Chromosome-level genome of Thymus mandschuricus reveals molecular mechanism of aroma compounds biosynthesis.

Background: Thymus mandschuricus is an aromatic and medicinal plant with notable antibacterial and antioxidant properties. However, traditional breeding methods rely on phenotypic selection due to a lack of molecular resources. A high-quality reference genome is crucial for marker-assisted breeding, genome editing, and molecular genetics. Results: We utilized PacBio and Hi-C technologies to generate a high-quality chromosome-level reference genome for T. mandschuricus, with a size of 587.05 Mb and an N50 contig size of 8.41 Mb. The assembled genome contained 29,343 predicted protein-coding genes, and evidence of two distinct whole-genome duplications in T. mandschuricus was discovered. Comparative genomic analysis revealed rapid evolution of genes involved in phenylpropanoid biosynthesis and the CYP450 gene family in T. mandschuricus. Additionally, we reconstructed the gene families of terpenoid biosynthesis structural genes, such as TPS, BAHD, and CYP, and identified regulatory networks controlling the expression of aroma-synthesis genes by integrating transcriptome data from various organs and developmental stages. We discovered that hormones and transcription factors may collaborate in controlling aroma-synthesis gene expression. Conclusion: This study provides the first high-quality genome sequence and gene annotation for T. mandschuricus, an indigenous thyme species unique to China. The genome assembly and the comprehension of the genetic basis of fragrance synthesis acquired from this research could potentially serve as targets for future breeding programs and functional studies.

SAFE and SBSE combined with GC-MS and GC-O for characterization of flavor compounds in Zhizhonghe Wujiapi medicinal liquor.

Volatile compounds in Chinese Zhizhonghe Wujiapi (WJP) medicinal liquor were extracted by solvent-assisted flavor evaporation extraction (SAFE) and stir bar sorptive extraction (SBSE), respectively, and identified by gas chromatography-mass spectrometry. Results showed that a total of 123 volatile compounds (i.e., 108 by SAFE, 50 by SBSE, and 34 by both) including esters, alcohols, acids, aldehydes, ketones, heterocycles, terpenes and terpenoids, alkenes, phenols, and other compounds were identified, and 67 of them were confirmed as aroma-active compounds by the application of the aroma extract dilution analysis coupled with gas chromatography-olfactometry. After making a simulated reconstitute by mixing 41 characterized aroma-active compounds (odor activity values ≥1) based on their concentrations, the aroma profile of the reconstitute showed good similarity to that of the original WJP liquor. Omission test further corroborated 34 key aroma-active compounds in the WJP liquor. The study of WJP liquor is expected to provide some insights into the characterization of special volatile components in traditional Chinese medicine liquors for the purpose of quality improvement and aroma optimization.

Effects of superfine grinding on asparagus pomace. Part I: Changes on physicochemical and functional properties.

The effects of superfine grinding on the physicochemical and functional properties of asparagus pomace were investigated. The results showed that in terms of the specific surface area, water solubility, soluble dietary fiber content, and ratio of insoluble dietary fiber to soluble dietary fiber, finer samples usually possessed better physicochemical properties compared with coarse samples. However, grinding samples excessively to produce small particle sizes could reduce the water-holding capacity, oil-binding capacity, and swelling capacity. In addition, the extraction of both free and bound phenolics in asparagus pomace powder samples and the samples' absorption of both nitrite ion and glucose showed typical bell-shaped curves, demonstrating that superfine grinding could significantly impact the various properties of asparagus pomace. This study should provide insights into the effect of micronization on the functionalities of fiber-rich food materials. PRACTICAL APPLICATION: This article deals with the effects of superfine grinding on the physicochemical and functional properties of asparagus pomace. The results showed that the properties of asparagus pomace did not always improve gradually with decreasing particle size. With a decrease in granularity, some parameters showed a bell-shaped curve whereas others initially increased and then stabilized, indicating that in actual production, the crushing particle size should be determined according to actual needs or target parameters.

Anti-fatigue activity of polysaccharide fractions from Lepidium meyenii Walp. (maca).

The two fractions of polysaccharide MPS-1 and MPS-2 were extracted from Lepidium meyenii Walp. (maca) by water, and purified using a DEAE-52 and a Sephadex G-100 column. The molecular weight (MW) of MPS-1 was 7.6kDa, and the MW of MPS-2 was 6.7kDa. The MPS-1 was composed of xylose, arabinose, galactose and glucose, with the mole ratio 1:1.7:3.3:30.5; the MPS-2 was composed of arabinose, galactose and glucose, with the mole ratio 1:1.3:36.8. The IR spectrum implied that only α-pyranose existed in MPS-1, and both α-pyranose and ß-pyranose existed in MPS-2. The anti-fatigue activities of MPS-1 and MPS-2 were measured by the forced swimming test, along with the determination of blood lactate (BLA), urea nitrogen (BUN), lactic dehydrogenase (LDH) activity and liver glycogen (LG). The results indicated that both MPS-1 and MPS-2 presented dose-dependently positive effects on the fatigue related parameters. Additionally, MPS-2 has a better anti-fatigue effect than MPS-1.