Obesity is a global chronic disease epidemic that is attributed to the abnormal accumulation of lipids in adipose tissue. Astaxanthin (AST) from Haematococcus pluvialis, a natural carotenoid, exhibits antioxidant, anti-lipogenic, anti-diabetic and other potent effects. Herein, we evaluated the effect of AST to illuminate its efficacy and mechanisms in high-fat diet-fed mice. AST supplementation not only significantly decreased body weight and lipid droplet accumulation in the liver but also modulated liver function and serum lipid levels. Lipidomic analysis revealed that 13 lipids might be potential biomarkers responsible for the effects of AST in lipid reduction, such as total free fatty acids (FFAs), triacylglycerols (TGs) and cholesterol esters (CEs). The gut microbiota sequencing results indicated that AST alleviated HFD-induced gut microbiota dysbiosis by optimizing the ratio of Firmicutes to Bacteroides and inhibiting the abundance of obesity-related pathogenic microbiota while promoting the abundance of probiotics related to glucose and lipid metabolism. In addition, qRT-PCR demonstrated that AST could regulate the gene expressions of the AMPK/SREBP1c pathway by downregulating lipogenesis correlated-genes and upregulating the lipid oxidant related-gene. The present study revealed the new function of AST in regulating lipid metabolism, which provided a theoretical basis for the development of high-quality AST functional food and the application of diet active substances in obesity, as demonstrated in mice.

Root mustard is plentiful in vitamins and minerals but shrivels and molds easily. In this study, freshly harvested root mustard was fumigated with various concentrations of 1-Methycyclopropene(1-MCP) (1 µL L⁻¹, 1.5 µL L⁻¹, and 2.0 µL L⁻¹) for 24 h and stored at ambient temperature (17 ± 1 °C) for 35 d. Our data showed that 1-MCP fumigation had a striking preservation effect on maintaining weight loss, fruit firmness, lignin, Vc content, and moisture content, inhibiting respiratory intensity and ethylene release rate, as well as decreasing cell permeability and malondialdehyde (MDA) accumulation and maintaining cell membrane integrity of root mustard. In addition, lipoxygenase (LOX), pyruvate dehydrogenase (PDH), and polyphenol oxidase (PPO) activities were significantly reduced throughout the storage period. In contrast, the activities of succinate dehydrogenase (SDH), superoxide dismutase (SOD), ascorbate peroxidase (APX), phenylalanine deaminase (PAL), and peroxidase (POD) remained at high levels. Results showed that 1-MCP treatments were effective in maintaining the quality of root mustard, and the preservation effect of 1.0 μL·L⁻¹ 1-MCP was better than other concentrations of 1-MCP. This study could serve as a theoretical reference for root mustard preservation.

The yellowing of green broccoli is a phenomenon that indicates a serious deterioration of freshness. The green broccoli has been more popular than the yellow one, with its higher nutritional value. Chitosan coating has been employed in vegetables for green-keeping, owing to its functions of regulating chlorophyll metabolism and antioxidant defense. Furthermore, selenium was commonly utilized in the pre-harvest of fruit and vegetables as an antioxidant and chlorophyll regulator. However, there have not yet been concerns about the effects of selenium-chitosan on vegetable yellowing. This study first investigated the impact of selenium-chitosan on the quality of fresh-cut broccoli yellowing during storage by analyzing the chromatic aberration and phytochromes. Additionally, then, the gene expression related to chlorophyll metabolism (POR, CAO, HO, CHLI, NYC1), carotenoid metabolism (VDE, CCS, LCYE, ZEP, HYD), and transcription factors (NAC92, ZIPPER, bHLH66, APL, PIF4) were analyzed using the RT-qPCR technique. Test results showed that treatment with selenium-chitosan can slow down the reduction in h° (Hue angle values) and reduce ethylene release rate and respiration intensity. Via the molecular approach, it was further identified that this treatment could inhibit chlorophyll degradation and carotenoid biosynthesis, accompanied by lower expression levels of heme oxygenase (HO), chlorophyllide A oxygenase (CAO), violaxanthin de-epoxidase (VDE), β-carotene 3-hydroxylase (HYD), NAC92, basic leucine zipper (ZIPPER), bHLH66, PIF4 and APL, and higher expression levels of magnesium chelatase subunit I (CHLI) and lycopene ε-cyclase (LCYE) genes. This work can be used to explore the molecular mechanism of selenium-chitosan in inhibiting the yellowing of fresh-cut broccoli. This study will be of great economic importance in marketing and export by increasing the shelf life of fruits and vegetables.

This study aimed to investigate the impact of selenium (Se) treatment on the accumulation of reactive oxygen species (ROS) and the expressions of related genes in broccoli. To achieve this, one group of broccoli heads was treated with a selenite solution of 2 mg L⁻¹, while another group was soaked in distilled water, serving as the control. The effects of these treatments were evaluated by analyzing the browning, hydrogen peroxide (H₂O₂) and malondialdehyde (MDA) contents, enzyme activity, and gene expression levels of WARK and RBOH. Our results show that the Se treatment effectively inhibited H₂O₂ accumulation in the broccoli and reduced harmful MDA levels. The inhibition of ROS accumulation following the Se treatment was associated with enhanced activity of the CAT and SOD enzymes, increased expression levels of BoCAT and BoSOD, and decreased expression levels of the WRKY and RBOH transcription factors. Our study provides insights into the mechanism of action of selenium and its potential application in vegetable storage.

Maintaining the vibrant color of fruit is a longstanding challenge in fruit and vegetable preservation. Chitosan and selenium, known for their protective and antioxidant properties, have been applied to preserve these produce. This study aimed to investigate the influence of selenium–chitosan treatment (comprising 25 mg L⁻¹ selenium and 1.0% chitosan) on the color of “Red Globe” grapes and to analyze the relative expression of genes associated with anthocyanin synthesis enzymes (VvCHS, VvCHI, VvF3H, VvF3′H, VvF3′5′H, VvDFR, VvLDOX, VvUFGT, VvOMT, Vv5GT, and VvGST) using RT-qPCR. Our goal was to uncover the regulatory mechanisms governing grape color. Comparing various treatments, we observed that selenium–chitosan treatment had a significant effect in reducing decay, maintaining the soluble solids content of grape flesh, and preserving the vivid color of grape. This research indicated that selenium–chitosan treatment slowed down browning and prevented the reduction in total phenolic, flavonoids, and anthocyanin in the grape. Moreover, gene expression analysis revealed that selenium–chitosan treatment increased the expression of VvCHS, VvF3H, VvF’3′H, VvLDOX, and Vv5GT, while also stabilized the expression of VvCHI, VvF3′H, and VvDFR in grape skins. These findings shed light on the potential mechanism by which selenium–chitosan impacts grape color. This study established a theoretical foundation for investigating the molecular mechanisms behind selenium–chitosan’s ability to slow down grape browning and provides a novel approach to enhancing fruit and vegetable preservation techniques.