Study on the effect of enzymolysis combined fermentation on reducing the off-flavor of egg white powder.

BACKGROUND: The application of egg white powder (EWP) was subject to its off-flavor. In the present study, flavourzyme and lactic acid bacteria were used to treat egg white powder (EWP) and the mechanism effects of enzymolysis-fermentation were explored. RESULTS: Compared with the control group, enzymolysis combined with fermentation treatment group (EW-EF) reduced the four-representative off-flavor compounds (geranyl acetone, 1-octen-3-ol, octanal and nonanal) by more than 62.66%. Fermentation produced esters with good flavor, and enzymolysis produced fresh amino acids. Characterization of protein structure indicated that fermentation decreased both fluorescence intensity and surface negative charges, accelerating the aggregation of proteins; enzymolysis promoted aggregation and degradation, improving the stability of the egg white proteins. Meanwhile, enzymolysis broke down the hydrophobic cavities bound to off-flavor compounds, releasing protein-bound off-flavor compounds and removing them through fermentation. CONCLUSION: EW-EF had the best effect of off-flavor removal on EWP. The results of the present study could provide a green and effective method for improving the flavor of EWP. © 2024 Society of Chemical Industry.

Exploration of markers in oxidized rancidity walnut kernels based on lipidomics and volatolomics.

Walnut kernels are prone to oxidation and rancidity due to their rich lipid composition, but the existing evaluation indicators are not sensitive enough to promote their industrial development. This study aims to investigate the potential markers in oxidative rancidity walnut kernels using lipidomics and volatolomics. The results showed that the antioxidant capacity of walnut kernels significantly decreased after oxidation, with the decreasing of total phenolic content from 36276.34 mg GAE/kg to 31281.53 mg GAE/kg, the DPPH and ABTS free radical scavenging activity from 89.25% to 73.54%, and 61.69% to 43.73%, respectively. The activities of lipoxygenase (LOX) and lipase (LPS) increased by 6.08-fold and 0.33-fold, respectively. By combining volatolomics and chemometrics methods, it was found that significant differences existed in the content of hexanal, caproic acid, 1-pentanol, (E)-2-octenal, and 2-heptanenal before and after walnut kernel oxidation (VIP > 1). Based on the results of lipidomics, it can be concluded that the above five compounds can serve as characteristic markers for walnut kernel oxidative rancidity, mainly produced through glycerol phospholipid (GPL), glyceride, linoleic acid (LA), and α-linolenic acid (ALA) metabolism pathways. Possible mechanisms of lipid degradation in oxidized walnut kernels were also proposed, providing technical support for the storage, preservation, and high-value utilization of walnut kernels.

Vocational-technical teachers' mindfulness: Does it matter for teachers' well-being and motivation?

Teaching in vocational-technical schools can pose many challenges, which can lead to stressful situations as all aspects of instruction and teaching in this domain involve a high level of anxiety and exhaustion. So, the significant issue in this territory is teachers' motivation which plays a crucial role in enhancing the various types of performance, including organizational performance and it is positively related to job performance and accordingly their well-being. Therefore, teachers' motivation and well-being should be taken into consideration in the vocational-technical academic environment and an increasing number of programs have been in quest of fostering these constructs. To this end, there is growing interest in the function of mindfulness which is very efficient in decreasing teachers' stress while increasing their motivation and well-being. Indeed, as a mental characteristic of vocational-technical educators, mindfulness functions as a technique one can employ. This paper tries to examine the possible contribution of vocational-technical teachers' mindfulness to their efficiency with a focus on well-being and motivation. Accordingly, teachers' well-being and motivation have been the subject of studies that seek to shed light on the potential contributors to teachers' careers; yet, few, if any, studies have been carried out on the contribution of mindfulness to motivation and well-being among the teachers working in the vocational-technical setting. As a result, these insights can have implications for the stakeholders involved in the vocational-technical context, including teachers and teacher trainers.

Huangshui Polysaccharide Exerts Intestinal Barrier Protective Effects through the TLR4/MyD88/NF-κB and MAPK Signaling Pathways in Caco-2 Cells.

