Stable Nitrogen and Carbon Isotope Signatures (δ¹⁵N and δ¹³C Values in ‰) of Fresh and Preserved Button Mushrooms (Agaricus bisporus) from the German Market

Abstract

Fresh and preserved button mushrooms (Agaricus bisporus) are among the most consumed varieties worldwide. The cultivation is highly optimized and largely based on the use of different compost materials from agricultural wastes as substrates. In this study, we determined the stable carbon (¹³C) and nitrogen (¹⁵N) isotope signatures of the fruiting bodies and used the measured δ values (‰) to obtain indirect information on the medium on which they were grown. The δ¹³C values (‰) of the investigated fresh and processed button mushrooms from the German market were quite narrow (δ¹³C values −24.8 ± 0.9 ‰, n = 72), which indicated C₃ plant materials as carbon sources. Overall high δ¹⁵N values (δ¹⁵N values > 5.5 ‰) of the cultivated mushrooms enabled a differentiation to wild growing saprophytes. Furthermore, the broad range of δ¹⁵N values (Δ=7 ‰) pointed toward a cultivation on compost materials with varying shares of farmyard manure. While only few samples suggested a cultivation on dominantly plant-based substrates, more than 50% of the investigated button mushrooms were related to high shares of animal manures in the compost mixture. Little variation of δ¹⁵N values (‰) in related products collected on subsequent years indicated a high level of standardization of the individual cultivation processes over several years. Analysis of the carbon and nitrogen isotope signatures of cultivated button mushrooms could thus be valuable parameters used for long-term monitoring and controlling purposes.

Keywords:

• Button mushroom (Agaricus bisporus)
• stable isotope ratio mass spectrometry (IRMS)
• substrate materials

Conflicts of interest

The authors declare no competing financial interests.

Additional information

Funding

The project is supported by funds of the Federal Ministry of Food and Agriculture (BMEL) based on a decision of the Parliament of the Federal Republic of Germany via the Federal Office for Agriculture and Food (BLE) under the innovation support program.