Abstract:Red pigments have attracted extensive attention in the fields of medicine and food because of the anti-cancer, antioxidant and other biological activities. Using microorganisms to produce red pigments has gradually become a research hotspot in recent years because of the low costs of raw materials and the stable yield. The author reviewed the key microbial red pigments and systematically summarized and compared the extraction methods of microbial red pigments. Furthermore, this article expounded the activities of microbial red pigments, discussed the limitations of microbial red pigments in resource development and production, and then proposed the future development prospects, providing reference for the subsequent in-depth research on microbial red pigments.

Abstract:Cardiovascular and cerebrovascular diseases with increasing incidence rates in recent decades have become a great challenge to public health on a global scale, posing a threat to human health. Monascus can produce various bioactive components such as statins, Monascus pigment, and γ-aminobutyric acid through metabolic processes. These components can help decrease the levels of blood lipid, blood pressure, and blood glucose while preventing and treating diseases such as tumors, inflammation, and osteoporosis. Therefore, Monascus has been widely used in multiple fields such as medical treatment, food supplements, brewing foods, and biocatalysis. Especially, blood lipid-lowering preparations based on Monascus are gradually becoming a new choice for people's health management. The author provides an overview of the blood lipid-lowering effects of Monascus and its metabolites, as well as the current application status of blood lipid-lowering supplements produced from Monascus, providing reference for the research and application of functional foods related to Monascus.

Abstract:Smilax glabra is a Chinese medicinal material with both medicinal and edible values. Because of the rich flavonoids, organic acids, polysaccharides, saponins and other components, Smilax glabra possesses various physiological activities and has been widely used in combination with other Chinese medicinal materials in clinical practice. Currently, researchers have explored the application of Smilax glabra in the research and development of health-care food and functional food. However, the marketization rate is still low. It is important to rationally use the effects of Smilax glabra to develop products that meet the market demand as part of its industrial development. The author introduced the main components in Smilax glabra and reviews the research progress in the antibacterial, antioxidant, immunomodulatory, lipid-lowering, antidiabetics, and liver- and kidney-protecting activities of this medicinal material. Additionally, the author summarized the active mechanisms of Smilax glabra based on network pharmacology. This review aims to provide a reference for the value-added utilization of Smilax glabra resources and the development of related functional products.

Abstract:Neonicotinoid pesticides are one of the most widely used neurotoxic insecticides in crops, and their excessive residue levels have long been a significant concern. Developing efficient, rapid detection technology for neonicotinoid pesticides is crucial for ensuring food safety. Immunoassay-based rapid detection has gained increasing application in food safety monitoring due to its technical advantages. The author primarily reviews the current national standards for maximum residue limits of neonicotinoid pesticides and summarizes the principle, characteristics, and research progress of commonly used rapid immunoassay techniques including enzyme-linked immunosorbent assay (ELISA) technology, immunochromatography assay technology, fluorescence immunoassay (FIA) technology, chemiluminescence immunoassay (CLIA） technology, and biomimetic ELISA technology for their detection. The advantages and limitations of these techniques are also evaluated. Finally, the challenges and prospects of applying rapid analysis and detection of neonicotinoid pesticides in food safety are discussed, with the aim of providing a reference for the development of immunoassay-based rapid detection methods for food safety.

Abstract:Single-stranded DNA (ssDNA) aptamer is a short single-stranded deoxyribonucleotide sequence obtained by the systematic evolution of ligands by exponential enrichment (SELEX) in vitro. It can achieve high affinity and specific binding to targets through conformational changes and possesses the advantages of simple preparation, low cost, relative stability, ease of modification, and low immunogenicity, earning it the name “chemical antibodies”. ssDNA aptamers have shown great potential in the field of food safety detection. This paper reviewed the ssDNA aptamer screening technology based on SELEX, its application in the detection of foodborne pathogens, current research limitations and potential future development directions. The aim is to provide a theoretical basis for improving food safety supervision and the prevention and control of foodborne disease.

