Mass spectrometry-based metabolomics approach to reveal differential compounds in pufferfish soups: Flavor, nutrition, and safety

Dynamic changes in flavor characteristics of black tea during solid-state fermentation with Eurotium cristatum

This study employed GC-MS, GC-IMS, and sensory evaluation to investigate dynamic changes in flavor during the solid-state fermentation of black tea by Eurotium cristatum. The results revealed a notable decrease in the bitter and astringent tastes of the black tea infusion following fermentation, while the mellow taste increased significantly. A total of 152 and 129 VOCs were detected by GC-MS and GC-IMS, respectively. And 4 key aroma-active compounds were identified by ROAV. These specific VOCs contributed floral, honey, and sweet scents, which were responsible for the fungal floral aroma in the processed black tea. Furthermore, OPLS-DA identified 31 key VOCs that played a crucial role in differentiating various fermentation stages, with day 4 recognized as a pivotal point for aroma development. The solid-state fermentation with Eurotium cristatum resulted in fermented black tea characterized by a mellow taste and a rich fungal floral aroma, enhancing the flavor quality of the tea.

Comparison of the flavor characteristics in three kinds of strawberry fruits

Strawberries represent a significant economic crop, with various cultivars exhibiting notable differences in taste, aroma, and nutritional value. Consequently, the discrimination and characterization of different strawberry varieties to assess their quality have become pressing issues that require attention. This study evaluated the flavor characteristics of three strawberry varieties (HY, ZJ, BXGZ) through sensory evaluation, physicochemical analysis, E-nose, HS-SPME-GC-MS, and HS-GC-IMS. The results indicated that ZJ strawberries exhibited the highest levels of sweetness, whereas HY strawberries were the hardest. BXGZ strawberries displayed the highest concentrations of vitamin C, total phenols, and flavonoids. Additionally, 18, 30, and 33 volatile organic compounds (VOCs) with odor activity values (OAV) greater than 1 were identified in HY, ZJ, and BXGZ strawberries, respectively. Based on the results from partial least squares discriminant analysis (PLS-DA), 3 physicochemical indicators, 18 VOCs detected using HS-SPME-GC-MS, and 26 VOCs detected using HS-GC-IMS were identified as potential biomarkers. These findings offer valuable insights into the flavor differences among strawberry varieties and establish a rapid analysis method for strawberry fruit aroma using GC-IMS.

Comparative analysis of intestinal structure, enzyme activity, intestinal microbiota and gene expression in different segments of pufferfish (Takifugu Obscurus)

The structure of fish intestines does not have a clear regional division, while the function of the intestines may be related to their structure. Therefore, in this study, the delimitation of intestinal segments in pufferfish (Takifugu obscurus) was achieved by morphological analysis. Subsequently, enzyme activity, intestinal microbiota, and gene expression were examined to compare the differences among the pufferfish various segments. According to four morphological parameters: height of mucosa folds (HF), width of mucosa folds (WF), thickness of muscularis (TM), and cross-sectional area (CSA), the pufferfish's intestine was divided into anterior intestine (AI), middle intestine (MI), and posterior intestine (PI). The activity levels of amylase, lipase, and trypsin in the AI and MI were significantly higher than these in the PI. According to the analysis of 16S rDNA, the dominant microbiota at the phylum level in the different segments were Epsilonbacteraeota, Spirochaetes, and Proteobacteria. At the genus level, there were variations observed in the relative abundance of Brevinema, Mycobacterium, Bradyrhizobium, and Microvirga. α diversity analysis revealed that the richness indexes (Ace and Chao1) were the lowest in the MI, while β diversity analysis revealed significant difference in intestinal microbial community composition among the three intestinal segments. Furthermore, RNA-Seq was used to identify differential expression genes (DEGs) and biological pathways among the different intestinal segments. The DEGs between the AI and MI were enriched in pancreatic secretion and protein digestion and absorption, those between AI and PI were involved in ascorbate and aldarate metabolism and glutathione metabolism, and those between MI and PI were involved in steroid biosynthesis, fat digestion and absorption, vitamin digestion and absorption, and glycine, serine and threonine metabolism. In conclusion, the presented results compare and analyze the differences in various intestinal segments of pufferfish, which will be conductive to future exploration of the functions of these different segments.

