Terahertz Spectroscopic Identification of Roast Degree and Variety of Coffee Beans.

In this study, terahertz time-domain spectroscopy (THz-TDS) was proposed to identify coffee of three different varieties and three different roasting degrees of one variety. Principal component analysis (PCA) was applied to extract features from frequency-domain spectral data, and the extracted features were used for classification prediction through linear discrimination (LD), support vector machine (SVM), naive Bayes (NB), and k-nearest neighbors (KNN). The classification effect and misclassification of the model were analyzed via confusion matrix. The coffee varieties, namely Catimor, Typica 1, and Typica 2, under the condition of shallow drying were used for comparative tests. The LD classification model combined with PCA had the best effect of dimension reduction classification, while the speed and accuracy reached 20 ms and 100%, respectively. The LD model was found with the highest speed (25 ms) and accuracy (100%) by comparing the classification results of Typica 1 for three different roasting degrees. The coffee bean quality detection method based on THz-TDS combined with a modeling analysis method had a higher accuracy, faster speed, and simpler operation, and it is expected to become an effective detection method in coffee identification.

The substitution sites of hydroxyl and galloyl groups determine the inhibitory activity of human pancreatic α-amylase in twelve tea polyphenol monomers.

Tea polyphenols have been reported as potential α-amylase inhibitors. However, the quantitative structure-activity relationship (QSAR) between tea polyphenols and human pancreas α-amylase (HPA) is not well understood. Herein, the inhibitory effect of twelve tea polyphenol monomers on HPA was investigated in terms of inhibitory activity, as well as QSAR analysis and interaction mechanism. The results revealed that the HPA inhibitory activity of theaflavins (TFs), especially theaflavin-3'-gallate (TF-3'-G, IC50: 0.313 mg/mL), was much stronger than that of catechins (IC50: 18.387-458.932 mg/mL). The QSAR analysis demonstrated that the determinant for the inhibitory activity of HPA was not the number of hydroxyl and galloyl groups in tea polyphenol monomers, while the substitution sites of these groups potentially might play a more important role in modulating the inhibitory activity. The inhibition kinetics and molecular docking revealed that TF-3'-G as a mixed-type inhibitor had the lowest inhibition constant and bound to the active sites of HPA with the lowest binding energy (-7.74 kcal/mol). These findings could provide valuable insights into the structures-activity relationships between tea polyphenols and the HPA inhibitors.

Fabrication and 3D printing of Pickering emulsion gel based on Hypsizygus marmoreus by-products protein.

Pickering emulsion gel (PEG) stabilized by the protein extracted from the by-product of Hypsizygus marmoreus, combining with xanthan gum (XG), was formulated as 3D printing ink. Hydrogen bonds are formed in XG/protein hybrid particles. Afterwards, PEG was developed. Results indicated that it has shear-thinning properties. The apparent viscosity, yield stress, Elastic modulus (G') and gel strength increased with the increased XG addition, while the size of emulsion decreased. XG incorporation improved the 3D printing performance with desired self-supporting capability and printing precision if its concentration reached 2.0% (w/v). This study provides ideas for the application of Hypsizygus marmoreus by-products protein in stabilizing PEG used for 3D printing, which has a potential to replace traditional hydrogenated cream for cake decoration.

Preparation and characterization of 3D-printed antibacterial hydrogel with benzyl isothiocyanate.

