The purpose of this present study is to determine the amount of vitamin A in the dehydrated sweet potato made from the yellow Puerto Rico variety grown in Texas by using a reference oil.

A Florida strain of sweet potato whitefly, Bemisia tabaci (Gennadius), was found to have an expanded range which includes several new food crops. To determine why, we examined how it processes plant nutrients. The amino acid and carbohydrate content of phloem sap from poinsettia and pumpkin and of honeydew produced by the Florida strain were analyzed Honeydews produced by a strain from Arizona feeding on both plants were also analyzed Poinsettia phloem sap contained 15 amino acids; 14 of these were in pumpkin phloem sap. Almost all the same amino acids were in the honeydews produced by the two strains on the two hosts. Carbohydrates in phloem sap and honeydew were common transport sugars, like sucrose. Both honeydews contained trahalulose, a disaccharide not previously associated with insects. Both strains processed phloem sap and honeydew from both plants in the same manner, but the Florida strain produced significantly larger quantities of honeydew; it is therefore assumed to process more phloem sap. Since this strain has access to more phloem sap it also has access to more of the amino acids, which are in short supply in the phloem sap of some plants, allowing it to broaden its range.

Although problems associated with the sweet potato whitefly, Bemisia tabaci (Gennadius), are not as dramatic as they were in 1992. they were still significant in 1993. Laboratory research in 1993 focused on defining the cues that result in migratory behavior, specifically host quality. In addition, field studies were conducted to learn more about timing, direction, and distance flown. Our goal is to develop a predictive model that can be used for forecasting whitefly movement. During our behavioral studies, B. tabaci was presented with two cues that lead to disparate behaviors. More than 70% of the whiteflies we tested ended their flights (within three presentations of the cue) when given a choice between settling on a 'host' (550 nm interference filter) and continued flight. Only 6% of the individuals we tested, demonstrated what would be considered to be true migration Both endogenoous and exogenous factors can play an important role in determining when insects will fly. Finally, although the oogenesis-flight syndrome is thought to be a strong component of insect migratory activity, whiteflies do not appear to postpone egg production until after they have engaged in flight. In the field marked whiteflies were also collected in the most distant of these traps. These field results support our hypothesis that most whitefly movement in the fall in the Yuma Valley is in a SW direction (prevailing winds are from the NE). Within a 3 hr time frame whiteflies can travel as far as 2.2 miles from the source field. We examined the effects of female flight distance and eggload. We found significant differences in the eggload of field collected whiteflies versus whiteflies collected in traps at all distances from the source field. There was no relationship between distance flown and eggload. These results may indicate that dispersing individuals are capable of delaying egg laying until a suitable host plant is located

A batata-doce possui grande importância na alimentação humana e expressivo potencial para produção de etanol. A produção brasileira desta cultura é a 20ª no ranking mundial, com produção de 525.814 t em 2014, destacando-se o Rio Grande do Sul, responsável por 30,68% da produção do país. Shochu é a bebida alcoólica destilada mais consumida no Japão, produzida por destilação de fermentados de diversas fontes amiláceas, incluindo a batata-doce. Em sua fabricação é utilizado o koji, cultura sólida de fungos tradicional dos países asiáticos, mas que torna o processo produtivo lento e com alto risco de contaminação. Considerando a alta produtividade de batata-doce e a influência da cultura japonesa no Brasil, principalmente na culinária, percebe-se uma grande oportunidade de agregar valor a essa matéria-prima. Os objetivos deste trabalho são fazer o estudo de um processo alternativo - mais rápido e com menor risco de contaminação - para produção de destilado de batata-doce similar ao shochu, e a avaliação da viabilidade econômica para produção do mesmo. No processo alternativo proposto, o koji foi substituído pela enzima Stargen 002, mistura contendo alfa-amilase e glucoamilase, e utilizou-se uma pectinase para redução da viscosidade do meio. O tempo de processo reduziu de 14 dias para apenas 1 dia. As análises dos compostos de interesse foram realizadas por HPLC e GC. Quanto às matérias-primas, o teor de açúcares redutores totais foi maior na batata-doce de casca creme e polpa creme (30,42±1,54%), seguida pela batata-doce de casca púrpura e polpa creme (27,44±0,36%) e por último a batata-doce de casca rosada e polpa alaranjada (20,57±0,49%), e o teor de umidade seguiu a ordem inversa. Os resultados obtidos pelo processo padrão não foram satisfatórios em razão do baixo rendimento da fermentação