Objective To increase the production of exopolysaccharides (EPS) from lactobacillus by optimizing fermentation conditions and evaluate the antioxidant activity of the extracted EPS. Methods P1-10 was isolated as a high yield EPS producing lactobacillus from kefir grains and identified by 16S rDNA sequencing. Meanwhile, the effects of carbon source composition and content in the medium and fermentation time on the EPS yield of P1-10 were investigated and compared. Additionally, scanning electron microscopy and in vitro antioxidant study was studied from the obtained EPS as well. Results Among the 12 kinds of isolated strains from kefir grains, P1-10 formed gram-positive colonies under microscopic examination after Gram staining, could coagulate milk, and had a string length greater than 15 mm. It was identified as Pediococcus acidilactici strain (MH143596.1 Pediocuccus acidilactici strain D15) by 16S rDNA sequencing and the maximum content of EPS was 6.52 mg/mL. In addition, the optimal conditions for P1-10 were obtained under the condition of MRS (DeMan-Rogosa-Sharpe medium) medium with the carbon source replaced by 40 g/L sucrose and fermenting at 35 ℃, pH 6.0 for 60 hours, while the highest yield of EPS was 29.09 mg/mL. Furthermore, the surface of EPS under the scanning electron microscopy was relatively rough, with a sense of layering and different sizes voids. Moreover, the elimination rates of 1,1-diphenyl-2-picrylhydrazyl (DPPH) and 2,2’-azinobis-(3-ethylbenzthiazoline-6-sulphonate) (ABTS) free radicals in the 1.0 mg/mL vitamin C (vitamin C, VC), EPS and fermentation supernatant were 86.21%, 95.03%; 81.32%, 93.91% and 58.54%, 65.73%, respectively. Conclusion P1-10 can effectively increase the extraction efficiency of EPS compared to the normal culture with the optimizing of the culture conditions. As for the in vitro antioxidant experiments, EPS is indicated a strong ability to scavenge free radicals and antioxidant capacity due to the highly DPPH and ABTS radical scavenging rates. This study may provide a theoretical basis for the screening, extraction and functional activity research of EPS from lactic acid bacteria.

Objective To develope a co-microencapsulated probiotic-stachyose functional dairy product. Methods This research employed spray-drying technology using sodium alginate and stachyose as wall materials for probiotic encapsulation, with optimized parameters. The optimal yogurt formulation was determined through orthogonal experiments. Results The mass ratio of sodium alginate and stachyose was 3:1, the concentration of materials was 2.00%, and the spray drying was carried out at 140 ℃ and a feeding speed of 40%, the best embedding rate of the composite probiotics was achieved. Through orthogonal experiments, the yogurt formula was optimized to determine that the optimal combination was an addition rate of 0.08% for the starter culture, 3.00% for white granulated sugar, and 0.30% for stachyose. Under optimized conditions, the microencapsulation efficiency of probiotics reached optimal levels. Microscopic examination confirmed effective probiotic encapsulation, preventing thermal damage and improving stability. The final yogurt product demonstrated excellent color, taste, texture, and received outstanding sensory evaluations. Conclusion This study successfully developes a functional yogurt combining probiotic viability with superior sensory qualities, providing valuable technical insights for functional food innovation while meeting consumer demand for dairy products that balance health benefits with excellent taste.

