The Effect of Edible Chitosan Coatings Incorporated with Thymus capitatus Essential Oil on the Shelf-Life of Strawberry (Fragaria x ananassa) during Cold Storage.

Keydis Martínez,Carlos Grande Tovar,Marta Ortiz,Clara Gilma Gutiérrez Castañeda,Alberto Albis,Mayra Valencia

doi:10.3390/biom8040155

Keydis Martínez, Carlos Grande Tovar + Show 4 more

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https://doi.org/10.3390/biom8040155

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Abstract

The strawberry is a fruit appreciated in the food industry for its high content of bioactive compounds. However, it is considered a highly perishable fruit, generally attacked by pests of phytopathogenic origin, which decreases its shelf-life. Normally, to diminish the losses caused by pathogenic microbes, coatings of polysaccharides in combination with natural products like essential oils are applied. In this work, we describe the effect of edible coatings from chitosan (CT) incorporating Thymus capitatus essential oil (TCEO), applied to strawberries stored under refrigeration conditions (5 ± 0.5 °C). Different concentrations of TCEO were applied to chitosan coatings, with different effects on the physical and microbiological properties of the strawberries. All the products had greater acceptance and quality than the controls, being more effective those with essential oil incorporation. It is noteworthy that all the essential oil treatments lead to an increase in the shelf-life of strawberries of up to 15 days. Scanning electron microscopy (SEM) analysis of the microstructure showed a decrease in compactness with TCEO introduction, but without compromising food preservation after 15 days. In addition, treated strawberries delayed the loss of physicochemical and antioxidant properties, due to protection against the microbial development of aerobic mesophylls, molds, and yeasts.

Highlights

The strawberry (Fragaria x ananassa) is a nutraceutical fruit, appreciated in the food industry for its high content of bioactive compounds, such as vitamin C and phenolic constituents with antioxidant capacity [1]
Essential oil of Thymus capitatus was acquired from Sigma, and its composition was determined by gas chromatography-mass spectrometry (GC-MS) according to the methodology reported by [44]
The compounds corresponded to 23 monoterpenes (99.7%), a sesquiterpene (0.2%), and an unidentified compound corresponding to the remaining percentage

Summary

Introduction

The strawberry (Fragaria x ananassa) is a nutraceutical fruit, appreciated in the food industry for its high content of bioactive compounds, such as vitamin C and phenolic constituents with antioxidant capacity [1]. It is consumed fresh or processed in juices. In Colombia, losses of food from agriculture correspond to 64% of the total produced, mainly during the stages of production, post-harvest, storage, and industrial processing [2]. Fruits and vegetables are rich in water and nutrients, and, during storage, are ideal substrates for development of pathogenic microorganisms, such as Penicillium spp., Monilinia spp., and Botrytis spp. Biomolecules 2018, 8, 155 these foods, the strawberry is considered a highly perishable fruit, generally attacked by pests of phytopathogenic origin, which decreases its shelf-life and consumer acceptance [3].

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