Original article Reinforcement of banana flour biocomposite film with beeswax and montmorillonite and effects on water barrier and physical properties Aungkana Orsuwan 1 & Rungsinee Sothornvit 1,2 * 1 Department of Food Engineering, Faculty of Engineering at Kamphaengsaen, Kasetsart University, Kamphaengsaen Campus, Nakhonpathom 73140, Thailand 2 Center of Advanced Studies in Industrial Technology, Kasetsart University, Bangkok, Thailand (Received 29 March 2018; Accepted in revised form 31 May 2018) Summary Unripe banana flour (BF) has potential as an edible film but its hydrophilic nature requires amendment to provide a better water barrier. Beeswax (BW) and montmorillonite Na + (MMT) are typically applied as reinforcing additives to obtain a water barrier, water solubility and mechanical strength in a biopoly- mer. Thus, the objective of this study was to investigate the effect of BW, MMT and their combination on banana biocomposite film properties. The results suggested that the addition of BW enhanced the film transparency and water barrier properties. However, the incorporation of MMT increased the water resis- tance as expressed through low water solubility. Nonetheless, the addition of BW and BW-MMT reduced the mechanical properties (tensile strength and elongation at break) of BF-BW and BF-BW-MMT films. Nonetheless, the added MMT did not change the mechanical properties of the BF film due to the poor dispersion quality of MMT as confirmed by scanning electron microscopy. Keywords Banana flour, beeswax, montmorillonite, water barrier properties, mechanical properties. Introduction An advantage of polysaccharide-based films obtained from agro-polymers is their excellent gas barrier prop- erty, which makes them an alternative for utilisation as food packaging material (Sothornvit & Pitak, 2007). Flour is an alternative polysaccharide-based biopoly- mer that can be easily produced without requiring haz- ardous chemical agents. The natural blend between many constituents such as starch, protein, fat, fibre and phenolic compounds in flour provides an interest- ing complex microstructure regarding biopolymer properties (Tapia-Bl acido et al., 2007; Dias et al., 2010; Pelissari et al., 2013). Banana (Musa sapientum Linn, ABB group ‘Kluai Namwa’) grows well in tropi- cal and subtropical countries in South-East Asia, espe- cially Thailand. Unripe banana is a potential source of flour production during the overproduction season (Sothornvit & Pitak, 2007; Pelissari et al., 2013; Orsu- wan et al., 2016, 2017). Banana flour can be classified as a hydrocolloid material due to its property of form- ing viscous dispersions and gels when dispersed in hot water. Banana flour can be used as a potential biodegradable material substitute for nonbiodegrad- able synthetic polymers to form a biopolymer with a high oxygen barrier (Milani & Maleki, 2012). The hydroxyl groups in the polysaccharide chain are still hydrophilic, which limits their application in food packaging and so this drawback requires mitigation (Tapia-Bl acido et al., 2007). Lipid coatings were applied in several kinds of food (fresh and processed foods, vegetables, fruits, meats, cheeses and bakery products) to protect against mois- ture loss from food products (Galus & Kadzi  nska, 2015). Biocomposite films from a blend of lipids and hydrocolloids had better properties (especially as a water barrier) than using pure lipids (Muscat et al., 2013). Waxes, such as beeswax, candelilla wax, car- nauba wax and fatty acids, are the most efficient lipids to enhance the water barrier properties of biopolymer films because of their high hydrophobicity related to the high contents of long-chain fatty alcohols and alkanes (Sothornvit et al., 2009; Muscat et al., 2013; Rodrigues et al., 2014). Beeswax (BW), a natural wax produced by honey bees of the genus Apis, is composed of many long-chain alcohols and the esters of fatty acids. BW has been reported to improve the water barrier properties of hydroxypropyl methylcellulose *Correspondent: E-mail: fengrns@ku.ac.th International Journal of Food Science and Technology 2018 doi:10.1111/ijfs.13859 © 2018 Institute of Food Science and Technology 1