Objective To study the decontamination effects of different photosensitizers combined with blue light irradiation on Porphyra yezoensis. Methods This study first compared the bactericidal effects of 4 kinds of photosensitizers (curcumin, vitamin K3, riboflavin, and sodium copper chlorophyllin) and 3 kinds of wavelengths (405, 420 and 460 nm) on Escherichia coli and Staphylococcus aureus. Two kinds of blue light wavelengths (405 nm and 420 nm) and photosensitizers (curcumin and riboflavin) were then applied to fresh Pyropia yezoensi before drying. The influences of curcumin concentration, irradiation time, and distance were examined. The changes in hygienic indicator bacteria, color difference (ΔE), and nutritional content were measured before and after treatment and drying. Results The decontamination effect on fresh Pyropia yezoensi were consistent with those in the pure bacterial system. Blue light combined with photosensitizers exhibited stronger sterilization efficiency. The optimal treatment was 420 nm blue light combined with 100 μmol/L curcumin (5 cm distance, 150 min). The total viable count and coliforms in untreated fresh Pyropia yezoensi were 5.69 log CFU/g and 4.34 log CFU/g, respectively, which increased to 6.63 log CFU/g and 4.15 log CFU/g after primary drying. Total viable count and coliforms respectively decreased by 1.88 log CFU/g and 1.46 log CFU/g after treatment, and decreased by 1.94 log CFU/g and 1.35 log CFU/g after drying. ΔE of dried Pyropia yezoensi after treatment ranged between 0.5 and 1.5, indicating a slight but noticeable change, while no significant differences (P>0.05) were observed in nutritional components such as vitamin C and vitamin E. Conclusion After treatment with 420 nm blue light and 100 μmol/L curcumin, the total viable count of dried Pyropia yezoensi was reduced to 4.56-4.82 log CFU/g. Apart from slight color difference due to staining, there was no significant change in nutritional components. This study provides technical support for developing a safe, efficient and environmentally friendly preservation and processing method for Pyropia yezoensi.

Foodborne pathogenic bacteria are one of the main causes of foodborne illness, and pose a serious threat to global public health. At present, the detection of pathogenic bacteria in food primarily relies on conventional plate culture method and auxiliary means, such as chromogenic medium and biochemical identification. However, these methods are long-term, cumbersome and prone to false positives, making them inadequate to meet the demands of modern food safety for rapid and accurate detection. Therefore, the development of rapid and effective detection technologies is crucial for the timely detection, control and elimination of bacterial contamination. This paper took several common foodborne pathogenic bacteria, including Escherichia coli, Salmonella Typhimurium, Listeria monocytogenes, and Staphylococcus aureus, as examples to provide a detailed analysis of the principles, applications, advantages and limitations of various detection methods, and discussed the development trend of detection technology in the future. This study provides both theoretical support and practical guidance for enhancing existing detection methods and the developing new rapid detection technologies, with the goal of more effectively tackling challenges related to food safety.

The contamination problem of Bacillus cereus seriously affects the food safety of China, the development of prevention and control technology against Bacillus cereus is urgent. Lactic acid bacteria, as a safe and efficient biological control method, have a good prospect in controlling Bacillus cereus precisely. Previous studies have found that Lactiplantibacillus, Lactobacillus and Lacticaseibacillus are the main genus of antagonistic bacteria. The antibacterial components against Bacillus cereus are mainly bacteriocins, organic acids and extracellular polysaccharides. The antagonistic mechanism mainly included destroying the integrity of cell membrane, inhibiting spore germination, biofilm formation and toxin expression, but the mechanism of internal gene expression regulation is still lack of in-depth exploration. This paper reviewed the progress in controlling of Bacillus cereus by lactic acid bacteria, summarized the lactic acid bacteria species, antibacterial compounds and their antagonistic mechanisms against Bacillus cereus, as well as the applications in food, also prospected the investigation of new types of microbial antibacterial components, the mechanism of action and the future applications, to provide new insights for the development of green prevention and control technologies of foodborne pathogens.

Objective To optimize the ultrasonic extraction process of dihydromyricetin from Ampelopsis grossedentata using artificial neural networks combined with response surface methodology. Methods The stems and leaves of Ampelopsis grossedentata were used as the research material. An ultrasonic extraction system for dihydromyricetin was established, and the process parameters were systematically optimized using a combination of single-factor experiments, response surface methodology and artificial neural network models optimized by genetic algorithms. The extraction yields of dihydromyricetin from different parts of Ampelopsis grossedentata were then analyzed under optimal conditions. Results The artificial neural network model exhibited superior accuracy and predictive capability in comparison to the response surface methodology. The optimal extraction conditions were determined to be an ultrasonic power of 360 W, a temperature of 42 ℃, a liquid-to-solid ratio of 20:1 (mL:g), and an extraction time of 35 min. Under these conditions, the actual extraction yield of dihydromyricetin was (39.83±0.01)%, with a relative error of only 0.36% compared to the artificial neural network-predicted value of 40.19%. Furthermore, the extraction yield of dihydromyricetin from various parts of Ampelopsis grossedentata under optimal ultrasonic conditions followed the sequence: Stems and leaves of Ampelopsis grossedentata>branches of Ampelopsis grossedentata>pruned branches of Ampelopsis grossedentata. Conclusion This study successfully optimizes the ultrasonic extraction process to enhance the extraction efficiency of dihydromyricetin from Ampelopsis grossedentata and reveals significant differences in dihydromyricetin extraction yields among different parts of the plant.

