Research on properties of edible films prepared from Zein, soy protein isolate, wheat gluten protein by adding beeswax

Abstract

As the increasing awareness of environmental protection, the interest in the development of biodegradable materials has become increasingly popular. At present, wheat gluten protein (WGP), soybean protein isolate (SPI) and Zein have made some progress in the application of packaging materials. At the same time, beeswax (BW) is widely applied in the preparation of food coatings. In this study, composite films were prepared by adding BW to three different types of proteins. Various properties of the composite film, such as thickness, color, mechanical properties and thermal stability were tested. Our results suggested that the addition of BW significantly increased the thickness of the film. Regarding to mechanical properties, the tensile strength of all the composite films with BW were significantly decreased. The results of SEM indicated that the surface morphology of the composite films changed due to the interaction between BW and protein molecules. Besides, the addition of BW resulted in a decrease of thermal stability. The Td of the Zein film (77 ℃) and WGP film (106 ℃) were decreased to 72 ℃ and 98 ℃, respectively. The study shows that the composite films will have the opportunity to be applied in the food package field in the future and further replace the traditional petroleum-based films.

The characterisation of cornstarch‐based chlorophyllin composite film for preservation of shrimp under photodynamic irradiation

“…Lowering the crystallinity resulted in a less rigid, weaker and easily deformable structure. The ductile nature of the film directed to a lower value of tensile strength and a higher value for elongation at break in CS‐Chl 5 film (Duan et al ., 2023).…”

“…This, in turn, made the surface of the film rough. The rough surface structure increased the surface hydrophobicity, and the surface images of the films were consistent with these results (Duan et al ., 2023). In addition, the increased surface hydrophobicity also contributed to the lower WVP of CS‐Chl 5 film than that of CS‐Chl 3 film.…”

“…A lower level of Chl powder (1%) was disseminated better in the film matrix; however, with further increase in the Chl concentration (3% and 5%), the uniformity of the film matrix altered and the film surface evolved gradually rougher with more particles and a looser cross‐sectional structure. Higher Chl concentration affected the disruptions in the arrangement of starch molecules, built voids in the film structure, increased the water‐holding capacity of the film and reduced the overall cohesion and compactness of the film, leading to rougher surface and looser cross section (Abotbina et al ., 2021; Duan et al ., 2023). The rougher surface may lead to lower WVP of CS‐Chl 5 film than CS‐Chl 3 film and looser cross section may result in lower TS of CS‐Chl x film than CS film.…”

“…For the CS and CS‐Chl x films, all samples showed a broad endothermic peak around 25–180 °C, mainly related to the evaporation of bound water from the polymer and probably due to the effect of the volatilisation of added glycerol on the filmmaking process (Wardak et al ., 2021). When the temperature raised continuously beyond 180 °C, the second degradation transpired in the film samples around 300–390 °C, notably syndicated with the degradation of corn starch primarily caused by the decomposition of water‐soluble amylopectin and amylose (Abotbina et al ., 2021; Duan et al ., 2023). However, all film samples determined 70–76% weight loss after the second degradation, and the maximum weight loss temperature of all the films was around 315 °C.…”

“…This was attributed to the interruption of intermolecular interactions of CS, resulting in a more disordered structure that was more thermally labile. The increased randomness and irregular arrangement facilitated the movement and rearrangement of the polymer chain, ultimately leading to thermal degradation (Zhao et al ., 2021; Duan et al ., 2023).…”