Benzyl isothiocyanate (BITC) is an isothiocyanate of plant origin, especially the mustard family, which has good antibacterial properties. However, its applications are challenging due to its poor water solubility and chemical instability. We used food hydrocolloids, including xanthan gum, locust bean gum, konjac glucomannan, and carrageenan as three-dimensional (3D)-printing food ink base and successfully prepared 3D-printed BITC antibacterial hydrogel (BITC-XLKC-Gel). The characterization and fabrication procedure of BITC-XLKC-Gel was studied. The results show that BITC-XLKC-Gel hydrogel has better mechanical properties by low-field nuclear magnetic resonance (LF-NMR), mechanical properties, and rheometer analysis. The strain rate of BITC-XLKC-Gel hydrogel is 76.5%, which is better than that of human skin. Scanning electron microscope (SEM) analysis showed that BITC-XLKC-Gel has uniform pore size and provides a good carrier environment for BITC carriers. In addition, BITC-XLKC-Gel has good 3D-printing performance, and 3D printing can be used for customizing patterns. Finally, inhibition zone analysis showed that the BITC-XLKC-Gel added with 0.6% BITC had strong antibacterial activity against Staphylococcus aureus and the BITC-XLKC-Gel added with 0.4% BITC had strong antibacterial activity against Escherichia coli. Antibacterial wound dressing has always been considered essential in burn wound healing. In experiments that simulated burn infection, BITC-XLKC-Gel showed good antimicrobial activity against methicillin-resistant S. aureus. BITC-XLKC-Gel is a good 3D-printing food ink attributed to strong plasticity, high safety profile, and good antibacterial performance and has great application prospects.

Characterization of procyanidin extracts from hawthorn (Crataegus pinnatifida) in human colorectal adenocarcinoma cell line Caco-2, simulated Digestion, and fermentation identified unique and novel prebiotic properties.

The health-promoting activities of procyanidin extracts from hawthorn (HPCs) are closely related to their digestive behaviors, absorption, and colonic metabolism, all of which remain unknown for now and thus hinder further exploration. This study aims to explore the dynamic changes of HPCs during in vitro digestion and fermentation, as well as their Caco-2 permeability, focusing mainly on the interaction between gut microbiota and HPCs. The results showed that the digested HPC samples had characteristic absorption peaks at 280 nm, and there were absorption peaks in the stretching vibration zone, including OH and CC on the benzene ring, which suggested that procyanidins were the main components in HPCs after in vitro digestion. Meanwhile, HPCs had the highest stability in the oral phase. However, the total procyanidin content of HPCs decreased during gastrointestinal digestion, and flavan-3-ol dimers and trimers in HPCs are partially degraded into epicatechin. Uptake of epicatechin (4.07 %), procyanidin B2 (2.15 %), and procyanidin B5 (39.44 %) through Caco-2 monolayer was also observed in HPC treatment, while there was still a large portion of procyanidins that was not absorbed. Subsequent fermentation resulted in a decrease in pH along with the production of short-chain fatty acids (SCFAs), mainly due to the degradation and utilization of HPC, as indicated by a reduction of total procyanidins. Furthermore, the HPCs modulated gut microbial populations: down-regulated the abundances of Bacteroides, Fusobacterium, Enterococcus, Parabacteroides, and Bilophila, and up-regulated Escherichia-Shigella, Klebsiella, Turicibacter, Actinobacillus, Roseburia, and Blautia. Ultimately, epicatechin and procyanidin B2, B5 and C1 were converted into phenolic acids through the metabolism of Bacteroides, Sutterella, Butyrobacter and Blautia. 4-ethylbenzoic acid, 4-hydroxyphenylpropionic acid, 3,4-dihydroxyphenyl acetic acid were confirmed as the significant metabolites in the fermentation. These results elucidated the potential mechanisms of HPCs metabolism and their beneficial effects on gut microbiota and colonic phenolic acids production.

Protocols for extraction and purification of rutin from leafy by-products of asparagus (Asparagus officinalis) and characterization of the purified product.

Valorization of asparagus leafy by-products as a potential source of rutin through selected extraction and purification protocols was investigated. Protocol resulting in the highest extraction yield was first selected. Crude extract was subject to purification via multiple liquid-liquid back extraction using ethanol, methanol or water as a solvent; selection of the most appropriate purification solvent was made based on rutin solubility. The proposed purification protocol yielded yellow-color crystals, which were characterized by fluorescence microscopy, Fourier-transform infrared spectroscopy and liquid chromatography-mass spectrometry to confirm them as rutin. Purity of rutin was confirmed by ultra-performance liquid chromatography at 97.6%; yield of the purified rutin was determined to be 78.2%. The remaining rutin (21.8%) was found in the liquids collected at various stages of purification; such liquids could be recycled using the same purification process. The proposed protocols are simple, yet effective for rutin extraction and purification from asparagus leafy by-products.