Dynamic Changes of Active Components and Volatile Organic Compounds in Rosa roxburghii Fruit during the Process of Maturity

Rosa roxburghii (R. roxburghii), native to the southwest provinces of China, is a fruit crop of important economic value in Guizhou Province. However, the changes in fruit quality and flavor during R. roxburghii fruit ripening have remained unknown. Here, this study investigated the changes of seven active components and volatile organic compounds (VOCs) during the ripening of the R. roxburghii fruit at five different ripening stages including 45, 65, 75, 90, and 105 days after anthesis. The results indicated that during the ripening process, the levels of total acid, vitamin C, and soluble sugar significantly increased (p < 0.05), while the levels of total flavonoids, superoxide dismutase (SOD), and soluble tannin significantly decreased (p < 0.05). Additionally, the content of total phenol exhibited a trend of first decreasing significantly and then increasing significantly (p < 0.05). A total of 145 VOCs were detected by HS-SPME-GC-MS at five mature stages, primarily consisting of aldehydes, alcohols, esters, and alkenes. As R. roxburghii matured, both the diversity and total quantity of VOCs in the fruit increased, with a notable rise in the contents of acids, ketones, and alkenes. By calculating the ROAV values of these VOCs, 53 key substances were identified, which included aromas such as fruit, citrus, green, caramel, grass, flower, sweet, soap, wood, and fat notes. The aromas of citrus, caramel, sweet, and wood were predominantly concentrated in the later stages of R. roxburghii fruit ripening. Cluster heatmap analysis revealed distinct distribution patterns of VOCs across five different maturity stages, serving as characteristic chemical fingerprints for each stage. Notably, stages IV and V were primarily characterized by a dominance of alkenes. OPLS-DA analysis categorized the ripening process of R. roxburghii fruit into three segments: the first segment encompassed the initial three stages (I, II, and III), the second segment corresponded to the fourth stage (IV), and the third segment pertained to the fifth stage (V). Following the variable importance in projection (VIP) > 1 criterion, a total of 30 key differential VOCs were identified across the five stages, predominantly comprising ester compounds, which significantly influenced the aroma profiles of R. roxburghii fruit. By integrating the VIP > 1 and ROAV > 1 criteria, 21 differential VOCs were further identified as key contributors to the aroma changes in R. roxburghii fruit during the ripening process. This study provided data on the changes in quality and aroma of R. roxburghii fruit during ripening and laid the foundation for the investigation of the mechanism of compound accumulation during ripening.

Application of graphite carbon black assisted-laser desorption ionization-mass spectrometry for soy sauce product discrimination

In a previous study, we developed a novel analytical method to directly and simultaneously detect taste- and odor-active compounds using graphite carbon black (GCB)-assisted laser desorption ionization mass spectrometry (LDI-MS). In this study, we aimed to evaluate food quality using a variety of soy sauces using the method to discriminate each product. Graphite carbon black-laser desorption ionization-mass spectrometry allowed the provision of hundreds of MS peaks derived from soy sauces in both positive and negative modes without any tedious sample pretreatments. Principal component analysis using the obtained MS peaks clearly distinguished three soy sauce products based on the manufacturing countries (Japan, China, and India). Moreover, this method identified distinct MS peaks for discrimination, which significantly correlated with their quantitative amounts in the products. Thus, GCB-LDI-MS analysis was established as a simple and rapid technique for food analysis, illustrating the chemical patterns of food products.

