Pressure-controlled steam explosion as pretreatment for efficient extraction of Tremella fuciformis polysaccharide: Structure and bioactivity.

Tremella fuciformis (TF) is a mushroom with rich nutritional and medicinal value. This study aimed to develop an efficient extraction technique for TF polysaccharide (TFP) to enhance its health benefits. TF was subjected to steam explosion (SE) pretreatment at 0.5, 1.0, and 1.5 MPa for 60 s, followed by polysaccharide extraction. The extraction yield of TFP increased from 15.42 % to 50.16 % at 1.0 MPa. SE disrupted the dense structure of TFP, significantly improving total sugar and uronic acid contents, monosaccharide molar percentages of mannose and glucose, specific surface area, and ζ potential by 0.16, 0.4, 0.01, 0.83, 0.19, and 0.26 times at 0.5 MPa (P < 0.05). With increasing SE pressure, the thermal stability of TFP was enhanced, while its elasticity, viscosity, molecular weight, and particle size were reduced. TFP at 0.5 MPa significantly extended the lifespan of Drosophila melanogaster, with Tmax reaching 74 d for females and 60 d for males at a dosage of 0.015625 %, indicating a 0.32-fold enhancement. TFP enhanced climbing ability and antioxidant stress resistance, increased antioxidant enzyme activities and total antioxidant capacity, and reduced malondialdehyde levels, indicating its anti-aging effects. These findings provide theoretical and technical support for the high-value development and utilization of TFP.

Risk assessment of multiple pesticide residues in Agrocybe aegerita: Based on a 3-year monitoring survey.

The presence of pesticide residues in Agrocybe aegerita has raised an extensive concern. In this paper, based on a 3-year monitoring survey, the dietary exposure risks through A. aegerita consumption for different population subgroups were assessed using both deterministic and semi-probabilistic approaches under the best-case and the worst-case scenarios. Among the 52 targeted pesticides, 28 different compounds were identified in the concentration range of 0.005-3.610 mg/kg, and 87.4 % of samples contained one or more pesticide residues. The most frequently detected pesticide was chlormequat, followed by chlorfenapyr and cyhalothrin. The overall risk assessment results indicated extremely low chronic, acute, and cumulative dietary exposure risks for consumers. Using the ranking matrix, intake risks of pesticides were ranked, revealing endsoluran, chlorpyrifos, and methamidophos to be in the high-risk group. Finally, considering various factors such as the toxicity and risk assessment outcomes of each positive pesticide, use suggestions were proposed for A. aegerita cultivation.

Residue Behaviors and Degradation Dynamics of Insecticides Commonly Applied to Agrocybe aegerita Mushrooms from Field to Product Processing and Corresponding Risk Assessments.

Residual pesticides in Agrocybe aegerita mushroom have emerged as a significant concern and bring much uncertainty due to processing procedures. In this study, a modified QuEChERS sample preparation procedure and UPLC-MS/MS were used to analyze the residual levels of four commonly used pesticides in A. aegerita from field to product processing. The field results showed that dissipation of these targeted chemicals was consistent with the first-order kinetics, and the half-life time ranged from 20.4 h to 47.6 h. The terminal residues of the four pesticides at harvest time ranged from 9.81 to 4412.56 µg/kg in raw mushroom. The processing factors (PFs) of clothianidin, diflubenzuron, chlorbenzuron, and pyridaben ranged from 0.119 to 0.808 for the drying process and from 0.191 to 1 for the washing process. By integrating the data from the field trials, the PFs, and the consumption survey, the chronic dietary risks of the target chemicals via A. aegerita intake ranged from 2.41 × 10-5 to 5.69 × 10-2 for children and from 6.34 × 10-6 to 1.88 × 10-2 for adults, which are considerably below the threshold of 1, indicating no unacceptable risk to consumers in the Fujian province of China. This research offers foundational data for appropriate use and the maximum residue limit (MRL) establishment for these four insecticides in A. aegerita.

