition of michembe are also recommende

Cassava sun drying performance onvarious surfaces and drying bed depths

Tanzania Journal of Agricultural Sciences 2013, Vol. 12(1) : 31-36Processing of cassava (Manihot esculenta Crantz) to obtain flour is faced with a lot of technical constraints including inefficient drying. The traditional sun drying method is very inefficient as the product can take 2- 3 days to dry. Mould growth and other problems such as contamination of the product are likely and therefore necessitate intervention. Among the interventions was sun drying on a platform raised 1 m above ground in comparison with drying in a direct box solar dryer; by using trays with various bottom surfaces. The experiments were done using kiroba cassava variety obtained from the University farm, which was peeled and sliced into thin chips (2-3 mm) then sun dried on wire mesh, black polythene, white polythene and woven mat for three days. The material was dried for 8 hours daily after which it was kept indoors overnight. The surface with highest sun drying performance was wire mesh while white polythene was the least. The 10 mm bed depth attained constant weight in just about six hours of drying while for 20 and 30 mm bed depth it was about 16 hours and 40 mm bed depth for about 24 hours. There was moisture adsorption which was at 10, 22 and 28 hours for the 10 mm bed depth, 10, 20, 26 and 28 hours for 20 and 30 mm bed depths, and 28 hours for the 40 mm bed depth. The time 0,10 and 20 hours marked the beginning of drying whereas 8, 18 and 28 hours marked the end of drying. The best performance was therefore obtained on wire mesh and 10 mm bed depth and recommended for sun drying of cassava. However; there is need to investigate on whether there is significant quality difference between cassava sun dried at different bed depths investigated in this study

Cassava Sun Drying Performance on Various Surfaces and Drying Bed Depths

Tanzania Journal of Agricultural Sciences 2013, Vol. 12(1): PP 31-36Processing of cassava (Manihot esculenta Crantz) to obtain flour is faced with a lot of technical constraints including inefficient drying. The traditional sun drying method is very inefficient as the product can take 2- 3 days to dry. Mould growth and other problems such as contamination of the product are likely and therefore necessitate intervention. Among the interventions was sun drying on a platform raised 1 m above ground in comparison with drying in a direct box solar dryer; by using trays with various bottom surfaces. The experiments were done using kiroba cassava variety obtained from the University farm, which was peeled and sliced into thin chips (2-3 mm) then sun dried on wire mesh, black polythene, white polythene and woven mat for three days. The material was dried for 8 hours daily after which it was kept indoors overnight. The surface with highest sun drying performance was wire mesh while white polythene was the least. The 10 mm bed depth attained constant weight in just about six hours of drying while for 20 and 30 mm bed depth it was about 16 hours and 40 mm bed depth for about 24 hours. There was moisture adsorption which was at 10, 22 and 28 hours for the 10 mm bed depth, 10, 20, 26 and 28 hours for 20 and 30 mm bed depths, and 28 hours for the 40 mm bed depth. The time 0,10 and 20 hours marked the beginning of drying whereas 8, 18 and 28 hours marked the end of drying. The best performance was therefore obtained on wire mesh and 10 mm bed depth and recommended for sun drying of cassava. However; there is need to investigate on whether there is significant quality difference between cassava sun dried at different bed depths investigated in this stud

Cassava sun drying performance onvarious surfaces and drying bed depths

Tanzania Journal of Agricultural Sciences 2013, Vol. 12(1) : 31-36Processing of cassava (Manihot esculenta Crantz) to obtain flour is faced with a lot of technical constraints including inefficient drying. The traditional sun drying method is very inefficient as the product can take 2- 3 days to dry. Mould growth and other problems such as contamination of the product are likely and therefore necessitate intervention. Among the interventions was sun drying on a platform raised 1 m above ground in comparison with drying in a direct box solar dryer; by using trays with various bottom surfaces. The experiments were done using kiroba cassava variety obtained from the University farm, which was peeled and sliced into thin chips (2-3 mm) then sun dried on wire mesh, black polythene, white polythene and woven mat for three days. The material was dried for 8 hours daily after which it was kept indoors overnight. The surface with highest sun drying performance was wire mesh while white polythene was the least. The 10 mm bed depth attained constant weight in just about six hours of drying while for 20 and 30 mm bed depth it was about 16 hours and 40 mm bed depth for about 24 hours. There was moisture adsorption which was at 10, 22 and 28 hours for the 10 mm bed depth, 10, 20, 26 and 28 hours for 20 and 30 mm bed depths, and 28 hours for the 40 mm bed depth. The time 0,10 and 20 hours marked the beginning of drying whereas 8, 18 and 28 hours marked the end of drying. The best performance was therefore obtained on wire mesh and 10 mm bed depth and recommended for sun drying of cassava. However; there is need to investigate on whether there is significant quality difference between cassava sun dried at different bed depths investigated in this study

