Departamento de Engenharia de Alimentos, Faculdade de Zootecnia e Engenharia de Alimentos, Universidade de São Paulo, Rua Duque de Caxias Norte 225, CEP 13635-900, Pirassununga, SP, Brazil.
Departamento de Química, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Bandeirantes Avenue 3900, CEP 14040-901, Ribeirão Preto, SP, Brazil.
Carbohydr Polym. 2018 Oct 15;198:61-68. doi: 10.1016/j.carbpol.2018.06.053. Epub 2018 Jun 13.
This work is a comparative study of the application of mercerized soybean straw (MSS) and nanocellulose produced by acid (CNCs) or enzymatic hydrolysis (CNFs) as reinforcing fillers in soy protein isolate (SPI) films. CNCs presented average dimensions of about 10 nm-thick and 300 nm-long with a crystallinity index of 57%, whereas CNFs have similar diameters, though with greater lengths (>1 μm), lower crystallinity index (50%) and greater thermal stability. Incorporation of 5% of CNCs and CNFs (g/100 g of SPI) improved the SPI film tensile strength by 38 and 48% respectively, and decreased the SPI film elongation at break when compared to control films. The SPI-CNC films showed the lowest values for solubility, probably due to their higher crystallinity (63%). On the other hand, the water vapor permeability was solely reduced with CNF addition, which can be attributed to their higher aspect ratio (length/diameter) and a better incorporation into the protein matrix.
这项工作是对丝胶大豆秸秆（MSS）和酸法（CNCs）或酶法水解（CNFs）制备的纳米纤维素作为增强填料在大豆分离蛋白（SPI）薄膜中的应用进行的比较研究。CNCs 的平均尺寸约为 10nm 厚和 300nm 长，结晶度指数为 57%，而 CNFs 的直径相似，但长度更大（>1μm），结晶度指数（50%）和热稳定性较低。与对照薄膜相比，分别添加 5%的 CNCs 和 CNFs（g/100g SPI）可使 SPI 薄膜的拉伸强度分别提高 38%和 48%，并降低 SPI 薄膜的断裂伸长率。SPI-CNC 薄膜的溶解度最低，可能是由于其结晶度较高（63%）。另一方面，仅通过添加 CNF 就能降低水蒸气透过率，这可能归因于其较高的长径比（长度/直径）和更好地掺入蛋白质基质中。
