Preparation and characterization of edible starch film reinforced by laver Ying Chen a , Long Yu a,b, ⁎, Xiaoyan Ge a , Hongsheng Liu a,b , Amjad Ali a , Yanfei Wang c , Ling Chen a a Collage of Food Science and Engineering, South China University of Technology, Guangzhou 510640, China b Sino-Singapore International Joint Research Institute, Knowledge City, Guangzhou 510663, China c College of Food Science and Engineering, Qingdao Agricultural University, Qingdao, Shandong 266109, China abstract article info Article history: Received 1 December 2018 Received in revised form 6 February 2019 Accepted 7 February 2019 Available online 08 February 2019 Edible starch film reinforced by laver was developed and characterized. The relationship between processing technologies, microstructures and performances was established. When the laver was added into cold starch sus- pension, the laver flack (fiber) simply act as reinforcing agent to improve the mechanical properties of the starch matrix, which results in increasing modulus and tensile strength. When the laver was added into hot starch sus- pension and mixed under shear stress, the protein containing in laver will release out and mix with starch, which results in a starch-protein-laver fiber hybrid composites. In the hybrids system, fiber improves the mechanical properties of the starch-based film about 25%, while the protein reduces the moisture sensitivity and gas perme- ability about 45%. Scanning electron microscopic observation indicated good compatibility between starch ma- trix and laver. The cellulose containing in laver kept its semi-crystalline structure after processing, which was used to explain the reinforcing mechanism. Some chemical bounds between starch and protein containing in laver was detected by FTIR. Since all the components used in this work are from food sources, the prepared films are safe for food packaging and application as edible films. © 2019 Elsevier B.V. All rights reserved. Keywords: Starch film Laver Reinforcement Interface Moisture permeability 1. Introduction Starch films have been widely used in food and medicine packaging [1–3], in which the film should be edible in many cases, such as applica- tions in candy wrappers and medicine capsules etc. [4–6]. Such films maintain the shelf-life of foods for distant marketing either by acting as a barrier for gases and volatile compounds, or by controlling water permeability [4,6–9]. Improvement of mechanical properties and reduc- ing moisture sensitivity are two an ongoing challenges for starch-based materials. To achieve these two goals, various blending and compositing techniques have been developed, such as blending with other polymers or reinforcing with particle or fiber-fillers [10–14]. Different compatibilizers or cross-linking agents have also been developed to im- prove the interface between starch and other components [10,15–17]. However, incorporation of any additive is sensitive, in developing food contactable or edible packaging films, due to safety issue. In order to develop food contactable or edible packaging films, vari- ous natural fibers and polysaccharide-based particles have attracted great attentions to improve the mechanical properties of starch-based materials [10,18–20]. For examples, Panaitescu et al. [21] have showed that starch films filled with 7% cellulose nano-crystals had strength and stiffness close to that of polyolefins, and were regarded as a low- cost “green” substitute for application in food packaging and conserva- tion. Recently, Ali et al. [1] reported edible starch film reinforced by polysaccharide crystalline. However, neither fiber no particle fillers can improve gas or moisture permeability, which is important for food packaging. Based on the knowledge of polymeric materials, it is well known that the fillers with flat shape, such as delaminated talc or clay, can well resist gas permeation [22]. Laver was selected and used in this work since it is a kind of food and is a thin film containing mainly protein and cellulous fiber [23–25]. The purpose of this work is to develop high-performance starch- based films that are not-only safe for food packaging but-also for edible application. In this work, a commercially available food-grade modified (hydroxypropyl) cornstarch (80%) was used as a matrix because of it has acceptable mechanical as-well-as processing properties; and has been utilized to develop food packaging materials, such as edible films and medicinal capsules [5,26]. Laver was used as reinforce agent to im- prove the mechanical properties of starch film and moisture permeabil- ity. The effect of laver content and processing conditions on the microstructures and performances of the starch-based films was inves- tigated by scanning electronic microscopy, optical microscopy, International Journal of Biological Macromolecules 129 (2019) 944–951 ⁎ Corresponding author at: Collage of Food Science and Engineering, South China University of Technology, Guangzhou 510640, China. E-mail address: felyu@scut.edu.cn (L. Yu). https://doi.org/10.1016/j.ijbiomac.2019.02.045 0141-8130/© 2019 Elsevier B.V. All rights reserved. Contents lists available at ScienceDirect International Journal of Biological Macromolecules journal homepage: http://www.elsevier.com/locate/ijbiomac