The use of bacterial cellulose from kombucha to produce curcumin loaded Pickering emulsion with improved stability and antioxidant properties

Curcumin is a bioactive molecule with limited industrial application because of its instability and poor solubility in water.Herein,curcumin-loaded Pickering emulsion was produced using purified bacterial cellulose from fermented kombucha(KBC).The morphology,particle size,stability,rheological properties,and antioxidant activities of the curcumin-loaded Pickering emulsion were investigated.The fluorescence microscope and scanning electron microscopy images showed that the curcumin-loaded Pickering emulsion formed circular droplets with good encapsulation.The curcumin-load Pickering emulsion exhibited better stability under a wide range of temperatures,low p H,sunlight,and UV-365 nm than the free curcumin,indicating that the KBC after high-pressure homogenization improved the stability of the CPE.The encapsulated curcumin retained its antioxidant capacity and exhibited higher functional potential than the free curcumin.The study demonstrated that the KBC could be an excellent material for preparing a Pickering emulsion to improve curcumin stability and antioxidant activity.

3D printed lactic acid bacteria hydrogel:cell release kinetics and stability

In this study,a new type of 3 D printed living biological hydrogel was developed by integrating lactic acid bacteria(LAB)into biocompatible and non-toxic polymer materials.Interestingly,the living materials loaded with LAB can be freeze-dried and reused for more than 100 times.The bio-hydrogel can be used to co-culture different LAB and keep its fermentation performance stable in long-term use.The release kinetics model and response surface method were used to simulate and optimize the bacteria release mode in the bio-hydrogel.The results show that the release of bacteria from hydrogel is regulated by the coupling of Fickian diffusion and polymer swelling.The stability of LAB hydrogel was evaluated by reuse experiments.The images of confocal microscopy and scanning electron microscope showed that the bacteria with high cell viability were distributed in the hydrogel and intact structure of the living hydrogel was maintained after 100 times of reuse as yoghurt starter.In conclusion,the 3 D printed LAB bio-hydrogel developed in this study has the advantage of reuse and sustainability,which is expected to open up a new way for the preparation of food culture starter.

Artificial simulated saliva,gastric and intestinal digestion and fermentation in vitro by human gut microbiota of intrapolysaccharide from Paecilomyces cicadae TJJ1213

In this study,the in vitro digestion and fermentation of two intra-polysaccharide fractions(IPS1 and IPS2)from Paecilomyces cicadae TJJ1213 were investigated.The constituent monosaccharides of IPS1 and IPS2 were not changed after simulated saliva,gastric and small intestinal digestion.However,they can be hydrolyzed and utilized by gut microbiota,and short-chain fatty acids(SCFAs)level were increased after IPS1 and IPS2 treatments.Furthermore,16 S r RNA sequencing analysis of fermentation samples were performed.Alpha-diversity,beta-diversity and taxonomic composition differences analysis revealed that IPS1 and IPS2 promoted the proliferation of beneficial bacteria and modulated the overall structure of gut microbiota.Taxonomic comparison analysis found that IPS1 increased the relative abundances of beneficial bacteria including Megamonas,Bifidobacterium and Lactobacillus,while IPS2 could increase the abundance of Bacteroides,Parabacteroides and Phascolarctobacterium.In addition,they can also decrease the levels of pathogenic bacteria containing Escherichia-Shigella,Klebsiella and Fusobacterium.These results indicated that IPS from Paecilomyces cicadae TJJ1213 could be used as potential candidates for new functional foods.

Isolation and identification of Starmerella davenportii strain Do18 and its application in black tea beverage fermentation

The objective of this study was to isolate and identify a yeast strain from the kombucha beverage and evaluate its potential as a novel starter in beverage fermentation in vitro.Starmerella davenportii Do18 was characterized for its cholesterol reduction;growth at different conditions such as temperatures(25,30,37 and 42◦C),low pH(1.2,1.5,2.03.0,and 7.0),bile salts(0%,0.25%,0.5%,1%and 2%)high-sucrose stress(2%,10%,20%,40%and 60%);and in-vitro survival in gastric and intestinal environments.Results showed that the yeast strain has a cholesterol-lowering capacity of 45%±2%,grew at temperature of 37◦C and is resistant to pH 1.5,2%bile and 40%sucrose solution,could survive in simulated gastric and intestinal environments.The physicochemical characteristics of the fermented beverages were also evaluated,which indicated that the yeast has pH reduction capacity and can produce organic acids and volatile compound such as 2-phenylethanol.Furthermore,the fermented beverage also has high total phenolics and flavonoids content and showed great antioxidant and antimicrobial activities.Therefore,the findings of this research provide strong evidence that S.davenportii Do18 has good fermentation properties,can be a potential starter in food and beverage fermentation.

