Earticle

We investigated the catechin content in green tea leaf (GTL) and green tea seed (GTS), the antiproliferative and detoxifying phase II enzyme-inducing activities of the methanolic (80%, v/v) extracts from GTL and GTS. GTL and GTS contained 8,685±1,061 and 108±32 ug/g epigallocatechin gallate (EGCG), 11,486±506 and 116±72 ug/g epigallocatechin (EGC),3,535±308 and 821±95 ug/g epicatechin gallate (ECG), and 1,429±177 and 37±44 ug/g epicatechin (EC), respectively. The methanolic extract of GTS showed a greater increase in quinone reductase activity and antiproliferation potential against mouse hepatoma cells than GTL extract did. GTS treatment resulted in the accumulation at sub-G1 phase of mouse hepatoma hepa1c1c7 cells as assessed by flow cytometry. Enhancement of phase II enzyme activity by GTS extract was shown to be mediated, directly or indirectly, via interaction with the antioxidant response element (ARE) sequence in the genes encoding the phase enzymes. As the catechin content in GTS was significantly lower than that in GTL, components other than catechins appear to be responsible for the anticarcinogenic activity of the seed. In summary, these results suggest that the 80% methanolic extract of GTS deserves further study to evaluate its potential as an anticarcinogenic agent and to investigate its mechanism of action.

This paper investigates the production and optimization of β-galactosidase enzyme using synthetic medium by Kluyveromyces lactis NRRL Y-8279 in stirred tank bioreactor. Response surface methodology was used to investigate the effects of fermentation parameters on β-galactosidase enzyme production. Maximum specific enzyme activity of 4,622.7 U/g was obtained at the optimum levels of process variables (aeration rate 2.21 vvm, agitation speed 173.4 rpm, initial sugar concentration 33.8 g/L, incubation time 24.0 hr). The optimum temperature and pH of the β-galactosidase enzyme produced under optimized conditions were 37oC and pH 7.0, respectively. The enzyme was stable over a pH range of 6.0-7.5 and a temperature range of 25-37oC. The Km and Vmax values for O-nitrophenol-β-D-galactopyranoside (ONPG) were 1.20 mM and 1,000 μmol/min·mg protein, respectively. The response surface methodology was found to be useful in optimizing and determining the interactions among process variables in β-galactosidase enzyme production. Hence, this study fulfills the lack of using mathematical and statistical techniques in optimizing the β-galactosidase enzyme production in stirred tank bioreactor.

The protective effect of the water extract of Fraxinus rhynchophylla leaves (FLE) was determined using an animal model of acetaminophen (AAP)-induced nephrotoxicity. The BALB/c male mice used in this study were divided into 3 groups; the normal, AAP-administered, and FLE-pretreated AAP groups. A single dose of AAP induced necrosis of renal tubules and congestion along with edema to a remarkable degree as observed by hematoxylin and eosin stain, and also increased the numbers of terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick end labeling (TUNEL)-positive renal tubular epithelial cells. Blood urea nitrogen and plasma creatinine levels were determined to be significantly higher in the AAP group than in the normal group. However, FLE pretreatment resulted in an attenuation of renal tubule necrosis. Regeneration and dilatation of renal tubules were noted, and the numbers of TUNEL-positive cells were reduced in the FLE-pretreated groups. In an effort to detect the bioactive compounds exerting protective effects in FLE, the analysis of phenolic compounds via gas chromatography/mass spectrometry (GC/MS) were performed, and identified esculetin and esculin. The present study indicates that these compounds may exert a protective effect against AAP-induced nephrotoxicity.

Three Korean soybean varieties - Shinpaldal-2, Seomoktae and Seoritae - were investigated for changes in their physical properties and the amount of functional components (i.e. isoflavones and oligosaccharides), during germination. Soybeans were germinated at 20℃ for 96 hr in complete darkness. The dry weights of cotyledone, hypocotyl, seed coat, and hilum of Seoritae were heavier than those of other varieties. The dry weights of the three bean varieties decreased steadily in spite of root growth. The largest amount of isoflavone content was observed from Shinpaldal-2 (1.824 mg/g), followed by Seoritae (1.216 mg/g) and Seomoktae (1.125 mg/g). Total isoflavone content increased by 13% during initial germination, and then decreased thereafter. Aglycone types such as daidzein and genistein dominated the increase in isoflavone contents. The increase in genistein content of Shinpaldal-2 was 17.5 fold compared with ungerminated soybean, while the amount of daidzein was 6.7 times as much as ungerminated Shinpaldal-2 over an 18-hr germination period. Oligosaccharide contents such as raffinose (Raf) and stachyose (Sta) rapidly decreased during germination, while the sucrose (Sue) content remained constant until 36-48 hr of germination. From these results, it was clearly shown that the germination process significantly changed the contents of functional nutrients in soybeans. Therefore, the optimization of germination process should be considered to improve the biological functionality of soybeans in food processing.

