The effect of structural changes on the activity of peroxidase with different initial state under high-pressure freezing.

The combined impact of initial state, pressure, and freezing on peroxidase denaturation during high-pressure freezing (HPF) processing of enzyme-containing foods remains unclear. This study investigated solid-liquid (initial low/high concentration) biphasic peroxidase using spectroscopic and computer simulation techniques to analyze structural changes affecting peroxidase (POD) activity under HPF. The results indicate that the primary factors determining POD activity during HPF treatment can be ranked as follows: concentration > physical state > pressure > freezing. Higher initial concentrations strengthen protein interactions, leading to a 1% increase in the molecular diameter and a 34% increase in molecular height of HL-POD, thereby increasing aggregation likelihood during crystallization and facilitating structural changes that activate enzymes by 6-17%. The amide I peak proves to be a reliable indicator for monitoring both POD activity and structural alterations. This study offers valuable insights for optimizing HPF technology in food processing.

A novel glycosyltransferase from Bacillus subtilis achieves zearalenone detoxification by diglycosylation modification.

Zearalenone (ZEN), a nonsteroidal estrogenic mycotoxin produced by Fusarium spp., contaminates cereals and threatens human and animal health by inducing hepatotoxicity, immunotoxicity, and genotoxicity. In this study, a new Bacillus subtilis strain, YQ-1, with a strong ability to detoxify ZEN, was isolated from soil samples and characterized. YQ-1 was confirmed to degrade more than 46.26% of 20 µg mL-1 ZEN in Luria-Bertani broth and 98.36% in fermentation broth within 16 h at 37 °C; one of the two resulting products was ZEN-diglucoside. Under optimal reaction conditions (50 °C and pH 5.0-9.0), the reaction mixture generated by YQ-1 catalyzing ZEN significantly reduced the promoting effect of ZEN on MCF-7 cell proliferation, effectively eliminating the estrogenic toxicity of ZEN. In addition, a new glycosyltransferase gene (yqgt) from B. subtilis YQ-1 was cloned with 98% similarity to Bs-YjiC from B. subtilis 168 and over-expressed in E. coli BL21 (DE3). ZEN glycosylation activity converted 25.63% of ZEN (20 µg mL-1) to ZEN-diG after 48 h of reaction at 37 °C. The characterization of ZEN degradation by B. subtilis YQ-1 and the expression of YQGT provide a theoretical basis for analyzing the mechanism by which Bacillus spp. degrades ZEN.

Pomelo (Citrus grandis (L.) Osbeck) sponge layers as a potential source of soluble dietary fiber: Evaluation of its physicochemical, structural and functional properties.

Pomelo sponge layer (PSL) had been considered as a potential source of soluble dietary fiber (SDF), while they were mostly disposed of as waste. To promote high-value utilization of pomelo wastes, this study extracted SDF from PSL of six varieties of pomelo, and their physicochemical, structural and functional properties were investigated. Results indicated that all PSL-SDFs showed good physicochemical and functional properties. Among them, PSL-SDF from grapefruit (GRSDF) showed better water holding capacity and swelling capacity, whereas Shatian pomelo PSL-SDF and Guanxi pomelo PSL-SDF had the highest thermal stability and oil holding capacity, respectively. Furthermore, compared with other PSL-SDFs, GRSDF displayed the lowest hydrolysis degree coupled with the best antioxidant and probiotic growth-promoting abilities. Finally, the correlation analysis showed that multiple beneficial effects of PSL-SDFs were markedly associated with their molecular weight and the concentrations of total phenolic, total flavonoids, rhamnose, galacturonic acid, glucose and arabinose. Collectively, these findings contributed to a better understanding of the physicochemical and functional properties of SDFs extracted from different PSLs, which provided a scientific basis for the development of PSL-SDFs into functional foods.

Effects of the Species and Growth Stage on the Antioxidant and Antifungal Capacities, Polyphenol Contents, and Volatile Profiles of Bamboo Leaves.

