Research advances in citrus polyphenols: green extraction technologies, gut homeostasis regulation, and nano-targeted delivery system application.

Citrus polyphenols can modulate gut microbiota and such bi-directional interaction that can yield metabolites such as short-chain fatty acids (SCFAs) to aid in gut homeostasis. Such interaction provides citrus polyphenols with powerful prebiotic potential, contributing to guts' health status and metabolic regulation. Citrus polyphenols encompass unique polymethoxy flavonoids imparting non-polar nature that improve their bioactivities and ability to penetrate the blood-brain barrier. Green extraction technology targeting recovery of these polyphenols has received increasing attention due to its advantages of high extraction yield, short extraction time, low solvent consumption, and environmental friendliness. However, the low bioavailability of citrus polyphenols limits their applications in extraction from citrus by-products. Meanwhile, nano-encapsulation technology may serve as a promising approach to improve citrus polyphenols' bioavailability. As citrus polyphenols encompass multiple hydroxyl groups, they are potential to interact with bio-macromolecules such as proteins and polysaccharides in nano-encapsulated systems that can improve their bioavailability. This multifaceted review provides a research basis for the green and efficient extraction techniques of citrus polyphenols, as well as integrated mechanisms for its anti-inflammation, alleviating metabolic syndrome, and regulating gut homeostasis, which is more capitalized upon using nano-delivery systems as discussed in that review to maximize their health and food applications.

Xenon-lamp simulated sunlight-induced photolysis of pyriclobenzuron in water: Kinetics, degradation pathways, and identification of photolysis products.

Pyriclobenzuron 1(PBU) is a novel molluscicide developed to control Pomacea canaliculate, and little information on its environmental fate has been published. In this study, the photolysis of PBU in an aqueous environment was simulated using a xenon lamp. Results showed that the photolysis of PBU in water followed first-order kinetics, exhibiting a t0.5 of 95.1 h and 83.6 h in Milli-Q water and river water, respectively. Two main photolysis products 2(PPs) were detected by HPLC-UV and identified by UPLC-Q/TOF MS, which were formed via the hydroxylation and photocatalytic hydro-dehalogenation of PBU, respectively. The initial relative abundance of photolysis product 1 3(PP-1) in Milli-Q water was 1.55 times higher than that in river water. PP-1 was detected at 26.5 % and 76.8 % of the maximum relative abundance in the river water and Milli-Q water after 720 h, respectively. Photolysis product 2 4(PP-2) was stable in water because of its weak hydrophilicity. The PP-2 detected after 720 h in Milli-Q water and river water was 93.7 % and 93.5 % of the maximum relative abundance, respectively. Finally, ECOSAR software was used to evaluate the acute aquatic toxicity of PBU and its PPs, revealing that the PPs had lower toxicity levels to non-target aquatic organisms.

Heterologous expression and characterization of Bacillus velezensis SW5 serine protease involved in the hydrolysis of anchovy protein.

BACKGROUND: Bacillus velezensis SW5, with good enzyme production ability, was isolated and identified in our laboratory from fermented fish sauce. Its galactosidase has been expressed in Escherichia coli, which could hydrolyze lactose in milk. The present study aims to express a novel serine protease gene (SPr-SW5) of this strain by Bacillus subtilis WB800N, and applies the expressed enzyme in hydrolysis of anchovy to prepare antioxidant substances, aiming to alleviate the waste of low-value fish resources. RESULTS: SPr-SW5 with the open reading frame of 1353 bp encodes a serine protease (SPr-SW5) with 450 amino acids. The theoretical molecular weight and isoelectric point are 47.2 kDa and 5.22, respectively. The successful expression of SPr-SW5 in B. subtilis WB800N was confirmed by a skim milk plate test. Its optimal temperature and pH were 50 °C and 8.0, respectively. SPr-SW5 activity was increased by Ca2+ and Zn2+ , but inhibited by Fe3+ . Furthermore, SPr-SW5 was tolerant to 1% Tween-40 and Tween-80; however, its activity was strongly inhibited by 10 mm phenylmethylsulfonyl fluoride. Additionally, SPr-SW5 could be capable of hydrolyzing anchovy, the hydrolysate (AHP) at 10 g L-1 , with 2,2-diphenyl-1-picrylhydrazyl and hydroxyl (·OH) scavenging rates of 73.21% and 79.71%, displaying good antioxidant activity. CONCLUSION: The novel SPr-SW5 was successfully expressed in B. subtilis WB800N. It exhibited excellent temperature stability and good tolerance to several metal ions. In addition, the anchovy hydrolyzed by expressed SPr-SW5 has good antioxidant ability. Overall, this research lays a good foundation for SPr-SW5 with respect to exploration and application in the food industry as enzyme preparation. © 2023 Society of Chemical Industry.

