Abstract:

The objective of this study was to investigate the effects of several polyphenolic compounds (ferullic acid, tannic
acid, rosmarinic acid and syringic acid) at various concentrations (1%, 2%, 3%, 4% and 5% based on protein) on structure
and properties of film from myofibrillar protein of common carp (Cyprinus carpio). Among all the investigated polyphenolic
compounds, tannic acid showed the highest cross-linking capacity on myofibrillar protein as evidenced by in the lowest free
amino group and sulfhydryl group contents in the film-forming protein solution. The addition of polyphenolic compounds
could enhance mechanical properties of the resulting films. With increasing concentration of polyphenolic compounds
added, Young’s modulus (E) and tensile strength (TS) of the films increased, while their elongation at break (EAB) decreased
(P < 0.05), suggesting stronger and stiffer film structure. At the same concentration used, tannic acid could result in higher
mechanical properties (elasticity and tensile strength) of the film when compared with other polyphenolic compounds. The
transparency and color of the film were reduced by polyphenolic compounds, depending on the type and concentration.
Therefore, polyphenolic compounds can potentially be applied in inner packaging materials for high-fat foods to prevent
lipid oxidation, thus prolonging the shelf-life of foods during storage.

Key words: polyphenolic compounds, myofibrillar proteins, structure, film, properties