Pickling is one of the methods for preserving food. However, this term may refer to both types of products, that is, to those subjected to lactic acid fermentation and to marinated ones (acidified) that are usually produced by the addition of acetic acid. Various raw materials are subjected to lactic acid fermentation (vegetable and animal origin), which yields food products with high nutritional and dietary value. In many regions of the world, the process of lactic fermentation is also traditionally used to preserve fruiting bodies of edible mushrooms. Mushrooms are appreciated for their organoleptic qualities as well as the presence of many different bioactive substances exhibiting healing and health‐promoting properties. This article reviews the literature related to the use of lactic fermentation in the process of mushroom preservation. Particular attention has been paid to the aspects of the technological process and its impact on the quality and suitability of the final products. Moreover, research results concerning the influence of lactic fermentation on chemical and physical changes in fruiting bodies of edible fungi are also presented.

The aim of the study was to assess changes in the basic quality parameters induced by controlled lactic fermentation of fruiting bodies of the button mushroom (Agaricus bisporus). Lactiplantibacillus plantarum 299v with documented probiotic properties and L. plantarum EK3, i.e., an isolate obtained from spontaneously fermented button mushrooms, were used as starter strains. The fruiting bodies of fresh, blanched, and fermented mushrooms were analyzed at different stages of the lactic fermentation process. The content of free sugars (high-performance liquid chromatography with charged aerosol detector method; HPLC-CAD) and organic acids (high-performance liquid chromatography with diode array detector method; HPLC-DAD) was determined both in the mushroom fruiting bodies and in the brine. Five free sugars (ribose, trehalose, sucrose, glucose, and fructose), mannitol, and six organic acids (lactic, malic, succinic, citric, acetic, and fumaric acids) were detected in the samples. Lactic acid dominated in the final products. The starter cultures exhibited varying degrees of utilization of available mushroom sugars and sucrose used as an additional substrate. Sucrose was utilized at a higher rate and in greater amounts by the L. plantarum EK3 isolate. This starter culture was characterized by a significantly higher final amount of produced lactic acid, a lower pH value, and higher numbers of LAB (lactic acid bacteria). These important quality parameters largely determine the stability of fermented products. Based on the analysis results and the high scores in the organoleptic evaluation of the fermented mushrooms, the L. plantarum EK3 isolate can be recommended as an appropriate starter culture for lactic fermentation of mushroom fruiting bodies.

Refractive index detector is usually used in the analysis of sugars in mushrooms, which is characterized by poor sensitivity, reproducibility, and susceptibility to interference from co-eluting sample components. In the current study, identification and determination of free sugars in mushroom samples by high-performance liquid chromatography coupled to corona charged aerosol detector (HPLC-CAD) were presented for the first time. The best chromatographic separation was performed on a Shodex Asahipak NH2P-50 4E 5 μm and mobile phase composed of 75% acetonitrile and 25% water with flow rate was 1 mL/min. The developed method offers good linearity in concentration range 0.001–0.01 or 0.01–0.2 mg/mL for tested compounds with R² > 0.99. Limit of detection (LOD) for analytes was in the range of 7.1–120.2 ng on column. HPLC-CAD method showed very good reproducibility (RSD < 5.1%). Fructose, mannitol, and glucose were detected in all examined mushroom samples. For white Agaricus bisporus, mannitol was the most abundant sugar (7.575 mg/g dw), whereas trehalose for Pleurotus ostreatus (3.426 mg/g dw). The developed method was successfully applied for quantification of free sugars and mannitol in mushrooms. The optimized method proved to be sensitive, reproducible, and accurate.

The paper discusses the influence of the addition of freeze-dried tomatoes on the chemical composition and selected physical properties of extruded corn snacks. Corn grits were replaced with dried tomatoes in the amount from 5 to 30% of corn mass. The total lycopene and phenolic content, the scavenging ability and the ferric reducing antioxidant power were determined along with the content of neochlorogenic, chlorogenic, p-coumaric acids and rutin. Also evaluated were selected physical properties, colour and the sensory profile of corn snacks enriched with tomatoes. A greater tomato addition increased the volume of bioactive compounds, especially the total phenolic content. Snacks enriched with tomato exhibited a lower expansion ratio, water absorption and solubility indices, lightness and sensory characteristics but higher density, hardness and redness than corn snacks. Powdered tomato seems to be a functional additive with the high content of biologically-active compounds, and the enriched snacks displayed good physical properties if the tomato level did not exceed 20%. A higher amount of the additive significantly lowered the expansion as well as increased the hardness of snacks. Still, the corn products with 25 and 30% of powdered tomato were more valuable due to their much higher level of bioactive components compared with the regular corn snacks.

In this study 6 species of wild edible mushrooms were evaluated in terms of their total phenolic content and antioxidant activity using 1,1-diphenyl-2-picrylhydrazyl radical and ferric reducing antioxidant power assay methods. The mushrooms, namely Armillaria mellea, Cantharellus cibarius, Lactarius deliciosus, Leccinum aurantiacum, Suillus luteus, and Boletus badius, were dried using both freeze drying and convection drying at 50°C. The amounts of phenolic compounds varied from 3.0 ± 0.1 to 12.8 ± 0.4 mg gallic acid equivalents/g dry weight (for water extracts) and from 2.4 ± 0.1 to 11 ± 0.5 mg gallic acid equivalents/g dry weight (for ethanolic extracts). The species that presented the highest antioxidant potential were B. badius and S. luteus. The impact of hot-air drying on the antioxidant activity of water and ethanolic extracts was evaluated. We demonstrated that hot-air drying may have either a negative or positive influence on phenolics and antioxidant activity, depending on the mushroom species. However, a negative effect was more frequent.