Improving the Three-Dimensional Printability of Potato Starch Loaded onto Food Ink.

This study focuses on improving the 3D printability of pea protein with the help of food inks designed for jet-type 3D printers. Initially, the food ink base was formulated using nanocellulose-alginate with a gradient of native potato starch and its 3D printability was evaluated. The 3D-printed structures using only candidates for the food ink base formulated with or without potato starch exhibited dimensional accuracy exceeding 95% on both the X and Y axes. However, the accuracy of stacking on the Z-axis was significantly affected by the ink composition. Food ink with 1% potato starch closely matched the CAD design, with an accuracy of approximately 99% on the Z-axis. Potato starch enhanced the stacking of 3D-printed structures by improving the electrostatic repulsion, viscoelasticity, and thixotropic behavior of the food ink base. The 3D printability of pea protein was evaluated using the selected food ink base, showing a 46% improvement in dimensional accuracy on the Z-axis compared to the control group printed with a food ink base lacking potato starch. These findings suggest that starch can serve as an additive support for high-resolution 3D jet-type printing of food ink material.

Printing Optimization of 3D Structure with Lard-like Texture Using a Beeswax-Based Oleogels.

In this study, we investigated the optimal conditions for 3D structure printing of alternative fats that have the textural properties of lard using beeswax (BW)-based oleogel by a statistical analysis. Products printed with over 15% BW oleogel at 50% and 75% infill level (IL) showed high printing accuracy with the lowest dimensional printing deviation for the designed model. The hardness, cohesion, and adhesion of printed samples were influenced by BW concentration and infill level. For multi-response optimization, fixed target values (hardness, adhesiveness, and cohesiveness) were applied with lard printed at 75% IL. The preparation parameters obtained as a result of multiple reaction prediction were 58.9% IL and 16.0% BW, and printing with this oleogel achieved fixed target values similar to those of lard. In conclusion, our study shows that 3D printing based on the BW oleogel system produces complex internal structures that allow adjustment of the textural properties of the printed samples, and BW oleogels could potentially serve as an excellent replacement for fat.

Anti-Obesity Effect of Red Radish Coral Sprout Extract by Inhibited Triglyceride Accumulation in a Microbial Evaluation System and in High-Fat Diet-Induced Obese Mice.

Rhodosporidium toruloides, an oleaginous yeast, can be used as a fast and reliable evaluation tool to screen new natural lipid-lowering agents. Herein, we showed that triglyceride (TG) accumulation was inhibited by 42.6% in 0.1% red radish coral sprout extract (RRSE)-treated R. toruloides. We also evaluated the anti-obesity effect of the RRSE in a mouse model. The body weight gain of mice fed a high-fat diet (HFD) with 0.1% RRSE (HFD-RRSE) was significantly decreased by 60% compared with that mice fed the HFD alone after the 8-week experimental period. Body fat of the HFD-RRSE-fed group was dramatically reduced by 38.3% compared with that of the HFD-fed group.

Oleaginous Yeast Rhodosporidium toruloides as a Tool for Rapid Evaluation of Anti-Obesity Candidates: Inhibitory Effect of Persimmon Leaf Fermentate on Lipid Accumulation.

The aim of this study was to examine the efficiency of Rhodosporidium toruloides as a new tool to evaluate the triglyceride (TG) reduction effects of anti-obesity candidate materials. Unfermented and fermented persimmon leaf hot water extracts (UFPLE and FPLE) were used as anti-obesity agents. The content of TG in R. toruloides treated with FPLE was less than those with UFPLE by about 11% (p < 0.05) relative to the control (R. toruloides incubated in YPD medium without the agents). Fat reduction in 3T3-L1 cells achieved by FPLE was about 13% higher than that achieved by UFPLE.

Optimization of ergosterol to vitamin D2 synthesis in Agaricus bisporus powder using ultraviolet-B radiation.