Structural, rheological, and gelling characteristics of starch-based materials in context to 3D food printing applications in precision nutrition.

Starch-based materials have viscoelasticity, viscous film-forming, dough pseudoplasticity, and rheological properties, which possess the structural characteristics (crystal structure, double helix structure, and layered structure) suitable for three-dimensional (3D) food printing inks. 3D food printing technology has significant advantages in customizing personalized and precise nutrition, expanding the range of ingredients, designing unique food appearances, and simplifying the food supply chain. Precision nutrition aims to consider individual nutritional needs and individual differences, which include special food product design and personalized precise nutrition, thus expanding future food resources, then simplifying the food supply chain, and attracting extensive attention in food industry. Different types of starch-based materials with different structures and rheological properties meet different 3D food printing technology requirements. Starch-based materials suitable for 3D food printing technology can accurately deliver and release active substances or drugs. These active substances or drugs have certain regulatory effects on the gut microbiome and diabetes, so as to maintain personalized and accurate nutrition.

A review of yeast: High cell-density culture, molecular mechanisms of stress response and tolerance during fermentation.

Yeast is widely used in the fermentation industry, and the major challenges in fermentation production system are high capital cost and low reaction rate. High cell-density culture is an effective method to increase the volumetric productivity of the fermentation process, thus making the fermentation process faster and more robust. During fermentation, yeast is subjected to various environmental stresses, including osmotic, ethanol, oxidation, and heat stress. To cope with these stresses, yeast cells need appropriate adaptive responses to acquire stress tolerances to prevent stress-induced cell damage. Since a single stressor can trigger multiple effects, both specific and nonspecific effects, general and specific stress responses are required to achieve comprehensive protection of cells. Since all these stresses disrupt protein structure, the upregulation of heat shock proteins and trehalose genes is induced when yeast cells are exposed to stress. A better understanding of the research status of yeast HCDC and its underlying response mechanism to various stresses during fermentation is essential for designing effective culture control strategies and improving the fermentation efficiency and stress resistance of yeast.

Metabolic changes of Issatchenkia orientalis under acetic acid stress by transcriptome profile using RNA-sequencing.

Issatchenkia orientalis (I. orientalis) is tolerant to various environmental stresses especially acetic acid stress in wine making. However, limited literature is available on the transcriptome profile of I. orientalis under acetic acid stress. RNA-sequence was used to investigate the metabolic changes due to underlying I. orientalis 166 (Io 166) tolerant to acetic acid. Transcriptomic analyses showed that genes involved in ergosterol biosynthesis are differentially expressed under acetic acid stress. Genes associated with ribosome function were downregulated, while energy metabolism-related genes were upregulated. Moreover, Hsp70/Hsp90 and related molecular chaperones were upregulated to recognize and degrade misfolded proteins. Compared to Saccharomyces cerevisiae, transcriptomic changes of Io 166 showed many similarities under acetic acid stress. There were significant upregulation of genes in ergosterol biosynthesis and for the application of wine production.

Effects of freeze drying in complex lyoprotectants on the survival, and membrane fatty acid composition of Lactobacillus plantarum L1 and Lactobacillus fermentum L2.

