Natural aromatic extract of black tea improved the water retention of pork meat batter.

The effect of varying proportions (w/w) of natural aromatic extract of black tea (NAEBT) with pre-emulsification on the water-holding capacity (WHC) of pork meat batter was investigated. The addition of NAEBT significantly reduced the cooking loss (CL) of pork meat batter from 23.95 % to 18.30 % (P < 0.05). Furthermore, NAEBT with pre-emulsification significantly improved the color stability and increased the springiness (P < 0.05). The results of TBARS and carbonyls indicated that NAEBT with pre-emulsification significantly alleviated oxidative damage to proteins (P < 0.05), resulting in an increased level of ß-sheet (P < 0.05), as confirmed by FT-IR analysis. As a result, the water mobility of pork meat batter was restricted (P < 0.05), resulting in an increase in the energy storage modulus (P < 0.05) and a decrease in the pore size. In summary, the WHC of pork meat batter was improved by the antioxidant effect of the NAEBT.

Intermolecular copigmentation of anthocyanins with phenolic compounds improves color stability in the model and real blueberry fermented beverage.

To improve the color stability of anthocyanins (ACNs) in blueberry fermented beverage, the intermolecular copigmentation between ACNs and 3 different phenolic compounds, including (-)-epigallocatechin gallate (EGCG), ferulic acid (FA), and gallic acid (GA) as copigments, was compared in the model and the real blueberry fermented beverage, respectively. The copigmented ACNs by EGCG presented a high absorbance (0.34 a.u.) and redness (27.09 ± 0.17) in the model blueberry fermented beverage. The copigmentation by the participation of the 3 different phenolic compounds showed all a spontaneous exothermic reaction, and the Gibbs free energy (ΔG°) of the system was lowest (-5.90 kJ/mol) using EGCG as copigment. Furthermore, the molecular docking model verified that binary complexes formed between ACNs and copigments by hydrogen bonds and π-π stacking. There was a high absorbance (1.02 a.u.), percentage polymeric color (PC%, 68.3 %), and good color saturation (C*ab, 43.28) in the real blueberry fermented beverage aged for 90 days, and more malvidin-3-O-glucoside had been preserved in the wine using EGCG as copigment. This finding may guide future industrial production of blueberry fermented beverage with improved color.

Dynamics changes in metabolites and pancreatic lipase inhibitory ability of instant dark tea during liquid-state fermentation by Aspergillus niger.

Instant dark tea (IDT), prepared by liquid-state fermentation using Aspergillus niger, is known for its high theabrownins content and lipid-lowering effect. To explore the impact of fungal fermentation on IDT compositions and its pancreatic lipase inhibitory ability (PLIA), untargeted and targeted metabolomic analysis were applied to track the changes of metabolites over a 9-day fermentation period, and correlation analysis was then conducted between metabolites and PLIA of IDT. There were 54 differential metabolites exhibited significant changes from day 3 to day 5 of fermentation. The concentrations of theabrownins and caffeine increased during fermentation, while phenols and free amino acids decreased. The PLIA of IDT samples significantly increased from day 5 to day 9 of fermentation. Theabrownins not only positively correlated with the PLIA but also exhibited a high inhibition rate. These findings provide a theoretical basis to optimize the production of IDT as functional food ingredient.

Revealing the variances in color formation and bioactivities of seven catechin monomers throughout the enzymatic reaction by colorimetric and mass spectrometry.

The capacity differences of seven catechin monomers to produce colors after treating with catechin-free extract were investigated. After 240-min reaction, only (-)-epicatechin (EC) and (+)-catechin (C) presented obvious luminous red color with L* values of 63.32-71.73, a* values of 37.13-46.44, and b* values of 65.64-69.99. Meanwhile, the decrease rate of EC and C was 43.52 %-50.35 %, which were significantly lower than those of other catechin monomers (85.91 %-100 %). The oxidized products of catechin monomers were analyzed by ultra-high performance liquid chromatography-quadrupole-time of flight-mass spectrometry coupled with diode array detector, wherein dehydro-dimers and -trimers (oxidative coupling products of catechins' A-B ring) were found to be the major chromogenic compounds of EC and C. Additionally, the antioxidant capacity of catechin monomers only decreased after 30-min reaction, while along with further enzymatic reaction, catechin monomers presented comparable oxyradical scavenging ability (e.g., the DPPH inhibitory rates of catechin monomers were in the range of 24.42 %-50.77 %) to vitamin C (positive control, DPPH inhibitory rate was 27.66 %). Meanwhile, the inhibitory effects of most catechin monomers on α-glucosidase were enhanced in different degrees. These results provided basis for the development of enzymatically-oxidized catechin monomers as functional food color additives.