Abstract:The extraction techniques, nutritional values, and bioactivities of silkworm pupa oil are key to its successful market adoption. The author summarizes the advantages and disadvantages of common extraction methods for silkworm pupa oil, and details the main nutritional and bioactive components, their respective concentrations, and functional properties. Additionally, the author discusses the bioactivities of silkworm pupa oil and its current applications in the food industry. In order to provide a theoretical foundation for its industrial production and high-value utilization in functional and healthy food sectors.

Abstract:Protein is a crucial nutrient for human beings, and its stable and high-quality supply is the key to improving people’s living standards and ensuring national food security. Currently, due to the high dependence on imported protein, there is a pressing need for new technologies to produce high-quality protein through non-food approaches. A promising candidate is the green microalga Chlamydomonas reinhardtii (C. reinhardtii), which has shown potential for producing dietary protein through fermentation on acetate. However, this method ignores the advantage of photosynthesis in green bio-manufactory. Here, the author demonstrated the feasibility of utilizing formate, one of the products of CO₂ reduction driven by clean energy, to enhance the photosynthetic production of C. reinhardtii. To eliminate the serious inhibition of HCOO^- on photosynthetic activity, the author employed adaptive lab evolution with the guide by chlorophyll fluorescence dynamic parameters and obtained a domesticated stain capable of growing under as high as 150 mmol/L HCOO^-.With the addition of 50~150 mmol/L HCOO^-, the strain maintained stable the maximum quantum yield of PSⅡ (F_v/F_m), preserved a consistent fatty acid profile, and achieved a growth rate similar to acetate addition in batch cultures. Moreover, the protein content of biomass obtained with HCOO^- was 30%~35%, comparable to or even higher than that of commercial fermentation on acetate. This work provides a novel green approach for non-food sourced protein production through artificial-natural hybrid photosynthesis. Furthermore, the high HCOO^--tolerant strain serves as an excellent model to investigate the regulation of photosynthesis.

Abstract:Cypermethrin, a pyrethroid insecticide, is widely used due to its high efficiency and low toxicity, leading to significant residues in vegetables. However, its degradation behavior during thermal processing of vegetables remains unclear. This study developed a simultaneous high performance liquid chromatography (HPLC) method for the determination of cypermethrin and 3-phenoxybenzoic acid (3-PBA) in crown daisy to investigate the degradation of cypermethrin residues during thermal processing. The results showed that the optimal extraction conditions for cypermethrin were achieved using 0.1% acetic acid-acetonitrile as the extraction solvent, ultrasonic extraction for 15 minutes, and sample purification with 100 mg of graphitized carbon black （GCB）, resulting in recoveries between 93% and 106%. After thermal processing, blanching caused a 16.87% degradation of cypermethrin, with no 3-PBA detected, while stir-frying led to a 76.76% degradation of cypermethrin, with trace amounts of 3-PBA detected. Three degradation products were detected by mass spectrometry, and combined with theoretical calculations, the degradation pathway of cypermethrin was suggested. This study can provide a basis for the dietary exposure assessment of cypermethrin and its metabolites.

Abstract:Deoxynivalenol (DON), also known as vomitoxin, is produced by Fusarium graminearum. It is neurotoxic, immunotoxic, embryotoxic, teratogenic, and carcinogenic. DON mainly contaminates wheat, which not only leads to the quality deterioration of wheat but also jeopardizes the health of human beings directly or indirectly. Liquid chromatography-tandem mass spectrometry (LC-MS/MS) and gold immunochromatographic assay (GICA) were employed to determine the mass fraction of DON in wheat. The accuracy and stability of the two methods were evaluated by the spiked recovery test, and the recovery of the two methods was 92.98%~97.43% and 104.53%~108.92%, respectively, with the relative standard deviations (RSD) less than 10%. Then, the two methods were used to determine the mass fraction of DON in each part of naturally polluted wheat after processing. After milling and processing, the mass fraction ratio of DON in flour to whole wheat flour averaged 0.56, and that of DON in bran to whole wheat flour averaged 1.55. The results showed that the mass fraction of DON in flour was significantly lower than that in whole wheat flour after milling and processing of wheat, while the mass fraction of DON in bran was significantly higher than that in whole wheat flour. Therefore, the separation of bran from wheat after processing to the maximal extent can effectively reduce the mass fraction of DON in flour.

