Changes in Bioactive Compounds in Barley By-Products During Fermentation Process

Objectives This study investigated the effect of Pediococcus acidilactici LUHS29 fermentation on the bioactive compound profile of barley bran by-products. Materials and Methods Barley bran (BB) was obtained from Ustukiu Malunas Ltd (Pasvalys, Lithuania). The P. acidilactici strain, stored at -80°C, was cultured in an MRS medium supplemented with fructose- and maltose at 30°C for two days prior to use. Fermentation was performed using two conditions: solid-state fermentation (SSF) with a water content of 450 g/kg in the BB, and submerged fermentation (SMF) with a water content of 650 g/kg. Under both conditions, P. acidilactici constituted 3% of the total cereal/water blend, and fermentation proceeded for 72 hours at 32 ± 2°C. The study analyzed changes in various technological parameters during fermentation, including: crude protein (CP) and fat (CF), ash, dietary fiber, biogenic amines (BAs) and bioactive compounds, such as free amino acids, phenolic compounds (PC), fatty acids (FAs), lignans and alkylresorcinols (ARs). Results Fermentation, regardless of method, resulted in a decrease in both CP (by 25.8%) and CF (by 35.9%) and enhance DF content. Both SSF and SMF increased the concentration of various FAs (oleic, eicosadienoic, arachidic) in fermented BB. The control samples exhibited the highest BAs amount (290.6 mg/kg), with putrescine being the most abundant BA in BB. To achieve greater concentrations of the ARs C19:0, it is preferable to use SSF. After 24 hours of SSF, C19:0 amount increased by 75.9%. Vanillic acid levels increased by 18.9% in both SSF and SMF groups after 72 hours of fermentation, in compare with control samples. Additionally, p-hydroxybenzoic acid levels showed a more significant rise, increasing by 534.5% in SSF and 46.5% in SMF after the same time period. Conclusions The obtained results showed significant changes in the bioactive compound profile of BB following SSF and SMF, indicating its potential as a valuable resource for food, feed, and pharmaceutical applications.