Enhancement of ester biosynthesis in blueberry wines through co-fermentation via cell-cell contact between Torulaspora delbrueckii and Saccharomyces cerevisiae.

This study investigated the effects of co-fermentation of T. delbrueckii and S. cerevisiae on the volatile composition and sensory characteristics of blueberry wines. Mixed fermentation led to higher levels of terpenes, higher alcohols, and esters compared to wines fermented with each yeast individually. Conversely, when T. delbrueckii were physically separated from S. cerevisiae in the double-compartment fermenter, contrasting outcomes emerged. The stronger fruity aroma induced by mixed fermentation were linked to higher ester concentrations, including isoamyl acetate, ethyl isovalerate, ethyl hexanoate, and diethyl succinate. The enhanced esters in mixed fermentation can be attributed to the upregulated alcohol acyltransferase activity and the expressions of ACC1, FAS2, ELO1 and ATF1 genes in late fermentation stage via the cell-cell contact between T. delbrueckii and S. cerevisiae. These findings can deepen the understanding of the interaction between non-Saccharomyces and S. cerevisiae in ester production, assisting wineries in effectively controlling wine aroma through mixed fermentations.

Enhancing blueberry wine aroma: Insights from cultivar selection and berry sorting.

This study aimed to improve the aroma quality of blueberry wine by employing cultivar selection and precise berry sorting. We conducted a comprehensive analysis of volatile profiles in blueberry wines derived from nine cultivars commonly cultivated in the middle region of China. 'Misty' and 'V3' blueberry wines exhibited pronounced floral aromas, closely linked to elevated terpenoid and phenylacetaldehyde content. 'Legacy' and 'Star' displayed a distinct fruity aroma profile attributed to the presence of ethyl 2-methylbutyrate, ethyl phenylacetate, and diethyl succinate. 'Jewel' featured an intense buttery aroma, correlated with higher concentrations of ethyl dodecanoate, ethyl decanoate, and ethyl octanoate. Subsequently, 'Misty' and 'Star', with distinct aroma profiles, were selected to further unravel the impact of berry size on blueberry wine aroma. The findings revealed that small berries significantly enhanced 'Misty' blueberry wines, increasing higher alcohol, ester, and terpenoid content, resulting in a more intense fruity and floral aroma. Interestingly, berry size had no discernible influence on 'Star' blueberry wine aroma. This study provides valuable insights into the enhancement of blueberry wine production, shedding light on the intricate interplay of cultivar selection, berry sorting, and their impact on the aromatic attributes of the final product.

Sensomics-Assisted Characterization of Fungal-Flowery Aroma Components in Fermented Tea Using Eurotium cristatum.

Fermented tea (FT) using a single Eurotium cristatum strain can produce a pleasant fungal-flowery aroma, which is similar to the composite aroma characteristic of minty, flowery, and woody aromas, but its molecular basis is not yet clear. In this study, solvent-assisted flavor evaporation and gas chromatography-mass spectrometry/olfactometry were applied to isolate and identify volatiles from the FT by E. cristatum. The application of an aroma extract dilution analysis screened out 43 aroma-active compounds. Quantification revealed that there were 11 odorants with high odor threshold concentrations. Recombination and omission tests revealed that nonanal, methyl salicylate, decanoic acid, 4-methoxybenzaldehyde, α-terpineol, phenylacetaldehyde, and coumarin were the major odorants in the FT. Addition tests further verified that methyl salicylate, 4-methoxybenzaldehyde, and coumarin were the key odorants for fungal-flowery aroma, each corresponding to minty, woody, and flowery aromas, respectively. 4-Methoxybenzaldehyde and coumarin were newly found odorants for fungal-flowery aroma in FT, and 4-methoxybenzaldehyde had not been reported as a tea volatile compound before. This finding may guide future industrial production optimization of FT with improved flavor.