alcoólica (40,59-42,51%) e da formação de compostos acima do limite da legislação, resultantes de fermentação acética. O rendimento experimental da fermentação alcoólica foi maior utilizando a levedura Angel Thermal Resistance Alcohol® (73,65%), seguida da Lalvin DV10® (70,39%) e por último a Lalvin EC1118® (67,31%), sendo maiores do que os obtidos com o uso das técnicas convencionais de produção de shochu, pois a não contaminação por bactérias acéticas no fermentado possibilitou maior rendimento em etanol. Por destilação em batelada, foram separadas frações de cabeça, coração e cauda, e em todas elas o componente álcool metílico mostrou-se acima dos limites da legislação. Realizou-se, então, experimento sem adição de pectinase, e o problema de formação de metanol foi eliminado. Entretanto, houve queda no rendimento da fermentação alcoólica (51,65-54,75%), indicando que a menor desintegração da batata-doce prejudica o andamento do processo fermentativo. Todos os compostos analisados mostraram-se dentro dos limites das normas vigentes. As frações cabeça e cauda foram descartadas e a fração coração foi diluída até teor alcoólico de 25% (v.v-1) e envasada. O destilado produzido, batizado de “Tchêchu”, e o shochu comercial apresentaram as mesmas bandas de adsorção em análise FTIR, identificando semelhança entre os mesmos. O custo de produção de uma garrafa (750 mL) de “Tchêchu” foi estimado em R$ 8,75. Com preço unitário de R$ 15,75 e utilizando-se a taxa SELIC (9,25% a.a.) como taxa mínima de atratividade, tem-se VPL de R$ 1.815.107,34, TIR de 26%, e payback descontado de 2,44 anos, o que mostra que a implantação de uma destilaria para produção de “Tchêchu” é economicamente viável. / Sweet potatoes have great importance in human food and have significant potential for ethanol production. The Brazilian production of this crop is the 20th in the world ranking, with production of 525,814 t in 2014, standing out Rio Grande do Sul, responsible for 30.68% of the country's production. Shochu is the most widely consumed spirit in Japan, produced by the distillation of fermented mash from a variety of starchy sources, including sweet potatoes. In its manufacture is used koji, a solid fungus culture traditional of the Asian countries, but that makes the productive process slow and at high risk of contamination. Considering the high productivity of sweet potatoes and the influence of Japanese culture in Brazil, a great opportunity to add value to this raw material is perceived. The objectives of this work are to study an alternative process - faster and with less risk of contamination - for the production of sweet potato distillate similar to shochu, and to study the economic viability analysis for its production. In the alternative process proposed, koji was replaced by the enzyme Stargen 002, a mixture containing alpha-amylase and glucoamylase, and a pectinase was used to reduce the viscosity of the medium. The process time reduced from 14 days to only 1 day. Analyzes of the compounds of interest were performed by HPLC and GC. Total reducing sugar content was higher in sweet potatoes with cream peel and cream pulp (30.42 ± 1.54%), followed by sweet potatoes with purple peel and cream pulp (27.44 ± 0.36%) and finally sweet potatoes with rose peel and orange pulp (20.57 ± 0.49%), and the moisture content followed the reverse order. The results obtained by the standard process were not satisfactory due to the low yield of alcoholic fermentation (40.59-42.51%) and the formation of compounds above the limit of the legislation, resulting from acetic fermentation. The experimental yield of alcoholic fermentation was higher using Angel Thermal Resistance Alcohol® (73.65%), followed by Lalvin DV10® (70.39%) and Lalvin EC1118® (67.31%), being higher than those obtained with the use of conventional methods of shochu production, since the non-contamination by acetic bacteria in the fermentation allowed a higher yield in ethanol. Fractions of head, heart and tail were separated by distillation, and in all of them the methyl alcohol component showed above the limits of the legislation. An experiment was performed without addition of pectinase, and the problem of methanol formation was eliminated. However, there was a decrease in the yield of alcoholic fermentation (51.65-54.75%), indicating that lower disintegration of sweet potatoes impairs the progress of the fermentation process. All compounds analyzed were within the limits of the current laws. Head and tail fractions were discarded and heart fraction was diluted up to 25% alcoholic strength (v.v-1) and bottled. The distillate produced, named "Tchêchu", and commercial shochu presented the same adsorption bands in FTIR analysis, identifying similarity between them. The cost of producing a bottle (750 mL) of "Tchêchu" was estimated at R $ 8.75. With a unit price of R$ 15.75 and using the SELIC rate (9.25%) as minimum acceptable rate of return there is a NPV of R$ 1,815,107.34, an IRR of 26%, and a discounted payback of 2.44 years, which shows that the implementation of a distillery to produce "Tchêchu" is economically viable.