The aim of this study was to investigate the effects of freeze-drying protective agents on the viability, survival and membrane fatty acid composition of Lactobacillus plantarum L1 and Lactobacillus fermentum L2. Cell survival rates of Lactobacillus plantarum L1 after freeze-drying without any additives was 6.57% (control group), 37.4% with a single protective agent, as compared to 97.4% when L.plantarum L1 was freeze-dried in a solution of four protectants (10% skim milk, 13% sucrose, 2% sorbitol, and 0.8% tyrosine (p < 0.05).) The L.fermentum L2 strain had the highest survival rate 92.3% when was freeze-dried in a solution containing 10% skim milk, 7% trehalose, 2% sorbitol and 0.6% tyrosine (p < 0.05). Freeze drying in the presence of all four protective agents maintained cell membrane integrity, as determined by reduced leakage of ß-galactosidase and LDH, and increased ATPase activity. LAB Incubation and freeze drying in the complex protective solution increased the content of unsaturated fatty acids in the cell membrane such as oleic acid (C18:1) and C19cyc11 and it is speculated that this may correlate with the improved outcomes.

Tea polyphenols-loaded nanocarriers: preparation technology and biological function.

Tea polyphenols (TP) have various biological functions including anti-oxidant, anti-bacterial, anti-apoptotic, anti-inflammatory and bioengineered repair properties. However, TP exhibit poor stability and bioavailability in the gastrointestinal tract. Nanoencapsulation techniques can be used to protect TP and to uphold their original characteristics during processing, storage and digestion, improve their physiochemical properties and enhance their health promoting effects. Nano-embedded TP show higher antioxidant, antibacterial and anticancer properties than TP, allowing TP to play a better role in bioengineering restoration after embedding. In this review, recent advances in nanoencapsulation of TP with biopolymeric nanocarriers (polysaccharides and proteins), lipid-based nanocarriers and innovative developments in preparation strategies were mainly discussed. Additionally, the strengthening biological functions of stability and bioavailability, antioxidant, antibacterial, anticancer activities and bioengineering repair properties activities after the nano-embedding of TP have been considered. Finally, further studies could be conducted for exploring the application of nanoencapsulated systems in food for industrial applications.

Overexpression and characterization of a novel GH4 galactosidase with ß-galactosidase activity from Bacillus velezensis SW5.

A novel galactosidase gene (gal3149) was identified from Bacillus velezensis SW5 and heterologously expressed in Escherichia coli BL21 (DE3). The novel galactosidase, Gal3149, encoded by gal3149 in an open reading frame of 1,299 bp, was 433 amino acids in length. Protein sequence analysis showed that Gal3149 belonged to family 4 of glycoside hydrolases (GH4). Gal3149 displayed higher enzyme activity for the substrate 2-nitrophenyl-ß-d-galactopyranoside (oNPG) than for 4-nitrophenyl-α-d-galactopyranoside (pNPαG). This is the first time that an enzyme belonging to GH4 has been shown to exhibit ß-galactosidase activity. Gal3149 showed optimal activity at pH 8.0 and 50°C, and exhibited excellent thermal stability, with retention of 50% relative activity after incubation at a temperature range of 0 to 50°C for 48 h. Gal3149 activity was significantly improved by K+ and Na+, and was strongly or completely inhibited by Ag+, Zn2+, Tween-80, Cu2+, carboxymethyl cellulose, and oleic acid. The rate of hydrolyzed lactose in 1 mL of milk by 1 U of Gal3149 reached about 50% after incubation for 4 h. These properties lay a solid foundation for Gal3149 in application of the lactose-reduced dairy industry.

Homology- and cross-resistance of Lactobacillus plantarum to acid and osmotic stress and the influence of induction conditions on its proliferation by RNA-Seq.

