The purpose of this study was to reveal the changes in total phenolic content and antioxidant capacity of broccoli, and an untargeted metabolomics approach was developed to investigate the effect of lactic acid bacteria fermentation on the metabolome of broccoli florets. The results showed that the total phenolic content and antioxidant capacity significantly increased after fermentation. The untargeted metabolite profile showed that the main chemical components of fermented and unfermented broccoli are lipids and lipid-like molecules, organic acids and derivatives and organoheterocyclic compounds. Univariate and multivariate statistical analyses of the identified metabolites showed some metabolites such as sorbitol are upregulated after fermentation, and that other metabolites such as l-malic acid are downregulated after fermentation. Moreover, metabolite pathway analyses were used to study the identification of subtle but significant changes among groups of related metabolites that cannot be observed with conventional approaches. KEGG pathway analysis showed that metabolites are mainly enriched in the glucagon signaling pathway, pyruvate metabolism, glycolysis/gluconeogenesis and fructose and mannose metabolism after fermentation, compared with raw broccoli. The results of this study can help to further our understanding of the impact of LAB fermentation on bioactivity changes in and the metabolites profile of fermented broccoli, and the application of fermented broccoli in health foods and special dietary foods.
In our previous study, a new fermented food (PWF) created by utilizing pineapple by-products and whey proteins as a matrix via co-fermentation with lactic acid bacteria and yeast was developed, and, in the current study, we examined the impact of a pineapple–whey protein fermentation product on a cefixime-induced dysbiosis model in mice using 16S sequencing and untargeted metabolomics techniques. The results indicated that the pineapple–whey protein fermentation product played a positive role in restoring the intestinal flora. In this study, cefixime reduced the overall abundance of intestinal flora and decreased the relative abundance of probiotics in the gut, while also inhibiting amino acid metabolism. The addition of PWF normalized the intestinal flora to a steady state, significantly increasing the populations of Weissella, Lactococcus, Faecalibaculum, and Bacteroides acidophilus, while decreasing the numbers of Akkermansia and Escherichia-Shigella. Additionally, PWF modulated microbial metabolites, such as L-glutamate and L-threonine, and upregulated amino-acid-related metabolic pathways, including those involving glycine, serine, and threonine. In conclusion, PWF can alleviate intestinal flora dysbiosis and metabolic disturbances induced by antibiotic interventions. It is suggested that PWF could be a potential dietary strategy for patients with antibiotic-associated diarrhea.
Biodegradable photodynamic antimicrobial hydrogel films have gained significant attention for food preservation. Konjac glucomannan (KGM) based hydrogels offer commendable biocompatibility and biodegradability but exhibit low antimicrobial activity. While curcumin (Cur) is widely incorporated into biodegradable antimicrobial packaging, it often compromises transparency and shortens the functional lifespan of hydrogel films. In this study, we report a biodegradable photosensitive film based on KGM, polyvinyl alcohol (PVA), D-sorbitol and Curcumin‑carbon dots (Cur-CDs). The water penetrating in the film show the Fick diffusion behavior, and biodegraded 27.90 % within 4 weeks. Cur-CDs enhanced hydrogen bonding between KGM and PVA, resulting in a smoother film surface, a 17.80° reduction in water contact angle, and a 24.91 % increase in transparency. Besides, the light stability of Cur-CDs in film was significantly enhanced. Accordingly, 1.74 × 104 CFU microbial colony was photodynamic eliminated when applied on pork preservation, showing the promising potential application in food preservation.
Skipjack tuna oil that is rich in polyunsaturated fatty acids, is prone to developing fishy odors under high-temperature or oxidative conditions. This study investigated the effects of four treatments—low-temperature thermal, low-concentration oxidation, high-concentration oxidation, and high-temperature thermal—on oxidation degree, volatile compounds, fatty acids, and sensory characteristics. GC–MS identified five key volatile compounds: hexadecanoic acid, ethyl ester; octadecanoic acid, ethyl ester; ethyl oleate; ethyl 9-hexadecenoate; and ethyl 6,9,12,15-octadecatetraenoate. Oxidation induction significantly increased peroxide value and acid value, primarily by generating aldehydes (e.g., hexanal, heptanal), which intensified fishy odors. In contrast, by GC-IMS analysis, higher concentrations of fishy odor markers, 1-octen-3-ol (0.48 ± 0.05 %), 2-ethylfuran-D (0.75 ± 0.01 %), and (E)-2-heptenal-D (0.08 ± 0 %) were found in the high temperature thermal group, showing a more pronounced impact of thermal induction on flavor dynamics than oxidative pathways. These findings elucidate the dual roles of oxidation and thermal degradation in fishy odor formation.