Binuclear cobalt(II) and two-dimensional manganese(II) coordination compounds self-assembled by mixed bipyridine-tetracarboxylic ligands with single-ion magnet properties.

A cobalt(II) complex and manganese(II) coordination polymer, formulated as [Co2(H2btca)(mbpy)4][H2btca]·4H2O (1) and {Mn2(btca)(mbpy)2(H2O)2}n (2) (H4btca = 1,2,4,5-benzenetetracarboxylic acid; mbpy = 4,4'-dimethyl-2,2'-bipyridyl), constructed by mixed bipyridine-tetracarboxylic ligands were synthesized and characterized. Single-crystal structural analyses reveal that compound 1 is a discrete neutral binuclear molecule, while compound 2 is a two-dimensional (2D) coordination polymer. The metal ions in these compounds are well isolated, with an intramolecular Co2+⋯Co2+ distance of 9.170 Å for 1 and Mn2+⋯Mn2+ separation of 10.984 and 11.164 Å for 2 due to the bulk tetracarboxylic linker. This isolation gives rise to a single-ion magnetism origin of the compounds. Magnetic studies reveal a large zero-field splitting parameter D of 82.6 cm-1 for 1, while a very small D of 0.42 cm-1 was observed for 2. Interestingly, dynamic ac magnetic measurements exhibited slow magnetic relaxation under the external dc field of the two compounds, revealing the field-supported single-ion magnet (SIM) of 1 and 2. The detailed theoretical calculations were further applied to understand the electronic structures, magnetic anisotropy, and relaxation dynamics in 1 and 2. Combined with our recently reported compound (Eur. J. Inorg. Chem., 2022, e202200354), the foregoing results provide not only a rare binuclear cobalt(II) SIM and the first 2D manganese(II) SIM coordination polymer but also a bipyridine-tetracarboxylic ligand approach toward novel SIMs.

Aroma enhancement of blueberry wine by postharvest partial dehydration of blueberries.

Blueberries with 20%, 30%, and 40% weight loss were used for winemaking, aiming to explore the feasibility of applying postharvest dehydration for improving blueberry wine aroma. Postharvest dehydration decreased the titratable acidity of blueberries and their resultant wines. Total anthocyanins and phenols in blueberries with 30% weight loss were increased by 25.9% and 16.1%, respectively, due to concentration effects, while further dehydration resulted in a decline. Similar trends were observed in blueberry wines. Moderate postharvest dehydration increased total terpenes, benzeneacetaldehyde and phenylethyl alcohol, ethyl butanoate, methyl salicylate, 1-hexanol, and γ-nonalactone content in blueberries and wines, which could enhance the floral, fruity, and sweet notes of blueberry wines. Wines made from blueberries under severe dehydration (40% weight loss) had the lowest overall aroma score, which was related to the higher content of 4-ethyl-phenol and 4-ethylguaiacol. In conclusion, moderate postharvest dehydration benefited the aroma enhancement of blueberry wine.

Coordinated encapsulation by ß-cyclodextrin and chitosan derivatives improves the stability of anthocyanins.

To improve the stability of anthocyanins (ACNs), ACNs were loaded into dual-encapsulated nanocomposite particles by self-assembly using ß-cyclodextrin (ß-CD) and two different water-soluble chitosan derivatives, namely, chitosan hydrochloride (CHC) and carboxymethyl chitosan (CMC). The ACN-loaded ß-CD-CHC/CMC nanocomplexes with small diameters (333.86 nm) and had a desirable zeta potential (+45.97 mV). Transmission electron microscopy (TEM) showed that the ACN-loaded ß-CD-CHC/CMC nanocomplexes had a spherical structure. Fourier-transform infrared spectroscopy (FT-IR), nuclear magnetic resonance (1H NMR) and X-ray diffraction (XRD) confirmed that the ACNs in the dual nanocomplexes were encapsulated in the cavity of the ß-CD and that the CHC/CMC covered the outer layer of ß-CD through noncovalent hydrogen bonding. The ACNs from the dual-encapsulated nanocomplexes improved stability of ACNs under adverse environmental conditions or in a simulated gastrointestinal environment. Further, the nanocomplexes exhibited good storage stability and thermal stability over a wide pH range when added into simulated electrolyte drinks (pH = 3.5) and milk tea (pH = 6.8). This study provides a new option for the preparation of stable ACNs nanocomplexes and expands the applications for ACNs in functional foods.

