Structural and functional analysis of a new co-processed tableting excipient for food compaction processes

Food compacts are convenient to industry and customers and must primarily possess a sufficient strength to withstand packaging processing and customer handling. In contrast to pharmaceutical applications, the choice of excipients is usually limited to necessary ingredients of the final food product. In accordance, novel, better performing materials derived from advanced processing of common food constituents are highly attractive. This study thoroughly characterizes the properties of such a novel, co-processed food material called “Salt-Starch” to demonstrate its superior tableting behavior and to investigate the cause of its superiority. For a fundamental understanding of the binding mechanisms and the resulting structure, tabletability, compressibility, compactibility and elastic recovery of compacts based on Salt-Starch, its sole starting components with different particle sizes and their physical blends are investigated. Results indicate, that the specific structure of a viscoelastic continuous phase of starch and a brittle-ductile dispersed phase of (sub-)micron-sized sodium chloride lead to superior strength of Salt-Starch, which cannot be achieved by physical mixtures. Compacts tensile strength is elevated 40 times at an applied pressure of 55 MPa and elastic recovery is less than half compared to the elastic recovery of binary mixture tablets.