Vacuum frying is a promising method for preserving the desired color, texture, and flavor of products with high sugar content. Since most vegetables and fruits degrade when processed with traditional frying, vacuum frying is an excellent alternative to high temperature processing. However, in vacuum frying the product should be pre-treated before frying to obtain a better texture. The kinetics of oil absorption and oil distribution in sweet potato chips (total, internal, and surface oil content) was studied so that effectiveness of the de-oiling system could be established. An analysis of product quality attributes (PQA) such as moisture content, oil content, microstructure, diameter shrinkage, and thickness expansion, as well as, color, texture, bulk density, true density, and porosity of chips fried at different temperatures (120, 130, and 140°C) was performed to evaluate the effect of process temperature on the product. The final oil content of the sweet potato chips was 0.178±0.007, 0.178±0.011, and 0.172±0.002 g/g solid for frying temperatures of 120, 130, and 140ºC, respectively. These values were lower (~60% less) than those found in traditionally fried sweet potato chip, which indicates that the de-oiling mechanism is crucial in vacuum frying processing. It was found that the rate of change in PQAs is greatly affected by temperature; however, the final values of bulk density, true density, porosity, diameter shrinkage, and thickness expansion were not affected by temperature. The texture of the samples was affected by temperature, with the chips fried at 140 degrees C being crispier. In terms of color, the L* and color b* values decreased as temperature increased. While color a* was not affected by temperature. In this study, a two-stage frying process was also evaluated to improve the flavor and texture of sweet potato chips. First, a basket filled with the sweet potato slices was submerged into the oil under atmospheric conditions. As soon as the potato slices were partially cooked (1 min), the pressure was lowered to 1.33 kPa (vacuum frying stage) and the product fried for 2 more min. The products were fried at 130 degrees C for different interval of times. Starch gelatinization, texture, moisture content, and oil content were evaluated at each time interval. Sensory analysis was accomplished by using a consumer panel with 50 members. The samples were compared with the on-stage frying and atmospheric frying processes. The two-stage fried chips had better appearance and texture compared to the ones that were only fried under vacuum or atmospheric conditions. The samples were lighter and more yellow than the chips fried under the single-stage process. In vacuum frying, the temperature of the chips does not reach the gelatinization temperature until most of the water is evaporated. Therefore, there is not sufficient moisture content in the product for gelatinization to occur completely. As a result, the product has a glassy texture. In the two stage frying, the atmospheric frying prior to vacuum frying helps the starch to gelatinize thus producing a better product in terms of texture, oil content, and flavor. The atmospheric fried samples were darker in color and had a scorch taste. The degree of starch gelatinization was 21% higher for the two-stage fried samples than the single-stage fried ones. The application of the dual stage enhances the quality of sweet potato chips, improves consumer satisfaction, and reduces the need for space, cost, and any other needs of blanching pre-treatment to the sweet potato manufacturers.

Ethylene is a plant growth regulator and plays a key role in leaf senescence. Its signaling, however, remains mostly unclear in sweet potato. Ethephon, an ethylene releasing compound, induced sweet potato detached leaf senescence and associated gene expression, and the effects were repressed by mitogen-activated protein kinase (MAPK) kinase inhibitor PD98059. These data suggest that MAPK cascade is likely involved in ethylene signaling leading to leaf senescence and associated gene expression. With gene-specific primers and RT-PCR methods, a full-length cDNA, SPMAPK, was isolated from ethephon-treated sweet potato leaves. SPMAPK contained 1098 nucleotides (365 amino acids) in the open reading frame. Sweet potato SPMAPK also exhibited high amino acid sequence identities (ca. 79.8% to 83.4%) with plant MAPKs, and was most close to Arabidopsis MPK3 and MPK6 in phylogenetic tree analysis. RT-PCR analysis showed that SPMAPK gene expression was detected in roots, stems, and leaves. The mature and partial yellowing leaves expressed higher amount. SPMAPK gene expression was also inducible and significantly enhanced by ethephon. Results from studies with inhibitors or effectors showed that ethephon treatment resulted in acceleration of leaf senescence in detached sweet potato leaves, promotion of leaf chlorophyll content reduction and decrease of photochemical Fv/Fm, and induction of associated gene expression. These ethephon-mediated effects were all delayed or repressed by pretreatment with ethylene receptor inhibitor 1-methylcyclopropene (1-MCP), MAPK kinase inhibitor PD98059, NADPH oxidase inhibitor diphenyleneiodonium (DPI), antioxidant reduced glutathione, calcium ion chelator EGTA, and de novo protein synthesis inhibitor cycloheximide, respectively. Based on these results we conclude that an ethylene-inducible mitogen-activated protein kinase SPMAPK was isolated from sweet potato leaves, and expressed higher amount in mature and partial yellowing leaves. Ethephon-induced sweet potato SPMAPK expression was significantly repressed by 1-MCP, PD98059, DPI, reduced glutathione, EGTA and cycloheximide. These data also suggest that the possible signal components in ethephon-mediated leaf senescence and associated gene expression in sweet potato leaves likely include ethylene receptor, MAPK cascade, elevated H2O2 , external calcium influx, and de novo synthesized proteins. A possible ethylene signaling model leading to sweet potato leaf senescence and associated gene expression was also proposed.