Three recombinant peroxidases as a degradation agent of aflatoxin M1 applied in milk and beer.

The aim of this work was to estimate the effects of three recombinant peroxidases (rPODs) on the degradation of aflatoxin M1 (AFM1) in a model solution and were applied in milk and beer to study the AFM1 degradation. Besides, the contents of AFM1 in model solution, milk and beer were evaluated, and the kinetic parameters of rPODs were determined (Michaelis-Menten constant - Km and maximal velocity - Vmax). The optimized reaction conditions (The degradation was over 60 %) for these three rPODs in the model solution were, respectively as follows: pH were 9, 9, and 10; hydrogen peroxide concentrations were 60, 50, and 60 mmol/L; at an ionic strength of 75 mmol/L and reaction temperature of 30 °C with 1 mmol/L K+ or 1 mmol/L Na+. These three rPODs (1 U /mL) presented the maximum activity for degradation of AFM1 of 22.4 %, 25.6 %, and 24.3 % in milk, while 14.5 %, 16.9 %, and 18.2 % in beer, respectively. Meanwhile, the survival rate of Hep-G2 cells raised about 1.4 times after treated with peroxidase-generated AFM1 degradation products. Therefore, POD may be a promising alternative to reduce the pollution of AFM1 in model solution, milk, beer, and minimize their impact on the environment in humans.

Study on Lactiplantibacillus plantarum R6-3 from Sayram Ketteki to prevent chronic unpredictable mild stress-induced depression in mice through the microbiota-gut-brain axis.

The prevention, mitigation and treatment of depression has become a global issue that needs to be solved urgently. Sayram Ketteki, a traditional natural fermented yoghurt from the region with the world's fourth highest life expectancy, has been known as the "longevity secret", whose longevity and anti-depression factors are speculated to come from its rich microorganisms. Therefore, for the first time, we systematically studied in depth the microbes of Sayram Ketteki, screened a new edible probiotic strain, Lactiplantibacillus plantarum R6-3, and explored its anti-depression effect in chronic unpredictable mild stress (CUMS)-induced depression in mice. It is encouraging that L. plantarum R6-3 was significantly superior to the classic anti-depressant drug, fluoxetine, in the performance of promoting sucrose preference test (SPT) behavior by 18% (p < 0.001), lowering the serum CORT content by 5.6% (p < 0.05), accelerating the brain-derived neurotrophic factor (BDNF) level by 5.9% (p < 0.01), increasing the serum IL-10 concentration by 2.3% (p < 0.05), up-regulating the expression of BDNF and phosphorylated-ERK by 74% (p < 0.01) and 45% (p < 0.001), respectively, and facilitating the secretion of fecal short-chain fatty acids (SCFAs), including n-butyric, n-valeric, and isovaleric acid by 47% (p < 0.01), 42% (p < 0.05) and 38% (p < 0.05), respectively. Through the microbiota-gut-brain axis, L. plantarum R6-3 promoted the secretion of intestinal SCFAs through regulation of the composition and function of the gut microbiota, and activated the production of the monoamine neurotransmitter, renewed the level of brain neurotrophic factor, and suppressed the hyperactivity of the hypothalamic-pituitary-adrenal (HPA) axis by adjusting the hippocampal BDNF/TrkB/ERK/CREB signaling pathway, thereby improving the immune and oxidative stress status, protecting hippocampal tissue from damage, maintaining a healthy weight and preventing CUMS-induced depressive behavior in mice. It has great prospects for the development of natural functional foods, the prevention and treatment of depression and in innovative microecological preparations.

Optimization of Mopan Persimmon Wine Fermentation with Pectinase and Analysis of Its Mechanism of Action.

