Dong-Un Lee

Antiproliferative Effects of Carotenoids Extracted from Chlorella ellipsoidea and Chlorella vulgaris on Human Colon Cancer Cells

The antiproliferative activity of carotenoids separated from marine Chlorella ellipsoidea and freshwater Chlorella vulgaris has been evaluated. HPLC analysis revealed that the main carotenoid from C. ellipsoidea was composed of violaxanthin with two minor xanthophylls, antheraxanthin and zeaxanthin, whereas the carotenoid from C. vulgaris was almost completely composed of lutein. In an MTT assay, both semipurified extracts of C. ellipsoidea and C. vulgaris inhibited HCT116 cell growth in a dose-dependent manner, yielding IC(50) values of 40.73 +/- 3.71 and 40.31 +/- 4.43 microg/mL, respectively. In addition, treatment with both chlorella extracts enhanced the fluorescence intensity of the early apoptotic cell population in HCT116 cells. C. ellipsoidea extract produced an apoptosis-inducing effect almost 2.5 times stronger than that of the C. vulgaris extract. These results indicate that bioactive xanthophylls of C. ellipsoidea might be useful functional ingredients in the prevention of human cancers.

Optimization of pressurized liquid extraction of carotenoids and chlorophylls from Chlorella vulgaris.

Pressurized liquid extraction (PLE) was applied to the extraction of carotenoids and chlorophylls from the green microalga Chlorella vulgaris. Four extraction techniques such as maceration (MAC), Soxhlet extraction (SOX), ultrasound assisted extraction (UAE), and PLE were compared, and both the extraction temperature (50, 105, and 160 degrees C) and the extraction time (8, 19, and 30 min), which are the two main factors for PLE, were optimized with a central composite design to obtain the highest extraction efficiency. The extraction solvent (90% ethanol/water) could adequately extract the functional components from C. vulgaris. PLE showed higher extraction efficiencies than MAC, SOX, and UAE. Temperature was the key parameter having the strongest influence on the extraction of carotenoids and chlorophylls from chlorella. In addition, high heat treatment (>110 degrees C) by PLE minimized the formation of pheophorbide a, a harmful chlorophyll derivative. These results indicate that PLE may be a useful extraction method for the simultaneous extraction of carotenoids and chlorophylls from C. vulgaris.

Rapid identification of furanocoumarins in Angelica dahurica using the Online LC-MMR-MS and their nitric oxide inhibitory activity in RAW 264.7 cells

INTRODUCTION Angelica dahurica (Fisch. Ex hoffm.) Benth. Et Hook. is a perennial herb that grows throughout Korea whose dried roots have been used to treat various diseases in Korean traditional medicine. The root extract contains diverse constituents, and it is necessary to determine the active compounds. OBJECTIVE To investigate the nitric oxide (NO) inhibitory activity in a root extract of A. dahurica and identify the most active compounds using LC-NMR-MS. METHODOLOGY In search of the anti-inflammatory constituents of A. dahurica extract, the HPLC-based activity profiling approach was used to investigate the extracts NO inhibitory activity. To directly identify the compounds, a hyphenated LC-NMR-MS technique was applied. Reversed-phase isocratic chromatography was performed using the acetonitrile-water solvent system on a C(30) column. The identification of the compounds was based on information from ESI/MS and 1H-NMR. RESULTS NO inhibitory activities for five main fractions of the extract were evaluated, which were identified by LC-NMR-MS as containing furanocoumarins: byakangelicol, oxypeucedanin, imperatorin, phellopterin and isoimperatorin. CONCLUSION The results obtained showed that the anti-inflammatory activities of A. dahurica could be linked to imperatorin and phellopterin.