Ethylene is a gaseous growth regulator, and plays an important role in response to plant developmental and environmental stimuli. Ethylene also plays a key role in leaf senescence. Calcium is a second message, and participates in the signal transduction pathways of many plant physiological responses. In this research, ethephon, an ethylene-releasing compound, was used to induce sweet potato leaf yellowing, chlorophyll content reduction, photochemical Fv/Fm decrease, H2O2 elevation and senescence-associated gene expression. These ethephon-mediated effects were all delayed or repressed by pretreatment of a calcium ion chelator, EGTA. Treatment with a calcium ionophore A23187 also induced senescence-associated gene expression in sweet potato detached leaves, and the induction was repressed by EGTA pretreatment. Calcium signaling in general is transmitted by calcium sensor proteins, including calmodulin to translate into appropriate responses to developmental and environmental stimuli. Therefore, pretreatment with calmodulin inhibitor chlorpromazine (CPZ) delayed or repressed ethephon-mediated leaf senescence, H2O2 elevation and senescence-associated gene expression. These CPZ-mediated effects were reversed by the exogenous application of an ethephon-inducible calmodulin SPCAM fusion protein. These results suggest that external Ca2+ influx and calmodulin SPCAM play a role in ethephon signaling leading to leaf senescence, H2O2 elevation and senescence-associated gene expression. In addition, NaCl salt stress also caused sweet potato leaf senescence, H2O2 elevation and senescence-associated gene expression. Pretreatment with CPZ delayed or repressed NaCl salt stress-mediated leaf senescence, H2O2 elevation and senescence-associated gene expression. These CPZ-mediated effects were also reversed by the exogenous application of calmodulin SPCAM fusion protein. These results suggest that calmodulin SPCAM may play a role in NaCl salt stress signaling leading to leaf senescence, H2O2 elevation and senescence-associated gene expression. Based on these results, external Ca2+ influx is required for ethephon induced leaf senescence. Ethephon-inducible calmodulin SPCAM likely participates in ethylene and NaCl salt stress signaling leading to leaf senescence, H2O2 elevation and senescence-associated gene expression in sweet potato in order to cope with different developmental cues or environmental stimuli.

Ethylene has long been considered as the main plant growth regulator that plays a key role in the regulation of leaf senescence. In sweet potato, ethephon, an ethylene releasing compound, promoted leaf senescence and H2O2 elevation. These ethephon-mediated effects were alleviated or attenuated by exogenous reduced glutathione and ascorbic acid. Ethephon treatment gradually increased endogenous total and reduced glutathione and ascorbic acid levels in sweet potato detached leaves 3 days after treatment. The H2O2 amount, however, was also increased at 72 h after treatment. Sweet potato detached leaves pretreated with reduced glutathione did significantly increased endogenous total and reduced glutathione levels at 24 h and remarkably decreased H2O2 amount at 72 h after ethephon application compared to that of ethephon alone control. Ethephon caused quick elevation of a small H2O2 peak at about 4 h after application, and the enhancement was eliminated by reduced glutathione pretreatment in treated sweet potato leaves. Pretreatment of diphenylene iodonium (DPI), an NADPH oxidase inhibitor, also repressed leaf senescence and H2O2 elevation at day 3 after ethephon treatment in sweet potato detached leaves, and the attenuation was effective within the first 4 h after ethephon treatment. For senescence-associated gene expression, ethephon and L-buthionine sulfoximine (BSO), an endogenous glutathione synthase inhibitor, did induced asparaginyl endopeptidase (SPAE) and cysteine proteases (SPCP1, SPCP2 and SPCP3) gene expression and the activation was repressed by reduced glutathione pretreatment. Based on these data we conclude that ethephon treatment may cause quick elevation of a small H2O2 peak likely via the NADPH oxidase, which may function as a signal component leading to leaf senescence, H2O2 elevation and senescence-associated gene expression in sweet potato detached leaves. The rate of endogenous antioxidant such as reduced glutathione elevation is also important and affects leaf senescence, H2O2 elevation and senescence-associated gene expression in sweet potato leaves.