Steam Explosion-Assisted Extraction of Polysaccharides from Pleurotus eryngii and Its Influence on Structural Characteristics and Antioxidant Activity.

Pleurotus eryngii (PE) has been sought after for its various health benefits and high content of phenolic compounds. This study explored the feasibility of steam explosion (SE)-assisted extraction of polysaccharides with high antioxidant capacities from PE. An orthogonal experimental design (OED) was used to optimize the SE-assisted extraction of PE. The influence of the optimized SE-assisted extraction on the physicochemical properties of PE polysaccharides was determined by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), monosaccharide compositional analysis and antioxidant capacity assays. Under optimal SE conditions, SE-assisted extraction increased the polysaccharide yield by 138% compared to extraction without SE-assistance. In addition, SEM demonstrated that SE-assisted extraction markedly altered the spatial structure of Pleurotus eryngii polysaccharides (PEP), and monosaccharide compositional analysis revealed that this pretreatment significantly increased the proportions of some monosaccharides, such as glucose, rhamnose and arabinose, in the isolated PEP. FTIR spectra indicated no change in the major chemical functional groups of PEP. PEP extracted by SE-assisted extraction had significantly increased free radical scavenging and antioxidant capacities. In conclusion, SE-assisted extraction appears to be a novel polysaccharide extraction technology, which markedly increases extraction yields and efficiency and can increase the biological activity of polysaccharide extracts.

Influence of Heat Treatment on Tea Polyphenols and Their Impact on Improving Heat Tolerance in Drosophila melanogaster.

This study investigated the potential mechanism of action of tea polyphenols (TPs), one of the major active ingredients in tea, to enhance heat resistance in Drosophila and the attenuating effect of heat treatment of TPs on their efficacy. The results showed that TPs were able to prolong the average survival time of Drosophila under high-temperature stress (p < 0.05), but the effect of TPs in prolonging the survival time of Drosophila melanogaster was significantly reduced (p < 0.05) with increasing TP heat-treatment time until it disappeared. The composition of TPs changed after heat treatment. It was also shown that the weakening of the effect of TPs in improving the heat tolerance of Drosophila was related to the decrease in the content of catechins and phenolic acids in their fractions as well as with the increase in the content of laccase. Transcriptomic analysis showed that the effect of TPs on heat tolerance in Drosophila melanogaster was closely related to the longevity regulation pathway, the neuroactive ligand-receptor interaction signaling pathway, and the drug metabolism-cytochrome P450 pathway. Metabolomics analysis showed that the effect of TP intervention in improving the body's heat tolerance was mainly related to amino acid metabolism and energy metabolism. However, thermal processing weakened the relevance of these transcriptomes and metabolomes. The present study reveals the mechanism of action by which heat-treated TPs affect the body's heat tolerance, which is important for the development and utilization of the heat-protection function of tea.

Characterization, stability and antioxidant activity of curcumin nanocomplexes with soy protein isolate and pectin.

Curcumin (Cur) has antioxidant, anti-inflammatory and other biological activities, but its poor stability, low water solubility and other defects limit the application. Herein, Cur was nanocomposited with soy isolate protein (SPI) and pectin (PE) for the first time and its characterization, bioavailability and antioxidant activity were discussed. The optimal encapsulation process of SPI-Cur-PE was as follow: the addition amount of PE was 4 mg, Cur was 0.6 mg and at pH of 7. It was observed by SEM that SPI-Cur-PE were partially aggregated. The average particle size of SPI-Cur-PE was 210.1 nm and the zeta potential was -31.99 mV. Through XRD, FT-IR and DSC analysis, the SPI-Cur-PE was formed through hydrophobic interaction and electrostatic interaction. The SPI-Cur-PE released more slowly in simulated gastrointestinal treatment and displayed higher photostability and thermal stability. SPI-Cur-PE, SPI-Cur and free Cur had scavenging activities for 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) and 1,1-diphenyl-2-picryl-hydrazyl (DPPH) radicals.

Effective Preservation of Chilled Pork Using Photodynamic Antibacterial Film Based on Curcumin-ß-Cyclodextrin Complex.