Accelerated Drying and Improved Color Properties of Red Pepper by Pretreatment of Pulsed Electric Fields

A pulsed electric field (PEF) treatment was applied to red pepper (Capsicum annuum L.) as a drying pretreatment. The PEF treatment was conducted with electric field strength of 1.0–2.5 kV/cm using a fixed pulse width of 30 µs and at a pulse frequency of 100 Hz. The PEF treatment times were 1, 2, and 4 s. PEF treatment resulted in cell membrane disruption, without visible changes in the surface structure of red pepper. The degree of cell membrane disruption was field strength dependent. Drying of control and PEF-pretreated samples was conducted at 45°C. The untreated control reached the target moisture ratio of 0.15 after 4.9 h of drying, whereas the PEF-pretreated sample (2.5 kV/cm, 100 Hz, 4 s) required only 3.2 h for the same moisture ratio, indicating a 34.7% reduction in drying time. Even the shortest PEF pretreatment (2.5 kV/cm, 100 Hz, 1 s) required 3.9 h to reach the target moisture ratio, which corresponded to a 20.4% reduction in drying time. The reduction in drying time by PEF pretreatment was beneficial to color quality of dried red pepper, because greater than 10% increases in b* value and the American Spice Trade Association (ASTA) unit were observed. The drying curves of control and PEF-pretreated red pepper were analyzed using thin-layer drying models. Five models were fitted to the drying data, and Pages model was selected as the best representative model to describe the drying procedure.

Tailoring physicochemical and sensorial properties of defatted soybean flour using jet-milling technology

The effects of jet-milling on the physicochemical and sensorial properties of defatted soybean flour (DSF) were investigated. Superfine DSF powder (DSF-JM; D50 = 4.3 ± 0.1 μm) was prepared from DSF powder (DSF-150; D50 = 257.0 ± 1.7 μm) via conventional sifting followed by jet-milling. The jet-milled DSF showed significant increases in hydration properties, with increases in the water-holding capacity, water-solubility index, and swelling capacity of 24%, 39%, and 32%, respectively. Soluble dietary fibre and fat-binding capacity of DSF-JM also increased significantly (p < 0.05). A quantitative descriptive analysis by trained panelists indicated that the sensorial properties of DSF were also modified by jet milling. The DSF-JM showed significant reductions in bitterness and roughness, but sweetness increased, and the colour of DSF-JM changed to a brighter achromatic colour. These results indicate that superfine DSF could be an ingredient used to modify physical and sensorial properties of food.

Effect of microfluidization on in vitro micellization and intestinal cell uptake of lutein from Chlorella vulgaris.

Chlorella is a nutrient-rich microalga that contains protein, lipid, minerals, vitamins, and high levels of lutein. This study evaluated the bioavailability of lutein from Chlorella vulgaris using a coupled in vitro digestion and human intestinal Caco-2 cell model. Lutein bioaccessibility was low, and approximately 75% of total C. vulgaris lutein was not micellized during the digestion process but remained in the insoluble digestate. Microfluidization improved lutein micellization efficiency during C. vulgaris digestion. C. vulgaris was microfluidized at a pressure exceeding 10000 psi, and the cell surface disruption was visualized by scanning electron microscopy. The mean C. vulgaris particle size was reduced from 3.56 to 0.35 μm with the microfluidization treatment. C. vulgaris microfluidization at 20000 psi was three times more efficient for aqueous lutein micelles production as compared with untreated C. vulgaris, and the final lutein content accumulated by intestinal Caco-2 cells was also higher with microfluidization. C. vulgaris lutein stability was not affected by microfluidization. These results indicate that microfluidization may be useful for improving lutein bioaccessibility from C. vulgaris during food processing.