Bamboo leaves contain high concentrations of various biologically active compounds, such as polyphenols and volatiles, making them attractive as raw resources for antioxidant additives in the food industry. Here, we investigated the total phenolic content (TPC) and total flavonoid content (TFC) of four bamboo leaf extracts from two species (Phyllostachys edulis and Chimonocalamus delicatus) at two growth stages (first and second years). Antioxidant capacity was determined based on the radical-scavenging capacity against 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS+). We also assessed the antifungal capacity based on mycelial growth inhibition of Colletotrichum musae (C. musae), Botrytis cinerea (B. cinereain), and Alternaria alternata (A. alternata). Pearson's correlation coefficients showed that the TPC was significantly (p < 0.01) negatively correlated with the half-maximal inhibitory concentrations against DPPH and ABTS+, whereas the TFC was positively correlated with C. musae and B. cinereain growth inhibition, which suggest that TPC and TFC might be the major contributors to the antioxidant and antifungal capacities of bamboo leaves, respectively. The volatile organic compounds (VOCs) of bamboo leaves were also analyzed using gas chromatography-ion mobility spectrometry. The VOCs included twenty-four aldehydes, eleven alcohols, four furans, seven esters, fifteen terpenes, three ketones, one pyrazine, and thirty unidentified compounds. Principal component analysis, partial least squares discriminant analysis, and hierarchical cluster analysis were performed to assess the differences in the volatile profiles of the four bamboo leaf samples, from which 23 discriminatory VOCs with variable importance in the projection values > 1 were screened, and part of them were impacted by species or growth stage. These findings provide a theoretical foundation for the use of bamboo leaves.

Identification and structural characterization of key prebiotic fraction of soluble dietary fiber from grapefruit peel sponge layer and its regulation effect on gut microbiota.

In this study, the key prebiotic fraction of grapefruit peel sponge layer soluble dietary fiber (GSLSDF) was identified, and its structure characteristics and modulatory effect on intestinal microorganisms were investigated. Firstly, two fractions (GSLSDF-1 and GSLSDF-2) were isolated from GSLSDF, and the GSLSDF-1 showed a better prebiotic activity. Subsequently, GSLSDF-1 was found to have a low molecular weight and crystallinity, a loose and porous microstructure, and a high glucose content. Meanwhile, GSLSDF-1 was a dextran with a main chain linked by ß-1, 4 glycosidic bonds and branched by a ß-1, 6 glycosidic bonds. These structural characteristics were responsible for the favorable prebiotic activity of GSLSDF-1. Finally, the regulation effect of GSLSDF-1 on gut microbiota was analyzed in vitro fecal fermentation. Compared with the blank and GSLSDF groups, GSLSDF-1 could increase the relative abundances of Lactobacillus, Bacteroides, Bifidobacterium and Faecalibacterium coupled with decrease the relative abundances of Clostridium and Clostridioides. Furthermore, GSLSDF-1 promoted the production of short-chain fatty acids (SCFAs) by modulating the SCFAs synthesis pathway of intestinal microorganisms, while the NH3-N synthesis of intestinal microorganisms was inhibited by GSLSDF-1. Above results indicated that GSLSDF-1 was the key prebiotic fraction of GSLSDF, which could effectively optimize the intestinal microorganism composition.

Tailoring the oral sensation and digestive behavior of konjac glucomannan-gelatin binary hydrogel based bigel: Effects of composition and ratio.

