The colors of pale and dark beers mainly arise from melanoidins, which are formed through the Maillard reaction. However, the melanoidins resulting from this reaction are complex and heterogeneous polymers. To enhance our understanding of the chemical aspects of beer color, we screened for lowmolecular-weight yellow pigments using HPLC with photo-diode-array detection. In this study, we isolated a yellow pigment from the neutral or lipophilic fraction of dark beer. This pigment was identified as xanthohumol through instrumental analyses. Xanthohumol, a component of hop resin, was found in dark beer at concentrations ranging from 0.07 to 0.47 mu g/mL, while pale beer contained only trace amounts. Using the color dilution method, we visually determined that xanthohumol contributed less than 0.1 % to the overall color of dark beer.
Matcha (MC) is a powdered green tea rich in polyphenols and catechins, although their extractability may be limited by the plant cell wall matrix. In this study, enzymatically hydrolyzed matcha (HMC) was prepared using viscozyme, and its polyphenol composition and antioxidant activities were evaluated. Total polyphenol content, total flavonoid content, and individual catechin profiles were quantitatively analyzed. Antioxidant capacity was assessed using DPPH, ABTS, and superoxide dismutase (SOD)-like activity assays. Cellular antioxidant effects were examined by measuring intracellular reactive oxygen species (ROS) levels and cell viability in hydrogen peroxide-treated SH-SY5Y cells. Compared with MC, HMC showed significantly higher levels of total polyphenols, flavonoids, and catechins, including epigallocatechin gallate. HMC also exhibited higher radical scavenging activity, increased SOD-like antioxidant activity, reduced intracellular ROS levels, and improved cell viability under oxidative stress conditions. These results indicate that viscozyme-assisted enzymatic treatment effectively enhances the antioxidant accessibility and cellular activity of MC.
This study evaluated the combined effects of three lactic acid bacterial strains and different thermal processing conditions (boiling at 100 degrees C for 15 min or autoclaving at 121 degrees C for 15 min) on the bioaccessibility of isoflavone aglycones and other forms in soymilk and fermented soymilk using an in vitro gastrointestinal digestion model. Autoclave treatment promoted the conversion of malonyl isoflavones to their glucoside forms, resulting in a higher glucoside content in autoclaved soymilk. Because Lactiplantibacillus plantarum TIG-0010 exhibited the highest beta-glucosidase activity, soymilk that was autoclaved and fermented with this strain showed a significantly higher aglycone content (292.6 nmol/g) than autoclaved soymilk (48.8 nmol/g) without fermentation. Gastrointestinal digestion results revealed lower digested amounts and bioaccessibility of aglycones than glucosides. Furthermore, two autoclave cycles (15 min at 121 degrees C per cycle) applied to soymilk fermented with L. plantarum TIG-0010 further enhanced both the digested amount and bioaccessibility of aglycone isoflavones.
This study aimed to develop a functional fermented tea beverage utilising Wuyi Rock Tea (WRT) stalks. Fermentation parameters were optimized using response surface methodology, yielding the following optimal conditions: tea stalks, 9 g/L; white sugar, 104 g/L; and dual-strain inoculum, 8 %. The resulting product achieved a sensory score of 84.7 and a total phenolic content of 519.13 mg gallic acid equivalents (GAE)/L. It exhibited strong antioxidant, hypoglycemic, and hypolipidemic activities, with a 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging rate of approximately 90 %, an alpha-glucosidase inhibition rate of 83.55 %, and a binding rate of approximately 68 %. Metagenomic analysis revealed that Gluconobacter oxydans dominated the early and late fermentation stages, whereas Starmerella bacillaris prevailed during the mid-stage. Efficient carbohydrate and amino acid metabolism by G. oxydans and S. bacillaris facilitated the synthesis and transformation of functional components. These findings provide a promising strategy for the high-value utilization of tea processing by-products.
Changes in the concentrations and quantities of radioactive cesium (137Cs) and inorganic elements in carrots grown in 137Cs-containing soil were investigated during sagohachi-zuke pickling. After pickling for 24 h, the concentrations of 137Cs and most of the measured inorganic elements increased, and their amounts were either unchanged or increased. Although dehydration by salt progressed during pickling, this finding might be attributed to no significant damage to the carrot's hard cell structure due to the osmotic action of salt at 24 h and practically no elution of solutes. Furthermore, we presumed that the transfer of elements from the pickling bed to the carrots depended on the relative concentration of the carrots and the solubilization of the pickling bed. The concentration and amount of only calcium decreased, which might be attributed to high levels of calcium in the cell wall/apoplast, and a low calcium concentration in the pickling bed.