In this study, homology- and cross-resistance of Lactobacillus plantarum L1 and Lactobacillus plantarum L2 to acid and osmotic stress were investigated. Meanwhile, its proliferation mechanism was demonstrated by transcriptomic analysis using RNA sequencing. We found that the homologous-resistance and cross-resistance of L. plantarum L1 and L. plantarum L2 increased after acid and osmotic induction treatment by lactic acid and sodium lactate solution in advance, and the survival rate of live bacteria was improved. In addition, the count of viable bacteria of L. plantarum L2 significantly increased cultivated at a pH 5.0 with a 15% sodium lactate sublethal treatment, compared with the control group. Further study revealed that genes related to membrane transport, amino acid metabolism, nucleotide metabolism, and cell growth were significantly upregulated. These findings will contribute to promote high-density cell culture of starter cultures production in the fermented food industry.

Characterization of an Intracellular Alkaline Serine Protease from Bacillus velezensis SW5 with Fibrinolytic Activity.

ISP-SW5 is an intracellular alkaline serine protease gene from Bacillus velezensis SW5 that was heterologously expressed in Escherichia coli BL21 (DE3). Sequence analysis indicated that the ISP-SW5 gene has 960 bp open reading frame and encodes a protein of 319 amino acid residues. Three-dimensional structure of ISP-SW5 with the fibrinolytic activity from Bacillus velezensis was predicted by in silico analysis. Gly219 was the most likely active site for the fibrinolytic activity of ISP-SW5. The recombinant enzyme ISP-SW5 was purified by Ni-NTA Superflow Column. SDS-PAGE showed that this enzyme had a molecular mass of 34 kDa. The result of native-PAGE and N-terminal sequencing showed that the N-terminal propeptide of ISP-SW5 was cleaved during the maturation of protease. The optimum pH and temperature were 8.0 and 40 °C, respectively. Enzyme activity was markedly inhibited by PMSF and EDTA but enhanced by 5 mM Ca2+ and 2 mM Zn2+ by up to 143% and 115%, respectively. Additionally, ISP-SW5 retained 93%, 78%, and 49% relative enzyme activity after incubation with 0.5 M, 1 M and 2 M NaCl, respectively, at 4 °C for 12 h. The enzyme activity determined by casein as substrate was 1261 U/mg. ISP-SW5 could degrade fibrin at an activity of 3428 U/mg, and its properties reflect its potential application in developing a novel biological catalyst for efficient fibrin hydrolysis in medical treatment.

RNA-seq transcriptomic analysis of green tea polyphenols regulation of differently expressed genes in Saccharomyces cerevisiae under ethanol stress.

Saccharomyces cerevisiae has been widely used to produce alcoholic beverages and bio-fuels; however, its performance is remarkably compromised by the increased ethanol concentration during the fermentation process. In this study, RNA-sequence analysis was used to investigate the protective effect of green tea polyphenols (GTP) on S. cerevisiae cells from ethanol-induced damage. GO and KEGG analysis showed that to deal with the stress of ethanol, large amounts of genes related to cell wall, cell membrane, basic metabolism and redox regulation were significantly differentially expressed (P < 0.05), while these undesired changes could be partly relieved by administration of GTP, suggesting its potential to enhance the ethanol tolerance of S. cerevisiae. The present study provided a global view of the transcriptomic changes of S. cerevisiae in response to the accumulation of ethanol and the treatment of GTP, which might deepen our understanding about S. cerevisiae and the fermentation process, and thus benefit the development of the bioethanol production industry.

Investigating the underlying mechanism of Saccharomyces cerevisiae in response to ethanol stress employing RNA-seq analysis.

Saccharomyces cerevisiae has been widely used for wine fermentation and bio-fuels production. A S. cerevisiae strain Sc131 isolated from tropical fruit shows good fermentation properties and ethanol tolerance, exhibiting significant potential in Chinese bayberry wine fermentation. In this study, RNA-sequence and RT-qPCR was used to investigate the transcriptome profile of Sc131 in response to ethanol stress. Scanning Electron Microscopy were carried out to observe surface morphology of yeast cells. Totally, 937 genes were identified differential expressed, including 587 up-regulated and 350 down-regulated genes, after 4-h ethanol stress (10% v/v). Transcriptomic analysis revealed that, most genes involved in regulating filamentous growth or pseudohyphal growth were significantly up-regulated in response to ethanol stress. The complex protein quality control machineries, Hsp90/Hsp70 and Hsp104/Hsp70/Hsp40 based chaperone system combining with ubiquitin-proteasome proteolytic pathway were both activated to recognize and degrade misfolding proteins. Genes related to biosynthesis and metabolism of two well-known stress-responsive substances trehalose and ergosterol were generally up-regulated, while genes associated with amino acids biosynthesis and metabolism processes were differentially expressed. Moreover, thiamine was also important in response to ethanol stress. This research may promote the potential applications of Sc131 in the fermentation of Chinese bayberry wine.

