Search Results (9)

Lactic Acid Bacteria (LAB)-derived antimicrobial compounds are recognized as a promising source of novel antimicrobial agents, particularly for the treatment of Methicillin-Resistant Staphylococcus aureus (MRSA), where the mode of action and associated cellular effects remain largely unexplored. This study aims to evaluate antibacterial activity of Limosilactobacillus fermentum YTPP05 isolated from pickled radish against MRSA. Upon the initial antibacterial evaluations, it was found that strain YTPP05 inhibited the growth of MRSA isolates. Multiplex PCR identified multiple resistance genes in our MRSA strains, including mecA, blaZ, and aacA genes, aligning with antibacterial susceptibility profiles determined by the disc diffusion assay. An agar overlay assay showed that YTPP05 possessed antibacterial potential, with the largest inhibition zone diameters of 40.83 ± 8.43 mm, while the inhibition zones of the Cell Free Supernatant (CFS) of YTPP05 by an agar well diffusion were 27.16 ± 2.93 mm against the MRSA isolates. The minimum inhibitory concentration and minimum bactericidal concentration of YTPP05-derived CFS were 125 mg/mL. Scanning Electron Microscopy (SEM) demonstrated YTPP05 extracts caused cell membrane disruption, bubble-like protrusion, and cell lysis. Collectively, this study highlights the anti-MRSA potential of YTPP05 as an alternative antimicrobial agent for combating MRSA infections. Full article

Background/Objectives: Equol, a gut microbial metabolite of the soy isoflavone, daidzein, is associated with estrogenic activity and potential benefits for women’s health. While equol production depends on individual gut microbial composition, its dietary and clinical correlates in young women remain incompletely characterized. This study explored the relationship between urinary equol production, dietary habits, and premenstrual symptom severity in healthy university-aged women. Methods: We conducted a cross-sectional study of 41 Japanese women, aged 19–20 years. Urinary equol was measured using a validated liquid chromatography–tandem mass spectrometry (LC–MS/MS) method, following enzymatic hydrolysis. Participants were classified as either equol producers or non-producers, based on urinary concentration thresholds. Dietary intake was evaluated using a dietary questionnaire focused on soy products and dietary fiber sources. Premenstrual symptoms were assessed using a standardized Japanese questionnaire for premenstrual syndrome and premenstrual dysphoric disorder. Results: Twelve percent of participants were classified as equol producers. Compared with non-producers, equol producers reported higher consumption of pumpkin, soybean sprouts, and green tea. Among non-producers, higher consumption of certain vegetables and fiber-rich foods, including broccoli, pickled radish, konjac, and konjac jelly, was associated with greater premenstrual symptom severity, whereas such associations were not observed among equol producers. The analytical method demonstrated high sensitivity and reproducibility for urinary equol measurement. Conclusions: These findings suggest that equol production status may be associated with distinct dietary patterns and with differences in the relationship between food intake and premenstrual symptom severity in young women. Although the cross-sectional design and limited sample size preclude causal inference, these findings suggest that urinary equol is a promising candidate biomarker for future research on diet-related modulation of premenstrual symptoms. Full article

This study investigated the changes in the physicochemical properties and metabolites of pickled purple radish during storage. Pickles of purple radish (‘Boraking’) prepared by the addition of acetic acid and sugar were stored in the dark at 4 °C for 60 days. The color of the pickled purple radish changed from purple to pink, while the pickling solution changed from pink to purple. During storage, sucrose content gradually decreased, while glucose and fructose levels increased. LC-ESI-QToF-MS metabolomic analysis indicated that metabolites, including organic acids, amino acids, sulfur-containing compounds, lysophosphatidylcholine, lysophosphatidylethanolamine, and anthocyanins, were identified. The antioxidant capacity and color meter of pickled purple radish may undergo changes due to the altered levels of non-volatile compounds (cyanidins, adenosine, and amino acids) during storage. Anthocyanins had negative correlations with the color of pickled purple radish. The radical scavenging activity and ferric-reducing antioxidant power of pickled purple radish declined during storage. These findings emphasized the need for further research to develop processing and storage methods that enhance the bioactivity and stability of pickled purple radish. Full article

To investigate the effects of lemongrass essential oil on the key volatile aroma compounds of pickled radish (PR) during storage, this study used headspace–gas chromatography–ion mobility spectrometry, fingerprint analysis, multivariate statistical analysis, and molecular docking to study different PR samples. The results indicated that a total of 48 volatile aromatic compounds were identified. Fingerprint analysis revealed that the aroma profiles of samples at different storage stages were different. Using the screening criteria of p < 0.05 and variable importance for the projection > 1 in multivariate statistical analysis, and relative odor activity value > 1, six potential key aroma compounds were selected. Furthermore, phenylethyl acetate, β-ocimene, 4-heptanone, and limonene were determined as the key aroma compounds that affect the PR aroma profile after adding lemongrass essential oil. Moreover, the addition of lemongrass essential oil increased the fruit and sweet aroma of PR samples during storage. The results of molecular docking indicated that the recognition of these four odors was mainly accomplished through hydrophobic interactions and hydrogen bond interactions by docking OR1A1 and OR5M3 receptors. This study can offer a preliminary foundation and theoretical support for the in-depth exploration of the paocai industry. Full article

