Instituto de Tecnología de Alimentos, CONICET- Facultad de Ingeniería Química, Universidad Nacional del Litoral, Santa Fe, República Argentina.
Centro de Investigación y Desarrollo en Criotecnología de Alimentos (CIDCA, CONICET CCT La Plata - Facultad de Ciencias Exactas, UNLP-CIC), La Plata, República Argentina.
J Sci Food Agric. 2020 Dec;100(15):5458-5465. doi: 10.1002/jsfa.10597. Epub 2020 Jul 24.
The development of brewer's spent grain protein (BSG-PC) films with potential active packaging properties was investigated. Films were prepared by casting protein dispersions at different pH values (2, 8, 11), plasticizers [polyethylene glycol (PEG) or glycerol] and levels (0-0.25 g g ) of PEG. Mechanical, water-barrier and solubility, optical, antioxidant (reducing power, ABTS and lipidic radical scavenging), and antimicrobial properties of films were determined. Also, the structural characteristics of films were evaluated by attenuated total reflectance-Fourier transform infrared spectroscopy.
Only films prepared at pH 2 and plasticized by PEG were homogeneous in appearance and could be manipulated; thus, different levels of PEG were studied at this pH. Higher PEG concentrations increased water solubility, water vapor permeability and elongation at break, and decreased tensile strength and elastic modulus. PEG increased α-helix structure only when 0.10 g PEG g-1 BSG-PC was used. This could be related to the better mechanical properties of F films (higher tensile strength, and elastic modulus) with respect to the other films. Antioxidant activity depended on PEG concentration, whereas no antimicrobial properties against Bacillus cereus, Salmonella newport and Penicillium corylophylum were detected.
The formulations with 0.10 and 0.15 g PEG g BSG-PC appear to be the most promising, balancing mechanical, water-barrier properties and the antioxidant capacity of these films. Moreover, BSG proteins could be a cheap alternative for the preparation of biodegradable films, which are capable of being used as active food packaging. © 2020 Society of Chemical Industry.
研究了具有潜在活性包装性能的啤酒糟蛋白（BSG-PC）薄膜的开发。通过在不同 pH 值（2、8、11）下铸造蛋白质分散体，制备了薄膜，使用了增塑剂[聚乙二醇（PEG）或甘油]和 PEG 水平（0-0.25 g g）。测定了薄膜的机械性能、水阻隔性和溶解度、光学性能、抗氧化性能（还原力、ABTS 和脂质自由基清除）和抗菌性能。还通过衰减全反射傅里叶变换红外光谱法评估了薄膜的结构特性。
只有在 pH 2 下用 PEG 塑化的薄膜外观均匀，可操作；因此，在该 pH 下研究了不同水平的 PEG。较高的 PEG 浓度增加了水溶性、水蒸气透过率和断裂伸长率，降低了拉伸强度和弹性模量。只有当 0.10 g PEG g-1 BSG-PC 时，PEG 才增加α-螺旋结构。这可能与 F 膜（较高的拉伸强度和弹性模量）的机械性能更好有关。抗氧化活性取决于 PEG 浓度，而对蜡状芽孢杆菌、纽波特沙门氏菌和石松青霉没有抗菌活性。
PEG 浓度为 0.10 和 0.15 g g-1 BSG-PC 的配方似乎最有前途，平衡了这些薄膜的机械性能、水阻隔性能和抗氧化能力。此外，BSG 蛋白可能是制备可生物降解薄膜的廉价替代品，这些薄膜可作为活性食品包装。 © 2020 化学工业协会。