Due to the high sugar content of Mopan persimmon, which has an annual output of more than 0.5 million tons in China, it can be processed to make fruit wine. In this study, a strain of yeast screened from different persimmon samples was used for persimmon wine fermentation. The optimal conditions of persimmon wine fermentation were determined through single-factor experiments as follows: Yeast addition of 0.08 g/kg; a fermentation temperature of 28 °C; sucrose addition of 18%; and pectinase addition of 0.01%. Under these conditions, the alcohol content of persimmon wine reached 12.9%. The addition of pectinase during persimmon wine fermentation was found to decompose pectin at high speed, reduce the viscosity of the fermentation liquid, increase the dissolved oxygen content in the fermentation liquid, promote the growth and reproduction of yeast, and effectively convert the sugars into alcohol. After fermentation, alcohol, residual sugars, and total phenolic content with or without pectinase treatment were 12.9 and 4.4%, 2.2 and 13.4 g/L, and 738.7 and 302 µg/mL, respectively. Scanning electron microscopy (SEM) results showed that compared with the mash without pectinase treatment, the mash with pectinase had a larger network structure and more pores and yeasts.

Microbiology, flavor formation, and bioactivity of fermented soybean curd (furu): A review.

Soybeans are an important plant-based food but its beany flavor and anti-nutritional factors limit its consumption. Fermentation is an effective way to improve its flavor and nutrition. Furu is a popular fermented soybean curd and mainly manufactured in Asia, which has been consumed for thousands of years as an appetizer because of its attractive flavors. This review first classifies furu products on the basis of various factors; then, the microorganisms involved in its fermentation and their various functions are discussed. The mechanisms for the formation of aroma and taste compounds during fermentation are also discussed; and the microbial metabolites and their bioactivities are analyzed. Finally, future prospects and challenges are introduced and further research is proposed. This information is needed to protect the regional characteristics of furu and to regulate its consistent quality. The current information suggests that more in vivo experiments and further clinical trials are needed to confirm its safety and the microbial community needs to be optimized and standardized for each type of furu to improve the production process.

Exploration of microbial profile of traditional starters and its influence on aroma profile and quality of Chinese steamed bread.

BACKGROUND: Chinese steamed bread (CSB) is a popular staple food in China with traditional ethnic characteristics. CSB with traditional starters has good flavor and texture but is unstable and requires a long preparation time. Therefore, it is necessary to analyze the traditional starters (ST) and their influence on the flavor and quality of steamed bread to meet people's requirements as a staple food. RESULTS: The count of yeast, lactic acid bacteria and total microbial population significantly varied in different traditional starters; Saccharomyces and Lactobacillus were the predominant genera. Among the tested samples, fungi were found in ST from Shijiazhuang (SJ), Handan (HD) and Langfang (LF), while bacteria were found in ST from Tangshan (TS) and SJ at sub-predominant levels. In terms of the bread quality, the highest specific volume and porosity were in XT-CSB (Xingtai); the highest height/diameter ratio was in SJ-CSB; and the highest sensory score was in TS-CSB. A total of 26 aroma compounds (VIP > 1; variable importance for predictive components) were identified to discriminate CSB fermented with different starters, which were separated by stepwise canonical discriminant analysis using two functions. The correlation analysis among microbiota, aroma compounds and bread quality showed a higher contribution of bacteria than of fungi. CONCLUSION: Differences in microbial profiles caused different aroma profiles and quality of CSB; and the CSB fermented with traditional starters were sufficiently separated by stepwise canonical discriminant analysis based on aroma compounds. © 2023 Society of Chemical Industry.

Photothermal and selective microbial inactivation behaviors of gluconamide-coated IR780 nanoparticles.

