Preservation of Brussels Sprouts by Pullulan Coating Containing Oregano Essential Oil.

In this study, the effectiveness of pullulan (a fungal polysaccharide) film containing oregano essential oil (OEO) at 1.0 to 10.0% was evaluated against bacteria, yeasts, and molds. The quality of the sprouts, as determined by weight loss, color, and appearance, was monitored during storage at 2 and 16°C. An organoleptic evaluation of odor preference and odor acceptability of OEO on the Brussels sprouts was also conducted. The antimicrobial activity of pullulan films with OEO increased significantly with the increase in OEO concentration (1 to 10%). Pullulan films with OEO were more effective for inhibiting the growth of yeasts and molds than for inhibiting gram-positive and gram-negative bacteria. Pullulan with 1.0% OEO was an effective combination and was used subsequently as the base coating for maintaining the safety and quality of fresh Brussels sprouts stored at 16°C for 14 days. The pullulan coating containing 1.0% OEO reduced Aspergillus niger populations by 2 log CFU/g. This coating also reduced weight loss in the sprouts. Compared with uncoated Brussels sprouts, the percent weight loss after 14 days was reduced in samples coated with pullulan and with pullulan plus 1% OEO by 3.81 and 6.06%, respectively, after storage at 2°C and by 8.04 and 9.30%, respectively, after storage 16°C. The coating also significantly reduced changes in general appearance and color during storage. Evaluation of the organoleptic properties indicated that pullulan containing OEO had only a slight detrimental effect on odor properties. Incorporating OEO into a delivery system for antimicrobial compounds in pullulan coatings extended the microbiological shelf life of Brussels sprouts.