Revealing the formation mechanisms of key flavors in fermented broad bean paste.

Pixian Douban (PXDB) is a popular Chinese condiment for its distinctive flavor. Broad bean fermentation (Meju) is the most important process in the formation of flavor substances. Key flavors were analyzed qualitatively and quantitatively, and metagenomic technology was applied to study the microbial diversity during broad bean fermentation.

HS-SPME-GC × GC/MS combined with multivariate statistics analysis to investigate the flavor formation mechanism of tank-fermented broad bean paste.

With the advancement of industrialization, tank fermentation technology is promising for Pixian broad bean paste. This study identified and analyzed the general physicochemical factors and volatile metabolites of fermented broad beans in a thermostatic fermenter. Headspace solid-phase microextraction (HS-SPME)-two-dimensional gas chromatography-mass spectrometry (GC × GC-MS) was applied to detect the volatile compounds in fermented broad beans, while metabolomics was used to explore their physicochemical characteristics and analyze the possible metabolic mechanism.

Sensory and Volatile Compounds Characteristics of the Sauce in Bean Paste Fish Treated with Ultra-High-Pressure and Representative Thermal Sterilization.

This study investigated the differences between three sterilized samples to reveal the unique aroma characteristics of the sauce in bean paste fish by multiple analysis methodologies. Samples were subjected to pasteurized (PS), high-temperature sterilization (HTS), and ultra-high-pressure treatment (UHP) tests. The UHP had a higher sensory evaluation and could better maintain the original flavor of the sample.

Insight into the protein degradation during the broad bean fermentation process.

Unlabelled: Broad bean fermentation is of vital importance in PixianDouban (PXDB) production, as well as a key process for microorganisms to degrade protein, which lays the foundation for the formation of PXDB flavor. In this study, two fungi and bacteria were screened, and their morphology, molecular biology, growth, and enzyme production characteristics were analyzed, and then they were applied to the broad bean fermentation simulation system. The protein, peptide, amino acid, amino nitrogen, and sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) in the system were evaluated.

Isolation, identification and characterization of taste peptides from fermented broad bean paste.

Pixian broad-bean paste (PBBP) is a famous fermented condiment in China, which may produce abundant flavor peptides during the fermentation process. Herein, the flavor peptides from fermented broad-bean (FB) were separated and identified ethanol precipitation, macroporous resin, and ultra-performance liquid chromatography quadrupole time-of-flight mass spectrometry (UPLC-QTOF-MS/MS) methods. The results showed that there were fifteen novel flavor peptides in FB.

Improving superamphiphobicity by mimicking tree-branch topography.

when a droplet impacts on a superhydrophobic structured surface below a certain impact velocity, the droplet can bounce off completely from the surface. However, above such velocity a fraction of the droplet will pin on the surface. Surfaces capable of repelling water droplets are ubiquitous in nature or have been artificially fabricated.

Fermentation characteristics of Pixian broad bean paste in closed system of gradient steady-state temperature field.

A closed system of gradient steady-state temperature field (GSTF) was constructed to ferment Pixian broad bean paste (PBP). The contents of physicochemical factors and organic acids in the fermentation under GSTF (FG) were closer to those in the traditional fermentation (TF). The taste intensities of 8 free amino acids in the FG were higher than those in the constant temperature fermentation (CTF), but 14 in the TF showed the highest among the processes of FG, CTF and TF.

Characterization of volatile compounds of Pixian Douban fermented in closed system of gradient steady-state temperature field.

As an essential flavor condiment in Sichuan cuisine, Pixian Douban (PXDB) is usually produced by open fermentation process in strip pools or ceramic vats. In this study, an experiment of PXDB fermentation was conducted for 90 days in a closed system of gradient steady-state temperature field (GSTF). To investigate the characterization of volatile compounds of PXDB in the closed system, the volatiles in three kinds of samples including samples of GSTF (SGT), samples of constant temperature (SCT), and samples of traditional fermentation (STF) were analyzed.

Dynamics and correlation of microbial community and flavor in Pixian Douban fermented with closed process of constant temperature.

Background: As a Chinese traditional flavor condiment, Pixian Douban (PXDB) is produced using a traditional open fermentation process. In this study, an experimental fermentation of PXDB was conducted at 40 °C for 90 days in a closed system, which has not been applied to PXDB production. The flavor, microbial community and correlations of the samples in the closed system were compared with those in the traditional fermentation.

An auto-inducible expression and high cell density fermentation of Beefy Meaty Peptide with Bacillus subtilis.

Currently, some cases about the expression of flavor peptides with microorganisms were reported owing to the obvious advantages of biological expression over traditional methods. However, beefy meaty peptide (BMP), the focus of umami peptides, has neither been concerned in its safe expression nor its overproduction in fermenter. In this study, multi-copy BMP (8BMP) was successfully auto-inducibly expressed and efficiently produced in Bacillus subtilis 168.

Oxidation of Chlorpromazine by Lipoxygenase Immobilized on Magnetic Fe3O4 Nanoparticles.

In this work, soybean lipoxygenase enzyme was immobilized on the magnetic Fe3O4 nanoparticles to oxidate chlorpromazine (CPZ). The physicochemical properties of the nanoparticles were characterized with transmission electronic microscopy (TEM), fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and thermal gravimetric analysis (TGA), and the magnetic properties were detected by a vibrating sample magnetometer (VSM). The TEM images indicated the surface and the size of the immobilized enzyme were much rougher and thicker than those of the naked particles.

Successful expression of the Bordetella petrii nitrile hydratase activator P14K and the unnecessary role of Ser115.

Background: The activator P14K is necessary for the activation of nitrile hydratase (NHase). However, it is hard to be expressed heterogeneously. Although an N-terminal strep tagged P14K could be successfully expressed from Pseudomonas putida, various strategies for the over-expression of P14K are needed to facilitate further application of NHase.

Estimates of minor ocean tide loading displacement and its impact on continuous GPS coordinate time series.

The site displacement due to ocean tidal loading is regarded as one of the largest uncertainties in precise geodetic positioning measurements, among which the effect of minor ocean tides (MOT), except for the 11 main tidal constituents, are sometimes neglected in routine precise global positioning system (GPS) data processing. We find that MOT can cause large vertical loading displacements with peak-to-peak variations reaching more than 8 mm at coastal/island stations. The impact of MOT on the 24-hour GPS solution is slightly larger than the magnitude of MOT loading itself, with peak-to-peak displacement variation at about 10 mm for the horizontal and 30 mm for the vertical components.