Properties of lysozyme/low methoxyl (LM) pectin complexes for antimicrobial edible food packaging

The objective of this study was to determine the properties of lysozyme/low methoxyl (LM) pectin complexes in order to develop an edible antimicrobial film. At a constant lysozyme concentration (0.714 g/L), the gradual LM pectin addition (0-2 g/L) induced an increase of turbidity up to a threshold LM pectin concentration above which turbidity decreased. These results were interpreted in terms of lysozyme/LM pectin complexes formation followed by a change in the apparent particle size distribution and the electrophoretic mobility (ζ-potential). This complex formation was shown to considerably decrease the lysozyme antimicrobial activity probably due to lysozyme substrate diffusional limitation and/or a decrease of the enzyme mobility. The formed complexes were then used to manufacture an edible antimicrobial film able to control the lysozyme release. The presence of pectinases in the release medium enhanced the lysozyme release confirming that the developed edible antimicrobial film can be used to protect foods against lysozyme sensitive microorganisms and particularly those producing pectinolytic enzymes.