Formation of Ethyl Carbamate during the Production Process of Cantonese Soy Sauce.

Kai Zhou,Zhenlin Xu,Francesca Patrignani,Yuanming Sun,Lorenzo Siroli,Rosalba Lanciotti

doi:10.3390/molecules24081474

Kai Zhou, Zhenlin Xu + Show 4 more

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https://doi.org/10.3390/molecules24081474

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Abstract

The aim of this work was to clarify the formation of ethyl carbamate (EC) and its influence factors throughout the production process of Cantonese soy sauce. The results showed that EC was not detected in the koji-making and early moromi fermentation stages, but started to be generated when pH of the moromi decreased to about 4.9—at the same time, the levels of ethanol, urea and citrulline increased significantly. Most EC was formed during raw soy sauce hot extraction (40.6%) and sterilization (42.9%) stages. The EC content exhibited the highest correlation with ethanol throughout the whole production process (R = 0.97). The simulation soy sauce produced in laboratory led the same conclusion—moreover, the contents of EC, ethanol and citrulline were higher in soy sauce fermented at 30 °C than in soy sauce fermented at 15 °C. Extraction of raw soy sauce by squeezing contributed little to EC formation. Further research showed that citrulline and ethanol led to significant increases in EC levels in raw soy sauce upon heating. These results indicate that ethanol and citrulline are two critical precursors of EC and that EC is mainly formed during the heat treatment stage of soy sauce.

Highlights

Soy sauce, an ancient condiment used for thousands of years, has long been one of the most popular seasonings in Asia
The aim of this study is to determine the content of Ethyl carbamate (EC) and its precursors during the whole production process of Cantonese soy sauce, in an effort to elucidate the critical EC accumulation stages and main precursors
The ethanol and urea in the moromi were first detected at day five

Summary

Introduction

An ancient condiment used for thousands of years, has long been one of the most popular seasonings in Asia. Its popularity in the Western world is growing dramatically due to its characteristic aroma and bioactive components [1]. This popular condiment tends to be contaminated by some harmful substances. Ethyl carbamate (EC), a byproduct that naturally forms in fermented foods, can cause tumors [2] and cell death [3]. This dangerous toxin was classified as a probable human carcinogen (Group 2A) by the International Agency for Research on Cancer (IARC) in 2007. Soy sauce has become the most remarkable source of EC exposure in some Asian countries due to its high consumption, especially among children [6,7]

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