Cuticular Wax Composition of Wild and Cultivated Northern Berries.

Linards Klavins,Maris Klavins

doi:10.3390/foods9050587

Abstract

The outer-most layer of plant surface, the cuticle, consists of epi- and intra-cuticular wax. It protects the plant from dehydration, extreme temperatures and UV radiation, as well as attacks from pests such as molds and bacteria. Berry cuticular waxes are studied to understand the metabolism character (factors affecting wax layer composition in different berry species) and increase the microbial resistance and shelf life of berries. The aim of this study was analysis of the surface wax composition of nine species of wild and cultivated berries from Northern Europe. Cuticular wax analysis were done using gas chromatography-mass spectrometry. A total of 59 different compounds were identified belonging to nine groups of compounds, namely, alkanes, phytosterols, alcohols, fatty acids, phenolic acids, ketones, aldehydes, esters and tocopherols. The analyzed blueberries had the highest amount of wax present on their surface (0.9 mg berry−1), triterpenoids were the main wax constituent in these berries, with up to 62% wax composition. Berry species and varieties were compared based on their surface wax composition—similarities were found between different blueberry varieties; however, other berries showed differences based on concentration and composition of cuticular wax.

Highlights

Plant interaction with biotic and abiotic factors is largely dependent on the plant cuticular waxes, which act as an interface between the plant and the environment
The identified groups of compounds can be used to distinguish the analyzed berry species and varieties from one another further of the studied compounds; Principal components analysis (PCA) was Triterpenoids, alcoholstoand fattyinvestigate acids were the the specificity main compounds identified in the cuticular wax done fatty acid berry
The data on blueberry varieties, when plotted separately, and aldehydes, which are attributed with protective ability against environmental or pathogen-induced stress, were identified as part of the cuticular wax

Summary

Introduction

Plant interaction with biotic and abiotic factors is largely dependent on the plant cuticular waxes, which act as an interface between the plant and the environment. The outermost layer of plant organs—the cuticle, which consist of epi- and intra-cuticular waxes (combined—cuticular wax)—protects the plant from abiotic stresses such as dehydration, extreme temperatures (frost, heat) and other factors presented by long-term environmental changes, like increase in the minimum/maximum temperature or disturbances in the precipitation regime in the growth area. Cuticular wax is a complex mixture; it contains various aliphatic and aromatic compounds. Plant waxes consist of low- to intermediate-polarity compounds, they are hydrophobic, long-chain (chain length from C12 up to C70) chemical compounds [2]. The main compound classes found in the wax are n-alkanes, fatty acids, primary alcohols, aldehydes, secondary alcohols, ketones, phytosterols and esters

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