Production optimization of food functional factor ergothioneine in wild-type red yeast Rhodotorula mucilaginosa DL-X01.

BACKGROUND: Ergothioneine (EGT) is a high-value food functional factor that cannot be synthesized by humans and other vertebrates, and the low yield limits its application. RESULTS: In this study, the optimal fermentation temperature, fermentation time, initial pH, inoculum age, and inoculation ratio on EGT biosynthesis of Rhodotorula mucilaginosa DL-X01 were optimized. In addition, the effects of three key precursor substances - histidine, methionine, and cysteine - on fungal EGT synthesis were verified. The optimal conditions were further obtained by response surface optimization. The EGT yield of R. mucilaginosa DL-X01 under optimal fermentation conditions reached 64.48 ± 2.30 mg L-1 at shake flask fermentation level. Finally, the yield was increased to 339.08 ± 3.31 mg L-1 (intracellular) by fed-batch fermentation in a 5 L bioreactor. CONCLUSION: To the best of our knowledge, this is the highest EGT yield ever reported in non-recombinant strains. The fermentation strategy described in this study will promote the efficient biosynthesis of EGT in red yeast and its sustainable production in the food industry. © 2024 Society of Chemical Industry.

Cost-effective production of ergothioneine using Rhodotorula mucilaginosa DL-X01 from molasses and fish bone meal enzymatic hydrolysate.

Ergothioneine (EGT) is a high-value natural antioxidant that cannot be synthesized by the human body. This study showed that Rhodotorula mucilaginosa DL-X01 can use untreated molasses and fish bone meal enzymatic hydrolysate as the substrates to synthesize EGT. By optimizing the growth conditions, the EGT yield reached 29.39 mg/L when molasses and fish bone meal (FBM) were added at 60 g/L and 400 g/L respectively. Finally, the EGT yield was increased to 216.25 mg/L by fed-batch fermentation in a 5 L bioreactor. Compared with the fermentation by yeast extract peptone dextrose medium, the feedstock cost of EGT production was reduced by 330.91 % by using molasses and FBM as substrates. These results showed that R. mucilaginosa DL-X01 can produce high-value EGT using two cheap processing by-products, molasses and FBM, which is of great significance for environmental protection and sustainable development.

The Screening and Isolation of Ethyl-Carbamate-Degrading Strains from Fermented Grains and Their Application in the Degradation of Ethyl Carbamate in Chinese Baijiu.

Ethyl carbamate (EC), a 2A carcinogen produced during the fermentation of foods and beverages, primarily occurs in distilled spirits. Currently, most studies focus on strategies for EC mitigation. In the present research, we aimed to screen strains that can degrade EC directly. Here, we report two Candida ethanolica strains (J1 and J116), isolated from fermented grains, which can reduce EC concentrations directly. These two yeasts were grown using EC as the sole carbon source, and they grew well on different carbon sources. Notably, after immobilization with chitosan, the two strains degraded EC in Chinese Baijiu by 42.27% and 27.91% in 24 h (from 253.03 ± 9.89 to 146.07 ± 1.67 and 182.42 ± 5.05 µg/L, respectively), which was better than the performance of the non-immobilized strains. Furthermore, the volatile organic compound content, investigated using gas chromatography-mass spectrometry, did not affect the main flavor substances in Chinese Baijiu. Thus, the yeasts J1 and J116 may be potentially used for the treatment and commercialization of Chinese Baijiu.

Characterizing e-Cigarette-Related Videos on TikTok: Observational Study.