Several reports have demonstrated that natural polysaccharides exert protective effects on intestinal barrier function. In our previous study, we isolated a polysaccharide named HSP-W from Huangshui (HS). In the present study, the protective role of HSP-W in LPS-induced intestinal barrier dysfunction was determined by several molecular biological techniques. The results showed that HSP-W treatment alleviated the deduced TEER and increased the permeability of intestinal epithelial cells induced by LPS through inhibiting the release of inflammatory cytokines and enhancing the expression of tight junction (TJ) proteins. The underlying molecular mechanisms were elucidated by RNA-seq technique, which indicated that the differentially expressed genes (DEGs) between the LPS-treated and LPS+HSP-W-treated groups were enriched in the "MAPK" signaling pathway. Notably, the overlapping DEGs reversed by HSP-W intervention highlighted the pathways of the "Toll-like receptor" and "NF-κB" signaling pathways. The suppression of p38 and NF-κB were mediated by the inhibition of MyD88. Furthermore, HSP-W treatment prevented the translocation of NF-κB to nucleus, thus inhibiting the release of TNF-α, IL-6, and IL-1ß. Overall, HSP-W has beneficial effects on LPS-induced inflammation; it protects the intestinal barrier from injury in Caco-2 cells through inhibiting the TLR4/MyD88/NF-κB and p38 MAPK signaling pathways.

RNA-seq based elucidation of mechanism underlying the protective effect of Huangshui polysaccharide on intestinal barrier injury in Caco-2 cells.

Polysaccharides from Huangshui (HS) have the function of antioxidant and immunoregulation, but its intestinal barrier protection activity and the underlying mechanism remains unclear. The present work mainly studied the intestinal barrier protection function and its potential molecular mechanism of a heteropolysaccharide named NLS-2 with a molecular weight of 51.9 kDa. NLS-2 reduced intestinal permeability by decreasing the content of inflammatory cytokines and increasing the expression of tight junction (TJ) protein in LPS-damaged Caco-2 cells, thus protecting the intestinal barrier function. RNA-seq results showed that the differentially expressed genes (DEGs) were mainly enriched in the signaling pathways of MAPK, Toll-like receptor, and NF-κB. Subsequent western blot validation experiments proved that NLS-2 could indeed inhibit the two pathways of MAPK and NF-κB by reducing the expression of TRL4, thereby down-regulating the release of downstream pro-inflammatory cytokines and playing the role of intestinal barrier protection. Collectively, NLS-2 has beneficial effects on LPS-damaged intestinal barrier by inhibiting the TRL4/MyD88/NF-κB and MAPK signaling pathways.

Structure elucidation and intestinal barrier protection of an α-D-glucan in Huangshui.

WLY-0, as an α-D-glucan with a molecular weight (Mw) of 11.12 kDa, was successfully isolated and purified from Huangshui (HS). The results of methylation and NMR indicated that the mainchain of WLY-0 was (1 â†’ 4)-α-D-glucan, with side chains linking at O-6. Meanwhile, the surface morphology characterization showed that WLY-0 had an irregular flake-like morphology with a rough and uneven surface and varies in sizes from nanometers to microns. Furthermore, WLY-0 relieved the increased paracellular permeability of FD4 and decreased TEER challenged by LPS, meanwhile inhibited the production of pro-inflammatory cytokines (TNF-α, IL-6, and IL-1ß) and up-regulated the expression of TJ protein (Occludin, Claudin-1, ZO-1, and JAM-A) in Caco-2 cells, so to improve the intestinal barrier function. Our findings about the structural characteristics and biological activities of WLY-0 provided a scientific foundation for the utilization of HS as a potent source of an effective adjuvant in intestinal barrier injury treatment.

Synthesis, characterization, and methylene blue adsorption of multiple-responsive hydrogels loaded with Huangshui polysaccharides, polyvinyl alcohol, and sodium carboxyl methyl cellulose.