Impact of the rearing environment on the metabolism of shrimps and tracing the origins and species of shrimps using specific metabolites

Herein, the link between rearing environmental condition and metabolism was explored. Metabolite fingerprint datasets of black tiger shrimp (Penaeus monodon) from three production sites were collected and studied using matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF MS) and HPLC-MS/MS. Two compounds, benzisothiazolinone and hippuric acid, were identified to be potentially related to pollution in the rearing environment and showed different abundances in the analysed shrimp samples with different origins. Furthermore, metabolomic analysis on three shrimp species, black tiger shrimp, kuruma shrimp (Penaeus japonicus) and sword shrimp (Parapenaeopsis hardwickii), under an identical rearing environment was also conducted. Two compounds, diethanolamine and benzisothiazolinone, potentially linked with pollution in the rearing environment were identified. The present protocol holds promise to be extended to the studies of exploring the relationship between rearing environmental conditions and metabolism. Furthermore, the analysis of single-blind samples was conducted. The results show that specific metabolites can be utilized as markers for tracing the origins of shrimp samples. The present protocol holds potential for application in tracing the origin and species of certain seafoods.

Liquid Chromatography-Mass Spectrometry-Based Metabolomics Reveals Dynamic Metabolite Changes during Early Postmortem Aging of Donkey Meat

BACKGROUND

Metabolic changes in donkey meat during the early postmortem period have not been previously reported.

METHODS

The LC-MS-based metabolomics technique was conducted to understand the metabolic profiles and identify the key metabolites of donkey meat in the first 48 h postmortem.

RESULTS

The pH values showed a decreasing trend followed by an increasing trend. Shear force was the lowest at 4 h and the highest at 24 h (p < 0.05). For the metabolome, some candidate biomarker metabolites were identified, such as adenine, inosine, n-acetylhistidine, citric acid, isocitrate, and malic acid. Predominant metabolic pathways, such as citrate cycle (TCA cycle), alanine, aspartate and glutamate metabolism, and purine metabolism, were affected by aging time. Overabundant n-acetylhistidine was identified in LT, declined at 12 h postmortem aging, and then increased. This may explain the significantly lower pH at 12 h postmortem. Adenine was higher at 4 h postmortem, then declined. Decreased ADP may indicate a fast consumption of ATP and subsequent purine metabolism in donkey meat.

CONCLUSIONS

The results of this study provided new insights into early postmortem aging of donkey meat quality.

From sound check to encore: A journey through high-resolution mass spectrometry-based food analyses and metabolomics

This manuscript presents a comprehensive review of high-resolution mass spectrometry in the field of food analysis and metabolomics. We have followed the historical evolution of metabolomics, its associated techniques and technologies, and its increasing role in food science and research. The review provides a critical comparison and synthesis of tentative identification guidelines proposed for over 15 years, offering a condensed resource for researchers in the field. We have also examined a wide range of recent metabolomics studies, showcasing various methodologies and highlighting key findings as a testimony of the versatility of the field and the possibilities it offers. In doing so, we have also carefully provided a compilation of the software tools that may be employed in this type of studies. The manuscript also explores the prospects of high-resolution mass spectrometry and metabolomics in food science. By covering the history, guidelines, applications, and tools of metabolomics, this review attempts to become a comprehensive guide for researchers in a rapidly evolving field.

Angelica sinensis aboveground part polysaccharide and its metabolite 5-MT ameliorate colitis via modulating gut microbiota and TLR4/MyD88/NF-κB pathway

The roots of Angelica sinensis have been used in Traditional Chinese Medicine for thousands of years. However, tons of aerial parts of this herb (aboveground part) are commonly discarded during the process of root preparations. A polysaccharide (ASP-Ag-AP) in the aboveground parts of A. sinensis was isolated and preliminarily characterized as typical plant pectin. ASP-Ag-AP exhibited noticeable protective effects against dextran sodium sulfate (DSS)-induced colitis, including reduction of colonic inflammation, modulation of barrier function, and alteration of gut microbiota and serum metabolite profile. Anti-inflammatory effects of ASP-Ag-AP were observed by inhibiting TLR4/MyD88/NF-κB signaling pathway in vitro and in vivo. Additionally, the level of serum metabolite 5-methyl-dl-tryptophan (5-MT) was reduced by DSS and restored by ASP-Ag-AP, which also negatively correlated with Bacteroides, Alistipes, Staphylococcus and pro-inflammatory factors. The protection from inflammatory stress on intestinal porcine enterocytes cells (IPEC-J2) of 5-MT was observed through the inhibition of TLR4/MyD88/NF-κB pathway. Besides, 5-MT also exhibited robust anti-inflammatory effect in colitis mice with improving colitis symptoms, barrier function and gut microbiota, which was the same as presented by ASP-Ag-AP. Therefore, ASP-Ag-AP could be a promising agent for colitis prevention and 5-MT could be the signal metabolite of ASP-Ag-AP on defending against intestinal inflammatory stress.

