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Rehydration Characteristics and Structural Changes of Sweet Potato Cubes after Dehydration  [PDF]
Ngankham Joykumar Singh,Ram Krishna Pandey
American Journal of Food Technology , 2011,
Abstract: Moisture removal from solids is an integral part of food processing with convective drying representing one of the most important techniques for preservation of biological products. However, removal of moisture during drying has detrimental effects on the physiochemical properties of the material. For evaluating of the rehydration capability the sweet potato cubes of 1.2x1.2x1.2 cm were dried to final moisture content of 6-7% (d.b.) under air temperature of 50, 60, 70, 80 and 90°C and air velocity of 3.5 m sec-1 in a laboratory scale hot air dryer. Deterioration of the physical attributes of the system was evaluated on the basis of rehydration characteristics, namely the coefficient of rehydration and rehydration ratio at different soaking time period of 10, 15, 20, 25 and 30 min. Structural changes in Sweet potato cubes after drying were studied by light microscopy. The rate and degree of dehydration was dependent on the drying conditions, with extent of cellular and structure disruption dictating the rehydrational capacity. The drying temperature had an effect on the shrinkage of cell structures of sweet potato. It was observed that the degree of shrinkage of sweet potato during low temperature drying is greater than at high-temperature during drying.
Localization of Sweet potato chlorotic stunt virus (SPCSV) in synergic infection with Potyviruses in sweet potato
Nome,Claudia Fernanda; Nome,Sergio Fernando; Guzmán,Fabiana; Conci,Luis; Laguna,Irma Graciela;
Biocell , 2007,
Abstract: among diseases reported worldwidely for sweet potato (ipomoea batatas (l) lam) crop, one of the most frequent is the sweet potato virus disease (spvd), caused by sweet potato chlorotic stunt virus (spcsv) and sweet potato feathery mottle virus (spfmv) co-infection. in argentina, there exists the sweet potato chlorotic dwarf (spcd), a sweet potato disease caused by triple co-infection with spcsv, spfmv and sweet potato mild speckling virus (spmsv). both diseases cause a synergism between the potyviruses (spfmv and spmsv) and the crinivirus (spcsv). up to date, studies carried out on the interaction among these three viruses have not described their localization in the infected tissues. in single infections, virions of the crinivirus genus are limited to the phloem while potyviral virions are found in most tissues of the infected plant. the purpose of this work was to localize the heat shock protein 70 homolog (hsp70h), a movement protein for genus crinivirus, of an argentinean spcsv isolate in its single infection and in its double and triple co-infection with spfmv and spmsv. the localization was made by in situ hybridization (ish) for electron microscopy (em) on ultrathin sections of sweet potato cv. morada inta infected tissues. the results demonstrated that viral rna coding hsp70h is restricted to phloem cells during crinivirus single infection, while it was detected outside the phloem in infections combined with the potyviruses involved in chlorotic dwarf disease.
Localization of Sweet potato chlorotic stunt virus (SPCSV) in synergic infection with Potyviruses in sweet potato
Claudia Fernanda Nome,Sergio Fernando Nome,Fabiana Guzmán,Luis Conci
Biocell , 2007,
Abstract: Among diseases reported worldwidely for sweet potato (Ipomoea batatas (L) Lam) crop, one of the most frequent is the Sweet potato virus disease (SPVD), caused by sweet potato chlorotic stunt virus (SPCSV) and sweet potato feathery mottle virus (SPFMV) co-infection. In Argentina, there exists the sweet potato chlorotic dwarf (SPCD), a sweet potato disease caused by triple co-infection with SPCSV, SPFMV and sweet potato mild speckling virus (SPMSV). Both diseases cause a synergism between the potyviruses (SPFMV and SPMSV) and the crinivirus (SPCSV). Up to date, studies carried out on the interaction among these three viruses have not described their localization in the infected tissues. In single infections, virions of the crinivirus genus are limited to the phloem while potyviral virions are found in most tissues of the infected plant. The purpose of this work was to localize the heat shock protein 70 homolog (HSP70h), a movement protein for genus crinivirus, of an Argentinean SPCSV isolate in its single infection and in its double and triple co-infection with SPFMV and SPMSV. The localization was made by in situ hybridization (ISH) for electron microscopy (EM) on ultrathin sections of sweet potato cv. Morada INTA infected tissues. The results demonstrated that viral RNA coding HSP70h is restricted to phloem cells during crinivirus single infection, while it was detected outside the phloem in infections combined with the potyviruses involved in chlorotic dwarf disease.
