Food safety related to fresh and fresh-cut produce, such as cantaloupe, is a great challenge in the food industry. Various processing technologies, including the use of antimicrobial materials, have been applied to reduce pathogens. Nisin, an antimicrobial peptide, shows strong inhibitory activity against Listeria monocytogenes (LM); however, it suffers from quick depletion in foods. In this study, the protective effect of starch octenyl succinate (starch-OS) stabilized emulsion on nisin was evaluated in a cantaloupe juice model. Results showed that the proteolytic enzyme in cantaloupe juice caused nisin depletion, and the adsorption of nisin in emulsion led to considerable protection of antimicrobial activity. After 1, 3, and 6 d of incorporation with cantaloupe juice, the size of LM inhibitory ring were 7.64, 7.60, and 2.97 mm, respectively for emulsion formulations, whereas it reduced from 3.60 mm to a negligible level for nisin-alone. This study showed the potential of using carbohydrate colloidal systems to prolong the efficacy of antimicrobial materials.
Keywords: Listeria monocytogenes; cantaloupe juice; emulsion; nisin; starch octenyl succinate.
© 2016 Institute of Food Technologists®.