Effect of chitosan beads incorporated with lavender or red thyme essential oils in inhibiting Botrytis cinerea and their application in strawberry packaging system

Abstract

Chitosan beads (C), those containing lavender (L) or red thyme (RT) essential oils at 2 levels: low or high (0.125 or 0.25 g/plate or sachet) were used to inhibit Botrytis cinerea on potato dextrose agar (PDA) and in strawberry clamshell. The system without beads served as control. L-high, RT-low and RT-high can effectively inhibit B. cinerea on PDA. The efficiency of beads was also tested with strawberry packed in clamshell by attaching a bag containing beads under clamshell lid and stored at 7 °C for 10 days. On Day10, decay of control strawberry, strawberry with C-low, C-high, L-low, L-high, RT-low and RT-high were 40%, 30%, 30%, 5%, 5%, 10% and 0%, respectively. The quality of strawberry during storage was evaluated. On Day10, weight loss of strawberry packed with C-high, L-high, RT-low and RT-high were significantly lower than control. Also these treatments had higher CO2 and lower O2 concentration in the clamshell. From sensory evaluation using 9-point hedonic scale, essential oils did not affect appearance, colour and firmness of strawberry but lowered odour, flavour and overall acceptability scores. However, on Day10, the control strawberry, strawberry with C-high, L-high and RT-high were acceptable with the score of 7.0, 7.2, 5.8 and 5.1, respectively.