Changding Gao,Mei Yang,Yihan Liu,Yuhan Wang,Ligong Zhai,Jinlong Zhao,Yijun Liu,Baoshi Wang
The insoluble dietary fiber (IDF) of pomegranate peel residue was treated by mixed solid-state fermentation (SSF) of Aspergillus niger and Rhizopus oryzae. The content of bound polyphenols (BP) reached a maximum of 26.50 mg GAE/g DW after 5 days of fermentation, which was 3.22-fold higher than that of the unfermented group. The BP release during fermentation was strongly correlated with the activities of CMCase, xylanase and β-glucosidase. A total of 35 polyphenolic compounds and catabolic metabolites were identified, and potential biotransformation pathways were proposed. Structural characterization of IDF before and after fermentation via SEM, XRD, and TGA revealed that the degradation of cellulose and disruption of hemicellulose and hemicellulose–lignin complexes played a key role in BP release. Moreover, the postfermentation BP in vitro showed enhanced antioxidant capacity and pronounced inhibition of α-amylase/α-glucosidase. Collectively, the mixed SSF significantly promote the BP release, facilitating pomegranate peel valorization.
Han Wu,Hao-Nan Liu,Ai-Min Ma,Jian-Zhong Zhou,Xiu-Dong Xia
In this study, Lactobacillus plantarum strains, namely 70810, B1-6, and ZR were used to confirm the synergetic effects of co-inoculation with Lactobacillus and Rhizopus oryzae on whole-oat solid state fermentation (SSF). The results indicated that number of viable bacterial cells increased more quickly (10.72–11.23-fold higher) during co-inoculated SSF than that during pure Lactobacillus fermentation. Fungal ergosterol content reached slightly less during co-inoculation (137.04–155.12 mg/kg) than that during R. oryzae fermentation (193.64 mg/kg). However, compared to R. oryzae , R. oryzae combined with Lactobacillus produced more obvious hydrolysis of macromolecules and accelerated more water transformation from confined to free form. As for co-inoculated SSF of oat, the reducing sugar content reached the highest at 41.09–47.42 g/100g and then dropped, and free amino acid nitrogen content varied gradually until 40.66–41.67 mg/100g. Fermented oats (FOs) had higher total phenolic content than unfermented oat (UO) (2.56–2.72-fold, FO vs . UO), and their DPPH radical scavenging activity, ferric reducing capacity, and hydroxyl scavenging activity were increased 2.04-, 2.10-, and 1.99-fold at maximum (FO vs . UO), respectively. The Lactobacillus showed strain dependence during co-inoculated SSF, among which B1-6 displayed the best to enhance oat's overall quality.
危险品化学品经营许可证（带存储）