Abstract:Flammulina filiformis has high nutritional and medicinal value. The CRISPR-Cas9 genome editing technology has been rapidly developed in recent years, with some successful applications in edible and medicinal fungus. However, its editing efficiency is comparatively low. The author targeted the pyrG gene for mutation, designing and synthesizing guide RNA (gRNA) in vitro. The gRNA was assembled with the SpCas9 protein to form ribonucleoprotein (RNP) complexes, which were introduced into the protoplasts of Flammulina filiformis using the PEG method, while the transformation parameters were optimized. The results demonstrated that computationally predicted high-scoring gRNA might not always exhibit activity and needed to be assembled with SpCas9 protein in vitro for cleavage verification of the target gene. Active RNP complexes specifically edited the target gene upon transformation into Flammulina filiformis protoplasts, whereas inactive complexes failed to induce genetic modifications. Adding Triton X-100 to the transformation system significantly enhanced RNP uptake into protoplasts. Sanger sequencing of mutant strains revealed small fragment insertions at the target site, indicating that genome modifications occurred primarily through the non-homologous end joining (NHEJ) pathway. The author successfully established an in vitro CRISPR-Cas9 genome editing technology in Flammulina filiformis, achieving an editing efficiency of 60%. Meanwhile, this study provides a theoretical basis and technical support for the breeding of new varieties of Flammulina filiformis with desirable traits, as well as other edible fungi.

Abstract:D-tagatose is a rare sugar with multiple physiological functions, but its current biological production methods face challenges such as high substrate costs and unstable supply. After molecular modification, the tagatoronate 3-epimerase from Thermotoga petrophila can synthesize D-tagatose through epimerization reaction with D-fructose as substrate, and this mutant is denoted as tagatose 4-epimerase (T4E). This study successfully expressed T4E in Escherichia coli BL21 (DE3) through fusion of T7 tag to its N-terminal, characterized its enzymatic properties, and optimized the bioconversion conditions for the synthesis of D-tagatose from D-fructose catalyzed by T4E. Meanwhile, the immobilization of recombinant E. coli BL21 (DE3) cells expressing heterologous T4E using diatomaceous earth-sodium alginate was studied. The results showed that under optimal conditions, the equilibrium conversion rate could reach 25% after 4 h of reaction with 300 g/L D-fructose as the substrate. Compared with the T4E in free cells, the whole-cell immobilized T4E exhibited significantly improved thermal stability, enabling continuous reaction for seven batches and demonstrating high industrial application potential.

Abstract:Soy protein concentrate was used as raw material, and two characteristic flavor compounds from beef (4-hydroxy-2,5-dimethyl-3(2H)-furanone and 2,5-dimethyl-pyrazine) and three characteristic flavor compounds from spices (geraniol, linalool, and citral) were added during the extrusion process to improve the flavor of soy protein extrudates. Headspace solid-phase microextraction combined with gas chromatography-mass spectrometry (HS-SPME-GC-MS) and a sensory preference evaluation method were used to evaluate the flavor changes of extrudates. The results showed that the addition of exogenous volatile compounds caused significant changes in the types and concentrations of flavor compounds in the extrudates. After the addition of 2,5-dimethyl-pyrazine, furaneol, and linalool, the mass fraction ratio of off-flavor compounds to pleasant-flavor compounds in the soy protein extrudates decreased from 87∶13 in the control group to 83∶17, 57∶43, and 80∶20, respectively. Consumer preferences scores for the extrudates increased from 3.25 in the control group to 7.65, 6.34 and 5.62, respectively. Additionally, the evaporation of water during extrusion reduced the concentrations of three furan compounds in the extrudates by 67%~100% and two aldehyde compounds by 15%~83%, while the concentrations of other higher-boiling-point compounds remained unchanged.