Effects of processing parameters on the inactivation of Bacillus cereus spores on red pepper (Capsicum annum L.) flakes by microwave-combined cold plasma treatment

The efficacy of microwave-combined cold plasma treatment (MCPT) for inactivating Bacillus cereus spores contaminating red pepper (Capsicum annum L.) flakes was investigated. The effects of red pepper drying method, particle size, and water activity (aw) were also evaluated at two levels of microwave power (1700 and 2500W/cm2). The inactivation effect of MCPT was higher at higher microwave power. Spore reduction was more effective with vacuum-dried red pepper than far-infrared-dried flakes. A significantly higher level of spore reduction was observed with the red pepper sample with a smaller surface to volume ratio when one surface (exterior surface) was inoculated (p<0.05). Spore reduction by MCPT at high microwave power increased from 1.7 to 2.6logspores/cm2 when the aw of flake increased from 0.4 to 0.9 (p<0.05). MCPT did not change the color of red pepper flakes. MCPT demonstrated potential as a microbial decontaminating technology for red pepper flakes.

Increased sulforaphane concentration in brussels sprout following high hydrostatic pressure treatment

High hydrostatic pressure (HHP) treatment was used to increase the concentration of sulforaphane in Brussels sprout, a cruciferous vegetable known to have health benefits. The highest concentration of sulforaphane was 1021.8 μmol per kg fresh weight of Brussels sprouts after HHP treatment at 500 MPa, which corresponded to a 317% increase compared to the HHP-untreated control.

SOLVENT COMPOSITION EFFECTS ON EFFICIENCY OF PRESSURIZED LIQUID EXTRACTION OF BIOACTIVE ISOFLAVONOIDS FROM BELAMCANDA CHINENSIS RHIZOMES

A pressurized liquid extraction (PLE) technique was developed for the extraction of bioactive isoflavonoids including tectoridin (1), iridin (2), tectorigenin (3), iristectorigenin A (4), irisflorentine (5), and irigenin (6) from Belamcanda chinensis using aqueous ethanol as the extraction solvent. The effects of various key factors of PLE, including solvent composition (0–100% ethanol in water), temperature (80–180°C) and extraction time (5–20 min), were evaluated with respect to the extraction efficiency. Only solvent compositions altered the extraction yields of isoflavonoids with 60% ethanol providing the best extraction efficiency. When compared with conventional extraction methods, such as reflux or sonication extraction, PLE resulted in higher extraction efficiency with shorter extraction time and lower solvent consumption. We also tested the thermal stability of tectoridin, isoflavonoid glycoside, at various temperatures (80–180°C) in 60% ethanol for a 20 min extraction time to mimic conditions that could be encountered during PLE. Tectoridin was degraded to tectorigenin (aglycone) at temperatures over 150°C, therefore, care should be taken in the choice of temperature used for PLE.

Efficacy of UV-TiO2 photocatalysis technology for inactivation of Escherichia coli K12 on the surface of blueberries and a model agar matrix and the influence of surface characteristics

Surface disinfection of fresh blueberries is an important food safety challenge due to the delicate texture and short shelf life of these small fruits. A newly designed water-assisted photocatalytic reactor was developed for disinfection of fruits with a delicate texture and complex surface characteristics. Efficacy of UV-TiO2 photocatalysis was evaluated in comparison with UV alone for inactivation of Escherichia coli K12 (as a surrogate for Escherichia coli O157:H7) inoculated onto the surface of the blueberry skin, calyx, and an experimentally prepared agar matrix that was used as a model matrix. Influence of surface characteristics such as surface hydrophobicity and surface free energy on bacterial adhesion were also investigated. The initial bacterial population on all surfaces was approximately 7.0 log CFU/g. UV-TiO2 photocatalysis (4.5 mW/cm2) for 30 s achieved comparatively higher bacterial reductions of 5.3 log and 4.6 log CFU/g on blueberry skin and agar matrix surfaces, respectively, than 4.5 log and 3.4 log CFU/g reductions for UV alone (6.0 mW/cm2). Total phenolic and total anthocyanin contents of fruits were significantly increased after both UV-TiO2 and UV treatments, compared with water washed control fruits. UV-TiO2 photocatalysis technology is a non-chemical and residue-free method with reduced water usage for surface disinfection of fresh blueberries.