The hazard of nitrite caused by microorganisms is the main food safety problem in the pickle production. To seek a method to control the nitrite hazards of pickles by regulating microbial community without additional substances, we focused on cold plasma because Gram-negative and Gram-positive bacteria have different degrees of sensitivity to the sterilization of cold plasma. Using radish pickles as the experimental object, based on colony counting, dynamic monitoring of pH and nitrite, qPCR and high-throughput sequencing, it was found that when the raw material was treated with dielectric barrier discharge (DBD) cold plasma at 40 kV for 60 s, Gram-negative bacteria with the potential to produce nitrite were preferentially sterilized. Meanwhile, Gram-positive bacteria dominated by the lactic acid bacteria were retained to accelerate the acid production rate, initiate the self-degradation of nitrite in advance and significantly reduce the peak value and accumulation of nitrite during the fermentation process of pickled radish. This study preliminarily verified that DBD cold plasma can inhibit the nitrite generation and accelerate the self-degradation of nitrite by regulating the structure and abundance of microbial community in radish pickles, which provides an important reference for the control of nitrite hazards in the fermentation process of pickles without additives. Full article

Pickled radish (Raphanus sativus) is a traditional Asian ingredient, but the traditional method takes decades to make this product. To optimize such a process, this study compared the saponin content of pickled radishes with different thermal processing and traditional processes (production time of 7 days, 10 years, and 20 years) and evaluated the effects of different thermal processes on the formation of radish saponin through kinetics study and mass spectrometry. The results showed that increasing the pickling time enhanced the formation of saponin in commercial pickled radishes (25 °C, 7 days, 6.50 ± 1.46 mg g⁻¹; 3650 days, 23.11 ± 1.22 mg g⁻¹), but these increases were lower than those induced by thermal processing (70 °C 30 days 24.24 ± 1.01 mg g⁻¹). However, it was found that the pickling time of more than 10 years and the processing temperature of more than 80 °C reduce the saponin content. Liquid chromatography–mass spectrometry (LC-MS) analysis showed that the major saponin in untreated radish was Tupistroside G, whereas treated samples contained Asparagoside A and Timosaponin A1. Moreover, this study elucidated the chemical structure of saponins in TPR. The findings indicated that thermal treatment could induce functional saponin conversion in plants, and such a mechanism can also be used to improve the health efficacy of plant-based crops. Full article

This study was performed to clarify the enhancement of the 4-methylthio-3-butenyl isothiocyanate induced yellowing of salted radish root (takuan-zuke) by low pH during short-term salt-aging at low temperature and low salinity. We used two different methods to prepare the dehydrated daikon prior to salt-aging: air-drying outdoors (hoshi takuan-zuke) or salting with a stone press (shio-oshi takuan-zuke). Low salt-aging at low temperature was carried out under pH control with citrate-phosphate buffer. The yellowing of both types of takuan-zuke was accelerated below pH 5, and the color of air-dried takuan-zuke was deeper than that of salt-pressed takuan-zuke. To elucidate this phenomenon, several previously reported yellowing-related compounds were analyzed by high-performance liquid chromatography. The result showed that the production of the primary pigment, 2-[3-(2-thioxopyrrolidin-3-ylidene)methyl]-tryptophan, was low compared with that in previous reports. Therefore, we suggest that an unknown pigment was generated through a previously unreported pathway. Full article

2-thioxo-3-pyrrolidinecarbaldehyde (TPC) is an important intermediate in the yellowing of Japanese pickles “takuan-zuke”. TPC has been reported to have antibacterial activity against bacteria causing food poisoning and microorganisms associated with the development of caries, as well as various physiological functions such as antimutagenicity. However, since TPC has high reactivity, robust quantitative analysis is difficult with the extraction method or pre-column derivatization method using 2,4-dinitrophenylhydrazine. In this study, a high-performance liquid chromatography (HPLC) method involving labeling with 4-(N,N-dimethylaminosulfonyl)-7-hydrazino-2,1,3-benzoxadiazole (DBD-H) was developed for the determination of the level of TPC in takuan-zuke. DBD-TPC was successfully stabilized by adding a buffer solution to the reaction solution, which established continuous analysis by HPLC using an autosampler. The DBD-TPC calibration curve was linear in the range of 0.25–250 nmol/mL (final concentration) and showed a wide dynamic range. The lower limit of detection was 0.205 nmol/mL in TPC standard. The proposed method was successfully applied to the measurement of TPC in daikon-oroshi. The results reveal the possibility of determining the variation of TPC level in processed foods containing radish. We concluded that the proposed method is useful for evaluating the quality of processed radish products. Full article

Red radish (Raphanus L.) pickles are popular appetizers or spices in Asian-style cuisine. However, tons of radish brines are generated as wastes from industrial radish pickle production. In this study, we evaluated the dynamic changes in colour properties, phenolics, anthocyanin profiles, phenolic acid composition, flavonoids, and antioxidant properties in radish brines during lactic acid fermentation. The results showed that five flavonoids detected were four anthocyanins and one kaempferol derivative, including pelargonidin-3-digluoside-5-glucoside derivatives acylated with p-coumaric acid, ferulic acid, p-coumaric and manolic acids, or ferulic and malonic acids. Amounts ranged from 15.5–19.3 µg/mL in total monomeric anthocyanins, and kaempferol-3,7-diglycoside (15–30 µg/mL). 4-Hydroxy-benzoic, gentisic, vanillic, syringic, p-coumaric, ferulic, sinapic and salicylic acids were detected in amounts that varied from 70.2–92.2 µg/mL, whereas the total phenolic content was 206–220 µg/mL. The change in colour of the brine was associated with the accumulation of lactic acid and anthocyanins. The ORAC and Fe²⁺ chelation capacity of radish brines generally decreased, whereas the reducing power measured as FRAP values was increased during the fermentation from day 5 to day 14. This study provided information on the phytochemicals and the antioxidative activities of red radish fermentation waste that might lead to further utilization as nutraceuticals or natural colorants. Full article