Isolation and identification of fungi found in contaminated fermented milk and antifungal activity of vanillin

Fungi contamination is an important factor affecting the quality and commercial value of fermented milk.Vanillin is known as a safe and efficient natural antimicrobial additive with great potential value as a food bio-preservative.In this study,the microbiological quality of fermented milk of different brands retailed in China and the antimicrobial activity of vanillin were investigated.A total of 27 fermented milk samples were purchased and evaluated.Fungal isolates obtained were characterized by DNA sequencing of the internal transcribed spacer(ITS)region.The effects of vanillin on the growth of fungi were studied by plate dilution method,radical colony diameter,and mycelium biomass.The result showed that 14.8%of the samples were contaminated with three different species of fungi with Cladosporium spp.being the most predominant fungal contaminant.The study further showed that vanillin had significant inhibitory activity against the growth of the fungi species.The cell number,radical colony diameter,and the mycelium biomass of the fungal contaminant were significantly reduced by the inhibitory action of the vanillin.The study thus provides reliable data evidence that will help relevant stakeholders in the fermented milk industries to improve their quality control strategies and consider vanillin as a bio-preservative with the potential to increase the shelf-life and safety of fermented milk.

A multi-layer genome mining and phylogenomic analysis to construct efficient and autonomous efflux system for medium chain fatty acids

Medium-chain fatty acids(MCFAs)are important components for food,pharmaceutical and fuel industries.Nevertheless,engineering microorganisms to produce MCFAs often induces toxicity and stresses towards host strains,which could be alleviated via accelerating the export of MCFAs from cells.However,current secretory systems are inefficient and require inducible promoters.Here,a multi-layer genome mining and phylogenomic analysis was developed to identify efficient efflux transporters.Firstly,based on the genomic mining of 397 strains throughout various representative species,the evolutionary history of efflux transporters was recapitulated,and further experimental analysis revealed that acrE from Citrobacter exhibited the best performance.Secondly,according to the further mining of 797 Citrobacter genomes and 1084 Escherichia genomes,a detailed phylogenomic analysis of efflux transporter-centric genomic vicinities was performed.This led to the identification of efficient efflux pump combination acrE and acrF.These efflux pumps were then combined with the quorum-sensing circuit from Enterococcus faecalis to regulate MCFA efflux in an autonomous manner,which achieved a 4.9-fold boost in MCFA production and firstly demonstrated the efficient and autonomous efflux pump specially for MCFAs.The integrative omics technologies described here are enabling the utilization of the increasingly large database and the effective mining of target gene diversities.

Biotransformation of soy whey into a novel functional beverage by Cordyceps militaris SN-18

Soy whey,a liquid nutritional by-product of soybean manufacture,is rich in proteins,oligosaccharides and isoflavones.Soy whey can be used to produce functional beverages,instead of discarding it as a waste.In this study,unfermented soy whey(USW)and Cordyceps militaris SN-18-fermented soy whey(FSW)were investigated and compared for their physicochemical and functional properties by high performance liquid chromatography(HPLC)and DNA damage assay.Results show that C.militaris SN-18 fermentation could increase the contents of essential amino acids,total phenolic and flavonoid and isoflavone aglycones and eliminate the oligosaccharides in soy whey.Furthermore,C.militaris SN-18 could significantly enhance the ABTS radical scavenging ability,reducing power and ferric reducing power of soy whey,and its fermented products could prominently attenuate Fenton reaction-induced DNA damage.These findings indicate that soy whey can potentially be converted into a novel soy functional beverage by C.militaris SN-18 fermentation.