Características físico-químicas de amidos extraídos de batatas cultivadas sob diferentes doses de adubação nitrogenada
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Data
2017-01-30
Autores
Eburneo, Juliana Aparecida Marques [UNESP]
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Universidade Estadual Paulista (Unesp)
Resumo
A batata é a hortaliça com maior área cultivada no Brasil, sendo que sua produção se concentra nos estados da região sul e sudeste. Na cultura da batata o manejo inadequado da adubação nitrogenada pode causar crescimento exagerado da parte aérea, reduzir a qualidade de tubérculos e aumentar o custo de produção. Além disso, as condições de cultivo também podem influenciar as características do amido, principal carboidrato de reserva da batata, o que pode levar a interferências na aplicabilidade deste pelas indústrias alimentícias. Frente ao exposto, este trabalho teve por objetivo caracterizar amidos extraídos de batata cv Ágata cultivada sob diferentes doses de adubação nitrogenada e avaliar a possível interferência desta prática sobre a morfologia e distribuição de tamanho dos grânulos de amido, teor de amilose, teores de fósforo, cálcio, potássio e magnésio, composição físico-química, propriedades de pasta e térmicas; parâmetros estes determinantes para o estabelecimento das potencialidades de aplicabilidades do amido pelas indústrias. Para o alcance deste objetivo foram utilizados tubérculos de batata resultantes da colheita de ensaio experimental com adubação nitrogenada instalado em propriedade rural na região da cidade de Avaré, estado de São Paulo. Após o cultivo de 117 dias, as batatas foram colhidas, lavadas e processadas para a extração e análise do amido. Os resultados obtidos mostram que o amido de batata extraído de plantas cultivadas sem a aplicação de adubo nitrogenado apresentou grânulos redondos e ovalados, com predomínio de diâmetro maior na faixa de 26 a 50μm, padrão de difração de raio X do tipo B, 22,16% de cristalinidade relativa, elevada pureza, presença de 1090 ppm de fósforo, 893 ppm de potássio, 200 ppm de cálcio e 88 ppm de magnésio. Temperatura de pasta de 67,94°C, pico de viscosidade de 796,88 RVU, quebra de viscosidade de 622,03 RVU, viscosidade final de 236,28 RVU e tendência a retrogradação de 65,76 RVU. A gelatinização iniciou em 65,85°C, com pico em 68,03°C e final em 70,79°C, com variação de entalpia de 9,92 J g-1. A análise dos dados mostrou interferência da adubação nitrogenada sobre as características do amido de batata cv Ágata, sendo que o incremento nas doses de nitrogênio levou a obtenção de amidos com menor cristalinidade relativa, menores teores de fósforo, cálcio e magnésio, menor resistência à temperatura e agitação e menores temperaturas de gelatinização. Estes resultados indicam que o manejo cultural pode afetar importantes propriedades determinantes de aplicabilidade do amido de batata.
Potato is a vegetable with the largest cultivated area in Brazil and its production is concentrated in the states of the southeast region. In potato cultivation nitrogen fertilization management can cause overgrown growth, reduce the quality of tubers and increase the cost of production. In addition, the cultivation conditions may also influence the characteristics of the starch, main reserve carbohydrate of the potato, which can lead to interference in applicability of starch by industries. In view of the above, the objective of this work was to characterize starches extracted from Ágata cultivar cultivated under different rates of nitrogen fertilization, and to evaluate possible interference on morphology and size distribution of starch granules, amylose content, phosphorus, calcium, potassium and magnesium, physical-chemical composition, pasting and thermal properties, important characteristics for establishing the potential of starch application by industries. In order to reach this objective was analyzed tubers obtained from experimental area in the region of the Avaré city, state of São Paulo. After cultivation of 117 days potatoes were harvested, washed and processed for extraction and analysis of the starches. The results obtained show that potato starch extracted from plants cultivated without a nitrogen fertilizer application showed round and oval granules, with a larger diameter in the range of 26 to 50μm, pattern type B of X-ray diffraction, 22,16% of relative crystalline, high purity, presence of 1090 ppm of phosphorus, 893 ppm of potassium, 200 ppm of calcium and 88 ppm of magnesium. The pasting temperature was 67.94°C, viscosity peak was 796.88 RVU, viscosity breakdown was 622.03 RVU, final viscosity was 236.28 RVU and seatback was 65.76 RVU. The gelatinization of starch granules started at 65.85°C, with peak at 68.03°C, and final at 70.79°C, with enthalpy variation of 9.92 J g-1. The analysis of the data showed the interference of nitrogen fertilization on the characteristics of Ágata potato starch. The increase in nitrogen rates led to the obtaining of starches with lower relative crystalline, lower phosphorus, calcium and magnesium contents, lower resistance to temperature and agitation and lower gelatinization temperatures. These results indicate that cultural management can affect important determining properties of potato starch application, which is of great interest to the food industry.
Potato is a vegetable with the largest cultivated area in Brazil and its production is concentrated in the states of the southeast region. In potato cultivation nitrogen fertilization management can cause overgrown growth, reduce the quality of tubers and increase the cost of production. In addition, the cultivation conditions may also influence the characteristics of the starch, main reserve carbohydrate of the potato, which can lead to interference in applicability of starch by industries. In view of the above, the objective of this work was to characterize starches extracted from Ágata cultivar cultivated under different rates of nitrogen fertilization, and to evaluate possible interference on morphology and size distribution of starch granules, amylose content, phosphorus, calcium, potassium and magnesium, physical-chemical composition, pasting and thermal properties, important characteristics for establishing the potential of starch application by industries. In order to reach this objective was analyzed tubers obtained from experimental area in the region of the Avaré city, state of São Paulo. After cultivation of 117 days potatoes were harvested, washed and processed for extraction and analysis of the starches. The results obtained show that potato starch extracted from plants cultivated without a nitrogen fertilizer application showed round and oval granules, with a larger diameter in the range of 26 to 50μm, pattern type B of X-ray diffraction, 22,16% of relative crystalline, high purity, presence of 1090 ppm of phosphorus, 893 ppm of potassium, 200 ppm of calcium and 88 ppm of magnesium. The pasting temperature was 67.94°C, viscosity peak was 796.88 RVU, viscosity breakdown was 622.03 RVU, final viscosity was 236.28 RVU and seatback was 65.76 RVU. The gelatinization of starch granules started at 65.85°C, with peak at 68.03°C, and final at 70.79°C, with enthalpy variation of 9.92 J g-1. The analysis of the data showed the interference of nitrogen fertilization on the characteristics of Ágata potato starch. The increase in nitrogen rates led to the obtaining of starches with lower relative crystalline, lower phosphorus, calcium and magnesium contents, lower resistance to temperature and agitation and lower gelatinization temperatures. These results indicate that cultural management can affect important determining properties of potato starch application, which is of great interest to the food industry.
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Palavras-chave
Nitrogênio, Viscosidade, Cristalinidade, Nitrogen, Starch, Viscosity, Crystallinity