Effect of Heat Moisture Treatment Conditions on Swelling Power and Water Soluble Index of Different Cultivars of Sweet Potato (Ipomea batatas (L). Lam) Starch  [PDF]
Suraji Senanayake,Anil Gunaratne,KKDS Ranaweera,Arthur Bamunuarachchi
ISRN Agronomy , 2013, DOI: 10.1155/2013/502457
Abstract: A study was done to analyse the change in swelling power (SP) and the water soluble index (WSI) of native starches obtained from five different cultivars of sweet potatoes (swp 1 (Wariyapola red), swp 3 (Wariyapola white), swp 4 (Pallepola variety), swp 5 (Malaysian variety), and swp 7 (CARI 273)) commonly consumed in Sri Lanka. Extracted starch from fresh roots, two to three days after harvesting has been modified using 20%, 25%, and 30% moisture levels and heated at 85°C and 120°C for 6 hours and determined the SP and WSI. Results were subjected to general linear model, and analysis of variance (ANOVA) was carried out by using MINITAB version 14. Overall results showed a significantly high level ( ) of SP and WSI in all the cultivars of moisture—temperature treated starches than their native starch. Correlation analysis showed an effect on SP with the variation in the cultivar, temperature, and moisture; temperature combination and moisture alone had no significant effect. Significantly high levels of swelling power ( ) were observed in 20%—85°C, and 30%—120°C and the highest amount of swelling in the modified starch than its native form was observed in swp 7 cultivar. Results revealed a nonlinear relationship in the WSI with the cultivar type, moisture level, and the lower moisture—temperature combinations but higher temperature—moisture combinations had a significant effect. SP and WSI had a slight positive linear relationship according to analysis. Based on the results, a significantly high level of swelling and water solubility of native starches of different cultivars of sweet potatoes can be achieved by changing the moisture content to 30% and heating at 120°C for 6 hours. 1. Introduction For a wide range of starch applications, native starches cannot be used due to inability to bring out the desired properties. Native starches can be modified to obtain the desired qualities by starch modification methods. Chemical modification of starch molecules is commonly used in achieving the desired properties. Also by using specific moisture and temperature conditions, some physicochemical properties of starch can be altered. There are more trends in the world for physical modification of starch which is used in food industrial applications as there is an increasing difficulty in obtaining regulatory approval of the new chemical reagents and higher levels of treatment as described by BeMiller [1]. Since most physical modifications involve only water and heat, these hydrothermal treatments are considered to be natural and safe materials by Jacobs and
Chemical Elemental Compositions and Nutrition Quality of Yacon, Sweet Potato and Potato
Yue Wang,Guojun Shi,Bo Yuan,Sichuan Xu
Journal of Modern Agriculture , 2013,
Abstract: Elemental compositions from Yacon, Sweet Potato and Potato have been analyzed and determined by X-ray fluorescence (XRF) spectrum to study the relationship of their chemical elemental compositions with their nutrition quality. In the dry matters of Yacon, Sweet Potato and Potato, the content of carbon element is about 40%, not only to indicate that the similar carbon content is a common nature of the three fruits belonging to Potato species, but also to demonstrate that they are classified to low alloy steel calorie food. The content of nitrogen element is determined to be a bigger value in the dry matters of Yacon, Sweet Potato and Potato, namely their protein content is high; especially, the protein content in the dry matter of Potato is the similar to that in millet, which can explain that Potato is a relative nutrition foodstuff in principle of protein. Because of a large proportion of oxygen (47.88%) as well as the biggest sugar content in the dry matter of Yacon, Yacon is the sweetest foodstuff among all its kind. The main metal elemental contents are up to 3.75%, 2.64% and 2.50% in the dry matters of Yacon, Sweet Potato and Potato respectively, which is larger not only than those in common foodstuffs, but also than 2.42% in soybean. In particular, the contents of K, Fe, Ca, Mg, Mn and Cu in the dry matters of Yacon, Sweet Potato and Potato all are high. It can be ascertained in light of the microelement properties that their nutrition quality is similar to what soybean possesses. Therefore, the obtained results by investigating elemental compositions prove that Yacon, Sweet Potato and Potato are comprehensive and balanced nutrition foodstuffs with high content of protein, trace elements as well as sugar compositions and low content of carbon element. The cultivation of Yacon, Sweet Potato and Potato is an available approach to the food shortage of China, taking advantages of high yield without difficulty, strong adaptability to fertile and paddy field and high nutrition value comparable to rice and flour.
PENGARUH ISOTERM SORPSI AIR TERHADAP STABILITAS BERAS UBI [Effect of Moisture Sorption Isotherm to Stability of “Sweet Potato Rice”]  [cached]
Sri Widowati1)*,Heti Herawati1),Rizal Syarief2),Nugraha Edhi Suyatma2)
Jurnal Teknologi dan Industri Pangan , 2010,
Abstract: “Sweet Potato Rice” stability as a dry food product was determined by water activity (aw) and equilibrium moisture content (Me). This relationship is known as moisture sorption isotherm. This research were aimed 1) to study moisture sorption isotherm of “Sweet Potato Rice” from sweet potato flour (Cangkuang variety) and native/heat moisture treatment (HMT) starch which was stored at the range of aw:0.06 - 0.96 and 28oC; 2) to determine an appropriate model for describing product moisture sorption isotherm and 3) to predict “Sweet Potato Rice” shelf of life. Experimental design used was a random complete design with two factor, namely: 1) sweet potato starch: native and HMT, and 2) packaging material: polyethylene (PE) and polypropylene (PP).The result showed that the moisture sorption isotherm profiles were sigmoid. Smith equation was the best model which described moisture sorption isotherm with R2= 0,991-0,993 for adsorption and R2= 0,964-0,971 for desorption. Shelf life test showed that “Sweet Potato Rice” from Cangkuang flour and modified starch had longer shelf life (5.67 months when packed in PP bag and 2.3 months when packed in PE bag); while shelf life artificial sweet potato made from Cangkuang flour and native starch was 4.24 months when packed in PP bag and 1.72 months when packed in PE bag.
