Efficacy of chitosan-pectin beads encapsulated with combined garlic and holy basil essential oils on shelf life extension of ready to eat food

Abstract

Chitosan-coated pectin beads containing mixed garlic and holy basil essential oils (GEO + HBEO) were prepared to inhibit microbial growth and extend shelf life of chilled stir-fried pork with basil leaves on rice. The factors affecting release of GEO + HBEO were determined. Increasing environmental relative humidity, temperature and time enhanced a release rate of mixed oils from the beads. Antimicrobial activity of beads was evaluated by disc volatilisation method. Beads, at 2.20 and 4.40 g, could inhibit Bacillus cereus, Clostridium perfringens, Escherichia coli, Pseudomonas fluorescens, Listeria monocytogenes and Staphylococcus aureus. The beads were applied in packaging of chilled stir-fried pork with basil leaves on rice. During storage, samples containing beads had Total Plate Count (TPC) less than that of the sample without beads. Furthermore, sample without beads had TPC over the limit on Day9, whereas sample with beads had TPC <106 CFU/g until Day24. A sensory triangle test showed that the sample without beads was significant different in appearance, odour and off flavour attributes from the control (sample kept in freezer) on Day5, while the sample with beads was significant different from the control on Day8; therefore, the shelf life based on sensory differences could be extended by 3 days.