天然染色可食胶原膜的制备及表征

为改善胶原膜的使用性能，采用胭脂虫红和高粱红色素复配着色剂对其染色，考察染料质量分数、温度、pH值以及时间等染色条件，确定最佳染色工艺。结果表明：在质量分数3%、温度40 ℃、pH 5的染液中上染8 min染色效果最佳。对染色后胶原膜的天然结构、耐热性能和机械强度进行分析，接触角和吸水率测定显示，染色后胶原膜的亲水性增加；红外光谱分析表明，染料分子与胶原纤维产生了结合；差示扫描量热分析和热重分析表明，染色后胶原膜的热变性温度提高了20 ℃左右，起始分解温度升高了约100 ℃，耐热性得到了较大的改善。拉力测试结果显示，染色后胶原膜的机械强度提高。

Preparation and Characterization of Edible Collagen Film Dyed By Natural Colorants

In order to improve the performance of collagen film, a colorant consisting of cochineal carmine and sorghum
red pigment was used to dye the collagen film. The optimum dyeing process was determined with respect to different
dyeing conditions such as colorant concentration, temperature, pH value and time. The results showed that the best dyeing
efficiency could be obtained by using 3% colorant at 40 ℃ and pH 5.0 for 8 min. The measurement of contact angle
and water absorption ratio indicated that the surface hydrophilicity of the dyed collagen film was improved obviously.
The Fourier transform infrared spectrum showed that the dyed molecules reacted with collagen film. The differential
scanning calorimetry (DSC) and thermogr avimetric (TG) analysis suggested that the denaturation temperature and initial
decomposition temperature of the dyed collagen film were increased by 20 ℃ and 100 ℃ or so, respectively. Mechanical
tests confirmed that the tensile strength of the dyed collagen film was higher than that of native collagen film.