1H NMR-Based Metabolic Profiling to Follow Changes in Pomelo Cultivars during Postharvest Senescence

This study investigated metabolite changes in three pomelo cultivars during postharvest senescence using ¹H NMR-based metabolic profiling. Three pomelo cultivars, 'Hongroumiyou', 'Bairoumiyou' and 'Huangroumiyou', abbreviated as "R", "W" and "Y" according to the color of their juice sacs, were stored at 25 °C for 90 days, and NMR was applied to determine the metabolite changes in juice sacs during storage. Fifteen metabolites were identified, including organic acids, sugars, amino acids, fatty acids, phenols and naringin. Partial least squares discriminant analysis (PLS-DA) was used to screen the significant metabolites according to the variable importance for the projection (VIP) scores in three pomelo cultivars during 90 days of storage. Additionally, eight metabolites, naringin, alanine, asparagine, choline, citric acid, malic acid, phosphocholine and β-D-glucose, were screened to be the crucial biomarkers with VIP > 1. The undesirable flavor of "bitter and sour" during the 60 days of storage was mainly attributed to the naringin, citric acid and sugars. According to the correlation analysis, the citric acid content determined by NMR showed a significantly positive relationship with that analyzed by HPLC. These findings suggested that NMR technology was accurate and efficient for metabolomic analysis of pomelo fruit, and the ¹H NMR-based metabolic profiling can be efficient during quality evaluation and useful for improving the fruit flavor quality during postharvest storage.

Combined Effects of Cold and Hot Air Drying on Physicochemical Properties of Semi-Dried Takifugu obscurus Fillets

The physicochemical properties of semi-dried Takifugu obscurus fillets in cold air drying (CAD), hot air drying (HAD), and cold and hot air combined drying (CHACD) were analyzed based on pH, water state, lipid oxidation, protein degradation, and microstructure, using a texture analyzer, low-field nuclear magnetic resonance, thiobarbituric acid, frozen sections, sodium dodecyl sulfate polyacrylamide gel electrophoresis, and differential scanning calorimetry. Water binding to the samples was enhanced by all three drying methods, and the immobilized water content of CHACD was between that of HAD and CAD. The pH of the semi-dried fillets was improved by CHACD. When compared to HAD and CAD, CHACD improved the springiness and chewiness of the fillets, especially cold air drying for 90 min (CAD-90), with values of 0.97 and 59.79 g, respectively. The muscle fibers were arranged compactly and clearly in CAD-90, having higher muscle toughness. CHACD reduced the drying time and degree of lipid oxidation compared to HAD and CAD. CAD better preserved protein composition, whereas HAD and CHACD promoted actin production; CHACD had a higher protein denaturation temperature (74.08-74.57 °C). CHACD results in better physicochemical properties than HAD or CAD, including shortened drying time, reduced lipid oxidation, enhanced protein stability, and denser tissue structure. These results provide a theoretical basis for selecting the appropriate drying method for T. obscurus in industrial applications.

Real-time qPCR for the detection of puffer fish components from Lagocephalus in food: L. inermis, L. lagocephalus, L. gloveri, L. lunaris, and L. spadiceus

