Mechanical and water barrier properties of paperboards can be modified by biopolymer coatings. Though TS of paperboards was decreased by biopolymer coating, ring crush force was not decreased. Water barrier properties were increased by biopolymer coating especially for SPI or alginate coating with CaCl2 posttreatment. This result indicates that water barrier properties of paperboards can be improved by the proper choice of biopolymer material and coating
method. The improved water barrier properties of the paperboards can be exploited in the preparation of water-resistant corrugated fiberboard boxes for the storage and distribution of high-moisture foods such as fresh agricultural produce.