Extending the Shelf Life of Raw Milk and Pasteurized Milk with Plantaricin FB-2.

Raw milk and pasteurized milk are characterized by a short shelf life, and drinking expired raw milk and pasteurized milk causes illness. In the study, Plantaricin FB-2 (extracted from Lactiplantibacillus plantarum FB-2) was added to liquid milk. By evaluating the microbial growth, acidity changes, protein content, and sensory changes in raw milk and pasteurized milk during storage, it was found that when Plantaricin FB-2 was added at 0.4 g/kg, the shelf life of raw milk was extended by 3 days (7 days if not added). The shelf life of pasteurized milk with Plantaricin FB-2 was extended to 31 days (25 days in the control group), and the optimal amount was 0.3 g/kg. This confirmed that Plantaricin FB-2 can effectively prolong the shelf life of raw and pasteurized milk. This study provides valuable information for the application of bacteriocins produced by Lactiplantibacillus plantarum in raw milk and pasteurized milk to improve their shelf life.

Improving the viability of powdered Lactobacillus fermentum Lf01 with complex lyoprotectants by maintaining cell membrane integrity and regulating related genes.

In this study, Lactobacillus fermentum Lf01, which was screened out in the early stage of the experiment, had better fermentation performance as the research objectives, and was prepared into powder by vacuum freeze-drying technology. We used response surface methodology to optimize the composition of the mixture used to protect powdered L. fermentum. Our data demonstrated that 10% skim milk, 12% sucrose, 0.767% tyrosine, and 2.033% sorbitol ensured the highest survival rate (92.7%) of L. fermentum. We have initially explored the potential mechanism of the complex protectants through the protection effect under the electron microscope, and the analysis methods of Fourier transform infrared spectroscopy and transcriptomics. The complex protectants could effectively maintain the permeability barrier and structural integrity of cell membrane and avoid the leakage of cell contents. Transcriptomic data have also indicated that the protective effect of the complex protectants on bacteria during freeze-drying was most likely achieved through the regulation of related genes. We identified 240 differential genes in the treatment group, including 231 up-regulated genes and 9 down-regulated genes. Gene ontology (GO) and Kyoto encyclopaedia of genes and genomes (KEGG) analyses of differential expression genes (DEGs) indicated that genes involved in amino acid metabolism, carbohydrate metabolism, membrane transport, fatty acid biosynthesis and cell growth were significantly up-regulated. These new results provided novel insights into the potential mechanism of lyoprotectants at the cellular level, morphological level, and gene level of the bacteria. PRACTICAL APPLICATIONS: In our study, a strain of Lactobacillus fermentum Lf01 with good fermentation performance was selected to be prepared into powder by freeze-drying technique. Bacterial cells were unavoidably damaged during the freeze-drying process. As a result, we investigated the protective effects on L. fermentum of ten distinct freeze-dried protectants and their mixtures. We were also attempting to explain the mechanism of action of the complex protectants at the cellular level, morphological level, and gene level of the bacteria. This presents very important theoretical and practical significance for the preservation of strains and the production of commercial direct-investment starter.

The interaction effect between tea polyphenols and intestinal microbiota: Role in ameliorating neurological diseases.