In the food industry, there is a growing demand for bigels that offer both adaptable oral sensations and versatile delivery properties. Herein, we developed bigels using a binary hydrogel of konjac glucomannan (KGM) and gelatin (G) combined with a stearic acid oleogel. We closely examined how the oleogel/hydrogel volume ratio (φ) and the KGM/G mass ratio (γ) influenced various characteristics of the bigels, including their microstructure, texture, rheological properties, thermal-sensitivity, oral tribology, digestive stability, and nutraceutical delivery efficiency. A noteworthy observation was the structural evolution of the bigels with increasing φ values: transitioning from oleogel-in-hydrogel to a bicontinuous structure, and eventually to hydrogel-in-oleogel. Lower γ values yielded a softer, thermally-responsive bigel, whereas higher γ values imparted enhanced viscosity, stickiness, and spreadability to the bigel. Oral tribology assessments demonstrated that φ primarily influenced the friction sensations at lower chewing intensities. In contrast, γ played a significant role in augmenting oral friction perceptions during more intense chewing. Additionally, φ dictated the controlled release and bioaccessibility of curcumin, while γ determined digestive stability. This study provides valuable insights, emphasizing that through meticulous selection and adjustment of the hydrogel matrix composition, bigels can be custom-fabricated to achieve specific oral sensations and regulated digestive behaviors.

Effects of Lactobacillus plantarum FM 17 fermentation on jackfruit polysaccharides: Physicochemical, structural, and bioactive properties.

Fermentation is a novel technology for modifying polysaccharides in fruits and improving their bioactivities. In this work, we introduced Lactobacillus plantarum FM 17 to ferment jackfruit pulp and subsequently purified polysaccharides from unfermented (JP) and fermented jackfruit pulp (JP-F). Furthermore, the physicochemical, structural, and bioactive properties of JP and JP-F were investigated. Results showed fermentation dropped the glucuronic acid, molecular weight, and particle size of JP-F by 15.62 %, 23.92 %, and 39.43 %, respectively, compared with those of JP. JP-F showed higher solubility than JP but lower apparent viscosity and thermal stability. Additionally, FT-IR spectra and X-ray diffraction analysis showed that fermentation did not alter the different types of glycosidic bonds and the fundamental polysaccharide structure. Moreover, JP-F exhibited stronger DPPH and ABTS free radical scavenging properties than JP and stronger stimulation on macrophage secretion of NO and IL-6 in RAW 264.7 cells. Therefore, using L. plantarum FM 17 for fermentation can alter physical and chemical properties of jackfruit pulp polysaccharides, enhancing their bioactivities.

Analysis of Flavonoid Metabolites in Citrus reticulata 'Chachi' at Different Collection Stages Using UPLC-ESI-MS/MS.

Flavonoids are essential substances with antioxidant properties and high medicinal value. Citrus reticulata 'Chachi' peel (CRCP) is rich in flavonoids and has numerous health benefits. The different maturity periods of CRCP can affect the flavonoid contents and pharmacological effects. In this study, we successfully performed UPLC-ESI-MS/MS-based metabolic analysis to compare the metabolites of CRCP at different harvesting periods (Jul, Aug, Sep, Oct, Nov, and Dec) using a systematic approach. The results revealed the identification of a total of 168 flavonoid metabolites, including 61 flavones, 54 flavonols, 14 flavone C-glycosides, 14 dihydroflavones, 9 flavanones, 8 isoflavones, 3 flavanols, 3 dihydroflavonols, and 2 chalcones. Clustering analysis and PCA were used to separate the CRCP samples collected at different stages. Furthermore, from July to December, the relative contents of isoflavones, dihydroflavones, and dihydroflavonols gradually increased and flavanols gradually decreased over time. The relative content of flavonoid C-glycosides showed an increasing and then decreasing trend, reaching the highest value in August. This study contributes to a better understanding of flavonoid metabolites in CRCP at different harvesting stages and informs their potential future utilization.

Flexible control of bigel microstructure for enhanced stability and flavor release during oral consumption.

