Bum-Keun Kim

Effect of salinity stress on phenolic compounds and carotenoids in buckwheat (Fagopyrum esculentum M.) sprout

The effect of salinity stress on the nutritional quality of buckwheat sprouts cultivated for 1, 3, 5, and 7d was investigated by analysis of the antioxidant activity and levels of phenolic compounds and carotenoids. Treatment with various concentrations of NaCl (10, 50, 100, and 200mM) resulted in an increase in the amount of phenolic compounds and carotenoids in the sprouts compared with the control (0mM). The phenolic contents of sprouts treated with 10, 50, and 100mM after 7d of cultivation were 57%, 121%, and 153%, respectively, higher than that of the control (0mM NaCl). Moreover, the accumulation of phenolic compounds was primarily caused by an increase in the levels of 4 compounds: isoorientin, orientin, rutin, and vitexin. The carotenoid content of sprouts treated with 50 and 100mM NaCl was twice higher than that of the control. In addition, the antioxidant activity of ethanol extracts of the sprouts was increased by NaCl treatment. Although the growth rate of sprouts decreased with >50mM NaCl, these results suggest that treatment of an appropriate concentration of NaCl improves the nutritional quality of sprouts, including the level of phenolic compounds, carotenoids, and antioxidant activity.

Effects of a chitosan coating on properties of retinol-encapsulated zein nanoparticles

Zein nanoparticles coated with chitosan were prepared for encapsulation of retinol. The mean particle size of retinol-loaded zein nanoparticles was approximately 300 nm. After coating with chiotsan, the mean particle size increased to >500 nm. The zeta potential of retinol-loaded zein nanoparticles was approximately -30 mV, which was changed to >+24 mV after chitosan coating. The encapsulation efficiency of zein nanoparticles increased from 64.9% to >80% after chitosan coating. The release profile was greatly improved with a chitosan coating, and a slow release rate was observed. FTIR analysis of retinol-loaded chitosan-coated zein nanoaprticles showed cross-linking between zein and retinol through electrostatic interactions. Photochemical stability against UV light was greatly improved to >90% after encapsulation. The concentration of chitosan, the Mw of chitosan, and the zein/chitosan volume ratio were important parameters affecting the properties of nanoparticles.

Enhancing oral bioavailability using preparations of apigenin-loaded W/O/W emulsions: In vitro and in vivo evaluations

We analyzed the physical properties and digestibility of apigenin-loaded emulsions as they passed through a simulated digestion model. As the emulsion passed through the simulated stages of digestion, the particle size and zeta potential of all the samples changed, except for the soybean oil-Tween 80 emulsion, in which zeta potential remained constant, through all stages, indicating that soybean oil-Tween 80 emulsions may have an effect on stability during all stages of digestion. Fluorescence microscopy was used to observe the morphology of the emulsions at each step. The in vivo pharmacokinetics revealed that apigenin-loaded soybean oil-Tween 80 emulsions had a higher oral bioavailability than did the orally administrated apigenin suspensions. These results suggest that W/O/W multiple emulsions formulated with soybean oil and tween 80 have great potential as targeted delivery systems for apigenin, and may enhance in vitro and in vivo bioavailability when they pass through the digestive tract.

Extraction Optimization for Obtaining Artemisia capillaris Extract with High Anti-Inflammatory Activity in RAW 264.7 Macrophage Cells

Plant extracts have been used as herbal medicines to treat a wide variety of human diseases. We used response surface methodology (RSM) to optimize the Artemisia capillaris Thunb. extraction parameters (extraction temperature, extraction time, and ethanol concentration) for obtaining an extract with high anti-inflammatory activity at the cellular level. The optimum ranges for the extraction parameters were predicted by superimposing 4-dimensional response surface plots of the lipopolysaccharide- (LPS-) induced PGE2 and NO production and by cytotoxicity of A. capillaris Thunb. extracts. The ranges of extraction conditions used for determining the optimal conditions were extraction temperatures of 57–65°C, ethanol concentrations of 45–57%, and extraction times of 5.5–6.8 h. On the basis of the results, a model with a central composite design was considered to be accurate and reliable for predicting the anti-inflammation activity of extracts at the cellular level. These approaches can provide a logical starting point for developing novel anti-inflammatory substances from natural products and will be helpful for the full utilization of A. capillaris Thunb. The crude extract obtained can be used in some A. capillaris Thunb.-related health care products.