Changes in the volatile compounds and characteristic aroma during liquid-state fermentation of instant dark tea by Eurotium cristatum.

Instant dark tea (IDT) was prepared by liquid-state fermentation inoculating Eurotium cristatum. The changes in the volatile compounds and characteristic aroma of IDT during fermentation were analyzed using gas chromatography-mass spectrometry by collecting fermented samples after 0, 1, 3, 5, 7, and 9 days of fermentation. Components with high odor activity (log2FD ≥ 5) were verified by gas chromatography-olfactometry. A total of 107 compounds showed dynamic changes during fermentation over 9 days, including 17 alcohols, 7 acids, 10 ketones, 11 esters, 8 aldehydes, 37 hydrocarbons, 4 phenols, and 13 other compounds. The variety of flavor compounds increased gradually with time within the early stage and achieved a maximum of 79 compounds on day 7 of fermentation. ß-Damascenone showed the highest odor activity (log2FD = 9) in the day 7 sample, followed by linalool and geraniol. These results indicate that fungal fermentation is critical to the formation of these aromas of IDT.

Effects of Torulaspora delbrueckii co-fermented with Saccharomyces cerevisiae on physicochemical and aromatic profiles of blueberry fermented beverage.

To investigate the effects of mixed fermentation with T. delbrueckii on aroma profiles of blueberry fermented beverage, five fermentations were conducted: monoculture of T. delbrueckii and S. cerevisiae, respectively; co-inoculation of two strains; sequential inoculation of two strains at time intervals of 24 h and 48 h, respectively. Compared with pure S. cerevisiae fermentation, ethanol level was decreased by up to 1.1% vol., while total anthocyanins were increased by 27.7%-85.0% in mixed fermentations. Marker aroma compounds in different fermentations with relative odor activity values higher than 1were identified. T. delbrueckii significantly decreased volatile acid content (especially acetic acid) by 22.2%-83.3%. Ethyl 3-methylbutanoate, ethyl hexanoate and ethyl octanoate, in pure T. delbrueckii fermentation were significantly decreased, while their concentrations were increased by 1.6-4.4 folds in sequential fermentations. Besides, linalool, rose oxide, benzeneacetaldehyde were significantly increased by sequential fermentation, which was associated with the enhancement of fruity and sweet notes.

Untargeted and targeted metabolomics reveal changes in the chemical constituents of instant dark tea during liquid-state fermentation by Eurotium cristatum.

Instant green tea powder was used as raw material to prepare an instant dark tea via liquid-state fermentation by Eurotium cristatum. To understand how the chemical constituents present in fermented green tea develop during fermentation, samples were collected on different days during fermentation for qualitative analyses by ultra-performance liquid chromatography-Q Exactive Orbitrap/Mass spectrometry. Untargeted metabolomics analyses revealed that the levels of original secondary metabolites in the instant green tea changed significantly from day 3 to day 5 during fermentation. Targeted metabolomics indicated that the levels of galloylated catechins (GCs) and free amino acids (FAAs) significantly decreased, but the nongalloylated catechins (NGCs), alkaloids, thearubigins and theabrownins increased dramatically after fermentation. The changes in the contents of catechins, gallic acid and free amino acids in the instant dark tea samples were positively related to the DPPH radical scavenging activities in vitro, and the phenolic acids and FAAs were positively related to the inhibitory effects towards α-glucosidase. These results showed that fermentation by Eurotium cristatum is critical to the formation of certain qualities of instant dark tea.

Influence of Eurotium cristatum and Aspergillus niger individual and collaborative inoculation on volatile profile in liquid-state fermentation of instant dark teas.