Edible delivery systems such as emulsions and gels that possess flexible oral flavor sensation and comprehensive stability under freeze-thaw processing are highly demanded in the frozen food industry. Bigels were fabricated via emulsification of stearic acid based oleogel with konjac glucomannan (KGM)-gelatin (G) based binary hydrogel. By varing the KGM/G mass ratio (γ) and oleogel/hydrogel volume ratio (φ) of bigels, modulation over the micromorphology, tribology, flavor sensation and cheese stick imitating capacity were achieved. Notably, as φ increased from O4:W6 to O5:W5, the microstructural transformation from oleogel-in-hydrogel to bicontinuous morphology emerged as a remarkable feature. The influence of γ was evident in bicontinuous bigels, significantly enhancing water holding capacity (WHC) by 3.38-fold as γ transitioned from 1KGM:5G to 6KGM:5G during freeze-thaw cycles. φ and γ both played pivotal roles in altering the microstructure and rheological properties of the bigels, enabling customizable release of bioactive components and flavor perception. Oleogel-in-hydrogel bigels effectively prevented bioactive compound leakage during freeze-thaw conditions, while bicontinuous bigels demonstrated sustained flavor release during oral mastication. Release behaviors were dual-controlled by φ and γ, reducing oil-soluble flavor release with increased φ and lowering hydrophilic volatile release with elevated γ. Moreover, bigel-based cheese sticks showcased lower viscosity, higher creep recovery rates, and enhanced mouthfeel during minimal oral chewing, suggesting their potential in mimicking the properties of commercial counterparts. These findings extend insights into bigel design for tailored flavor release and bioactive preservation in food products.

Interaction mechanism of carotenoids and polyphenols in mango peels.

In this study, carotenoids and polyphenols were demonstrated to be the major active substances in the crude pigment extracts (CPE) of mango peels, accounting for 0.26 mg/g and 0.15 mg/g, respectively. The interactions between carotenoids and polyphenols in CPE was observed, as evidenced by that polyphenols significantly improved the antioxidant activity and storage stability of carotenoids in the CPE. Meanwhile, scanning electron microscopy showed that polyphenols are tightly bound to carotenoids. To further elucidate the interaction mechanism, the monomers of carotenoids and polyphenols were identified by HPLC and LC-MS analysis. Lutein (203.85 µg/g), ß-carotene (41.40 µg/g), zeaxanthin (4.20 µg/g) and α-carotene (1.50 µg/g) were authenticated as the primary monomers of carotenoids. Polyphenols were mainly consisted of gallic acid (95.10 µg/g), quercetin-3-ß-glucoside (29.10 µg/g), catechin (11.85 µg/g) and quercetin (11.55 µg/g). The interaction indexes between carotenoid and polyphenol monomer of CPE were calculated. The result indicated that lutein and gallic acid showed the greatest synergistic effect on the scavenging of DPPH and ABTS radical, suggesting the interaction between carotenoids and polyphenols in CPE was mainly caused by lutein and gallic acid. Molecular dynamics simulations and thermodynamic parameters analysis demonstrated that hydrogen bonding, electrostatic interactions, and van der Waals forces played dominant roles in the interaction between lutein and gallic acid, which was confirmed by Raman and X-ray diffraction. These results provided a new perspective on the interaction mechanism between carotenoids and polyphenols, which offered a novel strategy for the enhancement of the activities and stability of bioactive substances.

Structural elucidation and physicochemical properties of litchi polysaccharide with the promoting effect on exopolysaccharide production by Weissella confusa.

Exopolysaccharide (EPS), as a secondary metabolite of microorganisms, has been commonly used in the dairy industry to replace the traditional stabilizers. However, the EPS production by microorganism is generally low, which limits its application. A litchi polysaccharide (Lzp2-2) with the promoting effect on EPS production by Weissella confusa was purified. The SEM and FT-IR analysis indicated that Lzp2-2 displayed a compact netlike structure and typical bands of carbohydrates. The structure of Lzp2-2 was further elucidated, which was comprised of a major backbone structure [→3)-ß-D-Galp-(1→6)-ß-D-Galp-(1 â†’ 6)-ß-D-Galp-(1 â†’ 3)-ß-D-Glcp-(1 â†’ 6)-α-D-Glcp-(1 â†’ 3)-α-D-Glcp-(1→] linked with two side chains [α-L-Araf-(1 â†’ 5)-α-L-Araf-(1→, and ß-D-Glcp-(1 â†’ or α-L-Araf-(1→] at the O-3 and O-6) of ß-D-Galp-(1→, respectively. Finally, Lzp2-2 was applied as an additive to the medium of yoghurt fermented by W. confusa. The results indicated Lzp2-2 not only promoted the EPS production to improve the viscosity, texture and mouthfeel of yoghurt, but also facilitated the generation of other secondary metabolites (volatile organic compounds), thus elevating the flavor of yoghurt.