Puffer fish is a type of precious high-end aquatic product, is widely popular in Asia, especially in China and Japan, even though it naturally harbors a neurotoxin known as tetrodotoxin (TTX) that is poisonous to humans and causes food poisoning. With the increasing trade demand, which frequently exceeds existing supply capacities, fostering fraudulent practices, such as adulteration of processed products with non-certified farmed wild puffer fish species. To determine the authenticity of puffer fish processed food, we developed a real-time qPCR method to detect five common puffer fish species in aquatic products: Lagocephalus inermis, Lagocephalus lagocephalus, Lagocephalus gloveri, Lagocephalus lunaris, and Lagocephalus spadiceus. The specificity, cross-reactivity, detection limit, efficiency, and robustness of the primers and probes created for five species of puffer fish using TaqMan technology have been determined. No cross-reactivity was detected in the DNA of non-target sample materials, and no false-positive signal was detected; the aquatic products containing 0.1% of a small amount of wild puffer fish materials without certification can be reliably tracked; the statistical p-value for each method's Ct value was greater than 0.05. The developed qPCR method was sensitive, highly specific, robust, and reproducibility, which could be used to validate the authenticity of wild puffer fish in aquatic products sold for commercial purposes.

Sensory and metabolite migration from tilapia skin to soup during the boiling process: fast and then slow

This study mainly studied sensory and metabolite migration from the skin to the soup in the boiling process of tilapia skin using content analysis, electronic nose technique, electronic tongue technique, and metabolomics technique based on ultra-high performance liquid chromatography-mass spectrometry/mass spectrometry and gas chromatography-time-of-flight-mass spectrometry. The content changes, flavor changes, taste changes, metabolite numbers and differential metabolite numbers for both tilapia skin and soup mainly occurred in the initial 30 min. Moreover, the initial 10 min was the key period for the metabolite changes in the boiling process. Further, the differential metabolites in these three periods (0–10, 10–30, and 30–60 min) were identified to show the metabolites migration process. Six (adenine, gingerol, terephthalic acid, vanillin, pentanenitrile, and 2-pyrrolidinonede) and seven (butyramide, lysope(0:0/20:4(5z,8z,11z,14z)), lysope(22:6(4z,7z,10z,13z,16z,19z)/0:0), linoleic acid, N-acetylneuraminic acid, L-threose, and benzoin) chemicals were screened out in the differential metabolites of tilapia skin and soup, respectively, with Variable Importance in the Projection of >1 and p value of <0.05. This work would be beneficial to understand the sensory and metabolite migration in the preparation process of fish soup and provided a metabolomic analysis route to analyze metabolites migration in food.

CRISPR-Based Colorimetric Nucleic Acid Tests for Visual Readout of DNA Barcode for Food Authenticity

Food authenticity is a critical issue associated with the economy, religion, and food safety. Herein, we report a label-free and colorimetric nucleic acid assay for detecting DNA barcodes, enabling the determination of food authenticity with the naked eye. This method, termed the CRISPR-based colorimetric DNA barcoding (Cricba) assay, utilizes CRISPR/Cas12a (CRISPR = clustered regularly interspaced short palindromic repeats; Cas = CRISPR associated protein) to specifically recognize the polymerase chain reaction (PCR) products for further trans-cleavaging the peroxidase-mimicking G-quadruplex DNAzyme. Based on this principle, the presence of the cytochrome oxidase subunit I gene could be directly observed with the naked eye via the color change of 3,3',5,5'-tetramethylbenzidine sulfate (TMB). The whole detection process, including PCR amplification and TMB colorimetric analysis, can be completed within 90 min. The proposed assay can detect pufferfish concentrations diluted to 0.1% (w/w) in a raw pufferfish mixture, making it one of the most sensitive methods for food authenticity. The robustness of the assay was verified by testing four common species of pufferfish, including Lagocephalus inermis, Lagocephalus spadiceus, Takifugu bimaculatus, and Takifugu alboplumbeus. The assay is advantageous in easy signal readout, high sensitivity, and general applicability and thus could be a competitive candidate for food authenticity.

The investigation of storage situation of fish muscle via the analysis of its exudate by MALDI-TOF MS

The potential of MALDI-TOF MS was investigated in terms of its capability to determine the change of exudates of fish muscle with different freeze-thaw cycles (0, 1 and 2), and frozen storage periods. The exudates were collected from dead chilled marine fish species, large yellow croacker (Larimichthys crocea, LC) and freshly slaughtered freshwater fish species, Japanese seabass (Lateolabrax japonicus) to be studied as models. 109 proteins, in which, 32 are extracellular proteins, and 15 are intracellular proteins, were identified by analyzing exudate of LC using MALDI-TOF MS and HPLC-MS/MS. The results show that the present method may be able to determine the change of fish muscle foods in a more sensitive mode than K value indicated quality control. The feasibility of verifying the storage situation of fish sample was performed by analyzing fish samples obtained from the local market. It is promising to estimate the storage situation of fishery products or other animal muscle foods by analyzing their muscle exudates based on the presently developed strategy.

