To develop biodegradable food packaging, different biopolymer blend ratios of cassava starch (S) and soy protein isolate (P) (S100, S85P15, S70P30, S55P45, S40P60, and P100) were prepared by the extrusion method and then characterized. Before their application in foods, these blends must be characterized to enable the selection of the optimum materials for different packaging applications. For this purpose, the thermal and structural properties of the blends and possible interactions between the polymers were analyzed by thermogravimetric analysis (TG), dynamic mechanical analysis (DMA), X-ray diffraction (XRD), and Fourier-transform infrared (FTIR) spectroscopy. The moisture and oil resistance (surface energy, water vapor permeability (WVP), moisture content and solubility, and oil permeability), mechanical properties (tensile and puncture strength), and transparency of the blends were also investigated. The addition of protein resulted in crosslinking between the starch and protein chains and increased the crystallinity, as observed by FTIR, XRD, and DMA. Consequently, the stiffness of S40P60 increased, presenting a 120 % higher elastic modulus, and the WVP decreased 25 % compared to S100, likely due to the crosslinking of the polymer chains promoted by the addition of protein. In contrast, the S70P30 blend had greater hydrophilicity, leading to 68 % increase in moisture content and WVP, respectively. The S40P60 blend presented 22 % higher water solubility than the other blends. The S85P15 blend exhibited higher dispersive energy ability, and consequently, higher permeability to oil. P100 was 19 % less transparent than the other samples. Concerning the studied blends, S40P60 presented a low water vapor and oil permeability and low dispersive energy, while also presenting low transparency. Therefore, the use of this blend should be considered for packaging for foods with high lipid contents.

为了开发可生物降解的食品包装，通过挤压法制备了木薯淀粉（S）和大豆分离蛋白（P）（S100，S85P15，S70P30，S55P45，S40P60和P100）不同的生物聚合物混合比，然后进行了表征。在将其应用于食品之前，必须对这些混合物进行表征，以使其能够针对不同的包装应用选择最佳材料。为此，通过热重分析（TG），动态力学分析（DMA），X射线衍射（XRD）和傅立叶变换红外（FTIR）分析了共混物的热和结构性质以及聚合物之间可能的相互作用。光谱学。耐湿和耐油性（表面能，水蒸气渗透率（WVP），水分含量和溶解度以及油渗透性）还研究了机械性能（拉伸强度和穿刺强度）以及共混物的透明度。FTIR，XRD和DMA观察到，蛋白质的添加导致淀粉和蛋白质链之间的交联并增加了结晶度。因此，与S100相比，S40P60的刚度增加，弹性模量提高了120％，WVP降低了25％，这可能是由于蛋白质添加促进了聚合物链的交联。相反，S70P30共混物具有更大的亲水性，分别导致水分含量和WVP增加68％。S40P60共混物的水溶性比其他共混物高22％。S85P15共混物显示出更高的分散能，因此对油的渗透性也更高。P100的透明度比其他样品低19％。关于所研究的共混物，S40P60具有较低的水蒸气和油渗透性以及较低的分散能，同时还具有较低的透明度。因此，应考虑将这种混合物用于脂质含量高的食品的包装。