ADAPTABILITY OF POTATO DRYING TO YAM PROCESSING

Sweet potato (Ipomoea batatas L.) is the most grown storage root crop in Eswatini. However, its storage root yield is low among smallholder farmers partly due to use of inappropriate varieties and agronomic practices such as planting method. Thus, a field experiment was conducted at the University of Eswatini, Faculty of Agriculture, Luyengo, during 2019/2020 cropping season to determine the effects of planting method on growth and yield of the three sweet potato varieties. Two planting methods, namely horizontal and vertical; and three sweet potato varieties, namely Kenya-white, Ligwalagwala and Lamngititi were evaluated in a factorial arrangement in randomized complete block design in three replications. Results showed non-significant difference between the planting methods in most growth and yield parameters recorded for the sweet potato varieties. However, the vertical method of planting had relatively higher vine length, number of branches, mass of storage roots and storage root yield than the horizontal method. On the other hand, there were significant (P<0.05) differences among the sweet potato varieties for most of parameters recorded. The sweet potato variety Ligwalagwala had the highest vine length, number of storage roots per plant (6.47), mass of storage roots per plant (1137 g) and storage root yield (12.01 tonnes/ha). Thus, either horizontal or vertical method of planting and variety Ligwalagwala can be used to increase the productivity of sweet potato in the study area.

The article highlights the results of research on the study of different storage conditions for sweet potato tuber crops: temperature regime from +10°С to 22°С, relative humidity 75-90%, as well as the influence of different storage methods: in wood shavings, in cereal straw, in sand, in a paper bag and a cardboard box. The research was carried out in the biotechnology laboratory of the Institute for Potato Research NAAS.The following ten introduced samples of sweet potato varieties were used as parent material in the research: Vinnytskyirozhevyi, Afhanets, Betti, Murasaka, Bonita, Tai-Nung, Porto-Amarello, Manchzhyrskyi, Hoha, Dzhordzhiia Red. The objective of the research was to study and optimize the methods of determining the biochemical indicators of the quality of sweet potato tuber crops,to improve the methods of storing sweet potatoes and, based on the conducted research, determine the optimal storage regimes. The research method is laboratory. Research results. It has been established that when the temperature dropped to 10°C, the tuber crops of Afhanets, Manchzhyrskyi, and Hoha varieties began to rot in boxes with wood shavings, straw, and sand. Bonita and Tai-Nung tuber crops in boxes with straw also began to rot. At temperatures above 20о С, the tuber crops of almost all varieties began to germinate. Table and semi-dessert sweet potato varieties - Dzhordzhiia Red and Vinnytskyirozhevyi began to germinate already at a temperature of 18 о С, and the dessert variety - Betti did not germinate even at a temperature of 21 о С. The chemical composition of sweet potato tuber crops can vary depending on the specific variety and growing conditions (climate, agricultural techniques used). According to the research results, the content of dry matter in tuber crops of sweet potato varieties ranged from 15.8 to 27.8%. The following varieties were characterized by a high dry matter content: Betti (27.8%), Tai-Nung (26.5%), Dzhordzhiia Red(25.5%), Afhanets (24.3%). Hoha variety had the lowest dry matter content (15.8%). The content of crude protein in tuber crops of different sweet potato varieties ranged from 1.4 to 2.4%. Conclusions. Tuber crops of Vinnytskyirozhevyi, Betti, Murasaka, Bonita, Tai-Nung, Porto-Amarello, Dzhordzhiia Redvarieties are best stored in boxes with sand, paper bags, cardboard boxes at a storage temperature of 13-16°С and a relative humidity of 85-90 %. Studies of biochemical parameters showed that the best varieties in terms of dry matter and starch content were: Afhanets(24.3; 17.1 %), Betti (27.8; 20.2 %), Tai-Nung (26.5; 19.0%), Dzhordzhiia Red(25.5; 18.1 %).