Photothermal therapy (PTT) is a promising alternative treatment for bacterial infection. In this study, a photothermal nanoparticle was prepared by encapsulating IR780 into N-octyl-D-gluconamide (GA). The photothermal nanoparticle (IR780-GA NP) was evenly suspended in water with an average particle size of 42.2 nm. After exposure to near-infrared light, the temperature of the IR780-GA NP suspension was increased by around 15 °C within 5 min. This leads to an obvious microbial inactivation effect when it is adsorbed to methicillin-resistant Staphylococcus aureus (MRSA, 2 orders of magnitude reduction of CFU concentration) and Escherichia coli (1.5 orders of magnitude reduction of CFU concentration). Interestingly, Salmonella typhimurium survived after the same treatment. Different strains also showed variations. The hemolysis test showed that IR780-GA NPs had good blood compatibility. In vivo experiments collaborated with the in vitro findings. The IR780-GA NP-triggered photothermal effects killed 63-100% of bacteria in the wound site of mice depending on the IR780-GA NP concentration. Overall, this study provided the fundamental basis of IR780-GA NPs in four aspects: fabrication, photothermal characterization, selective adsorption, and microbial inactivation (in vitro and in vivo). The findings of this study provide a practical approach for the development of mild photothermal therapy which targets specific bacterial strains and treats MRSA infection effectively.

Copper inhibits postacidification of yogurt and affects its flavor: A study based on the Cop operon.

Yogurt and its related products are popular worldwide. During transportation and storage, Lactobacillus delbrueckii ssp. bulgaricus in yogurt continues to metabolize to form lactic acid, the postacidification phenomenon of yogurt. Postacidification of yogurt is a widespread phenomenon in the dairy industry. Many scholars have done research on controlling the postacidification process, but few report on the molecular mechanisms involved. In this study, we used a molecular-assisted approach to screen food additives that can inhibit postacidification and analyzed its effects on yogurt quality as well as its regulatory mechanism from multi-omics perspectives in combination. The copper ion was found to upregulate the expression of the LDB_RS05285 gene, and the copper transporter-related genes were regulated by copper. Based on the metabolic-level analysis, copper was found to promote lactose hydrolysis, accumulate a large amount of glucose and galactose, inhibit the conversion of glucose to lactic acid, and reduce the production of lactic acid. The significantly greater abundance of l-isoleucine and l-phenylalanine increased the abundance of 3-methylbutyraldehyde (∼1.2 times) and benzaldehyde (∼7.9 times) to different degrees, which contributed to the formation of the overall flavor of yogurt. Copper not only stabilizes the acidity of yogurt, but also it improves the flavor of yogurt. Through this established method involving quantitative and correlation analyses at the transcriptional and metabolic levels, this study provides guidance for the research and development of food additives that inhibit postacidification of yogurt and provide a reference for studying the changes of metabolites during storage of yogurt.

Spatial and Temporal Distribution of Phenolic and Flavonoid Compounds in Sour Jujube (Ziziphus. Acidojujuba Cheng et Liu) and Their Antioxidant Activities.

In order to comprehensively analyze the antioxidant substances in sour jujube, total phenolic content (TPC) and total flavonoids contents (TFC) in different organs, including stem, leaf, flower, fruit pulp, and seed were analyzed for their contents and antioxidant activities. The results showed that leaves possessed significantly higher TPC and TFC (20.4 and 20.5 mg/g, respectively) than the other organs and have the highest antioxidant activity, which were also higher than the wild blueberry (A well-known for its high TPC). Subsequently, the variations in the antioxidant content and antioxidant activity of leaves were analyzed during leaf development. TPC in leaves sampled in may and august were significantly higher than that in other months, while the highest one was found in may. The n-hexane, ethyl acetate, n-butanol, and water fractions obtained from the main methanol extract of sour jujube leaves were evaluated for TPC and TFC and their antioxidant activity and it was found that ethyl acetate fraction displayed the highest TPC and TFC (184.5 and 193.3 mg/g, respectively), as well as the best antioxidant activity. In addition, using LC-MS and HPLC, ethyl acetate fraction was analyzed from qualitative and quantitative aspects; 31-one phenolic compounds, including catechin (33.0 mg/g), epigallocatechin (15.3 mg/g), quercetin 3-O-glucoside (11.4 mg/g), naringenin (6.7 mg/g), esculetin (4.8 mg/g), and chlorogenic acid (4.6 mg/g) were identified. Catechin, esculetin, epigallocatechin, chlorogenic acid, quercetin 3-O-glucoside, and naringenin exhibited high antioxidant activity. These results provide a theoretical basis for further study and utilization of flavonoid and polyphenols in sour jujube.