Effects of high pressure synergistic enzymatic physical state and concentration on the denaturation of polyphenol oxidase.

The synergistic effect of the initial state of the enzyme and pressure level on the denaturation of PPO has not been clear yet, but it significantly affects the application of high hydrostatic pressure (HHP) in the enzyme-containing food processing. Solid (S-) and low/high concentration liquid (LL-/HL-) polyphenol oxidase (PPO) was used as the study object, and the microscopic conformation, molecular morphology and macroscopic activity of PPO under HHP treatments (100-400 MPa, 25 °C/30 min) were investigated by spectroscopic techniques. The results show that the initial state has a significant effect on the activity, structure, active force and substrate channel of PPO under pressure. The effec can be ranked as follows: physical state > concentration > pressure, S-PPO > LL-PPO > HL-PPO. High concentration has a weakening effect on the pressure denaturation of the PPO solution. Under high pressure, the α-helix and concentration factors play a crucial role in stabilizing the structure.

Induced Expression of the Acinetobacter sp. Oxa Gene in Lactobacillus acidophilus and Its Increased ZEN Degradation Stability by Immobilization.

Zearalenone (ZEN, ZEA) contamination in various foods and feeds is a significant global problem. Similar to deoxynivalenol (DON) and other mycotoxins, ZEN in feed mainly enters the body of animals through absorption in the small intestine, resulting in estrogen-like toxicity. In this study, the gene encoding Oxa, a ZEN-degrading enzyme isolated from Acinetobacter SM04, was cloned into Lactobacillus acidophilus ATCC4356, a parthenogenic anaerobic gut probiotic, and the 38 kDa sized Oxa protein was expressed to detoxify ZEN intestinally. The transformed strain L. acidophilus pMG-Oxa acquired the capacity to degrade ZEN, with a degradation rate of 42.95% at 12 h (initial amount: 20 µg/mL). The probiotic properties of L. acidophilus pMG-Oxa (e.g., acid tolerance, bile salt tolerance, and adhesion properties) were not affected by the insertion and intracellular expression of Oxa. Considering the low amount of Oxa expressed by L. acidophilus pMG-Oxa and the damage to enzyme activity by digestive juices, Oxa was immobilized with 3.5% sodium alginate, 3.0% chitosan, and 0.2 M CaCl2 to improve the ZEN degradation efficiency (from 42.95% to 48.65%) and protect it from digestive juices. The activity of immobilized Oxa was 32-41% higher than that of the free crude enzyme at different temperatures (20-80 °C), pH values (2.0-12.0), storage conditions (4 °C and 25 °C), and gastrointestinal simulated digestion conditions. Accordingly, immobilized Oxa could be resistant to adverse environmental conditions. Owing to the colonization, efficient degradation performance, and probiotic functionality of L. acidophilus, it is an ideal host for detoxifying residual ZEN in vivo, demonstrating great potential for application in the feed industry.

Effect of Heat Transfer Medium and Rate on Freezing Characteristics, Color, and Cell Structure of Chestnut Kernels.

This paper compared the effects of air and nitrogen on the freezing characteristics, color, and cell structures of chestnut kernels at different rates of heat transfer and adopted liquid nitrogen spray quick-freezing (NF-40 °C/-60 °C/-80 °C/-100 °C) and still air freezing (AF-20 °C/-40 °C) as the freezing methods. The ratio of heat transfer coefficients in N2 groups was two times as high as those in air groups, and NF-100 °C and NF-80 °C showed better freezing characteristics, good protection for cytoskeletons, and the color was similar to those of the fresh group. Taking both Multivariate Analysis of Variance (Principal Components Analysis and Cluster Analysis) and economic factors, NF-80 °C can be used as a suitable method for chestnut kernel freezing. When the ambient freezing temperature was lower than Tg, both NF and AF treatment groups presented poor quality. The rate and medium of heat transfer jointly influenced the freezing characteristics and quality. The former had a greater effect than the latter, however.