Response surface methodology (RSM) was applied to determine the optimum circumstances for conversion of ergosterol to vitamin D2 via ultraviolet-B (UV-B) in white button mushroom (Agaricus bisporus) powder. Three independent variables, namely, exposure time, ambient temperature, and irradiation intensity were investigated using a central composite rotatable design. The RSM ridge analysis determined the following ideal states: exposure time of 10.4 min, ambient temperature of 26.33°C, and UV-B irradiation intensity of 1.36 W/m2. A vitamin D2 content of 741.50±23.75 µg/g (the predicted value was 780.4 µg/g) was obtained under these ideal conditions.

Platycosides from the Roots of Platycodon grandiflorum and Their Health Benefits.

The extracts and pure saponins from the roots of Platycodon grandiflorum (PG) are reported to have a wide range of health benefits. Platycosides (saponins) from the roots of PG are characterized by a structure containing a triterpenoid aglycone and two sugar chains. Saponins are of commercial significance, and their applications are increasing with increasing evidence of their health benefits. The biological effects of saponins include cytotoxic effects against cancer cells, neuroprotective activity, antiviral activity, and cholesterol lowering effects. Saponins with commercial value range from crude plant extracts, which can be used for their foaming properties, to high purity saponins such as platycodin D, which can be used for its health applications (e.g., as a vaccine adjuvant). This review reveals that platycosides have many health benefits and have the potential to be used as a remedy against many of the major health hazards (e.g., cancer, obesity, alzheimer's) faced by populations around the world. Methods of platycoside purification and analysis are also covered in this review.

RNA-seq analysis of antibiotic-producing Bacillus subtilis SC-8 in response to signal peptide PapR of Bacillus cereus.

Bacillus subtilis SC-8 produces an antibiotic that has narrow antagonistic activity against bacteria in the Bacillus cereus group. In B. cereus group bacteria, peptide-activating PlcR (PapR) plays a significant role in regulating the transcription of virulence factors. When B. subtilis SC-8 and B. cereus are co-cultured, PapR is assumed to stimulate antibiotic production by B. subtilis SC-8. To better understand the effect of PapR on this interspecies interaction, the global transcriptome profile of B. subtilis SC-8 was analyzed in the presence of PapR. Significant changes were detected in 12.8 % of the total transcripts. Genes related to amino acid transport and metabolism (16.5 %) and transcription (15 %) were mainly upregulated, whereas genes involved in carbohydrate transport and metabolism (12.7 %) were markedly downregulated. The expression of genes related to transcription, including several transcriptional regulators and proteins involved in tRNA biosynthesis, was increased. The expression levels of genes associated with several transport systems, such as antibiotic, cobalt, and iron complex transporters, was also significantly altered. Among the downregulated genes were transcripts associated with spore formation, the subtilosin A gene cluster, and nitrogen metabolism.

Heterologous expression of polygalacturonase genes isolated from Galactomyces citri-aurantii IJ-1 in Pichia pastoris.

ABSTACT: The objective of this work was to isolate the polygalacturonase genes of Galactomyces citri-aurantii IJ-1 harvested from rotten citrus peels and to heterologously express these genes in Pichia pastoris. Two polygalacturonase (PG) genes from G. citri-aurantii IJ-1 were obtained and tentatively named PG1 and PG2. The genes were cloned into pPICZαC, and expressed in Pichia pastoris strain GS115 with a native signal peptide or the α-factor secretion signal peptide of Saccharomyces cerevisiae. All of the recombinant proteins were successfully secreted into the culture media and confirmed as a single band with a molecular weight of 35 to 38 kDa by SDS-PAGE. The specific enzyme activities of recombinant PG1 and PG2 purified by His-tag affinity resin were 4,749 and 6,719 U/mg, respectively, with an optimal pH and temperature of pH 4.0 and 50°C. The Michaelis-Menten kinetic constants for PG1 and PG2, K (m), were confirmed to be 0.94 and 0.84 mM, respectively. In the presence of Mn(2+), the activity of PG1 and PG2 were increased to 160.8 and 146.4% of normal levels, respectively. In contrast, Cu(2+) and Fe(3+) acted as strong inhibitors to the PGs.