A biodegradable photodynamic antibacterial film (PS-CF) was prepared using the casting method, with κ-Carrageenan (κ-Car) as the film-forming substrate and curcumin-ß-cyclodextrin (Cur-ß-CD) complex as photosensitizer. Chilled pork samples were coated with PS-CF and stored at 4 °C to investigate the effects of PS-CF combined with LED light irradiation (425 nm, 45 min) (PS+L+) on pork preservation during 10 days of storage. The total viable count (TVC) of bacteria, total volatile basic nitrogen value (TVB-N) and the pH of pork treated with PS+L+ were all lower than the control, and the water-holding capacity (WHC) was higher. Ten days later, the TVB-N value was 12.35 ± 0.57 mg/100 g and the TVC value was 5.78 ± 0.17 log CFU/g, which was within the acceptable range. Sensory evaluation determined that the color, odor, and overall acceptability of pork treated with PS+L+ were significantly better than the control. These findings suggest that PS+L+ treatment effectively extended the shelf life of chilled pork from ~4-5 to 10 days. Correlation analysis showed that the sensory quality of the chilled pork significantly correlated with total bacterial counts, TVB-N and thiobarbituric acid reactive substances (TBARS) (p < 0.05), suggesting that these biomarkers could be used as standard indicators for evaluating the freshness of chilled pork. These findings demonstrate the effectiveness of Cur-ß-CD photodynamic antibacterial film for the preservation of chilled pork and provide a theoretical basis for the application of the film for the preservation of fresh food in general.

Influence of ultrasonic-microwave power on the structure and in vitro digestibility of lotus seed starch-glycerin monostearin complexes after retrogradation.

The digestibility of starches with high amylose content can be modulated by the complexation with lipids, which is largely influenced by physical modification methods. In the current work, the impact of ultrasound-microwavre synergistic treatment on the structure and in vitro digestibility of lotus seed starch-glycerin monostearin complexes (LS-GMSc) after retrogradation were investigated. Results showed that 400 W of ultrasound treatment combined with microwave was more conducive to the formation of LS-GMSc, which increased the microcrystalline region and ordering degree of starch. However, excessively high ultrasound intensity weakened V-type diffraction and promoted amylose recrystallization. Investigation of the micromorphology and thermal properties revealed that the existence of V-complexes retarded starch retrogradation, and this effect was significantly enhanced after appropriate ultrasound (400 W) treatment. The digestion showed that 400 W of ultrasound treatment improved the digestive resistance of starch complexes and increased the content of resistant starch. These results are significant to the theoretical foundation and functional application of V-type complexes on anti-gelling and anti-digestion.

Corrigendum: Hsian-Tsao (Mesona chinensis Benth.) extract improves the thermal tolerance of Drosophila melanogaster.

[This corrects the article DOI: 10.3389/fnut.2022.819319.].

Chlorella unsaturated fatty acids suppress high-fat diet-induced obesity in C57/BL6J mice.

Chlorella has been identified as a rich source of unsaturated fatty acids. Since the antiobesity effects of unsaturated fatty acids have been well documented; therefore, we explored the antiobesity actions of chlorella unsaturated fatty acids (C.UFAs) in the current study. The obtained results demonstrated C.UFAs, which contain abundant linoleic acid, could retard body weight gain (reducing body weigh by 13.93% after 16 weeks of treatment), improve blood glucose (19.29% lower) and lipid profile (23.45% lower in TG, 8.76% lower in TC) compared to high-fat diet-fed C57BL/6J mice. The possible underlying mechanisms might involve reducing hepatic lipid accumulation via down-regulation of lipogenic genes (PPARγ, C/EBPα, LPL, aP2, FAS, and SREBP-1c) and up-regulation of lipolytic gene (adiponectin). We also demonstrate C.UFAs could reduce HFD-induced adipocyte hypertrophy via activation of AMPK signaling pathway in adipose tissue and liver. In summary, our study highlights the potential of C.UFAs as a functional food for obesity management. PRACTICAL APPLICATION: Chlorella has already been commercialized as a functional food antiobesity function. In the current study, the unsaturated fatty acids isolated from chlorella were found to exert beneficial effects on hyperglycemia, hyperlipidemia, hepatic steatosis, and adipocyte hypertrophy in high-fat diet-fed mice. This may provide theoretical foundation for developing novel chlorella-based functional foods.