BACKGROUND: As a popular social networking platform for sharing short videos, TikTok has been widely used for sharing e-cigarettes or vaping-related videos, especially among the youth. OBJECTIVE: This study aims to characterize e-cigarette or vaping-related videos and their user engagement on TikTok through descriptive analysis. METHODS: From TikTok, a total of 417 short videos, posted between October 4, 2018, and February 27, 2021, were collected using e-cigarette or vaping-related hashtags. Two human coders independently hand-coded the video category and the attitude toward vaping (provaping or antivaping) for each vaping-related video. The social media user engagement measures (eg, the comment count, like count, and share count) for each video category were compared within provaping and antivaping groups. The user accounts posting these videos were also characterized. RESULTS: Among 417 vaping-related TikTok videos, 387 (92.8%) were provaping, and 30 (7.2%) were antivaping videos. Among provaping TikTok videos, the most popular category is vaping tricks (n=107, 27.65%), followed by advertisement (n=85, 21.95%), customization (n=75, 19.38%), TikTok trend (n=70, 18.09%), others (n=44, 11.37%), and education (n=6, 1.55%). By comparison, videos showing the TikTok trend had significantly higher user engagement (like count per video) than other provaping videos. Antivaping videos included 15 (50%) videos with the TikTok trend, 10 (33.33%) videos on education, and 5 (16.67%) videos about others. Videos with education have a significantly lower number of likes than other antivaping videos. Most TikTok users posting vaping-related videos are personal accounts (119/203, 58.62%). CONCLUSIONS: Vaping-related TikTok videos are dominated by provaping videos focusing on vaping tricks, advertisement, customization, and TikTok trend. Videos with the TikTok trend have higher user engagement than other video categories. Our findings provide important information on vaping-related videos shared on TikTok and their user engagement levels, which might provide valuable guidance on future policy making, such as possible restrictions on provaping videos posted on TikTok, as well as how to effectively communicate with the public about the potential health risks of vaping.

Ergothioneine: new functional factor in fermented foods.

Ergothioneine (EGT) is a high-value natural sulfur-containing amino acid and has been shown to possess extremely potent antioxidant and cytoprotective activities. At present, EGT has been widely used in food, functional food, cosmetics, medicine, and other industries, but its low yield is still an urgent problem to overcome. This review briefly introduced the biological activities and functions of EGT, and expounded its specific applications in food, functional food, cosmetic, and medical industries, introduced and compared the main production methods of EGT and respective biosynthetic pathways in different microorganisms. Furthermore, the use of genetic and metabolic engineering methods to improve EGT production was discussed. In addition, the incorporation of some food-derived EGT-producing strains into fermentation process will allow the EGT to act as a new functional factor in the fermented foods.

Characterizing Heated Tobacco Products Marketing on Instagram: Observational Study.

BACKGROUND: Heated tobacco products (HTPs), including I Quit Ordinary Smoking (IQOS), are new tobacco products that use an electronic device to heat compressed tobacco leaves to generate an aerosol for consumers to inhale. Marketing of HTPs is prevalent on Instagram, a popular social media platform. OBJECTIVE: This study aims to characterize posts related to HTPs on Instagram and their associations with user engagement. METHODS: Through the Instagram application programming interface, 979 Instagram posts were collected using keywords related to HTPs, such as "IQOS" and "heat-not-burn." Among them, 596 posts were related to IQOS and other HTP marketing. The codebook was developed from a randomly selected 200 posts on the post content by hand coding, which was applied to the remaining 396 Instagram posts. Summary statistics were calculated, and statistical hypothesis testing was conducted to understand the popularity of Instagram posts on HTPs. Negative binomial regression models were applied to identify Instagram post characteristics associated with user engagement (eg, count). RESULTS: Among Instagram posts related to HTP marketing (N=596), "product display" was dominant (n=550, 92.28%), followed by "brand promotion" (n=41, 6.88%), and "others" (n=5, 0.84%). Among posts within "product display," "device only" was the most popular (n=338, 61.45%), followed by "heatstick only" (n=80, 14.55%), "accessory" (n=66, 12%), "device and heatstick" (n=56, 10.18%), and "capsule" (n=10, 1.82%). A univariate negative binomial regression model with pairwise comparisons across "product display" types showed that the number of likes for posts with HTP heatsticks was significantly lower compared to posts with HTP devices, accessories, and device-heatstick sets. Multivariate negative binomial regression models showed that HTP-related Instagram posts with a model or lifestyle elements (;=.60, 95% CI 0.36-0.84) or without obvious product advertising information (=.69, 95% CI 0.49-0.89) received more likes. CONCLUSIONS: It is shown that posts with product displays were dominant among HTP-related posts on Instagram. Posts with model or lifestyle elements are associated with high user engagement, which might be one of the web-based marketing strategies of HTPs.

Perceptions and Discussions of Snus on Twitter: Observational Study.