Characterisation of Tmmmian Local Sorghmn Varieties

Tanzania Journal of Agricultural Sciences 2000, Vol. 3(1) : 69-74Many local varieties of sorghum grown in Tanzania have not been characterised in terms of their end uses. This study was conducted to characterise 14 such varieties. Three improved varieties commonly grown in this country were includedfor comparison. Physical analyses that included 100-grain weight, percent dehulling loss and percent water absorption were done. Chemical analysis of the samples to determine protein, crude fibre, fat, ash, and carbohydrate contents was done. Results showed that the 1 OO-kernel weight ranged between 1.48 and 3. 18 g. Some of the local varieties had kernel sizes that were greater than those of the improved ones. Dehulling losses for the studied varieties ranged from 4.63 to 29.85%. These losses were generally low for the commonly used local varieties. Water absorption ranged between 6.10 and 28.85%. The flour making varieties showed low water absorption capacity. The protein contents of the studied varieties (8.27-13.52%) differed significantly (P<0.05). However, the crudefibre {1.23-2.30%),fat (3.00-4.30%), ash (1.96-4.25%), and carbohydrate contents (78.84-83.96%) ofsorghum varieties did not differ significantly (P>0.05). Studies on endosperm texture revealed that most floury varieties had generally high dehulling losses and were therefore unsuitable for producing dehulled products. Corneous varieties were considered suitable for producing dehulled products due to their low dehulling losses. The intermediate endosperm texture varieties, which also experienced intermediate dehulling losses, need more studies in order to be properly classified Some of these, varieties such as Langalanga are already being used for flour making without prior dehulling. The study, therefore, calls for more screening of the local sorghum varieties not used in this study to identifY their potential in relation to end uses for future exploitation and, where possible, to exploit the promising trait for incorporation in breeding programmes

Improvement of cassava production, processing, marketing and utilization through introduction of disease-tolerant cassava varieties

Tanzania Journal of Agricultural Sciences, 2008; 9(1): 69 - 78A baseline survey was conducted in Tongwe, Kabuku, Chanika and Mikongeni villages, located in the Districts of Muheza, Handeni, Ilala and Kibaha, respectively, in the cassava growing ecosystem of Tunga, Coast and Oar es Salaam regions. The objective was to establish baseline data as entry point for improving production, utilization, processing and marketing of cassava in these areas. The survey involved 104 households, represented by 62.5% male and 37.5% female farmers, using a structured questionnaire. The results were coded and analijsed using the SPSS statistical package. It was observed that majority of households farmed on land size of less than 2 ha, with about 80.2% farming on their own land and 91.8% farming on rented land. Most farmers (54.7%) produced less than 1.25 MT of fresh cassava roots per hectare, with a few producing as far as 10 times more. The crop was slightly more of a cash crop than a food crop, with yearly mean production of 2.18 MT compared with 1.44 MT (53%) sold. Production faced limitations, especially lack of market (37.6%) and low disease tolerance (19.8%). The varieties grown were mainly Kiroba, Cheupe, Cheusi Mwangia and Mkunungu in Tongwe, Chanika, Mikongeni and Kabuku villages, respectively. Introducing new varieties as a solution to the reported problems is required but the essential attributes should be: high disease tolerance (28.5%); high yield (25.9%); sweetness when chewed (13.8%) and early maturity (10.5%), which are potential factors towards solving marketing problems. In a follow-up program, Kiroba variety, which is a relatively high disease tolerant variety, was introduced in Kahuku, Mikongeni in Chanika villages to farmer groups and individual farmers. While results in Mikongeni and Chanikn did not show remarkable changes Kabuku village registered very positive impacts, just after two years. These include the increase of the numbers of farmers groups from 1 to 3, individual farmers from 20 to 37, overall area planted from 2 to 4.6 hectares, yield from average of 1.25 to 18 MT per hectare and cash earned per hectare from almost zero to 800,000 shillillgs and average price of about 4,500 shillings per 100 kg of fresh cassava. Introducing disease-tolemni cassava oarieties could change the stnius of this crop and contribute to iiuprooed lioelihood. For sustainability of tilt' processing iiidustri], pricing of raw nuuerinls should not exceed that for the [resli market during high price seasons