Huangshui (HS), a typical by-product of traditional Chinese Baijiu, has attracted more and more attention since its rich resources of polysaccharides. However, there's little information on hydrogels preparation by Huangshui polysaccharides (HSPs). A series of novel HSP-loaded hydrogels were synthesized using crude HSP (cHSP), polyvinyl alcohol (PVA), sodium carboxyl methyl cellulose (CMC), and in situ incorporation of Fe3O4 for methylene blue (MB) adsorption for the first time. Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), vibrating sample magnetometer (VSM) and texture tests indicated the paramagnetic hydrogels with porous structure were formed via physical crosslinking, and cHSP had no effect on hydrogel texture. Notably, cHSP enhanced the swelling capacity and MB adsorption ability of the hydrogels, and the corresponding maximum value was 38.67 g/g and 71.07 mg/g, respectively, when the additive amount of cHSP to the hydrogels was 2 % at 25°Ð¡. In addition, the swelling kinetics of hydrogels followed the Schott's second-order kinetics model, while MB adsorption fitted well with the Freundlich isotherm and pseudo-second-order model. Furthermore, intraparticle and film diffusion-controlled MB adsorption process. Significantly, cHSP amount could counteract the negative influence of high temperature on MB adsorption, and the prepared hydrogels could be reusable, demonstrating cHSP effectively promoted the properties of hydrogels and had potential application in MB removal. The adsorption mechanism of MB onto the hydrogels involved ion-exchange, hydrogen bonding, electrostatic interaction, and chemical reaction according to the above results together with the analysis by X-ray photoelectron spectroscopy (XPS) and energy-dispersive X-ray (EDX) characterizations, thermodynamic, etc.

The Role of Learners' Psychological Well-Being and Academic Engagement on Their Grit.

This review aimed at examining the related studies on the effect of English as a foreign language learners' (EFL) psychological well-being and academic engagement as positive emotional constructs on learners' grit. The positive significant effect of psychological well-being on learners' grit has been confirmed in the literature review. Studies have shown that resilience, enjoyment, engagement, lack of depression, interest, and world meaningfulness can act as mediator variables in the relationship between psychological well-being and grit. Furthermore, few studies have been done on the effect of academic engagement on learners' grit. The studies showed that some factors such as meticulousness, self-control, self-confidence, and motivation act as mediators in the relationship between academic engagement and grittiness. In the end, the pedagogical implications are expounded to promote the quality of language learning quality. This review also provides some suggestions for further research to clarify our perspective over positive emotional variables and their relationships with each other.

Protective Effects of Natural Polysaccharides on Intestinal Barrier Injury: A Review.

Owing to their minimal side effects and effective protection from oxidative stress, inflammation, and malignant growth, natural polysaccharides (NPs) are a potential adjuvant therapy for several diseases caused by intestinal barrier injury (IBI). More studies are accumulating on the protective effects of NPs with respect to IBI, but the underlying mechanisms remain unclear. Thus, this review aims to represent current studies that investigate the protective effects of NPs on IBI by directly maintaining intestinal epithelial barrier integrity (inhibiting oxidative stress, regulating inflammatory cytokine expression, and increasing tight junction protein expression) and indirectly regulating intestinal immunity and microbiota. Furthermore, the mechanisms underlying IBI development are briefly introduced, and the structure-activity relationships of polysaccharides with intestinal barrier protection effects are discussed. Potential developments and challenges associated with NPs exhibiting protective effects against IBI have also been highlighted to guide the application of NPs in the treatment of intestinal diseases caused by IBI.

Structural characterization and immuno-stimulating activities of a novel polysaccharide from Huangshui, a byproduct of Chinese Baijiu.