In vitro digestion and fecal fermentation behaviors of polysaccharides from Ziziphus Jujuba cv. Pozao and its interaction with human gut microbiota.

This study aimed to explore the dynamic changes of structural properties of polysaccharide from Ziziphus Jujuba cv. Pozao (JPS) during in vitro digestion and fermentation as well as its impacts on gut microbiota. Gastrointestinal digestion resulted a significant decrease in the reducing sugar content (CR), while a slight increase in the molecular weight. However, no free monosaccharide was detected. During the gut microbial fermentation, the CR showed a trend of increasing at first and then decreasing, while the carbohydrate residue decreased with the releases of monosaccharides. Meanwhile, pH decreased along with the production of short-chain fatty acids due to the utilization of JPS. Furthermore, JPS regulated the composition of gut microbiota, such as promoting Megasphaera and unclassified_f_Veillonellaceae, while inhibiting Bacteroides, Lachnoclostridium, Parabacteroides, Sutterella, Lachnospiraceae UCG-010, and Butyicimonas; Sutterella, Megasphaera, and unclassified_f_Veillonellaceae might be the characteristic bacteria in JPS group compared to the Inulin Control group. It was also found that JPS significantly enriched the metabolic pathways of carbohydrate, energy and amino acid after fermentation. These results indicated that JPS was indigestible but played an essential role by regulating gut microbiota composition and metabolic functions, which provided a basis for the conclusion that JPS could protect intestinal barrier and enhance immunity in our previous study.

Pear pomace soluble dietary fiber ameliorates the negative effects of high-fat diet in mice by regulating the gut microbiota and associated metabolites.

The gut microbiota and related metabolites are positively regulated by soluble dietary fiber (SDF). In this study, we explored the effects of SDF from pear pomace (PP) on the regulation of gut microbiota and metabolism in high-fat-diet-fed (HFD-fed) C57BL/6J male mice. The results showed that PP-SDF was able to maintain the HFD disrupted gut microbiota diversity with a significant increase in Lachnospiraceae_UCG-006, Akkermansia, and Bifidobacterium spp. The negative effects of high-fat diet were ameliorated by PP-SDF by regulating lipid metabolisms with a significant increase in metabolites like isobutyryl carnitine and dioscoretine. Correlation analysis revealed that gut microbiota, such as Akkermansia and Lachnospiraceae_UCG-006 in the PP-SDF intervention groups had strong positive correlations with isobutyryl carnitine and dioscoretin. These findings demonstrated that PP-SDF interfered with the host's gut microbiota and related metabolites to reduce the negative effects caused by a high-fat diet.

Edible Pleurotus eryngii Papery Food Prepared by Papermaking Process.

The objective of the current study was to evaluate the feasibility of papery food with Pleurotus eryngii (P. eryngii) as a raw material using the papermaking process. The physical, chemical, structural, and thermal degradation properties were studied as well as the sensory evaluation of the papery food from P. eryngii mycelia (PMP), stems (PSP), caps (PCP), and whole fruiting bodies (PEP). The results indicated that the colors from PSP, PCP, and PEP were clearly different from PMP. Thicker PSP and PMP had a smoother surface and better crispness compared to PCP. Moreover, PSP had better moisture resistance and thermal decomposition performance compared to the other groups. Nutritional composition and Fourier-transform infrared spectroscopy suggested abundant polysaccharide and protein content in all of the papery food. Finally, sensory evaluation showed that the formability, mouth feel, and overall palatability of PSP and PMP were more popular among consumers. Overall, this study provides a novel method for the preparation of papery food and provides a potential new mechanism for the further development and utilization of the fruiting bodies and mycelium of P. eryngii.

Effects of four cooking methods on flavor and sensory characteristics of scallop muscle.

