Trans-2-Hexenal-Based Antifungal Packaging to Extend the Shelf Life of Strawberries.

Raquel Heras-Mozos,María Monedero-Prieto,Ana Maria Tone,Rafael Gavara,Laura Higueras,Adrián García-Moreno,Pilar Hernández-Muñoz

doi:10.3390/foods10092166

Abstract

Strawberries are valuable because of their nutritional value, but they are also highly perishable fruits. Fungal decay is the overriding factor that alters the overall quality of fresh strawberries. Because no hygienic treatments to reduce the initial microbial load are feasible, molds develop during postharvest when using conventional packaging. In this study, an antifungal packaging system for strawberries was developed to improve safety and quality. Trans-2-hexenal (HXAL), a natural compound in strawberries, was incorporated into the modified atmosphere packaging (MAP) systems. Zero, 100, and 250 µL of HXAL were included in cellulosic pads and were covered with a polyamide coating to control its release. The pads were placed on the bottom of plastic trays; an amount of250 g of strawberries was added, flow packed in micro-perforated PP bags, and stored at 4 °C for 14 days. Fungal infection was monitored during the storage period, and the optical and textural properties of the strawberries were measured at days 0 and 14. Analysis of the package headspace was conducted to check for the HXAL concentration. HXAL was partially retained in the fruits and was converted into hexyl acetate and 2-hexen-1-ol acetate, but this was only measurably present in the headspace of the active systems. Mold growth was fully inhibited in active packaging although the strawberries were softer and darker than those in the control packages. The active package was not as efficient if the fruits were stored under thermal-abuse conditions (15 and 22 °C).

Highlights

The color, texture, freshness, and known nutritional value of berries are characteristics that make these fruits very appealing to consumers
Active packaging is a novel food processing technology in which the packaging system is actively involved in the improvement of the quality and safety of packaged goods
Some previous attempts to create active packaging systems applied on berries include the incorporation of diverse antimicrobial substances such as 2-nonanone [7], chitosan [8], bacteriocins [9], organic acids, or metabisulfites [10]

Summary

Introduction

The color, texture, freshness, and known nutritional value of berries are characteristics that make these fruits very appealing to consumers. Their postharvest preservation is difficult because berries present a fast metabolism and carry a microbiota that includes spoilage microorganisms that, in some berries such as strawberries, cannot be reduced by external washing because of an extremely sensitive surface. Several strategies to reduce postharvest losses have been attempted: (a) combinations of low temperature and headspace compositions rich in carbon dioxide have proven to reduce dehydration, respiration, and ethylene production rates [1], and (b) treatments with pulsed light or ultrasounds [2], (c) coating the fruit with edible polymers [3,4], or (d) the use of active packaging [5,6] have been proposed. None have suitably resolved strawberry postharvest fungal decay because of their low efficiency, the development of off-flavors, or their difficulty in industrial implementation

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Conclusion