Huangshui (HS), a byproduct of Baijiu, has been widely studied for the utilization of aromatic compounds and microorganisms. However, there is little information on the bioactive polysaccharides in HS. In this study, a novel complex polysaccharide (HSP-2) composed of mannose, glucose, galactose, arabinose, xylose, and rhamnose at approximate percentages of 53.0, 29.6, 11.5, 2.7, 2.1, and 1.0, respectively, was successfully extracted and purified from HS. The results of FT-IR, methylation analysis, and NMR showed that the backbone of HSP-2 was â†’ 2)-ß-D-Manp-(1 â†’ 2,6)-ß-D-Manp-(1 â†’ 6)-α-D-Glcp-(1 â†’ 4)-α-L-Rhap-(1 â†’ 3,4)-α-L-Rhap-(1→. In addition, HSP-2 showed significant immuno-stimulating effects via increasing the ROS and NO generation, and enhancing the pinocytic and phagocytic capacities of THP-1 cells in a dose-dependent manner. Meanwhile, HSP-2 treatment increased IFN-γ, TNF-α, IL-6 and IL-1ß secretion through activating the expression of the related mRNAs and proteins. These results will provide a molecular basis for immuno-stimulating effects of HSP-2 and lay a foundation for the potential application of HS in functional foods.

Isolation, purification, structure characterization of a novel glucan from Huangshui, a byproduct of Chinese Baijiu, and its immunomodulatory activity in LPS-stimulated THP-1 cells.

Huangshui (HS) has attracted considerable attention for the utilization of aroma compounds and microorganisms containing presently. However, little work has been done on biological polysaccharides in HS. In this study, a novel water-eluted HS polysaccharide, HSP-W, was identified as an α-D-glucan with a Mw of 166.00 kDa. It was consisted of a 1,4 linked α-D-Glcp backbone with the substitution at O-6 with 1,6-linked α-D-Glcp residue and non-reducing terminal of ß-Glc-1→ through monosaccharide composition, IR, methylation, and NMR analyses. SEM, AFM, and particle size distribution measurements showed that HSP-W had relatively clustered spherical shape with different sizes from nanoscale to micrometer. Additionally, HSP-W significantly induced NO and ROS production as well as the release of IL-1ß, IFN-γ, TNF-α, and IL-6, and upregulated pinocytic and phagocytic capacities of THP-1 cells. Meanwhile, HSP-W treatment markedly enhanced mRNA and protein expressions of these cytokines. HS probably has potential application as an immunostimulatory agent.

Immunomodulatory activity of a novel polysaccharide extracted from Huangshui on THP-1 cells through NO production and increased IL-6 and TNF-α expression.

Huangshui (HS), the by-product of Chinese Baijiu, has attracted considerable attention due to its nutrient and microbial composition; however, none of the studies has explored the polysaccharides in HS yet. Here, from HS, we isolated a novel polysaccharide, HSP-3, with an average molecular weight of 26.40 kDa. The structure was elucidated based on monosaccharide composition and methylation analysis, NMR, FT-IR, and AFM analysis. It is mainly composed of mannose (46.6%), galactose (17.3%), arabinose (11.2%), glucose (10.5%), xylose (8.2%), fucose (5.2%), and rhamnose (1.0%). The backbone of HSP-3 was made up of â†’ 2)-ß-d-Manp-(1 â†’ 2,6)-ß-d-Manp-(1 â†’ 6)-ß-d-Galp-(1 â†’ 3,6)-ß-d-Galp-(1 â†’ 4)-α-l-Rhap-(1 â†’ 3,4)-α-l-Rhap-(1 â†’ . Moreover, stimulation of the production of ROS, NO, TNF-α and IL-6, upregulation of the mRNA and protein expression levels of TNF-α and IL-6 in THP-1 cells, and enhanced the pinocytic and phagocytic capacities of THP-1 cells exhibited significant immunomodulatory properties of HSP-3. Altogether, this study suggests that HSP-3 could be used as an active component in functional foods.

Structural characterization of a tetrapeptide from Sesame flavor-type Baijiu and its interactions with aroma compounds.

