The Effect of Controlled-Release Carvacrol on Safety and Quality of Blueberries Stored in Perforated Packaging

Abstract

The objective of this research was to evaluate the use of a controlled-release carvacrol powder to delay storage decay and maintain the safety of blueberries. The controlled-release carvacrol powder was a microcapsule of carvacrol (11% (w/w) active carvacrol) surrounded by a pectin/sodium alginate matrix. The microcapsules were packed in an air-permeable pouch, and then attached to the top of a clamshell filled with blueberries. The blueberries, inoculated with Escherichia coli or Colletotrichum acutatum, or non-inoculated control, were monitored for microbial growth and quality for 10 days at 10 °C and 5 days at 20 °C. Three treatments were compared: controlled-release microencapsulated carvacrol, non-encapsulated carvacrol, and control. The results showed that both the microencapsulated carvacrol and the non-encapsulated carvacrol treatments significantly reduced the populations of yeast and mold, and of E. coli and mesophilic aerobic bacteria. The microencapsulated carvacrol treated berries retained better quality due to significantly lower weight loss than control after 10 days at 10 °C. Sensory panelists found that the microencapsulated carvacrol berries had significantly higher overall blueberry flavor and lower discernible off-flavor in comparison with the non-encapsulated treatment after 3 days at 20 °C. The fruit internal quality, including total soluble solids content (SSC), and titratable acidity (TA), was not significantly affected by any treatment. These results indicate that pectin/sodium alginate controlled-release microencapsulated carvacrol can be used for the preservation of blueberries or other small fruit.

Antifungal Activities and Mode of Action of Cymbopogon citratus, Thymus vulgraris, and Origanum heracleoticum Essential Oil Vapors against Botrytis cinerea and Their Potential Application to Control Postharvest Strawberry Gray Mold

“…Tv and Oh exhibited higher disease control efficiency in strawberry inoculated with B. cinerea than Cc, consistent with their in vitro antifungal efficiency. Studies also reported that the combination of modified atmosphere packaging with essential oils significantly reduced postharvest decay on blueberries, cherry tomatoes, lychees, and grapes [7,31].…”

“…In this study, we evaluated the inhibitory efficiency of Cc, Tv, and Oh on postharvest natural decay, and Oh exhibited strong efficiency, indicating that Oh might have high antifungal activity against Rhizopus spp., Mucor spp., Colletotrichum spp., or Penicillium spp. The main component in Oh, carvacrol, is a broad-spectrum antifungal agent and has been reported to inhibit a lot of fungal pathogens in vitro [7]. However, there is no report about Oh antifungal activity and further research is needed.…”

“…The in vivo evaluation of the selected essential oils on strawberries inoculated with B. cinerea was performed following the method of Sun et al [7] and Zhong et al [17], with some modification. The conidial suspension was collected as mentioned above and adjusted to 1 × 10 6 conidia per mL for fruit inoculation.…”

“…The use of natural plant extracts as an alternative to chemical fungicides has gained attention due to their safe and eco-friendly characteristics. Essential oils are volatile aromatic compounds extracted from plant materials by hydrodistillation or pressing processes [7]. The major components in the essential oils responsible for the antifungal properties are terpenes and terpenoids with different functional groups [8].…”

“…Meanwhile, the volatile nature of the essential oils also offers an alternative strategy for postharvest handling; the oil can be combined with fruit or vegetable package during postharvest transportation and marketing. A controlled release of essential oils in the package or storage conditions is a safe, effective, and convenient strategy to control postharvest decay, without causing an external bruise [7]. This approach is suitable for soft fruits such as berries that cannot tolerate physical handling during postharvest dipping and coating.…”