Effect of citric acid/ pomelo essential oil nanoemulsion combined with high hydrostatic pressure on the quality of banana puree.

In this work, the influence of citric acid & pomelo essential oil nanoemulsion (CA&PEN) assisted with HHP on microbial counts, oxidative enzyme activity and related quality of banana puree were examined. The total aerobic bacteria (TAB) counts of all groups decreased to 1.2 âˆ¼ 2.52 lg CFU/g from 3.97 lg CFU/g, except the CA&PEN group, which was still below the detection level. CA&PEN combined with HHP (500 or 600 MPa, 5 min) succeeded in keeping TAB counts of banana puree below the detection limit for 3 months of cold storage. During 90 days of cold storage, the color, total phenolics, DPPH and ABTS antioxidant capacities were better conserved in acidified groups than non-acidified groups. In conclusion, CA&PEN assisted with HHP can be utilized to promote the inhibition of enzymatic browning and maintain the quality of banana puree, due to its reduced oxidative enzyme activity, low pH, strong antioxidant capacity and excellent color retention.

Influence of Cultivar and Turbidity on Physicochemical Properties, Functional Characteristics and Volatile Flavor Substances of Pomelo Juices.

In this study, the influences of pomelo cultivars on physicochemical properties, functional characteristics, and volatile compounds of juices were investigated. Among these six varieties, the highest juice yield (73.22%) was obtained in grapefruit. Sucrose and citric acid were the main sugar component and organic acid of pomelo juices, respectively. The results showed that the cv. Pingshanyu pomelo juice and grapefruit juice had the highest sucrose (87.14 g L-1, 97.69 g L-1) and citric acid content (14.49 g L-1, 13.7 g L-1), respectively. Moreover, the naringenin was the main flavonoid of pomelo juice. Additionally, the total phenolics, total flavonoids, and ascorbic acid concentrations of grapefruit and cv. Wendanyu pomelo juice were higher than those of other varieties of pomelo juices. Furthermore, 79 volatile substances were identified from the juices of six pomelo cultivars. Hydrocarbons were the predominant volatile substances, and the limonene was the characteristic hydrocarbon substance of pomelo juice. In addition, the pulp content of pomelo juice also presented great effects on its quality and volatile compounds composition. Compared to low pulp juice, the corresponding high pulp juice had higher sucrose, pH, total soluble solid, acetic acid, viscosity, bioactive substances and volatile substances. The effects of cultivars and variation in turbidity on juice are highlighted. It is useful for pomelo breeders, packers and processors to understand the quality of the pomelo they are working with. This work could provide valuable information on selecting suitable pomelo cultivars for juice processing.

Evaluation of Dynamic Changes and Regularity of Volatile Flavor Compounds for Different Green Plum (Prunus mume Sieb. et Zucc) Varieties during the Ripening Process by HS-GC-IMS with PLS-DA.

Headspace gas chromatography-ion mobility spectrometry and partial-least-squares discriminant analysis (PLS-DA) were adopted to analyze the rule of change in flavor substances for different varieties of green plums at different levels of maturity (S1-immature, S2-commercially mature, and S3-fully mature). The results showed that 68 kinds of volatile flavor substances were identified in all green plum samples. The types and contents of such volatile substances experienced a V-shaped trend with an increasing degree of green plum maturity. During the S1 and S2 stages, aldehydes, ketones, and a small amount of alcohols were the main volatile flavor substances in the green plum samples. During the S3 stage, esters and alcohols were the most important volatile flavor components in the green plum pulp samples, followed by terpenes and ketones. YS had the most types and highest contents of volatile flavor substances in three stages, followed by GC and DZ. By using the PLS-DA method, this study revealed the differences in flavor of the different varieties of green plums at different maturity stages, and it identified eight common characteristic volatile flavor substances, such as ethyl acetate, 3-methylbutan-1-ol, and 2-propanone, produced by the different green plum samples during the ripening process, as well as the characteristic flavor substances of green plums at each maturity stage (S1-S3).