The small molecules in Chinese Baijiu have been widely reported, but there is little information on peptides since their low concentrations. A tetrapeptide, Asp-Arg-Ala-Arg (DRAR), was newly identified from Jingzhi Sesame flavor-type Baijiu (SFTB) by high-performance liquid chromatography and quadrupole-time-of-flight-mass spectrometry (HPLC-Q-TOF-MS) with a concentration of 13.159 ±â€¯0.202 µg/L (P > 0.05). Interactions between DRAR and volatile compounds were characterized using headspace solid-phase micro-extraction coupled with gas chromatography-mass spectrometry (HS-SPME-GC-MS), and the results indicated that DRAR could suppress the volatility of aroma compounds by 0.09-39.02 %, especially with respect to esters and alcohols. The involved binding modes of DRAR with esters or alcohols in 46% ethanol/water solutions (v/v) were respectively determined by ultraviolet (UV) absorption spectroscopy. According to the Van't Hoff equation, the thermodynamic parameters (for DRAR - esters complex, ΔH = -34.7 KJ mol-1, ΔS = -66.4 J mol-1 K-1 and for DRAR - alcohols complex, ΔH = -40.8 KJ mol-1, ΔS = -91.8 J mol-1 K-1) indicated that hydrogen bonds and van der Waals forces played major roles in stabilizing the DRAR-esters and DRAR-alcohols complexes. This study will help us to further understand the interaction mechanisms between aroma compounds and peptides, and the important role of peptides on the quality of Chinese Baijiu.

Interactions between p-Cresol and Ala-Lys-Arg-Ala (AKRA) from Sesame-Flavor-Type Baijiu.

The objective of this study was to investigate the influence of Ala-Lys-Arg-Ala (AKRA), a tetrapeptide newly identified from Chinese Sesame flavor-type Baijiu in our previous work, on its binding ability with aroma compounds. A method using headspace solid-phase microextraction combined with gas chromatography-mass spectrometry (HS-SPME-GC/MS) was employed to determine the corresponding binding ability between different concentrations of AKRA (10 - 1000 µg/L) and aromas in Baijiu. In comparison, the aroma molecules in Baijiu before and after adding AKRA were almost the same; only their volatility was altered, with mostly the esters, alcohols, and phenolic compounds being decreased. Additionally, AKRA slightly changed the whole aroma profile of Baijiu, especially with respect to p-cresol (an off-odor in sesame-flavor-type Baijiu), which was verified by systematic sensory experiments including gas chromatography-olfactometry (GC-O) and odor activity values (OAVs) analysis. The nonvolatile tetrapeptide favored the hydrogen bond interactions with p-cresol, forming the AKRA- p-cresol complex, thus reducing the headspace concentration of phenolic off-flavors as evidenced by HS-SPME-GC/MS, ultraviolet (UV) absorption spectroscopy, and nuclear magnetic resonance spectrum (1H NMR) analysis. Meanwhile, the hydrogen bond interaction was further confirmed with the intermolecular cross-peaks between the carboxyl hydrogen of AKRA and the phenolic hydroxyl of p-cresol by nuclear Overhauser effect spectroscopy (1H-1H NOESY).

Structural Characterization of a Tetrapeptide from Sesame Flavor-Type Baijiu and Its Preventive Effects against AAPH-Induced Oxidative Stress in HepG2 Cells.

Peptides are rarely reported from Chinese Baijiu (Chinese liquor) because they are often present in very low concentrations in the complex matrix. A tetrapeptide, Ala-Lys-Arg-Ala (AKRA), was recently identified by high-performance liquid chromatography and quadrupole-time-of-flight-mass spectrometry (HPLC-Q-TOF-MS) from sesame flavor-type Baijiu at a concentration of 8.497 ± 0.753 µg/L (P > 0.05), and this tetrapeptide showed preventive effects against 2,2'-azobis(2-methylpropanimidamidine) dihydrochloride (AAPH)-induced oxidative stress in HepG2 cells. The cellular antioxidant activity assay results showed that AKRA protected AAPH-induced oxidative stress in HepG2 cells in a concentration-dependent manner. Pretreatment of the cells for 2 h with AKRA (0.38-1.50 mg/mL) caused strong intracellular reactive oxygen species (ROS) scavenging activities and prevented a decrease in reduced glutathione (GSH) and increases in oxidized glutathione (GSSG) and malondialdehyde (MDA). In addition, AKRA treatment prevented significant decreases in glutathione peroxidase (GSH-Px), superoxide dismutase (SOD), and catalase (CAT) induced by AAPH. Thus, AKRA treatment ameliorated AAPH-induced oxidative stress in HepG2 cells. This study will be important for the design and regulation of functional Baijiu production.