ABSTRACTSweet potato weevils (Cylas spp.) are among the most important constraints to sweet potato (Ipomoea batatas [L.] Lam.) production in most agro-ecological zones of Tanzania. Integration of farmers’ perception on sweet potato weevil damage, production constraints, and variety preferences is crucial in developing sweet potato varieties with farmer-preferred traits and weevil resistance. The aim of this study was to identify farmers’ perceptions on sweet potato weevil damage, production constraints, postharvest storage options, and criteria used to select and grow the best sweet potato varieties in western Tanzania. Surveys were conducted in four selected districts of western Tanzania (Nzega, Sikonge, Kigoma rural, and Kasulu) known for sweet potato production. Data were collected using a structured questionnaire, focus group discussions (FGDs), and transect walk involving 122 sweet potato farmers. Weevil damage was reported by 84% of the respondents to be the overriding constraint to sweet potato production. Sweet potato diseases and drought were the next production constraints, reported by 57% and 54% of the respondents, respectively. Farmers’ preferred agronomic traits of sweet potato included high yield (25% of respondents), drought tolerance (24%), and disease and pest resistance (21%). Farmers’ preferred sweet potato culinary traits in the study areas were high dry matter content (reported by 21% of the respondents), followed by reduced cooking time, taste and fiber content (each reported by 19% of the respondents). The above-mentioned production constraints and farmers’ preferred traits are useful selection criteria for improving sweet potato with respect to weevil resistance and enhanced storage-root yield and quality.

В статье отражены результаты сравнения современных зарубежных сортов и адаптированных популяций батата в условиях полевого опыта. Площадь возделывания батата в мире в последние годы составляет более 9 млн га и продолжает устойчивый рост. Учитывая отсутствие в Российской Федерации собственных сортов батата и утери отечественным сельским хозяйством большей части советских наработок в отрасли бататоводства, актуальным является изучение адаптированных местных популяций и современных зарубежных, прежде всего североамериканских сортов батата в условиях нашей страны. С 2004 г. нами проводится поиск и исследование таких популяций, адаптированных овощеводами-любителями, а в последние годы появилась и возможность изучения зарубежных сортов; изучаются биологические особенности, потенциал и структура урожайности этой ценной культуры в условиях Центрально-Черноземного региона РФ. Представленные данные свидетельствуют о большом потенциале урожайности этой новой клубнеплодной культуры в условиях Центральной России. Важным преимуществом батата является его высокая устойчивость к болезням и вредителям, а значит, и большая экологическая чистота получаемой продукции. Посадки этой культуры в наших условиях не требуют обработок пестицидами, что также является положительным, и с точки зрения ресурсосбережения, повышает экономическую эффективность выращивания. Исследуемые сорта и сортообразцы батата показали различную урожайность. В группе лидеров — североамериканские сорта Порто-Рико (253,3 ц/га) и Вардаман (160 ц/га), а также сортообразцы — российский Новосибирский белый (220,0 ц/га) и американский ЛА07-146 (186,7 ц/га); в этих вариантах максимальная масса клубней в 1 кусте составляла 0,4 – 0,633 кг.

Today the present scenario is focused at energy production from agricultural biomass which has emerged as one of the dependable non-traditional feedstock for the production ofbioethanol. Production of this renewable fuel, especially from starchy materials such as tuber crops, holds a remarkable potential to meet the future energy. In recent years, with the increase in price of fossil fuels, the demand of biofuel production from tuber crops such as sweet potato has increased by leaps and bounds. Among different tuber crops, sweet potato (Ipomoea batatas L.) has been considered as a promising substrate for bioethanol production and has become very important to meet the future energy crisis in developing countries. In our present study, eight varieties of sweet potatoes were collected from different region of Odisha and biochemically analysed for ethanol production. Among them, the Gouri variety collected from Odisha University of Agriculture and Technology, Bhubaneswar, exhibited maximum amount of starch (293.69±2.9 gkg−1) and sugar (326.09±2.1 gkg−1) followed by Sree Krishna variety. The Gouri type also produced maximum ethanol of1 4 7.7±0.4 gkg−1 and showed ethanol yield of 90.6%. The other varieties were exhibiting low starch and sugar content (approximately 15% less) than the Gouri variety. As the Gouri variety was more potent for starch and sugar synthesis, so this variety can be utilised for enhanced bioethanol production.