LC-MS-based metabolomics reveals metabolite dynamic changes during irradiation of goat meat

The current study applied an untargeted metabolomics approach by ultra high performance liquid chromatography quadrupole-orbitaltrap high resolution mass spectrometry (UHPLC-Q-Oritrap-MS) to identify the chemical composition of irradiated goat meat and investigate the effect of irradiation on its metabolic profile and meat quality. A total of 103 metabolites were identified as differential metabolites responsible for metabolic changes in irradiated goat meat, which were involved in phenylalanine, tyrosine and tryptophan biosynthesis, phenylalanine metabolism and purine metabolism. Differential metabolites comprising amino acids, nucleotides and their derivatives were determined as the discriminating factors responsible for the meat quality during irradiation. Specifically, the levels of L-phenylalanine, L-isoleucine, L-histidine, guanosine, guanine, creatinine, glutathione and nicotinic acid were increased while inosine 5'-monophosphate (IMP) and guanosine 5'-monophosphate (GMP) were decreased. Overall, except for L-phenylalanine and guanine, other related metabolites significantly decreased with storage. This study contributes to a comprehensive understanding of the effect of irradiation doses and storage time on goat meat metabolism at the molecular level, so as to assess the quality of irradiated goat meat. Satisfactory results with linearity (R² > 0.995), precision (RSD less than 8.9%) and recovery (83%-106%) were obtained, demonstrating that the untargeted mebabolomics approach was appropriate for monitoring the changes of small molecular metabolites in irradiated goat meat and irradiation is a feasible method for goat meat preservation.

Mass spectrometry-based metabolomics to reveal chicken meat improvements by medium-chain monoglycerides supplementation: Taste, fresh meat quality, and composition

This study was conducted to reveal the differences of chicken fresh meat quality, composition and taste induced by medium-chain monoglycerides (MG) supplementation. Results demonstrated that both chicken broth and meat taste were improved by MG supplementation. The up-regulated l-carnosine, sarcosine, uridine and nicotinamide in the chicken broth of the MG group contributed to the umami and meaty taste. Dietary MG increased the total superoxide dismutase activity and amino acid content in the muscle of chicken breast and reduced the malondialdehyde content and drip loss. Moreover, meat metabolome revealed that creatine, betaine, l-anserine, inosine 5'-monophosphate, hypoxanthine, inosine and phospholipid, as well as amino acid and purine metabolism pathway connected to the improvements of meat quality, composition and taste of broilers by MG addition. In conclusion, these findings provide convincing evidence regarding the improvements of fresh meat quality, composition and taste of broilers by MG supplementation.

Evaluation of small molecular metabolites and sensory properties of Xuanwei ham salted with partial replacement of NaCl by KCl

The study was to understand the effect of the partial substitution of NaCl by KCl on small molecular metabolites and sensory quality of Xuanwei ham. Thirty green hams were randomly divided into five treatments, and salted with 100% NaCl (I), 70% NaCl+30% KCl (II), 60% NaCl+40% KCl (III), 50% NaCl+50% KCl (IV) and 40% NaCl+60% KCl (V), respectively. With the increase of KCl substitution, the moisture content of Xuanwei ham increased. Non-targeted ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-Q-Exactive-MS) was used to study the effect of partial substitution of NaCl by KCl, and twenty-eight metabolites were identified as markers of small molecular metabolites in the different treatments. KCl substitution promoted the release of tryptophan, histidine, citrulline, lysine, creatine and oleic acid, which contributed to improve the flavor and taste of ham. Therefore, the treatment II and III could reduce the NaCl content of Xuanwei ham by 30% and 40%, and maintained a better sensory acceptability.