Interspecies interaction of signal peptide PapR secreted by Bacillus cereus and its effect on production of antimicrobial peptide.

This study was carried out to investigate the interspecies interaction of PapR peptide secreted by Bacillus cereus on production of BSAP-254, an antimicrobial peptide produced by Bacillus subtilis SC-8 isolated from the Korean fermented soybean paste and exhibited narrow antagonistic activity against the B. cereus group, but not against other foodborne pathogens. PapR is a signal peptide that activates PlcR, which is a pleiotropic regulator controlling the expression of various virulence factors in B. cereus. When B. subtilis SC-8 was co-cultured with B. cereus, it completely inhibited the growth of B. cereus within 12 h, and the rate of BSAP-254 production was increased 34.2% at 12 h. Furthermore, 5 µM of synthetic PapR peptide added to the culture of B. subtilis SC-8 increased the rate of BSAP-254 production up to 59.7%. The growth of B. subtilis SC-8, however, was not significantly different with or without the addition of PapR. When B. cereus papR mutant was co-cultured with B. subtilis SC-8, the growth of the mutant was not inhibited and the rate of BSAP-254 production was decreased by 45%.

Characterization of Lactic Acid Bacteria Isolated from Sauce-type Kimchi.

This study was carried out to investigate the isolation and characterization of lactic acid bacteria (LAB) from naturally fermented sauce-type kimchi. Sauce-type kimchi was prepared with fresh, chopped ingredients (Korean cabbage, radish, garlic, ginger, green onion, and red pepper). The two isolated bacteria from sauce-type kimchi were identified as Pediococcus pentosaceus and Lactobacillus brevis by 16S rDNA sequencing and tentatively named Pediococcus sp. IJ-K1 and Lactobacillus sp. IJ-K2, respectively. Pediococcus sp. IJ-K1 was isolated from the early and middle fermentation stages of sauce-type kimchi whereas Lactobacillus sp. IJ-K2 was isolated from the late fermentation stage. The resistance of Pediococcus sp. IJ-K1 and Lactobacillus sp. IJ-K2 to artificial gastric and bile acids led to bacterial survival rates that were 100% and 84.21%, respectively.

Genome sequencing of Bacillus subtilis SC-8, antagonistic to the Bacillus cereus group, isolated from traditional Korean fermented-soybean food.

Bacillus subtilis SC-8 is a Gram-positive bacterium displaying narrow antagonistic activity for the Bacillus cereus group. B. subtilis SC-8 was isolated from Korean traditional fermented-soybean food. Here we report the draft genome sequence of B. subtilis SC-8, including biosynthetic genes for antibiotics that may have beneficial effects for control of food-borne pathogens.

Narrow antagonistic activity of antimicrobial peptide from Bacillus subtilis SCK-2 against Bacillus cereus.

Bacillus subtilis SCK-2, producing an antimicrobial peptide of this study, was isolated from Kyeopjang, the Korean traditional fermented-soybean paste. This strain showed a narrow antagonistic activity as it inhibited Bacillus cereus causing food poisoning in human. The antimicrobial peptide, tentatively named AMP IC-1, was purified, characterized, and compared to BSAP-254, another peptide which was previously recovered from traditionally fermented-soybean paste. AMP IC-1 was found to be more thermally stable than BSAP-254, retained inhibitory activity similar to that of BSAP-254 over wide range of pH values, and was also destroyed by proteolytic enzymes. Two compounds were detected by anti-BSAP-254 polyclonal antibody and showed to contain peptide moieties and aliphatic hydrocarbons by Fourier transform infrared analysis. AMP IC-1 had an identical R(f) value (0.69) on TLC plate and a molecular weight similar to that of BSAP-254 (AMP IC-1, m/z 3401; BSAP-254, m/z 3400 to 3473). AMP IC-1 was found to contain about 33 residues and 13 types of amino acids: Cys, Asp or Asn, Glu or Gln, Ser, Gly, Arg, Thr, Ala, Pro, Val, Ile, Leu, and Lys. Compared to BSAP-254, the molar ratios of Asp or Asn, Ser, Val, and Leu were different and only AMP IC-1 contained Arg, but not Trp. Both compounds showed non-hemolytic activity. A partial synergistic effect against B. cereus was observed in response to treatment when AMP IC-1 and BSAP-254 were administered in combination. Therefore, AMP IC-1 is a possible candidate as an antimicrobial agent to prevent food-borne infectious disease in human caused by B. cereus.