High-Amylose Corn Starch Regulated Gut Microbiota and Serum Bile Acids in High-Fat Diet-Induced Obese Mice.

High-amylose corn starch is well known for its anti-obesity activity, which is mainly based on the regulatory effects on gut microbiota. Recently, the gut microbiota has been reported to improve metabolic health by altering circulating bile acids. Therefore, in this study, the influence of high-amylose corn starch (HACS) on intestinal microbiota composition and serum bile acids was explored in mice fed with a high fat diet (HFD). The results demonstrated HACS treatment reduced HFD-induced body weight gain, hepatic lipid accumulation, and adipocyte hypertrophy as well as improved blood lipid profiles. Moreover, HACS also greatly impacted the gut microbiota with increased Firmicutes and decreased Bacteroidetes relative abundance being observed. Furthermore, compared to ND-fed mice, the mice with HFD feeding exhibited more obvious changes in serum bile acids profiles than the HFD-fed mice with the HACS intervention, showing HACS might restore HFD-induced alterations to bile acid composition in blood. In summary, our results suggested that the underlying mechanisms of anti-obesity activity of HACS may involve its regulatory effects on gut microbiota and circulating bile acids.

Hsian-Tsao (Mesona chinensis Benth.) Extract Improves the Thermal Tolerance of Drosophila melanogaster.

Global warming has prompted scientific communities to consider how to alleviate thermal stress in humans and animals. The present study assessed the supplementation of hsian-tsao extract (HTE) on thermal stress in Drosophila melanogaster and preliminarily explicated its possible physiological and molecular mechanisms. Our results indicated that the lethal time for 50% of female flies fed on HTE was significantly longer than that of male flies at the same heat stress temperature. Under thermal stress, the survival time of females was remarkably increased in the HTE addition groups compared to the non-addition group. Thermal hardening by acute exposure to 36°C for 30 min (9:00 to 9:30 a.m.) every day could significantly prolong the longevity of females. Without thermal hardening, HTE increased the antioxidant capacity of females under heat stress, accompanied by an increment of catalase (CAT) activity, and the inhibition for hydroxyl radicals (OH⋅) and superoxide anions (⋅O2 -). Superoxide dismutase (SOD) activity and the inhibition for ⋅O2 - was significantly affected by thermal hardening in the non-HTE addition groups, and significant differences were shown in CAT and SOD activities, and the inhibition for ⋅O2 - among groups with thermal hardening. After heat exposure, heat shock protein 70 (Hsp70) was only up-regulated in the group with high levels of added HTE compared with the group without and this was similar in the thermal hardening group. It was concluded that the heat stress-relieving ability of HTE might be partly due to the enhancement of enzymatic activities of SOD and CAT, and the inhibition for OH⋅ and ⋅O2 -. However, the expression levels of Hsp70 were not well related to thermal tolerance or heat survival.

Analysis of Mn2+ and Zn2+ Ions in Macroalgae with Heteroelement-Doped Carbon-Based Fluorescent Probe.

Kelp and laver are large economic macroalgae in China, which are rich in nutrients, especially Mn and Zn. Excessive intake of Mn and Zn can be harmful to the human body. Therefore, it is necessary to develop a convenient and efficient method to detect the contents of Mn and Zn in macroalgae. In this experiment, red carbon dots (R-CDs) doped with N and S elements were prepared by the thermal solvent method. The obtained R-CDs displayed excitation wavelength-independent fluorescent emission in the red spectral region. The R-CDs were used to construct a fluorescent probe for specific recognition of Mn2+ and Zn2+, achieving high-sensitivity detection of Mn2+ and Zn2+. The detection results showed a good linear relationship between fluorescence intensity and Mn2+ concentration, and the calculated detection limit was 0.23 nmol/L. For the detection of Zn2+, the detection limit was estimated as 19.1 nmol/L. At the same time, the content distribution of Mn and Zn elements in macroalgae produced in Fujian was investigated by the constructed fluorescence probe. It was found that kelp, laver, and their products are rich in Mn and Zn elements, and the content of Mn and Zn elements in laver is higher than that in kelp, which can be used as the optimal food supplement for Mn and Zn elements.