Effects of Pectinase Pre-Treatment on the Physicochemical Properties, Bioactive Compounds, and Volatile Components of Juices from Different Cultivars of Guava.

In this study, the physicochemical properties, antioxidant capacity, and volatile compounds of the juices of different guava cultivars before and after pectinase treatment were evaluated. The results showed that the guava juice of the small fragrant (SF) cultivar exhibited the highest ascorbic acid concentration (1761.09 mg/L), and the highest contents of total phenolics (329.52 mg GAE/L) and total flavonoids (411.13 mg RE/L) were both found in the juice of the watermelon red (WR) cultivar. After pectinase treatment, the juice yield and the titratable acid, sugar components, total phenolics and total flavonoids, and antioxidant capacity levels of the guava juices were all higher than those of the non-pectinase group. However, lower sensory evaluation scores were obtained in the pectinase-treated guava juices. Aldehydes and terpenoids were the main flavor components in the guava juices, which were responsible for the aroma of the juice, while their relative contents were different in the four cultivar guava juices. Furthermore, pectinase treatment could change the amounts and relative contents of volatile compounds in the guava juice. During the pectinase treatment process, the relative contents of the main aroma constituents in the guava juices were significantly decreased. The findings of this research provide valuable information for the processing of guava juice.

Effects of selected Bacillus strains on the biogenic amines, bioactive ingredients and antioxidant capacity of shuidouchi.

The control of biogenic amines (BAs) is crucial to guarantee the safety of fermented soybean products. In this study, the BAs composition of eleven shuidouchi samples was analyzed, and the BAs degradation strains were selected from shuidouchi samples with a low BAs content. Then the influences of screened BAs degradation strains on BAs, total phenolics (TP), total flavonoids (TF), isoflavones and the antioxidant ability of fermented shuidouchi were evaluated. Results showed that the total BAs content of all shuidouchi samples was within the safe range, while the GZXQ, GZQY and GZMX samples had higher levels of tyramine. Meanwhile, 109 strains were isolated from the YNLJ, GZLG, GZMZ, GZDY, and YNHY sample. Bacillus tropicus A11, Bacillus siamensis D11, Bacillus subtilis T2, and B. subtilis U2 with higher BAs degradation capacity and lower BAs production ability were selected to ferment shuidouchi. These four Bacillus strains could effectively control the BAs concentration of fermented shuidouchi, especially B. tropicus A11 and B. siamensis D11. Furthermore, compared to naturally fermented shuidouchi, higher levels of antioxidant ability, TP, TF, daidzein, glyciein, and genistein were found in the shuidouchi fermented with selected strains. These findings demonstrated that these screened strains could be applied as potential candidates for the production of high quality shuidouchi.

Cellulose nanofiber from pomelo spongy tissue as a novel particle stabilizer for Pickering emulsion.

For the high-value utilization of agricultural wastes to promote sustainable development, in this work, pomelo spongy tissue cellulose nanofibers (PCNFs) with lengths >3 µm and widths 33-64 nm were prepared by high pressure homogenization (HPH). The PCNFs were used to stabilized Pickering emulsion, and the emulsion with oil phase fraction in the range of 10 % to 50 % (w/w) exhibited outstanding stability. The increase in PCNFs concentration also enhanced the three-dimensional network structure, resulting in higher stability of the emulsion. Moreover, the droplet size distribution of emulsion would be greatly improved by moderate heating. No creaming was observed in emulsions over a wide range of ionic strengths (20-200 mM) after storage for 30 d. And the excellent emulsifying properties of the PCNFs were mainly attributed to their adsorption at the oil-water interface and the formation of a three-dimensional network structure. All the results indicated that the PCNF would be a promising novel stabilizer for Pickering emulsions.