Starches from four varieties of West African yams were extracted and characterised. The physicochemical properties investigated (granule size and morphology, amylose content, crystal form, gelatinisation and pasting behaviour) depended strongly on the yam variety. The starch granules extracted from water yam (Dioscorea alata), white yam (D rotundata) and yellow yam (D cayensis) varieties showed mononodal particle size distributions centred between 31 and 35 µm, while the bitter yam (D dumetorum) exhibited a binodal size distribution of starch granules centred at 4.5 and 9 µm. Light microscopy confirmed the variation in starch granule size and shape with yam variety. The X-ray diffractogram of yellow yam was of the B type, while bitter yam showed an A pattern. The starches extracted from the white and water yams were of the intermediate C-type patterns. The temperatures of onset of gelatinisation were derived from DSC and RVA measurements; values of 69.4 and 75.0 °C for the yellow yam, 71.5 and 78.2 °C for the white yam, 76.5 and 79.8 °C for the water yam and 78.1 and 83.1 °C for the bitter yam were obtained. © 1999 Society of Chemical Industry

Starches from four varieties of West African yams were extracted and characterised. The physicochemical properties investigated (granule size and morphology, amylose content, crystal form, gelatinisation and pasting behaviour) depended strongly on the yam variety. The starch granules extracted from water yam (Dioscorea alata), white yam (D rotundata) and yellow yam (D cayensis) varieties showed mononodal particle size distributions centred between 31 and 35 µm, while the bitter yam (D dumetorum) exhibited a binodal size distribution of starch granules centred at 4.5 and 9 µm. Light microscopy confirmed the variation in starch granule size and shape with yam variety. The X-ray diffractogram of yellow yam was of the B type, while bitter yam showed an A pattern. The starches extracted from the white and water yams were of the intermediate C-type patterns. The temperatures of onset of gelatinisation were derived from DSC and RVA measurements; values of 69.4 and 75.0 °C for the yellow yam, 71.5 and 78.2 °C for the white yam, 76.5 and 79.8 °C for the water yam and 78.1 and 83.1 °C for the bitter yam were obtained. © 1999 Society of Chemical Industry

BackgroundThis study aimed to compare the antioxidant activity, phenolic content, and β-carotene levels of three sweet potato varieties, namely, Beauregard, Centennial, and Georgia Jet, between their storage roots and leaves using specific methods such as ABTS assay, Folin–Ciocalteu method, and HPLC to assess the antioxidant activity, phenolic content, and β-carotene quantities, respectively.ResultsThree sweet potato varieties were cultivated and collected from the University of Arkansas at Pine Bluff research fields, and their leaf extracts were used to determine total antioxidant activity (ABTS method), total phenolic content (Folin–Ciocalteu reagent assay), and β-carotene quantity (HPLC–DAD). The total antioxidant activity was more significant in the leaves than in the roots, with the leaf activity nearly doubling the roots. The Centennial variety had the highest overall average for the roots (1373 µg/g dry weight basis) and the leaves (2666 µg/g dry weight basis) for the total antioxidant activity. On the other hand, the Georgia Jet had the lowest overall average for the roots (1053 µg/g dry weight basis), while the Beauregard had the lowest activity for the leaves (1920 µg/g dry weight basis). The Beauregard roots had the highest phenolic content average (66,231 µg/g dry weight basis), while the leaves had the second-highest average (110,721 µg/g dry weight basis). The Georgia Jet had the lowest total phenolic content average for roots and leaves. The roots had a higher β-carotene quantity than the leaves. The Georgia Jet root had the highest average (1320 µg/g dry weight basis), while the leaf average was 305 µg/g dry weight basis. The Centennial variety had the lowest β-carotene quantity for both root average (1203 µg/g dry weight basis) and leaf average (218 µg/g dry weight basis). The study found that the Beauregard variety had the highest phenolic content, while the Georgia Jet had the highest β-carotene levels.ConclusionsThe study concluded that sweet potato leaves have higher antioxidant activity and phenolic contents, while the roots have higher β-carotene levels. Among the varieties, Beauregard had the highest phenolic contents, whereas Georgia Jet had the highest β-carotene levels. Cultivars rich in phenolic compounds, antioxidants, and β-carotene are promising for future food security.

This study reports the inherent phytochemical contents in leaves and roots of nine sweet potato varieties from Kenya. Results indicated that vitamin C content varied significantly (P < 0.05) among the sweet potato varieties regardless of the plant part, leaves having significantly (P < 0.05) higher levels than in the roots. Total flavonoids and phenolic compounds differed significantly (P < 0.05) among varieties, higher values were found in leaves than in roots. Flavonoid contents in roots ranged from below detectable limits (Whitesp) to 25.8 mg CE/100 g (SPK031), while in leaves it ranged from 4097 to 7316 mg CE/100 g in SPK4 and Kenspot 5, respectively. Phenolic content was below detectable limits in the roots of whitesp but it was in substantial amounts in orange fleshed varieties. The β-carotene content was significantly (P < 0.05) higher in leaves (16.43–34.47 mg/100 g dry weight) than in roots (not detected—11.1 mg/100 g dry weight). Total and phytic phosphorus were directly correlated with phytate contents in leaves and the roots. Tannins and soluble oxalates varied significantly (P < 0.05) with variety and plant part being higher in leaves. The current information is important for ration formulations and dietary recommendations utilizing sweet potato leaves and roots. Future studies on effects of processing methods on these phytochemicals are recommended.