Tea polyphenols (TP) are one of the most functional and bioactive substances in tea. The interactions between TP and intestinal microbiota suggest that probiotics intervention is a useful method to ameliorate neurological diseases. Now, numerous researches have suggested that TP plays a significant role in modulating intestinal bacteria, especially in the area of sustaining a stable state of intestinal microbial function and abundance. Furthermore, homeostatic intestinal bacteria can enhance the immunity of the host. The close reciprocity between intestinal microbiota and the central nervous system provides a new chance for TP to modulate neural-related diseases depending on intestinal microbiota. Therefore, based on the bidirectional relationship between the brain and the intestines, this review provides a new clue to solve insomnia symptoms and related neurological diseases that will enable us to better study the bidirectional effects of TP and intestinal microbiota on the improvement of host health. PRACTICAL APPLICATIONS: This review provides a new clue to solve insomnia symptoms and related neurological diseases that will enable us to better study bidirectional effects of TP and intestinal microbiota on the improvement of host health.

Polysaccharide Regulation of Intestinal Flora: A Viable Approach to Maintaining Normal Cognitive Performance and Treating Depression.

The intestinal tract of a healthy body is home to a large variety and number of microorganisms that will affect every aspect of the host's life. In recent years, polysaccharides have been found to be an important factor affecting intestinal flora. Polysaccharides are widely found in nature and play a key role in the life activities of living organisms. In the intestinal tract of living organisms, polysaccharides have many important functions, such as preventing the imbalance of intestinal flora and maintaining the integrity of the intestinal barrier. Moreover, recent studies suggest that gut microbes can influence brain health through the brain-gut axis. Therefore, maintaining brain health through polysaccharide modulation of gut flora deserves further study. In this review, we outline the mechanisms by which polysaccharides maintain normal intestinal flora structure, as well as improving cognitive function in the brain via the brain-gut axis by virtue of the intestinal flora. We also highlight the important role that gut microbes play in the pathogenesis of depression and the potential for treating depression through the use of polysaccharides to modulate the intestinal flora.

The gut microbiota-brain axis: Role of the gut microbial metabolites of dietary food in obesity.

Obesity, a social epidemic disease, threatens human health and affects economic stability worldwide. With the emergence of knowledge implicating the human gut microbiome, a complex relationship between the enteric nervous system, the gut microbiota and the central nervous system has become the focus of research attention. Which allows for the microbiota to influence the metabolism of an organism significantly. To date, data from animal and human studies provide a theoretical basis, that is food-derived natural compounds can work on anti-obesity via the microbiota-gut-brain axis (MGBA). Thus, we systematically summarize the role of the major metabolites in dietary metabolism and the potential for combating obesity and metabolism disorder. Simultaneously, the review examines the sufficient evidence surrounding the MGBA as a regulator of obesity. It will provide a new clue for developing the potential of gut-microbiota-targeted strategies and lay a good foundation for its operation for food intervention in anti-obesity.

Single-Cell Transcriptomic Analysis Demonstrates the Regulation of Peach Polysaccharides on Circadian Rhythm Disturbance.

SCOPE: Plant polysaccharides are thought to have a prebiotic effect, promoting the growth of probiotics, which may regulate circadian rhythms. This study evaluates the regulation of peach polysaccharides (PPS) on circadian rhythm disturbance through intestinal microbiota by a mouse model. METHODS AND RESULTS: PPS is administered to mice with circadian rhythm disturbance for 4 weeks. The study finds that PPS ameliorated the structural disorder of intestinal microbiota induced by continuous darkness, decreasing the ratio of Firmicutes/Bacteroidetes (F/B), thereby regulating furfural degradation, penicillin and cephalosporin biosynthesis, and antibiotic biosynthesis. Single-cell transcriptomics is used to determine the type of hypothalamus cells and the expression of clock genes in mice, showing that the number of astrocytes and oligoendrocytes cells in the hypothalamus of the transplanted mice is up-regulated, and the expression of neuroprotective genes such as Sox9 and Mobp increased. In addition, clock genes such as Cry2 and Per3 show significant callback. CONCLUSION: This study shows that PPS can ameliorate the imbalance of intestinal microbiota and cell dysfunction caused by circadian rhythm disorder, suggesting that PPS is a feasible strategy for the prevention and treatment of circadian rhythm disorder and related cognitive impairment.