Curcumin-Mediated Sono-Photodynamic Treatment Inactivates Listeria monocytogenes via ROS-Induced Physical Disruption and Oxidative Damage.

Sono-photodynamic sterilization technology (SPDT) has become a promising non-thermal food sterilization technique because of its high penetrating power and outstanding microbicidal effects. In this study, Listeria monocytogenes (LMO) was effectively inactivated using curcumin as the sono-photosensitizer activated by ultrasound and blue LED light. The SPDT treatment at optimized conditions yielded a 4-log reduction in LMO CFU. The reactive oxygen species (ROS) production in LMO upon SPDT treatment was subsequently investigated. The results demonstrated SPDT treatment-induced excessive ROS generation led to bacterial cell deformation and membrane rupture, as revealed by the scanning electron microscope (SEM) and cytoplasmic material leakage. Moreover, agarose gel electrophoresis and SDS-PAGE further revealed that SPDT also triggered bacterial genomic DNA cleavage and protein degradation in LMO, thus inducing bacterial apoptosis-like events, such as membrane depolarization.

Spatial variation of volatile organic compounds and antioxidant activity of turmeric (Curcuma longa L.) essential oils harvested from four provinces of China.

The objective of this study was to investigate the spatial variation of volatile organic compounds and antioxidant activity of turmeric essential oils (TEOs) harvested from four provinces of China. The major chemical components of these TEOs were analyzed using headspace solid-phase micro-extraction gas chromatography-mass spectrometry. More than forty volatile organic compounds in TEOs were identified, which accounted for 82.09-93.64% of the oil components. The relative abundances of the main volatile organic compounds in TEOs at the genus level were visualized by a heat map. The antioxidant activity of the TEOs of five different origins was characterized by the DPPH free radical scavenging activity, in which the antioxidant activity of the TEOs from Guangxi was superior to those of other sources. Furthermore, the IC50 values of the antioxidants TEOs collected from Guangxi, Sichuan, Yunnan, Changting, and Liancheng were 33.30, 42.5, 35.22, 63.27, and 39.96 mg/mL, respectively, which indicated the excellent free radical scavenging activity of those TEOs. Therefore, the TEOs might be considered as a natural antioxidant with potential applications in food and pharmaceutical industries.

The impact of various exogenous type starch on the structural properties and dispersion stability of autoclaved lotus seed starch.

In order to investigate the effects of exogenous V-type starch on the structural properties and dispersion stability of lotus seed starch after autoclave treatment, the crystal structure, molecular structure, and dispersion stability were analyzed and discussed, as well as compared with exogenous A-type and B-type starches. Analysis of structural properties indicated that the addition of different crystal nuclei led the crystallization of disordered helices to a specific direction. The B- and V-type starch addition increased the crystallinities of starch and enhanced the ordered arrangement of disordered helices, whereas A-type starch had no significant positive influence on the stability of starch system. The microstructure observation showed that A- and B-type starch addition led to a rough and porous morphology of starch particles; the presence of V-type starch retarded the agglomeration and retrogradation of starch after autoclaving. Analysis of contact angle and dispersion stability revealed that the addition of various exogenous starch increased the contact angle of starch particles in different extent, suggesting the enhancement of hydrophobicity. But B-type starch addition resulted in the poor dispersion stability compared to A-type starch, instead V-type starch addition improved the dispersion stability of starch in aqueous solution, allowing the particles to stay dispersed for 141.12 ± 6.52 min. These results provided a theoretical basis for the effects of exogenous type starch on original starch properties, and revealed the potential of V-type starch as dispersion stabilizer.