Sweet potato varieties are distributed in Uganda by three systems: formal, project-based and informal. In a partial formal system, the National Sweetpotato Program (NSP) breeds and tests both orange (O)- and white (W)-fleshed sweet potato (FSP) varieties. The NSP and other national institutions provide vine stocks of mostly OFSP varieties to project-based seed systems involving large private sector multipliers, which are found predominantly in east and central Uganda. These are mainly either cooperatives derived from smallholder groups organized by projects or are individual farmers with large holdings who had hosted NSP variety trials. The private sector multipliers sell planting materials of released varieties to projects, which distribute them free to selected households. Projects buy hundreds and occasionally thousands of sacks of vines but they distribute them to only a limited number of needy households and for only one or a few seasons. The informal system functions predominantly in areas with a long dry season, in which vines cannot survive. Its vine multipliers use the wetter lowlands to maintain mostly landraces, which they sell as small bundles of vines to many smallholders at the onset of the rains. Very few multiply released varieties. Thus, with a ready market, the system is sustainable but quantities sold are price limited. All vine multipliers supplied healthy planting material. It is proposed that the NSP should aim their trials of new varieties at informal vine multipliers and projects should supply vines to these multipliers in order to improve their access to them. This would promote the sustainable distribution of vines, including new varieties, over a greater area and to a larger number of farmers.

Several varieties of sweet potato are being cultivated by many countries of the world including Nigeria. Data on physical and engineering properties required for the design and fabrication of handling and processing equipment for these important horticultural produce are either few or non-available. In this study the proximate composition and several physical and engineering properties of four popular varieties of Nigerian sweet potato (size, shape, mass, weight, volume, surface area, density, sphericity, latent heat, specific heat, thermal conductivity, thermal diffusivity) were determined using standard procedures. The surface areas for orange fleshed sweet potato (OFSP), yellow fleshed sweet potato (YFSP), purple fleshed sweet potato (PFSP) and white fleshed sweet potato (WFSP) are 2.36±0.30, 2.92±0.29, 2.43±0.41 and 1.97±0.19 (×104 mm2 ) respectively. The geometric mean diameter obtained are 82.02±5.43, 95.17±4.61, 84.33±8.27 and 77.03±4.02 mm for OFSP, YFSP, PFSP and WFSP respectively. The values for sphericity were OFSP, 54.15±3.00; YFSP, 55.82±4.55; PFSP, 59.31±4.15 and WFSP, 54.75±1.58 %. The latent heat ranged between 198.08±0.71 and 272.10±0.33 KJKg-1. Orange fleshed sweet potato had the highest thermal conductivity of 0.55±0.001 Wm-1K-1.while purple fleshed and white fleshed sweet potato had the lowest value of 0.44±0.001 Wm-1K-1. The specific heat capacity values were OFSP, 3.69±0.03; YFSP, 3.18±0.01; PFSP, 3.11±0.01 and WFSP, 3.11±0.02 KJ Kg-1K-1. Properties such as major diameters, intermediate diameters, sphericities, aspect ratio, unit volume, unit mass and unit weight were found not to be statistically different at P ≤ 0.05 ±SD.

ABSTRACTSweet potato (Ipomoea batatas) is a commonly cultivated root crop in tropical and subtropical regions, including Ghana. Different varieties of sweet potato have been bred, in order to expand its utilisation within the food and industrial sector. This study analysed flours made from 12 recently developed Ghanaian sweet potato varieties in terms of their amylose and amylopectin molecular fractions and amylopectin chain length distribution. Starch content of the sweet potato flours ranged from 49 to 77 g/100 g dry matter, with 11 of the varieties containing above 60 g/100 g dry matter. An orange-fleshed variety, Apomuden, had the lowest amount of starch (48.9 g/100 g dry matter), while the cream-fleshed variety Histarch had the highest (77.3 g/100 g dry matter). The flours from the 12 sweet potato varieties had intermediate amounts of amylose, within the range 10–30 g/100 g dry matter, and showed typical molecular distribution according to size-exclusion chromatography (SEC). The fine structures of amylopectin, as revealed by anion-exchange chromatography, contained features common for starches of C-type X-ray pattern, but some structural differences were also observed.

