Quantification of Morpholine in Peel and Pulp of Apples and Oranges by Gas Chromatography-Mass Spectrometry.

Kunho An,Joon-Kwan Moon,Hee-Jae Suh,Chan Lee,Jihyun Lee,Inhwan Kim

doi:10.3390/foods9060746

Kunho An, Joon-Kwan Moon + Show 4 more

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https://doi.org/10.3390/foods9060746

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Abstract

Morpholine salts of fatty acids have been used in wax coatings on the surfaces of fruit and vegetable commodities in China and the United States, etc. However, morpholine usage was prohibited in many other countries because of safety concerns. We optimized analytical methods to determine morpholine in the peel and pulp of fruits and vegetables by gas chromatography-mass spectrometry (GC-MS). This morpholine analysis method was applied to real samples of apples, citrus fruits, and vegetables from Korea, China, and the U.S. The method was validated using apple and citrus fruit peels and pulp. The method detection limit (MDL) was 1.3–3.3 µg/kg. The recovery rates of morpholine were 88.6–107.2% over a fortified level of 10–400 µg/kg. Intra-day and inter-day precisions were 1.4–9.4% and 1.5–2.8%, respectively. The morpholine concentrations were n.d. (not detected)–11.19 and n.d. (not detected)–12.82 µg/kg in apple and citrus peels, respectively. Morpholine was not detected in citrus or apple pulp samples or in vegetable samples.

Highlights

Wax coating is applied to fruits and vegetables before shipping them over long distances.This reduces the quality loss of fruits and vegetables between harvest and consumption by retaining moisture and preventing weight loss
Active compounds such as ascorbic acid, malic acid, calcium chloride, calcium lactate, citric acid, and glutathione are often incorporated in the formulations of edible wax coating matrix of apple fruits to improve shelf life [2]
We developed a method for analyzing morpholine in the peel and pulp of fruits using gas chromatography-mass spectrometry (GC-MS) for the first time

Summary

Introduction

Wax coating is applied to fruits and vegetables before shipping them over long distances. This reduces the quality loss of fruits and vegetables between harvest and consumption by retaining moisture and preventing weight loss. The wax coating is difficult to remove by typical washing of fruits and vegetables; wax coatings can be absorbed in the body without degradation [1] Active compounds such as ascorbic acid, malic acid, calcium chloride, calcium lactate, citric acid, and glutathione are often incorporated in the formulations of edible wax coating matrix (e.g., apple puree/pectin alginate, whey protein concentrates, alginate/apple puree, whey protein concentrates, and beeswax, etc.) of apple fruits to improve shelf life [2]. Morpholine has been added to the wax coating applied thinly and evenly to the fruit and vegetable surface [7]

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