Abstract:Monensin is a kind of polyether antibiotic produced by Streptomyces cinnamonensis (S. cinnamonensis), which is widely used in fields such as agriculture and animal husbandry with the advantages of low tendency to resistance and environmentally friendly properties. The author systematically investigated the fermentation performance improvement of S. cinnamonensis srain 2110 by combination of space mutation and genetic engineering breeding. High-yielding mutants from space mutation were selected through resistance screening combined with a microplate culture system. Results showed that a highly monensin producing mutant S. cinnamonensis G43 (G43) was obtained with a relatively good genetic stability, in which its monensin titer increased by 16.5% as compared to the parental strain. Subsequently, independent and tandem overexpression of monensin synthesis regulatory genes were conducted around the mutant strain. With successful integration of regulatory genes monRI and dasR, the engineering strain G43-dasR-monRI was finally obtained, and its monensin titer reached 11.3 kU/mL in a 5 L bio-fermenter, representing a 33.1% increase compared to the parental strain 2110. The results demonstrated that the combination of space mutation and genetic engineering breeding can be effectively applied to select high-yield strains for monensin production and may provide a reference for strain improvement of other polyether antibiotic-producing microorganisms.

Abstract:Proteins were extracted from buckwheat, highland barley, and wheat by alkaline extraction and acid precipitation. The relative molecular weight, amino acid composition of the digests, amino acid score (AAS), chemical score (CS), and essential amino acid index (EAAI) of the three cereal proteins during gastrointestinal digestion were characterized. Meanwhile, models of STC-1 cells and ICR mice were used to evaluate the effects of the digests on intestinal glucagon-like peptide-1 (GLP-1) secretion. The results showed that after gastrointestinal digestion of buckwheat, highland barley, and wheat proteins, the relative molecular weights of the digests were all less than 10 000. The peptides with relative molecular weights less than 3 000 in buckwheat, highland barley, and wheat protein digests accounted for 72%, 98%, and 56%, respectively. The proportions of essential amino acids in the protein digests of buckwheat, highland barley, and wheat were 38.33%, 30.74%, and 35.70%, respectively, and the essential amino acid indexes were 0.85, 0.88, and 0.91, respectively. All the digests lacked sulfur-containing amino acids (Met+Cys). The three protein digests significantly promoted the GLP-1 secretion in STC-1 cells. The results of mouse experiments also showed that the three protein digests significantly promoted the secretion of GLP-1 in the enteroendocrine cells of mice, and the digests of buckwheat and highland barley proteins outperformed that of wheat protein. The above results indicated that the nutritional values of buckwheat and highland barley proteins were lower than that of wheat protein, while the digests of buckwheat and highland barley proteins were superior to that of wheat protein in promoting GLP-1 secretion in enteroendocrine cells. This suggested that buckwheat protein and highland barley protein were more suitable than wheat protein for patients with metabolic diseases such as diabetes.