To enforce the maximum residue limit for residual hexane (0.005 g/kg) in commercially available Korean vegetable oil, convenient and accurate quantification methods were investigated. Using dual surrogate standards, pentane and heptane were dissolved in ethanol, and then added to hexane-tree sunflower oil for setting up the calibration curve. Gas Chromatograph-Flame Ionization Detector with a porous layer open tubular column, indicated good chromatographic separation of hexane from other inhibiting matrix components. The lowest calibration level was 0.5 ug/g, not exceeding a relative standard deviation of 10% (RSD%), and 1.0 ug/g$ not exceeding a deviation of 22% RSD% using heptane as an internal standard for the Static headspace analysis by using a headspace auto-sampler and manual injection, respectively. The residual hexane was detected in nine of the samples among 87 vegetable oil samples purchased on the local market.

A mathematical model was developed for predicting the growth rate of Enterobacter sakazakii in tryptic soy broth medium as a function of the combined effects of temperature (5, 10, 20, 30, and 40℃), pH (4, 5, 6, 7, 8, 9, and 10), and the NaCl concentration (0, 1, 2, 3, 4, 5, 6, 7, 8, 9, and 10%). With all experimental variables, the primary models showed a good fit (R²=0.8965 to 0.9994) to a modified Gompertz equation to obtain growth rates. The secondary model was 'In specific growth rate=-0.38116+(0.01281*Temp)+(0.07993*pH)+(0.00618*NaCl)+(-0.00018*Temp²)+(-0.00551*pH²)+(-0.00093*NaCl²)+(0.00013*Temp*pH)+(-0.00038*Temp*NaCl)+(-0.00023*pH*NaCl)'. This model is thought to be appropriate for predicting growth rates on the basis of a correlation coefficient (r) 0.9579, a coefficient of determination (R²) 0.91, a mean square error 0.026, a bias factor 1.03, and an accuracy factor 1.13. Our secondary model provided reliable predictions of growth rates for E. sakazakii in broth with the combined effects of temperature, NaCl concentration, and pH.

The aim of this study was to evaluate the antioxidant activities of enzymatic digests from citrus by-products(CBPs) prepared by high speed drying (HSD). HSD needs a short time (60 min) for drying and can be used in a commercialscale. Enzymatic digests were prepared from the CBPs using 6 enzymes such as aminoglucosidase (AMG), celluclast,pectinex, termamyl, ultraflo, and viscozyme. Antioxidant activities of AMG digest from CBPs were evaluated by different invitro models such as 1,1-diphenyl-2-picrylhydrazyl (DPPH), hydroxyl, alkyl, H2O2 scavenging, metal chelating, lipid peroxidation,and comet assays, and exhibited strong activities. The antioxidant compounds were detected by an high performance liquidchromatography (HPLC) coupled on-line to an 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid (ABTS+) scavengingdetection system, and found that hesperidin was the key compound. Therefore, the results obtained in this study suggest thatHSD is an effective method to transform wet CBPs into dried form, and CBPs are potential source of natural antioxidant.

Multiple beneficial properties of Opuntia ficus indica (OPF) are well established. In the present study, we have investigated the immunological role of OPF extract (OPFE) on murine plenocytes. OPFE dose- and time-dependently enhanced the proliferation of splenocytes without cytotoxicity. Our results also showed that the number of CD4+ helper T cells and CD45R/B220+ pan B cells increased markedly, but not CD8+ cytotoxic T cells or CD11b+ granulocytes/macrophages. In addition, OPFE significantly decreased the production levels of T helper (Th) 1 type cytokines, interferon (IFN)-γ, and tumor necrosis factor (TNF)-α, although had no significantly differences in those of interleukin (IL)-4, a Th2 type cytokine in concanavalin A (Con A)-stimulated blastogenic cells. Furthermore, OPFE alone strongly increased IL-4 roduction and decreased TNF-α production even in the absence of Con A. On the basis of these results, this study suggests that OPFE enhances immunity by regulating the pro- and anti-inflammatory response, indicating that this extract exerts a marked immunomodulatory effect, confirming its usefulness as therapy for immune-related diseases.

Cheonggukjang, a popular Korean traditional fermented soyfood, was manufactured by fermenting steamed soybeans in a temperature-controlled room by traditional methods in which steamed soy was exposed to rice straw naturally rich in Bacillus species. B. subtilus and B. licheniformis were found to be the major microorganisms present in cheonggukjang made by the traditional method. We analyzed the composition of 12 kinds of isoflavones and their glycosides present in cheonggukjang collected at various fermentation times. Total isoflavone content in raw soybeans was 2,867 mg/kg and this decreased by about 50% during cooking prior to cheonggukjang preparation. However, total isoflavone content changed slightly during 45 hr of fermentation. Total content of isoflavone glycosides, consisting mainly of daidzin, glycitein, and genistin, decreased by about 40% during 45 hr of fermenting cooked soybeans. The contents of tree isoflavones including daidzein, glycitein, and genistein showed a dramatic increase during fermentation in cheonggukjang preparation, with a 2.9-, 54.0-, and 20.6-fold increase in concentration, respectively, by the end of fermentation (45 hr). In conclusion, short-term fermentation of cooked soybeans with Bacillus species caused conspicuous changes in the composition of isoflavone derivatives, and its implication in terms of health benefits deserves further study.