Efeito do tamanho dos grânulos nas características estruturais e físico-químicas do amido de trigo

Abstract

*A quem a correspondência deve ser enviada ResumoA distribuição de tamanho dos grânulos influencia diretamente a composição química do amido, afetando sua funcionalidade, características de gelatinização, susceptibilidade enzimática, e cristalinidade. Os grânulos de amido de trigo possuem distribuição bimodal de tamanho e são divididos em grânulos tipo A (10-40 μm) e B (≤10 μm). Neste trabalho amidos de trigo obtidos de quatro diferentes cultivares foram isolados e fracionados por tamanho. Amidos de diferentes tamanhos foram analisados quanto ao teor de lisofosfolipídeos e amilose, difração de raios-X, microscopia eletrônica de varredura, susceptibilidade enzimática, poder de inchamento e propriedades térmicas e de pasta. O fracionamento possibilitou a divisão dos grânulos em grandes (>15 μm) e pequenos (≤10 μm). Independente da cultivar, grânulos grandes apresentaram diâmetro médio de 22 μm e formato lenticular, enquanto grânulos pequenos mostraram diâmetro médio de 6 μm e forma arredondada. Grânulos grandes apresentaram menor teor de lisofosfolipídeos, maior teor de amilose e menor índice de cristalinidade (IC) quando comparados aos pequenos. Apesar da maior cristalinidade, os grânulos pequenos foram mais susceptíveis à hidrólise que os grânulos grandes, sugerindo que a susceptibilidade enzimática dos grânulos pequenos está relacionada à sua maior área superficial. Palavras-chave: amido; trigo; tamanho de grânulos; propriedades físico-químicas. AbstractGranule size distribution directly influences the chemical composition of starch, affecting its functionality, characteristics of gelatinization, enzymatic susceptibility and crystallinity. Wheat starch granules exhibit a bimodal size distribution and are divided into type A (10-40 μm) and type B (≤10 μm) granules. In this work, wheat starches obtained from four different cultivars were isolated and fractionated by size. This fractionation allowed the granules to be divided into large (>15 μm) and small granules (≤10 μm). Starches of different sizes were analyzed to determine their lysophospholipid and amylose content, X-ray patterns, enzymatic susceptibility, swelling power, and thermal and pasting properties. They were also examined under a scanning electron microscope. Independent of the cultivar studied, large granules showed an average diameter of 22 μm and were lentil-shaped, while small granules showed an average diameter of 6 μm and were spherical. The large granules exhibited lower lysophospholipids content, higher amylose content and a lower index of crystallinity (IC) than the small granules. Despite their higher crystallinity, small granules were more susceptible to hydrolysis than large ones, suggesting that the enzymatic susceptibility of small granules is related to its larger surface area. Keywords: starch; wheat; granule size; physicochemical properties.Efeito do tamanho dos grânulos nas características estruturais e físico-químicas do amido de trigo Effect of granule size on the structural and physicochemical characteristics of wheat starchPatr...

Mathematical modeling of wheat hydration: Process and starch properties

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Effect of enzymatic hydrolysis on some physicochemical properties of root and tuber granular starches

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