This work aimed to explore the influence of four different cooking methods (Boiling, roasting, frying, and microwaving) on the sensory characteristics of scallop muscles. Headspace-gas chromatography-ion mobility spectrometry (HS-GC-IMS) and electronic nose (e-nose) were combined to analyze the aroma of scallops. Combined with the results of free amino acids and electronic tongue (e-tongue), the taste changes of different samples were analyzed. Furthermore, texture profile and microstructure analysis jointly showed the influence of cooking methods on texture. The results showed that frying was the most suitable cooking method for scallop muscle because it resulted the best tasted products, boiled scallops retain the highest similarity to fresh scallops. Besides, a higher level of lipid oxidation and Maillard reaction resulted in significant increase in aldehydes, ketones, furans, umami, and sweet amino acid. For the boiled sample, the loss of water-soluble compounds and less fat oxidation resulted in fewer flavor substances and free amino acids, along with looser organizational structure and poorer sensory quality. The research showed that besides the texture of scallop muscle, volatile organic compounds and free amino acids as well as their mutual roles in taste and smell were also important to sensory receptivity.

Effect of Multi-Mode Thermosonication on the Microbial Inhibition and Quality Retention of Strawberry Clear Juice during Storage at Varied Temperatures.

Strawberry juice, which is rich in nutrients and charming flavor, is favored by consumers. To explore whether multi-mode thermosonication (MTS) can ensure the quality stability of strawberry clear juice (SCJ) during storage, the effects of microbial inhibition, enzyme activity, and physicochemical properties of SCJ pretreated by MTS were evaluated during storage at 4, 25, and 37 °C in comparison with thermal pretreatment (TP) at 90 °C for 1 min. The MTS, including dual-frequency energy-gathered ultrasound pretreatment (DEUP) and flat sweep-frequency dispersive ultrasound pretreatment (FSDUP), were conducted at 60 °C for 5 and 15 min, respectively. Results showed that the total phenols, flavonoids, anthocyanins, ascorbic acid, and DPPH free radical scavenging ability of SCJ decreased during the storage period. The control sample of SCJ was able to sage for only 7 days at 4 °C based on the microbiological quality, while the FSDUP and DEUP group extended the storage period up to 21 and 14 days, respectively. The polyphenol oxidase in SCJ pretreated by MTS did not reactivate during the storage period. The MTS remarkably (p < 0.05) reduced the color deterioration, browning degree, and nutrient degradation during the storage period. Moreover, the FSDUP group exhibited the maximum shelf life with a minimum loss of quality, demonstrating that it was the most suitable processing method for obtaining high-quality SCJ. It can be concluded that the MTS has the potential to inhibit enzymatic browning, inactivating microorganisms, preserve original quality attributes, and prolong the shelf life of SCJ.

Screening of Single-Stranded DNA Aptamer Specific for Florfenicol and Application in Detection of Food Safety.

In this work, the single-stranded DNA (ssDNA) aptamers specific to florfenicol (FF) and having a high binding affinity were prepared using the magnetic bead-based systematic evolution of ligands by the exponential enrichment technique (MB-SELEX). After 10 rounds of the MB-SELEX screening, aptamers that can simultaneously recognize FF and its metabolite florfenicol amine (FFA) were obtained. The aptamer with the lowest dissociation constant (Kd) was truncated and optimized based on a secondary structure analysis. The optimal aptamer selected was Apt-14t, with a length of 43 nt, and its dissociation constant was 4.66 ± 0.75 nM, which was about 7 times higher than that of the full-length sequence. The potential binding sites and interactions with FF were demonstrated by molecular docking simulations. In addition, a colorimetric strategy for nanogold aptamers was constructed. The linear detection range of this method was 0.00128-500 ng/mL and the actual detection limit was 0.00128 ng/mL. Using this strategy to detect florfenicol in actual milk and eggs samples, the spiked recoveries were 88.9-123.1% and 84.0-112.2%, respectively, and the relative standard deviation was less than 5.6%, showing high accuracy.