Biopreservation of Hericium erinaceus By-Products via Lactic Acid Fermentation: Effects on Functional and Technological Properties.

Lactic acid fermentation is an effective strategy for food preservation and functional enhancement. This study evaluated the fermentation of Hericium erinaceus by-products using Lactoplantibacillus plantarum and Lactocaseibacillus rhamnosus, assessing microbial stability, physicochemical parameters, phenolic content, antioxidant activity, rheology, and biogenic amine formation over 240 h. Lp. plantarum promoted rapid acidification, reducing the pH from 6.0 to 4.65 within 72 h, while Ls. rhamnosus reached its lowest value of 3.8 at 144 h. Both strains effectively inhibited spoilage organisms: Lp. plantarum suppressed yeasts, molds, and Pseudomonas spp. by 144 h, whereas the control reached >6.0 log CFU/g of Pseudomonas at 240 h. Fermentation altered the texture, with the storage modulus (G') decreasing from ~17 kPa to <3 kPa. Functional enrichment was also observed, with total phenolic content increasing from 32 to 48 mg GAE/100 g and antioxidant activity (DPPH) reaching 2562 µmol TE/100 g compared with 1954 µmol TE/100 g in the control. Importantly, cadaverine accumulated to 70.3 mg/kg in the control but remained below 15 mg/kg in inoculated samples, while spermidine was consistently higher in Lp. plantarum-treated mushrooms (~45 mg/kg). These results demonstrate that lactic acid fermentation can transform perishable H. erinaceus by-products into safe, stable, and bioactive ingredients, supporting their application in functional foods, nutraceuticals, and clean-label products while contributing to circular bioeconomy goals.