Systematic comparison of the effects of exogenous inorganic selenium and organic selenium on the quality and antioxidant capacity of Pleurotus eryngii

Authors: ZHOU, FEI - Northwest A&f University; QI, MINGXING - Northwest A&f University; REN, RONGXIN - Northwest A&f University; SHI, JINGYI - Northwest A&f University; ZHAO, WANCHEN - Northwest A&f University; WU, HAO - Northwest A&f University; Banuelos, Gary; LIANG, DONGLI - Northwest A&f University

Submitted to: Journal of the Science of Food and Agriculture
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/23/2025
Publication Date: 5/5/2025
Citation: Zhou, F., Qi, M., Ren, R., Shi, J., Zhao, W., Wu, H., Banuelos, G.S., Liang, D. 2025. Systematic comparison of the effects of exogenous inorganic selenium and organic selenium on the quality and antioxidant capacity of Pleurotus eryngii. Journal of the Science of Food and Agriculture. Article 10970010. https://doi.org/10.1002/jsfa.14346.
DOI: https://doi.org/10.1002/jsfa.14346

Interpretive Summary: Selenium (Se) is an essential micronutrient for humans and animals. Food crops are a fundamental source of Se and consequently play a vital role for Se intake in humans. Plant Se content is, however, dependent on soil Se levels. In this regard, the distribution of soil Se is extremely uneven worldwide and is strongly influenced by geological factors and human activities. About two-thirds of the world's soil is deficient in Se, and the Se uptake ability of different plants varies greatly, leading to 15% of the population facing Se deficiency. Producing Se-enriched agricultural products through biofortification strategies may be a safe and effective way to improve human Se nutrition status. Among different crops used for Se biofortification, the mushroom is a viable candidate because of its high nutritional value and strong ability to accumulate and modify different forms of Se applied in this strategy. In this study, we compared the effects and different application rates of inorganic and organic Se (Se-enriched yeast), respectively, on the nutritional quality and Se concentrations in the mushroom. Results showed that all forms of applied Se increased crude protein content in the mushroom. Compared to inorganic Se treatments, organic Se most effectively enhanced both Se and other nutrient element accumulation and antioxidant capacity of the mushroom. Compared to inorganic Se, Se-enriched yeast was the optimal Se source for enhancing the nutritional quality of the mushroom by increasing crude protein content, Se and nutrient element concentrations, and antioxidant capacity. These findings confirm that Se-enriched yeast can be considered an optimal source for Se application to improve the nutritional quality and Se content in mushroom produced from Se biofortification strategies.

Technical Abstract: Selenium (Se) is an essential micronutrient for humans and animals. Soil Se is the fundamental source of Se in food crops and, consequently, for Se intake in humans. Because over 1 billion people worldwide experience some form of Se deficiency, Se biofortification strategies have been developed by applying exogenous forms of inorganic Se (selenite, selenate) or organic forms of Se (selenomethionine) onto edible crops. One edible food crop under consideration for Se biofortification is the mushroom (Pleurotus eryngii). However, the effects of the application of inorganic Se and organic Se on the accumulation of Se, nutritional quality and antioxidant activity of P. eryngii fruit body have not been systematically studied. Therefore, the objectives of this study were as follows: (i) compare the effects of exogenous inorganic Se and organic Se on the quality and nutrient element concentrations in the P. eryngii fruit bodies; (ii) explore selenium’s effects on the antioxidant capacity of P. eryngii fruit body extracts; and (iii) And (iii) evaluate the relationship between the species and application rates of exogenous Se and the nutritional value of the P. eryngii fruit bodies. In this study, Pleurotus eryngii cultivation substrates with Se concentrations were prepared by adding different dosages (0.5, 1, 2.5, and 5 mg'kg-1 fresh weight) of sodium selenite, sodium selenate, and Se-enriched yeast (Saccharomyces cerevisiae, source of selenomethionine). After being completely colonized by mycelium, the substrates were incubated at 15–18°C with 80–90% humidity for 90 days. Mature fruit bodies of P. eryngii (averaging 100 ± 10 g fresh weight per specimen) were collected, immediately weighed, lyophilized, and homogenized into fine powder using a cryogenic grinder. The contents of crude protein, crude fiber, crude polysaccharide, concentrations of Se and other nutrient elements, as well as the antioxidant capacity of the P. eryngii fruit bodies were determined. Results showed that the fruit bodies absorbed and utilized Se more effectively from Se-enriched yeast than Na2SeO4 but less than Na2SeO3. Organic Se was superior to inorganic forms (Na2SeO4 and Na2SeO3), significantly increasing Se, Zn, Mg, and Ca accumulation, as well as crude protein and phenolic content, which collectively improve antioxidant capacity. Selenium concentrations ranged from 1.71 to 17.65 mg kg-1 across treatments and exhibited dose-dependent increases. The total phenolic content in fruit body extracts was as follows with Se treatments: control [62.27 mg GAE kg-1 dry weight (DW)], selenate (69.47–71.07 mg GAE kg-1 DW) and Se-enriched yeast (69.35–70.08 mg GAE kg-1 DW)-all significantly increased total phenolic content (P < 0.05), whereas selenite (63.27–63.89 mg GAE kg-1 DW) showed no significant effect. Our results clearly show that organic Se was the most efficient source of Se to use for cultivating mushrooms in a Se biofortification strategy. Not only did organic Se result in an increase in the Se concentration but it also enhanced protein content, antioxidant capacity and accumulation of other essential nutrients.