Growth inhibition and induction of stress protein, GroEL, of Bacillus cereus exposed to antibacterial peptide isolated from Bacillus subtilis SC-8.

This study was conducted to investigate the antibacterial effect of BSAP-254 on Bacillus cereus with the induced stress proteins. The BSAP-254 is an antimicrobial peptide isolated from soybean-fermenting bacteria, Bacillus subtilis SC-8. It had a narrow spectrum of activity against B. cereus group. The growth inhibitory effect of BSAP-254 (50 µg/mL) reduced the population of B. cereus from >10(8) to 10(4) colony-forming units per milliliter within 30 min. In B. cereus exposed to BSAP-254, 14 intracellular proteins were differentially expressed as determined by 2-DE coupled with MS. Of the differentially expressed proteins identified, the stress protein GroEL, which is heat shock protein, was induced in B. cereus exposed to antibacterial peptide.

Isolation and characterization of a novel analyte from Bacillus subtilis SC-8 antagonistic to Bacillus cereus.

In this study, an effective substance was isolated from Bacillus subtilis SC-8, which was obtained from traditionally fermented soybean paste, cheonggukjang. The substance was purified by HPLC, and its properties were analyzed. It had an adequate antagonistic effect on Bacilluscereus, and its spectrum of activity was narrow. When tested on several gram-negative and gram-positive foodborne pathogenic bacteria such as Salmonella enterica, Salmonella enteritidis, Staphylococcus aureus, and Listeria monocytogenes, no antagonistic effect was observed. Applying the derivative from B. subtilis SC-8 within the same genus did not inhibit the growth of major soybean-fermenting bacteria such as Bacillus subtilis, Bacillus licheniformis, and Bacillus amyloquefaciens. The range of pH stability of the purified antagonistic substance was wide (from 4.0 to >10.0), and the substance was thermally stable up to 60 degrees C. In the various enzyme treatments, the antagonistic activity of the purified substance was reduced with proteinase K, protease, and lipase; its activity was partially destroyed with esterase. Spores of B. cereus did not grow at all in the presence of 5mug/mL of the purified antagonistic substance. The isolated antagonistic substance was thought to be an antibiotic-like lipopeptidal compound and was tentatively named BSAP-254 because it absorbed to UV radiation at 254nm.

Characterization of Lactobacillus spp. isolated from the feces of breast-feeding piglets.

Lactobacillus spp., referred to as IJ-1 and IJ-2, were isolated from the feces of breast-feeding piglets and analyzed for probiotic properties. According to the analyses of 16S rDNA sequence, Lactobacillus sp. IJ-1 showed greater than 99% homology with Lactobacillus reuteri DSM 20016(T), and Lactobacillus sp. IJ-2 had greater than 99% homology with the L. gasseri ATCC 33323(T) and L. johnsonii ATCC 33200(T). The pH changes in the culture media of Lactobacillus sp. IJ-1 and Lactobacillus sp. IJ-2 were from 6.5 to 4.2 and 4.6, respectively. Their respective resistance against artificial gastric acid and artificial bile acid led to survival rates of nearly 186+/-44% and 13+/-5%. Neither strain produced the carcinogenic enzyme beta-glucuronidase. Both strains inhibited the growth of pathogenic microorganisms, such as Listeria monocytogenes ATCC 19111, Salmonella enterica KCTC 12401, Salmonella enteritidis ATCC 13076, Staphylococcus aureus KCTC 3881, and Bacillus cereus 3711, within 24 h of growth.