Evaluation of Sensory and Functional Compounds in Fermented Lactarius deliciosus Mushrooms

The effects of pretreatment and the addition of probiotic bacteria on the functional properties of fermented Lactarius deliciosus mushrooms were analyzed. Caps of L. deliciosus were blanched in water for 30 or 120 s (both at 96°C–98°C) or blanched in the microwave for 2 min (power 1000 W) as a pretreatment and fermented at 21°C and 26°C until pH ≤ 4.5 as a mark of successful fermentation. Lactobacillus acidophilus strain LA-5 (Hansen) or Lactiplantibacillus plantarum strain SWA016 (Swanson) was added to the products to enrich the probiotic content. The type of pretreatment had a greater impact on the content of bioactive compounds in the products than fermentation temperature or the added probiotic bacteria. After fermentation, the pH of all products was below 4.5. Total dietary fiber (TDF) ranged from 45.74 ± 1.48 to 68.88 ± 2.84 g/100 g dm, and the highest content of TDF was observed in mushrooms blanched in water for 2 min. Beta-glucans accounted for 30%–60% of TDF; mushrooms blanched in water for 30 s had the highest content of beta-glucans (17.49 ± 0.46 to 30.38 ± 0.26 g/100 g dm) and phenolic compounds (1126.7 ± 52.2 to 1613.1 ± 40.4 mg/100 g dm), while microwave-blanched mushrooms had the highest vitamin B₁ (1.50 ± 0.08 to 2.78 ± 0.15 mg/100 g dm) and B₂ (4.24 ± 0.38 to 7.58 ± 0.11 mg/100 g dm) contents. Water-blanched mushrooms for 2 min scored the highest in the overall organoleptic analysis, and products with L. acidophilus strain LA-5 (Hansen) were regarded as the most unfavorable. This study shows that fermented L. deliciosus exhibits nutraceutical properties and can be used in designing functional foods.