The three instant dark teas were produced from instant green tea (IGT) by liquid-state fermentations using the microorganisms Eurotium cristatum (EFT), Aspergillus niger (AFT), and sequential inoculation of E. cristatum/A. niger (EAFT), respectively. The volatile compounds of four tea samples were extracted by headspace-solid phase microextraction (HS-SPME) and analyzed using gas chromatography-mass spectrometry (GC-MS) coupled with chemometrics. A total of 97 volatile compounds were tentatively identified to distinguish three fermented instant dark from IGT. Alcohols, acids, esters, ketones, aldehydes, and heterocyclics could be clearly distinguished by principal component analysis (PCA), venn diagram, heatmap analysis and hierarchical cluster analysis (HCA). Descriptive sensory analysis revealed that AFT had a moldy, woody and herbal aroma; EFT showed woody and herbal aroma; and EAFT smelled an herbal, sweet, minty and floral aroma. This study indicates that fermentation using different microorganisms is critical in forming unique aroma characteristics of instant dark teas.

Nanocomplexes derived from chitosan and whey protein isolate enhance the thermal stability and slow the release of anthocyanins in simulated digestion and prepared instant coffee.

Anthocyanins (ACNs) are naturally derived colorants and antioxidants added to manufactured foods. ACNs were encapsulated in nanocomplexes with chitosan hydrochloride (CHC), carboxymethyl chitosan (CMC) and whey protein isolate (WPI). The ACN-loaded CHC/CMC-WPI nanocomplexes (ACN-CHC/CMC-WPI) showed a preferred particle size (332.20 nm) and zeta potential (+23.65 mV) and a high encapsulation efficiency (60.70%). ACN-CHC/CMC-WPI nanocomplexes exhibited a smooth spherical shape by transmission electron microscopy. Fourier transform infrared (FT-IR) and Raman spectroscopy confirmed interactions between the ACNs and the encapsulation materials (CHC/CMC-WPI). The nanocomplexes or the nanocomplexes incorporated into coffee beverage better protected ACNs at high temperature compared to the unencapsulated ACNs. In simulated gastrointestinal fluids, the ACNs in the ACN-CHC/CMC-WPI were more stable and more slower released over time. The nanocomplexes maintained high DPPH and hydroxyl free radical scavenging activities. This study indicated that CHC/CMC-WPI nanocomplexes can improve the thermal stability and slow the release of ACNs added to food products.

Gallic acid as a copigment enhance anthocyanin stabilities and color characteristics in blueberry juice.

The aim of this study was to evaluate the influence of adding copigment gallic acid (GA) on the stability of anthocyanin and color in blueberry juice, and assays were carried out with different anthocyanin:GA molar ratios (1:0, 1:1, 1:3, 1:5) in accelerated experiments (40 °C for 10 days). Results showed that the addition of GA made blueberry juice to appear more crimson color tonality, color saturation and anthocyanins stability. The most obvious hyperchromic effect appeared in juice with 1:5 of anthocyanin:GA molar ratios, and in this ratio, total anthocyanin content (137.67 mg/L) and main anthocyanin peonidin-3-glucoside content (51.68 mg/L) of the blueberry juice were higher than juice without copigment (total anthocyanin of 116.96 mg/L and peonidin-3-glucoside of 34.2 mg/L). Furthermore, anthocyanins in blueberry juice copigmented with molar ratios 1:5 of anthocyanin:GA were more stable at 4 °C than that at 25 °C and 40 °C. Thus, the addition of gallic acid at appropriate levels might be a promising juice process technology to obtain juices with high color quality and anthocyanin stability.

Controlled release and antioxidant activity of chitosan and ß-lactoglobulin complex nanoparticles loaded with epigallocatechin gallate.

In order to investigate the influence of different embedding methods on the properties and function of polyphenols, the Epigallocatechin gallate (EGCG) loaded chitosan nanoparticles prepared with or without ß-lactoglobulin (ß-Lg) were obtained by ionic cross linking method. The average particle sizes of EGCG loaded chitosan nanoparticles (EGCG-CS NPs) decreased from 190 nm to 157 nm after adding with ß-Lg, whereas the encapsulation efficiency (EE) increased from 59.79 % to 76.29 %. The results of transmission electron microscopy (TEM) showed that the obtained nanoparticles had obvious core-shell structure. The results of simulated gastrointestinal digestion showed that the release rate of EGCG in CS/ß-Lg NPs was much lower than that of CS-NPs. Compared with free EGCG, the DPPH and FRAP assay showed that EGCG-CS NPs and EGCG-CS/ß-Lg NPs had slow-controlled antioxidant activity. Meanwhile, the study of cellular antioxidant activity (CAA) showed that the EC50 values of EGCG-CS NPs and EGCG-CS/ß-Lg NPs were decreased by 8.56 % and 18.35 %, respectively.