Effects of freeze-thaw pretreatment on the structural properties and digestibility of lotus seed starch-glycerin monostearin complexes.

To investigate the effects of freeze-thaw cycle pretreatment (in one cycle, frozen samples were reheated to 50 °C and then frozen at -20 °C) on the structural properties and digestibility of lotus seed starch-glycerin monostearin complexes, their complex index, crystal structure, molecular structure, micro-morphology, and digestibility were analyzed. The results showed that an appropriate number of freeze-thaw cycles facilitated the helical assembly of lotus seed starch and glycerin monostearin. Specifically, six cycles of freeze-thaw pretreatment were favorable for forming V6I-type complexes with high microcrystalline proportion. This contributed to the high stability of crystalline region and order arrangement of molecular structure. Moreover, V6I-complexes were in the form of lamellar debris in micro-morphology, and their total digestion and digestion rates were lower than those of other samples. These results were of significance for developing slowly digesting lotus seed starch-based food.

Ferulic acid ameliorates intrahepatic triglyceride accumulation in vitro but not in high fat diet-fed C57BL/6 mice.

Phenolic acids can improve obesity-related and metabolic syndrome-related conditions including non-alcoholic fatty liver disease (NAFLD). In this study, the effects of ferulic acid (FA) on the metabolic changes related to NAFLD were investigated in oleic acid (OA)-treated HepG2 cells and C57BL/6 mice fed a high fat diet (HFD). In vitro, FA (25 and 50 µg/mL) treatment significantly reduced cellular lipid accumulation with no obvious cytotoxicity, in-part mediated by the suppression of ERK1/2, JNK1/2/3, and HGMB1 expression. However, in vivo administration of FA (20 mg/kg bw·day) for 17 weeks led to no obvious effects on body weight and liver weight gain, blood lipid profiles, or histological abnormalities in obese C57BL/6 mice induced by HFD. Taken together, the positive effects of FA on the reduction of hepatic triglyceride accumulation were therefore demonstrated in cellular model, while its hepatic protective effects might need to be further explored in rodent models and clinical trials.

Effects of exogenous V-type complexes on the structural properties and digestibility of autoclaved lotus seed starch after retrogradation.

The effects of exogenous V-type complexes on the structural properties and digestibility of autoclaved lotus seed starch after retrogradation were investigated. The structural properties indicated that the addition of V-type complexes significantly retarded the initial recrystallization of amylose double helices and improved the disordered starch system to an ordered direction. However, the effects decreased with the increase in retrogradation time and the rearrangement completion of amylose chains, as reflected in the enhancement of starch retrogradation phenomenon in micro-morphology. On the other hand, exogenous V-type complexes added to the starch system enhanced the enzymatic resistance of the starch system and increased the proportion of resistant starch because of the highly indigestible microchip layer. These results provided a theoretical basis for the interaction between V-type complexes and autoclaved starch for functional application, and they revealed its potential as an anti-gel additive.

Effects of pullulanase pretreatment on the structural properties and digestibility of lotus seed starch-glycerin monostearin complexes.

The effects of pullulanase pretreatment, combined with ultrasound-microwave synergistic processing, on the structural properties and digestibility of lotus seed starch-glycerin monostearin complexes was investigated. The pullulanase pretreatment improved the complex index of the inclusion complexes. The structural properties analysis indicated the debranching of starch by pullulanase facilitated an increase in microcrystalline regions and ordering of starch. However, extensive debranching resulted in a blend of B- and V-type crystalline structures and a high degree of freedom of amylose chains. The microstructural morphology revealed that pullulanase debranching inhibited the gelatinization of starch by promotion of V-complex formation, while excessive enzymolysis did not. The stability of starch complex structure determined its digestibility, and the digestion analysis revealed that 100 min of pullulanase debranching contributed to the high content of V-type resistant starch. After that, starch helix conformations was more inclined to imperfect amylose double helices, reflecting an increase in slowly digestible starch content.