Extended missions to space have long been a goal of the National Aeronautics and Space Administration (NASA). Accomplishment of NASA's goal requires the development of systems and tools for sustaining human life for periods of several months to several years. This is the primary objective of NASA's Advanced Life Support (ALS) program. This work contributes directly to NASA efforts for ALS, particularly food production. The objective of this work is to develop a systematic methodology for analyzing and improving or modifying ALS technologies to increase their acceptability for implementation in long-duration space missions. By focusing primarily on the food production systems, it is an aim of this work to refine the procedure for developing and analyzing the ALS technologies. As a result of these efforts, researchers will have at their disposal, a powerful tool for establishing protocols for each technology as well as for modifying each technology to meet the standards for practical applications. To automate the developed methodology and associated calculations, a computer-aided tool has been developed. The following systematic procedures are interrelated and automatically integrated into the computer-aided tool: • Process configuration, with particular emphasis given to food production (e.g., syrup and flour from sweet potato, starch from sweet potato, breakfast cereal from sweet potato); • Modeling and analysis for mass and energy tracking and budgeting; • Mass and energy integration • Metrics evaluation (e.g., Equivalent System Mass (ESM)). Modeling and analysis is achieved by developing material- and energy-budgeting models. Various forms of mass and energy are tracked through fundamental as well as semiempirical models. Various system alternatives are synthesized and screened using ESM and other metrics. The results of mass, energy and ESM analyses collectively revealed the major consumers of time, equivalent mass, and energy, namely evaporation, condensation, dehydration, drying and extrusion. The targeted processes were subsequently targeted for modifications. In conclusion, this work provides a systematic methodology for transforming non-conventional problems into traditional engineering design problems, a significant contribution to ALS studies.

A batata-doce possui grande importância na alimentação humana e expressivo potencial para produção de etanol. A produção brasileira desta cultura é a 20ª no ranking mundial, com produção de 525.814 t em 2014, destacando-se o Rio Grande do Sul, responsável por 30,68% da produção do país. Shochu é a bebida alcoólica destilada mais consumida no Japão, produzida por destilação de fermentados de diversas fontes amiláceas, incluindo a batata-doce. Em sua fabricação é utilizado o koji, cultura sólida de fungos tradicional dos países asiáticos, mas que torna o processo produtivo lento e com alto risco de contaminação. Considerando a alta produtividade de batata-doce e a influência da cultura japonesa no Brasil, principalmente na culinária, percebe-se uma grande oportunidade de agregar valor a essa matéria-prima. Os objetivos deste trabalho são fazer o estudo de um processo alternativo - mais rápido e com menor risco de contaminação - para produção de destilado de batata-doce similar ao shochu, e a avaliação da viabilidade econômica para produção do mesmo. No processo alternativo proposto, o koji foi substituído pela enzima Stargen 002, mistura contendo alfa-amilase e glucoamilase, e utilizou-se uma pectinase para redução da viscosidade do meio. O tempo de processo reduziu de 14 dias para apenas 1 dia. As análises dos compostos de interesse foram realizadas por HPLC e GC. Quanto às matérias-primas, o teor de açúcares redutores totais foi maior na batata-doce de casca creme e polpa creme (30,42±1,54%), seguida pela batata-doce de casca púrpura e polpa creme (27,44±0,36%) e por último a batata-doce de casca rosada e polpa alaranjada (20,57±0,49%), e o teor de umidade seguiu a ordem inversa. Os resultados obtidos pelo processo padrão não foram satisfatórios em razão do baixo rendimento da fermentação alcoólica (40,59-42,51%) e da formação de compostos acima do limite da legislação, resultantes de fermentação acética. O rendimento experimental da fermentação alcoólica foi maior utilizando a levedura Angel Thermal Resistance Alcohol® (73,65%), seguida da Lalvin DV10® (70,39%) e por último a Lalvin EC1118® (67,31%), sendo maiores do que os obtidos com o uso das técnicas convencionais de produção de shochu, pois a não contaminação por bactérias acéticas no fermentado possibilitou maior rendimento em etanol. Por