Starch is a polysaccharide that finds versatile applications in pharmaceutical, food and other industries. Despite the presence of different varieties of sweet potatoes in Ethiopia, the physicochemical properties of their starches have not yet been studied. The aim of this study was therefore to isolate and characterize starches from three varieties of Ethiopian sweet potatoes [Ipomoea batatas (L.) Lam.] - Awassa83, Kulfo and Tulla. The starches were isolated using 0.075% (w/v) sodium metabisulphite solution. The proximate composition of the sweet potato starches, namely, amylose, protein, lipid, and fiber content were in the range of 11.13 - 18.15, 0.05 - 0.22%, 0.16 - 0.41% and 0.37 - 0.43%, respectively. The moisture content of the starches varied from 12.41 to 13.72%. Scanning electron microscopy of the starch granules showed polygonal, round and cupoliform/bell shaped granules. The average particle size of Awassa83 starch granules was 20.9 µm while Kulfo and Tulla exhibited similar average particle size of 12.1 µm. The swelling power and solubility of the starches ranged from 14.5 g/g to 21.7 g/g and 3.05% to 9.8%, respectively. X-ray diffraction pattern of the starches exhibited C-type with maximum characteristic peaks at 15o, 17o, and 23o2θ. DSC studies provided gelatinization temperatures, i.e., onset temperature (To:61.82 - 65.27 oC), peak temperature (Tp:65.60 - 69.09 oC), and end set temperature (Te: 72.13 - 73.69 oC); The enthalpy of gelatinization ranged from 5.45 mJ/mg to 6.85 mJ/mg). Variations in pasting characteristics were observed among the starches comprising peak viscosity (787 mPa.s to 873 mPa.s), hot paste viscosity (652 mPa.s to 723 mPa.s), breakdown viscosity (135 mPa.s to 158 mPa.s), cold paste viscosity (898 mPa.s to 997 mPa.s), and setback viscosity (111 mPa.s to 127 mPa.s). The peak time ranged from 4 min to 4.53 min and pasting temp. from 71.85 oC to 74.3 oC. Awassa83 starch exhibited relatively high peak and breakdown viscosities and low setback viscosity, and it may be suitable as a thickening and gelling agent.Keywords: Ipomoea batatas, Sweet potato starch, Awassa83, Kulfo, Tulla

Most sweet potato varieties currently grown by farmers are poorly adapted, have low root yields, less nutritive and white fleshed which have no beta carotene, a precursor to vitamin “A”. However, among the cheapest and richest sources of vitamin A; orange fleshed sweet potato varieties were rich in beta carotene are well accepted by young children. Hence the aim of this research project was conducted to evaluate the adaptability and performance of improved orange-fleshed sweet potato varieties on yield and other yield related traits during the 2020 main cropping season in southwest Ethiopia. The varieties used were Tulla, Kulfo, Guntutie, Vita, Kabode, Alamura and Dilla. The experiment was carried out using a randomized block design with three replications. The analysis of variance over locations depicted significant differences (p ≤0.05) among varieties for most of the studied traits. In this study, Alamura (31.42 t ha-1) and Dilla (27.8 t ha-1) varieties give a high yield among seven evaluated orange-fleshed sweet potato varieties. Based on farmer test preference, the first and second rank of test preference was recorded from Alamura and Dilla variety. Therefore, by considering both farmer’s test preference and the yield potential of the variety, Alamura and Dilla were selected as high yields and have the best test preference. Therefore, to fill the gap vitamin “A” deficiency at the community level Alamura and Dilla were selected as the best orange fleshed variety that has the best test preference with the highest yield in the humid tropics of Southwestern Ethiopia and these two varieties were recommended for production. Finally, since the result of this finding was based on data gathered from two locations and only one cropping season to test adaptability. So, one more additional season evaluation is necessary and also further studies are required to generate more reliable information on performance, nutrition and resistance to disease. Int. J. Agril. Res. Innov. Tech. 12(2): 111-116, December 2022

Screening of three sweet potato ( Ipomoea batatas L. ) cultivars for resistance to different virulence groups of root-knot nematodes ( Meloidogyne spp.) under controlled conditions