Agaricus bisporus Grown on Sustainable Peat Casing Alternatives—A Systematic Review on Quality Characteristics

Edible mushrooms are increasingly recognized for their high nutritional value and contribution to a healthy diet. Among them, Agaricus bisporus is the most commercially important species in Europe and North America. However, the environmental impact of traditional peat use in A. bisporus cultivation necessitates the development of sustainable alternatives, given the ecological significance of peatlands. When evaluating casing materials, it is essential to consider not only yield but also other critical factors influencing marketability, such as nutritional value, appearance, and texture. This systematic review examines seventeen studies published between 1989 and 2025 that investigated various peat substitutes while assessing a range of quality criteria. The findings were categorized into seven groups, encompassing both chemical composition and phenotypic characteristics of the fruiting bodies. Most studies focused on the organic and inorganic content of the fruiting bodies, followed by measurements of size and weight. Some alternative casings, for example, increased dry matter contents, which indicates a high solid substance content, such as of proteins or minerals. However, this was not always beneficial, as it could negatively affect texture. Overall, the reviewed studies demonstrate that different casing materials can directly influence quality parameters, and even minor adjustments in casing composition can enhance fruiting body quality.