Objective To develop a rapid and visual method for detecting Shigella by combining loop-mediated isothermal amplification (LAMP) with clustered regularly interspaced short palindromic repeats and associated protein 12b (CRISPR/Cas12b). Methods Based on the conserved invasion plasmid antigen H gene ipaH7 sequence of Shigella, LAMP primers were designed and screened to establish a LAMP method for detection of Shigella. The candidate sgRNAs were designed based on the target DNA sequence of LAMP amplified fragment, and then the sgRNA, which could specifically recognize and stimulate Cas12b cleavage, was screened. Finally, a rapid detection method for detecting Shigella was developed by combining LAMP with CRISPR/Cas12b, and the specificity and sensitivity were evaluated. Results A set of LAMP primers and sgRNA targeting Shigella ipaH7 were screened, and a LAMP CRISPR/Cas12b detection method was established. The detection could be completed within 1 hour with the lowest limit of detection of 1.1×10¹ CFU/mL for pure culture and 1.1×10¹ CFU/g for spiked pork samples, and no cross reactivity with other pathogens. Conclusion This study successfully establishes a rapid, sensitive and visual detection method for Shigella, which can achieve accurate detecting Shigella in food samples.

Objective To study the effects of in vitro simulated digestion on the content of total polyphenols and antioxidant activity of Canarium album and its products. Methods The study investigated the changes in total polyphenol content and scavenging capacities against 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical, 2,2’-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) cation (ABTS⁺) free radical, hydroxyl free radical and superoxide anion free radical during in vitro simulated gastrointestinal digestion using 5 samples: Canarium album polyphenol extract, fresh Canarium album, sweet Canarium album, salt-preserved Canarium album, and licorice-flavored Canarium album. Results The polyphenol content of the 5 samples in both the gastric and intestinal digestion stages was lower than that in the undigested samples. During the gastric digestion stage, the scavenging capacities of the 5 samples for ABTS⁺ free radicals and DPPH free radicals were significantly stronger than those of the undigested samples. In the intestinal digestion stage, the free radical scavenging capacities of most samples decreased. The hydroxyl radical scavenging capacities of Canarium album extract and fresh Canarium album were weaker than those of the other samples, but their scavenging capacities in the intestinal stage were stronger than those in the gastric stage. Significant differences were observed in the superoxide anion radical scavenging capacities among the 5 samples: The superoxide anion radical scavenging capacity of Canarium album polyphenol extract increased initially and then decreased over time during gastrointestinal digestion; the scavenging capacity of fresh Canarium album during gastrointestinal digestion was stronger than that of the undigested counterpart; due to the presence of processed ingredients, the scavenging capacities of sweet Canarium album, salte-preserved Canarium album and licorice-flavored Canarium album showed no obvious correlation with their polyphenol content. Conclusion Compared with the undigested samples, different Canarium album samples still exhibit good antioxidant activity after digestion. This study provides a reference for the further research and application of Canarium album polyphenols, and offers a theoretical basis for the development, deep processing and utilization of Canarium album and its products.

As a worldwide medicinal and edible homologous plant, Allium sativum L. has the functions of antitumor, prevention and treatment of cardiovascular diseases and anti-pathogenic microorganisms. Studies have shown that many active ingredients in Allium sativum L. exert antitumor effects mainly by inhibiting tumor cell proliferation, regulating signaling pathways to inhibit migration and invasion, inducing tumor cell apoptosis, and arresting cell cycle. At the same time, the Allium sativum L. active ingredient also enhances the antitumor effect of other drugs through its combination with other drugs. This article reviewed the research on the antitumor effect and mechanism of Allium sativum L. active ingredients in the past 30 years, as well as the effects of Allium sativum L. active ingredients in combination with other drugs, this provides an important theoretical basis and application reference for the study of the antitumor action mechanism of active ingredients in Allium sativum L. and the development of innovative drugs.