Abstract:Carotenoids are natural pigments found in plants, and their degradation products, such as ionone and β-cyclocitral, exhibit characteristics such as low threshold values and high-quality aroma, which contribute to the characteristic flavors of food and tobacco products. In this study, β?-carotene-degrading strains were screened using selective media, and volatile components were detected using headspace solid-phase microextraction coupled with gas chromatography-mass spectrometry (HP-SPME-GC-MS). The primary components of the activity ingredients were analyzed by high performance liquid chromatography-mass spectrometry (HPLC-MS). The degradation mechanism of β-carotene by the strain was investigated using molecular docking and hydrolyzed amino acid spectroscopy. The basic properties of the active components were analyzed using a spectrophotometer. A high-efficiency β-carotene-degrading bacterium, L-4, was isolated from rice wine koji and identified as Bacillus cereus. The optimal degradation conditions were a 3% inoculum volume fraction, a cultivation temperature of 37 ℃, and a pH of 7.0. The primary degradation products included β-ionone, formed by cleavage at the C₉—C₁₀ double bond of β-carotene, and β-cyclocitral, produced by cleavage at the C₇—C₈ double bond of β?-carotene. The active component FS1 is predominantly composed of four peptides: RF1 (ALTFR), RF2 (VYHYVTYQPPG), RF3 (WYMCC), and RF4 (KKPVLLHA). Hydrophobic amino acids in these peptides play a crucial role in the degradation of β-carotene. Bacillus cereus L-4 effectively degrades β-carotene by secreting hydrophobic peptides that destabilize the β-carotene emulsion, promoting double bond cleavage and decolorization through the action of amino acid residues in FS1 and metal ions. The carotenoid-degrading microbial resources identified in this study have significant implications for the food and tobacco industries.

Abstract:In this study, the flavor profiles of rice bran oil products prepared by heating fresh and extruded bran extracts with rice bran oil were evaluated and the formation mechanism of key flavor compounds was investigated. The results showed that rice bran oil prepared from fresh bran had more pronounced caramel sweetness and higher sensory quality score. Headspace solid-phase microextraction-gas chromatography and the flavor analysis based on relative odor activity values （ROAV） revealed that typical Maillard reaction products such as 4-hydroxy-2,5-dimethyl-3-(2H)furanone, 2,3-dihydro-3,5-dihydroxy-6-methyl-4(H)-pyran-4-one,3-methyl-butyraldehyde, phenylacetaldehyde, and maltol were the key flavor compounds in the oil samples prepared from fresh bran. There was no significant difference in the consumption of amino acids in the extract before and after reaction. However, the consumption of reducing sugar in fresh bran extract (5 514.26 mg/kg) was higher (4 715.69 mg/kg) than that in extruded bran extract. When reducing sugars were added to the extract of extruded bran, the product showed increased content of key aromatic compounds, with the sensory profile aligned with that of the product prepared from fresh bran. These findings suggest that flavor compounds of flavored rice bran oil were primarily produced by Maillard reaction and the flavor differences between the oil products prepared from extruded and fresh rice bran oil were due to the lower reducing sugar content in extruded bran. This study provides a theoretical basis for developing flavored rice bran oil.

Abstract:Solid-state fermentation of cut tobacco was conducted with a commercial brewer’s yeast strain under different conditions to obtain the products with different flavors. The different aroma compounds in the fermented cut tobacco under the three conditions with the highest mass fraction of total volatile flavor compounds were analyzed. The results showed that the mass fractions of alcohols, aromatics, ketones, esters, aldehydes, acids, and heterocyclic compounds were significantly increased in the cut tobacco after solid-state fermentation under different conditions. More flavor compounds were obtained after fermentation with a solid-to-liquid ratio of 1 g:1 mL and an inoculum amount of 1.0% at 25 ℃ for 36 h and fermentation with a solid-to-liquid ratio of 1 g:1 mL and an inoculum amount of 2.0% or 3.0% at 25 ℃ for 24 h. In addition, the mass fractions of classical aroma compounds such as (E,E)-farnesol, furfuryl alcohol, phenethyl alcohol, guaiacol, tabanone, damascenone, and dihydroactinidiolide varied in the cut tobacco fermented under different conditions. The cut tobacco products with special flavors that were obtained after fermentation with the yeast strain can enrich cut tobacco products. The results provide a basis for the application of commercial yeast in cut tobacco fermentation as well as the production of cigarettes with special flavors and the improvement of cut tobacco quality.