Antimicrobial Effect of Oxidized Starch and Its Application as a Coating for Strawberry Preservation

In this study the antibacterial effect of oxidized starch (OST) was analyzed by the inhibition zone method and the effect of OST on preserving the quality of strawberries was investigated by measuring mass loss percentage, decay incidence and total viable count. The results indicated that OST exhibited potent antimicrobial effects against common pathogenic bacteria such as Staphylococcus aureus and Escherichia coli, as well as penicillium, a common spoilage organism of strawberries. The higher the proportion of carboxyl groups in OST, the stronger the antimicrobial effect. Specifically, the diameters of the zones of inhibition of OST containing 57% carboxyl (OST-57) against Staphylococcus aureus, Escherichia coli, and penicillium were (29.00 ± 0.87), (28.00 ± 1.73) and (15.75 ± 0.65) mm, respectively. OST-57 coating effectively inhibited the growth of total viable count, significantly reduced the mass loss percentage and decay incidence of strawberries (P < 0.05), delayed the change of hardness and chewiness during the ripening process of strawberries, and preserved the contents of soluble solids, anthocyanins, and other nutrients (P < 0.05). To sum up, OST-57 can effectively delay the ripening and senescence of strawberries, and thus has application value for the post-harvest preservation of vegetables and fruits as a new coating material.