Protein biomarkers associated with frozen Japanese puffer fish (Takifugu rubripes) quality traits

This study was designed to investigate proteome changes in Japanese puffer fish (Takifugu rubripes) during short- and long-term frozen storage. In total, 1484 proteins were quantified, and 164 proteins were identified as differential abundance proteins (DAPs) in Japanese puffer fish from two frozen storage treatment groups (14 days and 60 days) compared with the fresh control group. Correlation analysis between the DAPs and quality traits of the puffer fish muscle showed that 106 proteins were correlated closely with colour and texture (hardness, elasticity, and chewiness). Bioinformatics analysis revealed and Western blot analysis verified that Putative prothymosin alpha species, Bridging integrator 3, NADH: the ubiquinone oxidoreductase subunit and Mx species are candidate biomarkers for puffer fish properties. This study offers valuable evidence to improve the quality control and monitoring of Japanese puffer fish during transportation and storage.

PL-S2, a homogeneous polysaccharide from Radix Puerariae lobatae, attenuates hyperlipidemia via farnesoid X receptor (FXR) pathway-modulated bile acid metabolism

Polysaccharides are important active constituents of Radix Puerariae lobatae (RPL). In this study, a novel homogeneous polysaccharide from RPL was successfully obtained by HP-20 macroporous resin and purified by Sepharose G-100 column chromatography. Nuclear magnetic resonance (NMR) analysis showed that the main glycosidic bonds were composed of α-1,3-linked and α-1,4-linked glucose. The molecular weight of PL-S2 was 18.73 kDa. The hypolipidemic effect of PL-S2 on hyperlipidemic rats was evaluated in histopathology and metabolomics analyses. PL-S2 significantly reduced plasma lipid levels and inhibited bile acid metabolism. We also demonstrated that treatment with PL-S2 activated FXR, CYP7A1, BESP, and MRP2 in rat liver. Our findings first indicate that PL-S2 decreases plasma lipid levels in hyperlipidemic rats by activating the FXR signaling pathway and promoting bile acid excretion. Therefore, PL-S2 derived from RPL is implicated as a functional food factor with lipid-regulating activity, and highlighted as a potential food supplement for the treatment of hyperlipidemia.

New method for rapid identification and quantification of fungal biomass using ergosterol autofluorescence

This research reports on the development of a method to identify and quantify fungal biomass based on ergosterol autofluorescence using excitation-emission matrix (EEM) measurements. In the first stage of this work, several ergosterol extraction methods were evaluated by APCI-MS, where the ultrasound-assisted procedure showed the best results. Following an experimental design, various quantities of the dried mycelium of the fungus Schizophyllum commune were mixed with the starchy solid residue (BBR) from the babassu (Orbignya sp.) oil industry, and these samples were subjected to several ergosterol extraction methods. The EEM spectral data of the samples were subjected to Principal Component Analysis (PCA), which showed the possibility to qualitatively evaluate the presence of ergosterol in the samples by ergosterol autofluorescence without the addition of any reagent. In order to assess the feasibility of quantifying fungal biomass using ergosterol autofluorescence, the EEM spectral data and known amounts of fungal biomass were modeled using partial least squares (PLS) regression and a procedure of backward selection of predictors (AutoPLS) was applied to select the Excitation-Emission wavelength pairs that provide the lowest prediction error. The results revealed that the amount of fungal biomass in samples containing interfering substances (BBR) can be accurately predicted with R²CV = 0.939, R²P = 0.936, RPDcv = 4.07, RPDp = 4.06, RMSECV = 0.0731 and RMSEP = 0.0797. In order to obtain an easy-to-understand equation that expresses the relationship between fungal biomass and fluorescence intensity, multiple linear regression (MLR) was applied to the VIP variables selected by the AutoPLS method. The MLR model selected only 2 variables and showed a very good performance, with R²CV = 0.862, R²P = 0.809, RPDcv = 2.18, RPDp = 2.35, RMSECV = 0.137 and RMSEP = 0.138. This study demonstrated that ergosterol autofluorescence can be successfully used to quantify fungal biomass even when mixed with agroindustrial residues, in this case BBR.