Jiasheng Lu,Yumeng Sui,Xin Liu,Jiawang Wang,Jiatong Li,Baohua Kong,Qian Chen,Weiwei Yang
The present study aimed to investigate the impact of 4,5-dihydroxy-2,3-pentanedione (DPD; 0, 300, 600, and 900 nmol/L), a crucial precursor in the LuxS/ AI-2 quorum sensing system, on flavour formation by Lactiplantibacillus plantarum HRB1 both in vitro and dry-sausage model. Firstly, L. plantarum HRB1 was selected from 18 strains of lactic acid bacteria due to its superior AI-2 and protease activity. In vitro , DPD significantly increased the activity of the AI-2 and the protease activity of L. plantarum HRB1. In the fermented dry-sausage, free amino acid content was significantly higher in the treatment with 600 nmol/L DPD compared to the other treatments. Notably, the dry sausage treated with 600 nmol/L DPD exhibited the highest concentrations of aldehydes (558.50 μg/kg), ketones (192.41 μg/kg), alcohols (1175.56 μg/kg), acids (202.27 μg/kg), esters (1504.48 μg/kg), and terpenes (1319.82 μg/kg). Sensory analysis revealed that the dry sausage treated with 600 nmol/L DPD had the most pronounced fermented and fatty odour. These results suggest that 600 nmol/L DPD enhances the flavour formation of L. plantarum HRB1. This research provides a theoretical foundation for utilizing the LuxS /AI-2 QS to optimize microbial fermentation processes and improve fermented food quality, especially flavour.
Ruilin Feng,Yanlong Qi,Shijun Liu,Long Cui,Quanquan Dai,Chenxi Bai
1,3-Pentadiene plays an extremely important role in the production of polymers and fine chemicals. Herein, the LaPO 4 catalyst exhibits excellent catalytic performance for the dehydration production of 1,3-pentadiene with 2,3-pentanediol, a C5 diol platform compound that can be easily obtained by hydrogenation of bio-based 2,3-pentanedione. The relationships of catalyst structure-acid/base properties-catalytic performance was established, and an acid-base synergy effect was disclosed for the on-purpose synthesis of 1,3-pentadiene. Thus, a balance between acid and base sites was required, and an optimized LaPO 4 with acid/base ratio of 2.63 afforded a yield of 1,3-pentadiene as high as 61.5% at atmospheric pressure. Notably, the Brønsted acid sites with weak or medium in LaPO 4 catalyst can inhibit the occurrence of pinacol rearrangement, resulting in higher 1,3-pentadiene production. In addition, the investigation on reaction pathways demonstrated that the E2 mechanism was dominant in this dehydration reaction, accompanied by the assistance of E1 and E1cb.
危险品化学品经营许可证（带存储）