High-mobility group nucleosomal binding domain 2 protects against microcephaly by maintaining global chromatin accessibility during corticogenesis.

The surface area of the human cerebral cortex undergoes dramatic expansion during late fetal development, leading to cortical folding, an evolutionary feature not present in rodents. Microcephaly is a neurodevelopmental disorder defined by an abnormally small brain, and many gene mutations have been found to be associated with primary microcephaly. However, mouse models generated by ablating primary microcephaly-associated genes often fail to recapitulate the severe loss of cortical surface area observed in individuals with this pathology. Here, we show that a mouse model with deficient expression of high-mobility group nucleosomal binding domain 2 (HMGN2) manifests microcephaly with reduced cortical surface area and almost normal radial corticogenesis, with a pattern of incomplete penetrance. We revealed that altered cleavage plane and mitotic delay of ventricular radial glia may explain the rising ratio of intermediate progenitor cells to radial glia and the displacement of neural progenitor cells in microcephalic mutant mice. These led to decreased self-renewal of the radial glia and reduction in lateral expansion. Furthermore, we found that HMGN2 protected corticogenesis by maintaining global chromatin accessibility mainly at promoter regions, thereby ensuring the correct regulation of the transcriptome. Our findings underscore the importance of the regulation of chromatin structure in cortical development and highlight a mouse model with critical insights into the etiology of microcephaly.

Effect of sodium alginate and carboxymethyl cellulose edible coating with epigallocatechin gallate on quality and shelf life of fresh pork.

The active edible coatings were prepared by incorporating epigallocatechin gallate (EGCG) into sodium alginate (SA) and carboxymethyl cellulose (CMC) to investigate the effect of SA-CMC-EGCG coatings on quality and shelf life of fresh pork stored at 4 ±â€¯1 °C for 7 days. The antioxidant effects against lipid oxidation (TBARS), total volatile basic nitrogen (TVB-N) and antimicrobial activity against total viable counts (TVC) were analyzed. Besides, the changes in color parameters and sensory attributes of all pork samples were evaluated. The results showed that fresh pork coated with SA-CMC edible coating with EGCG had a significant inhibitory effect on its microbial growth (P < 0.05), lipid oxidation and TVB-N. SA-CMC-EGCG also increased the L* value and maintained a* value of pork during storage. Besides, the sensory scores of pork samples coated with SA-CMC-EGCG were significantly improved (P < 0.05). Therefore, using SA-CMC-EGCG edible coating could prevent decay and significantly increase the shelf life of fresh pork.

Preparation and antioxidant activity of sodium alginate and carboxymethyl cellulose edible films with epigallocatechin gallate.

The active edible films were prepared by incorporating epigallocatechin gallate (EGCG) into sodium alginate (SA) and carboxymethyl cellulose (CMC). The effects of EGCG addition on the physical and morphological properties of SA-CMC films were evaluated. Meanwhile, the release characteristics of EGCG from edible films and its antioxidant activity in fat food simulant (95% ethanol) were also detected. The results showed that the addition of EGCG could improve the tensile strength (TS) of edible films and reduce their elongation at break (E). Especially, the color of edible film added with EGCG deepened and the transmittance decreased. Scanning electron microscopy (SEM) images displayed that the films were dense and compact with a little roughness. Fourier transform infrared spectroscopy (FTIR) analysis indicated that the incorporation of EGCG into SA-CMC caused interactions occurring between SA-CMC and EGCG. In addition, the release and DPPH radical scavenging assay of incorporating EGCG in SA-CMC films showed that the obtained SA-CMC films with high EGCG content could release EGCG slowly and had strong antioxidant activity in fatty foods. Thus, incorporating EGCG into SA-CMC film was an effective way in order to develop active and environmental friendly packing materials for food industry.