添加单宁对明胶可食膜性质的影响

如何提高明胶膜的机械性能和阻隔性能,一直以来是可食膜研究领域的重要内容。本文以不同剂量(0 mg/g、10 mg/g、20 mg/g、30 mg/g和40 mg/g)单宁添加于明胶液并以浇注法成膜,然后对膜的理化性质进行分析。研究结果发现单宁有效提高了明胶膜的拉伸强度,但降低了其断裂伸长率;当单宁添加量为30 mg/g(明胶干基)时,其拉伸强度最大(22.10 MPa),断裂延伸率最小(40.12%)。与对照膜相比,单宁的添加降低了复合膜水溶性,水蒸气透过率和氧气透过率。在单宁含量添加范围内,水蒸气透过性最低为1.49×10-11 g/(Pa·s·m);水溶性最低为27.76%,氧气透过率最低为21.63 meg/kg。同时,DSC分析表明单宁提高了明胶膜的热稳定性。FT-IR图谱表明单宁与明胶之间发生了以氢键和疏水键为主的物理交联作用。所以,单宁-明胶复合膜在食品包装方面具有潜在的开发价值。

Impact of Tannin on the Properties of Gelatin Edible Film

Methods to improve the mechanical and barrier properties of gelatin film have attracted considerable attention in the field of edible film manufacture. Here, different concentrations of tannins (0, 10, 20, 30, and 40 mg/g) were added to the gelatin solution and edible film was prepared by the casting method. The physicochemical properties of the film were investigated. The results suggested that incorporation of tannin effectively increased the tensile strength (TS), but reduced the elongation at break (EAB) of the film. The highest TS (22.10 MPa) and the lowest EAB (40.12%) were achieved with 30 mg/g tannin (dry weight). Compared with control, the film containing tannin showed decreased water solubility, water vapor permeability, and oxygen permeability. At the concentrations of tannin studied, the minimum values for water vapor permeability, water solubility, and oxygen permeability were 1.49×10-11 g/(Pa?s?m), 27.76%, and 21.63 Meg/kg, respectively. In addition, differential scanning calorimetry (DSC) analysis indicated that the thermal stability of tannin-gelatin films was also enhanced. Moreover, Fourier transform infrared spectroscopy (FT-IR) analysis showed physical crosslinking effect between tannin and gelatin, dominated by hydrogen bonding and hydrophobic bonding. Thus, the tannin-gelatin film shows potential development value in the field of food packaging.