Blueberry wine is popular among consumers due to its high nutritional value, appealing color, and potential health benefits. However, the instability of its color during the brewing process poses challenges for storage and the overall growth of the blueberry wine industry. This study found that vinylphenolic pyranoanthocyanins in blueberry wine provide a more stable color than their anthocyanin precursors. The presence of yeast with hydroxycinnamic acid decarboxylase (HCDC) enhances the formation of vinylphenolic pyranoanthocyanins. Metschnikowia pulcherrima Y4, isolated from decayed blueberry peels, promotes the production of six specific vinylphenolic pyranoanthocyanins in blueberry wine: malvidin-4-vinylcatechol, delphinidin-3-arabinoside-4-vinylcatechol, cyanidin-3-galactoside/glucoside (C3G)-4-vinylcatechol, cyanidin-3-O-arabinoside-4-vinylcatechol, malvidin-3-O-glucoside/galactoside-4-vinylcatechol, and C3G-4-vinylphenol. Blueberry wine fermented solely with M. pulcherrima Y4 exhibits a 25% increase in light stability under direct outdoor light conditions and a 19% increase in temperature stability at 60 °C compared to Saccharomyces cerevisiae K1. Furthermore, the use of M. pulcherrima Y4 in fermenting blueberry wine significantly decreases the time required to form vinylphenolic pyranoanthocyanins to eight days. Hence, M. pulcherrima Y4 is highly effective in accelerating the synthesis of these compounds, providing a valuable approach for improving the stability and color of blueberry wine.
Yang Shi-Xuan,Fan Zi-Yu,Zhang Feng-Yu,Li Si-Hao,Wu Yi-Xian
The random copolymers of isobutylene (IB) with polar comonomers of 4-acetoxystyrene (ACS) or 4- tert -butoxystyrene (TBO), P(IB- co -ACS) and P(IB- co -TBO), could be successfully synthesized via cationic copolymerization with FeCl 3 -based initiating system. The kinetics of the cationic copolymerization process was in situ investigated by inserting a diamond probe into the reaction system by ATR-FTIR spectroscopy. The chemical structure and incorporation content of polar comonomers in the copolymers were characterized by GPC with RI/UV dual detectors and 1 H-NMR spectroscopy. The corresponding functionalized random copolymers of IB with vinyl phenol P(IB- co -POH) carrying phenolic hydroxyl side groups could be further prepared via the complete hydrolysis of acetoxyl side groups in P(IB- co -ACS) or tert -butoxyl side groups in P(IB- co -TBO) copolymers. The functionalized P(IB- co -POH) copolymers became hydrophilic with water contact angle (WCA) of ca . 80° for the self-assembly in hot water, compared to the hydrophobic polyisobutylene with WCA of ca . 110°. The functionalized P(IB- co -POH) copolymers also displayed an excellent self-healing property due to the interaction of intermolecular hydrogen bonding and formation of three dimentional supramolecular networks from phenolic hydroxyl side groups. Furthermore, P(IB- co -POH) copolymers also provided a good matrix for the homogeneous dispersion for silica nanoparticles due to the formation of hydrogen bonding between copolymer chains and silica nanoparticles.
Yang Zhou,Lu Li,Lijun Jin,Jian Zhou,Zhiwei Shi,Yang Li,Haoquan Hu
Coal pyrolysis is generally considered to initiate by cleavage of weak covalent bonds bridged between aromatic rings. The C–C covalent bonds are predominant bridged linkages among the framework of coal, which have a critical influence on coal pyrolysis reaction but lack of direct online observation. Five representative coal-related model compounds containing C–C bridged bonds, polypropylene (PP), polyvinylpyrrolidone (PVP), poly-4-vinylpyridine (P4VP), polystyrene (PS) and poly-4-vinylphenol, were selected to pyrolyze in an in-situ pyrolysis vacuum ultraviolet photoionization mass spectrometry (Py-VUV-PIMS). The soft ionized mass spectral detection can provide product distribution and evolved information of original products and intermediates, which are the key evidence to understand the initiation, recombination and reaction routes during pyrolysis process. Online analysis of pyrolysis reaction was found to be priority with cracking of C–C bond in the five polymer samples, and homologous free radicals and original products, which mainly include monomers, dimers and their alkyl and alkenyl radicals, were detected. The results reveal the cleavage temperature of C–C covalent bond is deeply related to its chemical environment, and obvious conjugation effect and steric effect for the bridged linkage were observed. In addition, the effect of hydrogen bond was also observed during the pyrolysis of model compounds containing hydroxyl groups, and intramolecular or intermolecular hydrogen bonding reduced the temperature at which C–C bridged bonds break. The analogous fracture mode and pyrolysis behavior of coal-related model compounds, which are beneficial to understand the reaction route and mechanism of coal pyrolysis, were discussed based on the experimental observations and theoretical calculation.
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