BACKGROUND: With the increasing popularity of snus, it is essential to understand the public perception of this oral tobacco product. Twitter-a popular social media platform that is being used to share personal experiences and opinions-provides an ideal data source for studying the public perception of snus. OBJECTIVE: This study aims to examine public perceptions and discussions of snus on Twitter. METHODS: Twitter posts (tweets) about snus were collected through the Twitter streaming application programming interface from March 11, 2021, to February 26, 2022. A temporal analysis was conducted to examine the change in number of snus-related tweets over time. A sentiment analysis was conducted to examine the sentiments of snus-related tweets. Topic modeling was applied to tweets to determine popular topics. Finally, a keyword search and hand-coding were used to understand the health symptoms mentioned in snus-related tweets. RESULTS: The sentiment analysis showed that the proportion of snus-related tweets with a positive sentiment was significantly higher than the proportion of negative sentiment tweets (4341/11,631, 37.32% vs 3094/11,631, 26.60%; P<.001). The topic modeling analysis revealed that positive tweets focused on snus's harm reduction and snus use being an alternative to smoking, while negative tweets focused on health concerns related to snus. Mouth and respiratory symptoms were the most mentioned health symptoms in snus-related tweets. CONCLUSIONS: This study examined the public perception of snus and popular snus-related topics discussed on Twitter, thus providing a guide for policy makers with regard to the future formulation and adjustment of tobacco regulation policies.

Genetic Engineering Production of Ethyl Carbamate Hydrolase and Its Application in Degrading Ethyl Carbamate in Chinese Liquor.

Ethyl carbamate (EC), classified as a Group 2A carcinogen, is most abundant in the fermented foods, such as Cachaca, Shaoxing wine, and Chinese liquor (baijiu). Although biodegradation can reduce its concentration, a high ethanol concentration and acidic environment often limit its degradation. In the present study, a novel ethyl carbamate hydrolase (ECH) with high specificity to EC was isolated from Acinetobacter calcoaceticus, and its enzymatic properties and EC degradability were investigated. ECH was immobilized to resist extreme environmental conditions, and the flavor substance changes were explored by gas chromatography-mass spectrometry (GC/MS). The specific enzymatic activity of ECH was 68.31 U/mg. Notably, ECH exhibited excellent thermal stability and tolerance to sodium chloride and high ethanol concentration (remaining at 40% activity in 60% (v/v) ethanol, 1 h). The treatment of immobilized ECH for 12 h decreased the EC concentration in liquor by 71.6 µg/L. Furthermore, the immobilized ECH exerted less effect on its activity and on the flavor substances, which could be easily filtrated during industrial production.

Novel ACE inhibitors derived from soybean proteins using in silico and in vitro studies.

The widespread application of soybean-derived peptides is currently limited due to the challenges in the identification of peptides. In the present work, in silico and in vitro analysis were applied to identify ACE inhibitory tri-peptides from soybean protein. The soybean protein was cleaved by PeptideCutter. Then, unknown tri-peptides were selected to solubility estimation and ADME prediction. Subsequently, Discovery Studio was applied to evaluate the interaction mechanism between ACE and tri-peptides. Finally, in vitro activity of theoretical ACE inhibitory tri-peptides was verified by RP-HPLC method. As a result, DMG was selected as a potent ACE inhibitory peptide. Cell experiment showed that DMG had no cytotoxic effects on HEK-293 cells. And molecular docking results indicated that DMG contacted well with ACE's active sites (Gln281, His353, Ala354, Glu384, Lys511, His513, and Tyr520). Furthermore, DMG could exert potent activity against ACE, with IC50 value of 3.95 ± 0.11 mM. PRACTICAL APPLICATIONS: Present research showed soybean is a potential protein resource to obtain ACE inhibitory peptides. Simultaneously, virtual screening method is a feasible way to substitute for classical method in emerging nutritional fields. What's more, present study provides a theoretical basis for industrial research on foodstuff for ACE inhibitory peptides without side effects.

MALDI-TOF-MS characterization of N-linked glycoprotein derived from ginger with ACE inhibitory activity.

Herein, the ability of ginger glycoproteins to inhibit the angiotensin-converting enzyme (ACE) is characterized. The activity is monitored via HPLC, and then the crude glycoproteins are enriched with lectin microarrays and magnetic microspheres. The N-linked glycans released from the enriched glycoproteins by PNGase F are identified by MALDI-TOF-MS. The results suggest that the crude ginger glycoproteins are active against ACE with an IC50 value of 0.83 ± 0.09 mg mL-1. The ginger glycoproteins are enriched by concanavalin A (Con A) and solanum tuberosum (Potato) lectin (STL), and the structures of the N-glycans released from the ginger glycoproteins include high-mannose type glycans, fucosylated-type glycans, and hybrid-type glycans, as analyzed by MALDI-TOF-MS. The results of this study are expected to provide a reference for the glycan structure of ginger glycoproteins with ACE-inhibitory activity.