destilação em batelada, foram separadas frações de cabeça, coração e cauda, e em todas elas o componente álcool metílico mostrou-se acima dos limites da legislação. Realizou-se, então, experimento sem adição de pectinase, e o problema de formação de metanol foi eliminado. Entretanto, houve queda no rendimento da fermentação alcoólica (51,65-54,75%), indicando que a menor desintegração da batata-doce prejudica o andamento do processo fermentativo. Todos os compostos analisados mostraram-se dentro dos limites das normas vigentes. As frações cabeça e cauda foram descartadas e a fração coração foi diluída até teor alcoólico de 25% (v.v-1) e envasada. O destilado produzido, batizado de “Tchêchu”, e o shochu comercial apresentaram as mesmas bandas de adsorção em análise FTIR, identificando semelhança entre os mesmos. O custo de produção de uma garrafa (750 mL) de “Tchêchu” foi estimado em R$ 8,75. Com preço unitário de R$ 15,75 e utilizando-se a taxa SELIC (9,25% a.a.) como taxa mínima de atratividade, tem-se VPL de R$ 1.815.107,34, TIR de 26%, e payback descontado de 2,44 anos, o que mostra que a implantação de uma destilaria para produção de “Tchêchu” é economicamente viável. / Sweet potatoes have great importance in human food and have significant potential for ethanol production. The Brazilian production of this crop is the 20th in the world ranking, with production of 525,814 t in 2014, standing out Rio Grande do Sul, responsible for 30.68% of the country's production. Shochu is the most widely consumed spirit in Japan, produced by the distillation of fermented mash from a variety of starchy sources, including sweet potatoes. In its manufacture is used koji, a solid fungus culture traditional of the Asian countries, but that makes the productive process slow and at high risk of contamination. Considering the high productivity of sweet potatoes and the influence of Japanese culture in Brazil, a great opportunity to add value to this raw material is perceived. The objectives of this work are to study an alternative process - faster and with less risk of contamination - for the production of sweet potato distillate similar to shochu, and to study the economic viability analysis for its production. In the alternative process proposed, koji was replaced by the enzyme Stargen 002, a mixture containing alpha-amylase and glucoamylase, and a pectinase was used to reduce the viscosity of the medium. The process time reduced from 14 days to only 1 day. Analyzes of the compounds of interest were performed by HPLC and GC. Total reducing sugar content was higher in sweet potatoes with cream peel and cream pulp (30.42 ± 1.54%), followed by sweet potatoes with purple peel and cream pulp (27.44 ± 0.36%) and finally sweet potatoes with rose peel and orange pulp (20.57 ± 0.49%), and the moisture content followed the reverse order. The results obtained by the standard process were not satisfactory due to the low yield of alcoholic fermentation (40.59-42.51%) and the formation of compounds above the limit of the legislation, resulting from acetic fermentation. The experimental yield of alcoholic fermentation was higher using Angel Thermal Resistance Alcohol® (73.65%), followed by Lalvin DV10® (70.39%) and Lalvin EC1118® (67.31%), being higher than those obtained with the use of conventional methods of shochu production, since the non-contamination by acetic bacteria in the fermentation allowed a higher yield in ethanol. Fractions of head, heart and tail were separated by distillation, and in all of them the methyl alcohol component showed above the limits of the legislation. An experiment was performed without addition of pectinase, and the problem of methanol formation was eliminated. However, there was a decrease in the yield of alcoholic fermentation (51.65-54.75%), indicating that lower disintegration of sweet potatoes impairs the progress of the fermentation process. All compounds analyzed were within the limits of the current laws. Head and tail fractions were discarded and heart fraction was diluted up to 25% alcoholic strength (v.v-1) and bottled. The distillate produced, named "Tchêchu", and commercial shochu presented the same adsorption bands in FTIR analysis, identifying similarity between them. The cost of producing a bottle (750 mL) of "Tchêchu" was estimated at R $ 8.75. With a unit price of R$ 15.75 and using the SELIC rate (9.25%) as minimum acceptable rate of return there is a NPV of R$ 1,815,107.34, an IRR of 26%, and a discounted payback of 2.44 years, which shows that the implementation of a distillery to produce "Tchêchu" is economically viable.