Anti-inflammatory effects of 4 medicinal plant extracts in lipopolysaccharide-induced RAW 264.7 cells

The anti-inflammatory activity of 4 plant extracts [guava (Psidium guajava) leaf, capillary wormwood (Artemisia capillaris Thunb.), Chinese goldthread (Coptis chinensis), and dandelion (Taraxacum platycarpum)] was investigated in lipopolysaccharide (LPS)-stimulated RAW 264.7 cells. Six phenolic compounds (gallic acid, caffeic acid, chlorogenic acid, catechin, quercetin, and baicalin) were analyzed using LC-MS/MS. Guava leaf extracts showed the highest inhibitory effects on LPS-induced nitric oxide (NO, 52.58%) and prostaglandin E2 (PGE2, 43.45%) production. The total phenolic contents (TPC) in guava leaf, capillary wormwood, Chinese goldthread, and dandelion were 426.84, 154.42, 41.73, and 122.04 mg of gallic acid equivalent (GAE)/g of extract, respectively. TPC was positively correlated with the NO-inhibitory effect (r= 0.963, p<0.05) and the PGE2-inhibitory effect (r=0.971, p<0.05) at 30 μg/mL of treatment. The guava leaf extracts contained the highest levels of gallic acid and catechin, while the capillary wormwood extracts contained the highest levels of chlorogenic acid and quercetin.

Application of freeze-thaw enzyme impregnation to produce softened root vegetable foods for elderly consumers

The aims of this study were to determine the viability of using freeze-thaw infusion (FI) technology to produce a range of root vegetables using enzyme treatments with improved texture characteristics for elderly consumers with swallowing difficulties. We applied enzyme impregnation as a technology to soften the textures of root vegetables commonly consumed in Korea; balloon flower root (Platycodon grandiflorus), burdock root (Arctium lappa L.), carrot (Daucus carota L.), and lotus root (Nelumbo nucifera Gaertn) through the use of a texture analyzer after the FI of a commercial enzyme. Out of 15 commercial enzymes that were analyzed, three enzymes exhibited a marked softening effect on the tested carrots, burdock roots, balloon flower roots, and lotus roots. The hardness of the enzymes-treated food materials reached 1.4 × 104  N/m2 for carrots, 3.0 × 104  N/m2 for burdock roots, of 3.0 × 104  N/m2 for balloon flower roots, and 3.2 × 104  N/m2 for lotus roots without changing the original shapes of the samples. These findings confirmed the potential benefits of softening carrots, lotus roots burdock roots, and balloon flower roots and will contribute to the development of foods that can be easily eaten as part of a balanced diet by elderly adults with eating difficulties.

Development of a cooked rice model for bibimbap and resulting physico-digestive properties

A cooked rice model for bibimbap was developed using response surface methodology (RSM). The ratio of brown rice (X1), high amylose rice (X2) based on a white rice ratio of 1.0, and the ratio of water to total rice weight (X3), were independent variables. Stickiness (Y1), elasticity (Y2), and overall acceptability by sensory testing (Y3) of cooked rice were dependent variables. Optimal RSM conditions were white rice:brown rice:high amylose rice=1:1.07:0.56, and the ratio of water to total rice weight was 1.6. Coefficient of determination (R2) values of response surface equations were 0.909, 0.930, and 0.956 for Y1, Y2, and Y3, respectively (p<0.05). Experimental values measured under optimal conditions coincided with predicted values. Rapidly digestive starch (RDS) and expected glycemic index (eGI) values determined using the optimized rice model were much lower than for control white rice only.