Determination of Some Selected Engineering Properties of Sweet Potato Cuts as Function of Temperature
M.O. Oke,S.O. Awonorin,L.O. Sanni,C.T. Akanbi,A.O. Abioye
Journal of Food Technology , 2013,
Abstract: Some selected engineering properties of sweet potato as function of temperature (-18 to 33 C) and geometries (slab and cylinder) were studied. Transient heat transfer method was used for the determination of parameters among which is density, specific heat and thermal diffusivity at constant moisture level of 71.7 0.76% (wet basis). Both the density and specific heat of the sample increased with increase in temperature to maximum levels after which further increase led to a reduction of these parameters values and were independent of sample s geometry. The thermal diffusivity and computed thermal conductivity were found to increase with increase in temperature. Conclusively, these engineering properties were correlated with temperature using polynomials of the third order empirical equation.
Functional Properties of Wheat and Sweet Potato Flour Blends  [PDF]
R.O. Adeleke,J.O. Odedeji
Pakistan Journal of Nutrition , 2010,
Abstract: In this study the functional properties of wheat and sweet potato tuber (Ipomea batatas) flour blends were investigated. The sweet potato tubers were brought from local farm in Offa Kwara State. The tubers were thoroughly sorted, washed, peeled, sliced, blanched, soaked, drained, sundries and milled into flour. Wheat flour used was purchased at Orisumbare market in Osogbo Osun State. The wheat and sweet potato flour were blended using the following ratios (WF:SPF:100:0, 90:10, 85:15, 80:20, 75:25, 0:100). These samples were thereafter subjected to functional properties analysis. The results revealed that as more and more sweet potato flour was added to wheat flour, there was significant effect on the functional properties.
Pasting Characteristics of Wheat and Sweet Potato Flour Blends  [PDF]
J.O. Odedeji,R.O. Adeleke
Pakistan Journal of Nutrition , 2010,
Abstract: This study was conducted to investigate the pasting characteristics of wheat and sweet potato tuber (Ipomea batatas) flour blends. The sweet potato tubers were bought from a local farm in Offa, Kwara State. The tubers were thoroughly sorted, washed, peeled, sliced, balanced, drained, sundried and milled into flour. Commercial wheat flour was used and purchased from Igbona market in Osogbo, Osun State of Nigeria. The wheat and sweet potato flour were blended using the following ratios (WF : SPF : 100 : 0, 90 : 10, 85 : 15, 80 : 20, 75 : 25, 0 : 100). These samples were thereafter subjected to pasting characteristics analysis. The results revealed that as more and more sweet potato flour was added to wheat flour there was improvement in the pasting properties.
Influence of earthworm humus on sweet potato yield  [PDF]
Jo?o Felinto dos Santos,José Ivan Tavares Grangeiro,Luciano de Medeiros Pereira Brito,Marinevea Medeiros de Oliveira
Engenharia Ambiental : Pesquisa e Tecnologia , 2009,
Abstract: The Paraíba State is the higher producer of the northeast region and the fourth brazilian producer of sweet potato, where this crop has a very fodder, economic and social importance, promoting the creation of joy and rent, as well contributing for the fixation of man on rural zone. The purpose of the experiment was to evaluate the influence of organic fertilization on components of production and productivity of sweet potato. The experiment was carried out from May to September of 2005, at State of Paraíba, Brazil. The experimental design was randomized blocks with six treatments (0; 3; 6; 9; 12 and 15 t ha-1 of earthworm humus), in four replications. The evaluated variables were total and marketable roots number, raw yield and total and marketable yield of roots. The maximum total yield of roots, of commercial and non-commercial roots of sweet potato, estimated by models (curves) were respectively 18.76; 16.29 and 2.46 t ha-1, obtained with a dosage of 15.00 t ha-1 of earthworm humus. The maximum yield of raw sweet potato-estimated the equation was 12.82 t ha-1 obtained with 15 t ha-1 of the earthworm humus. The application of 15 t ha-1 of earthworm humus increased from 9.96 t ha-1 (109.69%) and 8.50 t ha-1 (105.20%) in total yield and commercial roots sweet potato, respectively, in relation to the treatment without fertilizer. For every R$ 1.00 invested in earthworm humus there was a return of R$ 2.17 from the sale of sweet potato roots.Key-words: Ipomoea batatas, organic fertilization, root production.
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