Changes in Lacto-Fermented Agaricus bisporus (White and Brown Varieties) Mushroom Characteristics, including Biogenic Amine and Volatile Compound Formation

This study aimed to evaluate the changes in Agaricus bisporus (white and brown) characteristics (colour and acidity parameters, lactic acid bacteria (LAB) and mould/yeast counts, biogenic amine content, fatty acid (FA) and volatile compound (VC) profiles, overall acceptability, and emotions induced for consumers) during a 48 h lactic acid fermentation with Lacticaseibacillus casei No. 210, Lactiplantibacillus plantarum No. 135, Lacticaseibacillus paracasei No. 244, and Pediococcus acidilactici No. 29 strains. Fermented white and brown A. bisporus showed higher LAB count and lower pH, lightness, redness, and yellowness than non-fermented ones. Yeast and fungi counts were similar between non-fermented and fermented samples. All samples contained spermidine (on average, 191.5 mg/kg) and some of the fermented samples had tyramine (on average, 80.7 mg/kg). Saturated FA was the highest in non-fermented brown A. bisporus. The highest monounsaturated and polyunsaturated FA contents were found in Lp. plantarum No. 135 fermented white and brown A. bisporus, respectively. For the first time, the VC profile of fermented A. bisporus was analysed. 1-Octen-3-ol content significantly decreased while benzyl alcohol, acetoin, and 2,3-butanediol increased in most fermented samples. Fermented A. bisporus received good acceptability scores. The emotional evaluation showed that the LAB strain and the interaction of the LAB strain and A. bisporus variety were significant on the intensity of emotions "happy" and "sad", while all analysed factors and their interactions were significant on the intensity of "angry" and "disgusted" (p ≤ 0.05). The findings of this study show the potential of the selected LAB strains and contribute to the increasing body of research on fermented mushrooms.