Instituto de Investigaciones en Ciencia y Tecnología de Materiales (INTEMA), Universidad Nacional de Mar del Plata - CONICET, Av. J.B. Justo 4302, B7608FDQ Mar del Plata, Argentina.
Instituto de Investigaciones en Ciencia y Tecnología de Materiales (INTEMA), Universidad Nacional de Mar del Plata - CONICET, Av. J.B. Justo 4302, B7608FDQ Mar del Plata, Argentina.
Food Chem. 2018 Mar 15;243:448-452. doi: 10.1016/j.foodchem.2017.08.069. Epub 2017 Aug 22.
Post-processing evolution of the functional properties of soybean protein concentrate (SPC) films, plasticized with varying levels of glycerol and processed by compression molding, was examined over a period of 90days. Films stored in the glassy state (25±2°C and 65±2% relative humidity) lost glycerol and water over time, as determined by gas chromatography and the decline in moisture content. SPC films plasticized with 40-50% glycerol showed a time-dependent increment of the elastic modulus and the tensile strength. In turn, the elongation, barrier properties, soluble mass and opacity of these films varied marginally with time. By contrast, films with 30% glycerol lost the most moisture and their elongation was reduced significantly, while water vapor permeability slightly increased with aging. The performance of aged films resulted from the balance between plasticizer and water loss, and the progressive replacement of unordered structures by intermolecular hydrogen bonded β-sheets and aggregates.
在 90 天的时间里，研究了不同甘油含量的增塑大豆浓缩蛋白（SPC）薄膜在压缩成型过程中的功能特性的后处理演变。通过气相色谱法和水分含量的下降，确定了储存在玻璃态（25±2°C 和 65±2%相对湿度）下的薄膜随时间流逝而损失甘油和水分。40-50%甘油增塑的 SPC 薄膜的弹性模量和拉伸强度随时间呈递增趋势。相反，这些薄膜的伸长率、阻隔性能、可溶性质量和不透明度随时间的变化很小。相比之下，含有 30%甘油的薄膜损失了最多的水分，其伸长率显著降低，而水蒸气透过率随老化略有增加。老化薄膜的性能源于增塑剂和水分损失之间的平衡，以及无规结构逐渐被分子间氢键β-片层和聚集体取代。
